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PUBLIC HEALTH ASSESSMENT

BEEDE WASTE OIL
PLAISTOW, ROCKINGHAM COUNTY
NEW HAMPSHIRE

ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

The tables below list the contaminants of concern (COCs) detected in all media both on-site and off-site. There are several criteria for listing a chemical as a COC. These criteria include 1) exceedance or lack of media specific health comparison values, 2) noted community health concerns and 3) the quality and extent of sampling data. Also, any contaminant listed in one media will by default be listed in all other media in which it is detected.

Media specific health comparison values are contaminant concentrations in specific media (i.e. air, soil and water) used to select contaminants for further evaluation. Exceedance of these health comparison values does not mean that a public health concern exists but rather signifies the need to consider the chemical further which is done in the Public Health Implications section of the public health assessment. The health comparison values used in this public health assessment include environmental media evaluation guides (EMEGs), cancer risk evaluation guides (CREGs), reference dose media evaluation guides (RMEGs), maximum contaminant levels (MCLs), lifetime health advisories (LTHAs) and ambient water quality criteria (AWQCs).

EMEGs are media-specific health comparison values that are used to select contaminants of concern at hazardous waste sites. EMEGs are derived from the minimal risk levels (MRLs) presented in the ATSDR Toxicological Profiles. An MRL is an estimate of daily human exposure to a chemical that is likely to be without a substantial risk of harmful (non-cancerous) effects over a specified duration of exposure. RMEGs are media-specific health comparison values derived from EPA's reference dose (RfD) that are used when EMEGs are not available. RfDs estimate the daily exposure to a contaminant below which adverse health effects are not anticipated. CREGs are estimated contaminant concentrations in a specific media which are anticipated to result in one excess cancer in one million persons exposed over a lifetime. CREGs are calculated from EPA's cancer slope factors (CSFs). CSFs are cancer potency estimates derived for chemicals shown to be carcinogenic in either animals or humans. MCLs are contaminant concentrations in water derived by EPA to be protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) at an ingestion exposure rate of 2 liters of water per day. MCLs are enforceable, regulatory values. LTHAs are non-enforceable guidelines derived for a lifetime ingestion exposure to a contaminant in drinking water. They are calculated for non-carcinogenic compounds from Drinking Water Equivalent Levels (DWELs) which in turn are based on oral RfDs. LTHAs do consider the contribution of other media to the overall exposure. Human health based AWQCs are derived for both carcinogens and non-carcinogens based on EPA's CSFs and RfDs, respectively. Two values are derived based on either ingestion of water (2 liters/day) or ingestion of both water and organisms (2 liters/day and 6.5 grams of fish/day). AWQCs used in this public health assessment considered both pathways.

Also, included in the COC tables are EPA's weight-of-evidence cancer classification for each contaminant. This classification scheme is due to be revised in the near future but currently consists of six groups: 1) Group A - Known Human Carcinogen, 2) Group B1 - Probable Human Carcinogen with sufficient animal data and limited human data, 3) Group B2 - Probable Human Carcinogen with sufficient animal data and inadequate or no human data, 4) Group C - Possible Human Carcinogen, 5) Group D - Not Classifiable as to Human Carcinogenicity and 6) Group E -Evidence of Non-carcinogenicity in Humans.

A. On-Site Contamination

Groundwater

Data is available for several sampling rounds of groundwater monitoring wells at the BWO site from February, 1984 through the most recent sampling round in June, 1995. All on-site monitoring wells are constructed in the overburden ⁽¹²⁾. Five monitoring wells (designated "MW") installed by Soils Engineering Inc. and Groundwater Technology Inc. between August, 1983 and February, 1984 do not contain surface seals and may allow surface soil contamination through the well shaft ⁽⁵⁾. An additional 25 monitoring wells (designated "AE") were installed by Environmental Drilling Inc. between January and September, 1991 and monitored by Aries Engineering Inc. (AEI). Fifteen more monitoring wells (designated "SH") were installed in June, 1995 during additional site characterization conducted by Sanborn, Head Associates (see Figure 2 for on-site monitoring well locations).

Contaminants associated with waste oil, fuel oil and organic solvents were detected at various locations throughout the site. Table 1 shows the contaminants of concern (COCs) detected in on-site monitoring wells giving both overall maximum detected values as well as the maximum value detected during the most recent sampling round (MaxR) performed in June, 1995 by SHA. Although SHA also sampled on-site groundwater in December, 1995, MaxR values were taken from the June, 1995 round since the December, 1995 sampling was less comprehensive. No PCBs were detected in aqueous on-site monitoring well samples taken by Haley and Aldrich Inc. in 1994 ⁽¹³⁾. SHA detected PCBs in only one on-site well (AE-4) at 1.0 ppb during groundwater sampling conducted in December, 1995. This detection may be the result of free product contamination in the sample ⁽²⁾.

Some of the maximum detected values are derived from the February, 1984 sampling of the original, improperly installed wells and are suspect for well shaft contamination from the surface. Of these original wells, MW-2 and MW-3 (which showed high levels of contamination), have not been retested. The high concentrations of VOCs detected in MW-2 were of particular concern due to its proximity to several residential drinking water wells located at residences on Shady Lane (see Figure 2). Sampling of monitoring wells SH-4S and SH-4D (S = shallow, D = deep), installed in the vicinity of MW-2, detected only low VOC levels in June, 1995. Analysis of free product samples obtained from on-site monitoring wells detected a maximum of chlorinated VOCs at 2,570 ppm (SH-5), non-chlorinated aromatic VOCs at 16,770 ppm (SH-10) and PCBs at 80 ppm (SH-6) ⁽²⁾.

A total of five groundwater contaminant plumes have been identified originating from source areas located on Parcel 1. Data included in the SHA report indicate that the former lagoon area is the source of a major contaminant plume moving in the overburden and impacting off-site residential wells. Free-product thickness associated with this plume has been measured as high as 5.4 feet (SH-5). Other groundwater contaminant plumes defined in the SHA investigation include the plume thought to be originating from the 140,000 gallon UST and nearby ASTs. Free product has also been detected in association with this plume at depths of up to 5.2 feet (AE-16) ⁽¹²⁾. Contaminant plumes associated with the surface water runoff pits have also been identified. Free product thickness associated with the SWRP 1 and SWRP 2 plumes have been measured at depths up to 2.1 (AE-3) and 2.8 (SH-6) feet, respectively. A fifth source consisting of a stained soil area around monitoring well AE-12 has been associated with a less significant plume ⁽²⁾. This plume is cause for concern, however, since the source area is towards the southern border of the site and proximal to off-site residential wells.

Overburden groundwater flow is estimated to be in an east-northeast direction across Parcel 1. On Parcel 2, however, overburden groundwater is expected to flow with Kelley Brook which turns to the southeast. Several VOCs detected in Parcel 2 monitoring wells and residential wells located further south and southeast are consistent with those detected in Parcel 1 monitoring wells closer to the suspected source areas. Common contaminants found in Parcel 1 on-site wells, Parcel 2 on-site wells and residential wells include vinyl chloride, cis-1,2-dichloroethylene (cis-1,2-DCE), 1,1,1-trichloroethane (1,1,1-TCA) and trichloroethylene (TCE). Other contaminants found in on-site wells may also be contributing to residential well contamination via breakdown products such as the degradation of TCE (on-site max of 2,200 ppm) to 1,2-dichloroethylene (1,2-DCE) and 1,2-DCE to vinyl chloride.

Table 1
Contaminants of concern in on-site groundwater at Beede Waste Oil, Plaistow, NH

Chemical Name EPA Cancer Group Concentration
(Max/MaxR)
(ppb) Health Comparison Value
(ppb) Source of Health Comparison Value Location^a Date
(Max/MaxR)

Benzene A 780/780 1 CREG SH-6/SH-6 6-95/6-95

Chloroethane NA 540/540 NONE NONE AE-16 6-95/6-95

Chloroform (trichloromethane) B2 17/2 6 CREG AE-12/AE-12 1-91/6-95

1,1-Dichloroethane C 3,000/3,000 81 STATE SH-6/SH-6 6-95/6-95

1,2-Dichloroethane B2 78/30 0.4 CREG MW-3/AE-8 2-84/6-95

1,1-Dichloroethylene C 140/40 0.06 CREG MW-3/SH-5 2-84/6-95

cis-1,2-Dichloroethylene D 2,200/2,200 70 LTHA SH-5/SH-5 6-95/6-95

trans-1,2-Dichloroethylene D 1,100/110 100 LTHA MW-2/SH-6 2-84/6-95

Ethylbenzene D 1,300/1,300 700 MCL SH-10/SH-10 6-95/6-95

Isopropylbenzene (cumene) NA 80/80 280 NH DPHS SH-10/SH-10 6-95/6-95

p-Isopropyl toluene NA 80/80 NONE NONE SH-10/SH-10 6-95/6-95

Methylene chloride B2 440/ND 5 CREG MW-3 2-84/6-95

4-Methyl-2-pentanone (methyl isobutyl ketone) D 300/200 NONE NONE AE-11S/AE-8 1-91/6-95

Naphthalene D 460/460 2 LTHA SH-10/SH-10 6-95/6-95

Alkylbenzenes^b NA 2,670/2,670 50 NH DPHS SH-10/SH-10 6-95/6-95

Polychlorinated Biphenyls B2 1/1 0.005 CREG AE-4/AE-4 12-95/12-95^c

Tetrachloroethylene B2 96/30 0.7 CREG AE-15/SH-10 1-91/6-95

Toluene D 1,500/1,500 1000 MCL AE-9B/AE-9B 6-95/6-95

1,1,1-Trichloroethane D 1,800/1,800 200 LTHA SH-5/SH-5 6-95/6-95

Trichloroethylene B2 2,000/2,000 3 CREG SH-5/SH-5 6-95/6-95

Vinyl chloride A 2,200/2,200 0.2 EMEG SH-6/SH-6 6-95/6-95

INORGANICS

Arsenic A 90/90 0.02 CREG AE-3/AE-3 6-95/6-95

Cadmium D 27/27 5 RMEG AE-3/AE-3 6-95/6-95

Chromium (VI/III) A/D 74/12 50 (VI) RMEG AE-3/SH-7 5-94/6-95

Lead B2 2,600/2,600 15 Action Level SH-7/SH-7 6-95/6-95

See Health Comparison Value definitions and Figure 2 for on-site monitoring well locations.
a = MW, AE and SH are on-site monitoring wells.
b = Alkybenzenes which do not have individual drinking water health comparison values are grouped and compared to an NH DPHS derived interim drinking water health comparison value. This sample included n-propylbenzene, sec-butylbenzene, 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene.
c = Represents the only time PCBs have been detected in aqueous groundwater samples.
Max = Maximum value ever detected.
MaxR = Maximum value from most recent sampling round conducted by SHA in June, 1995.
ND = non-detect.
NA = not available.
ppb = parts per billion.

Soil

On-site surface soil sampling was conducted by AEI in October, 1991 and by the Environmental Protection Agency (EPA) between September and December, 1993. Table 2 gives maximum concentrations of COCs in on-site surface soil. Five surface soil samples taken by AEI near the 86 ASTs detected PCBs (Aroclor-1242 and Aroclor-1254) in all samples at concentrations ranging from 2.1 to 5.4 ppm ⁽⁵⁾. Soil samples taken by EPA detected PCBs (Aroclor-1248) beneath a leaking valve of AST No. 22 at a maximum of 1,500 ppm. EPA surface soil sampling also detected Aroclor-1248 in the surface water runoff pit near the east end of the 86 ASTs (SWRP 2) at 3.7 ppm, in the sand blast grit pile near the western border of Parcel 1 at 0.3 ppm and at the base of the drum storage area at 1.4 ppm ^{(14, 15)}.

Sampling of Tank 22 contents by EPA detected Aroclor-1248 at 290 ppm ⁽¹⁶⁾. The tank was relocated along with approximately two feet of top soil to another area on-site. Surface soil concentrations of Aroclor-1248 around Tank 22's former location, however, remained above 50 ppm with a maximum of 500 ppm. This area was further excavated and backfilled with sand reducing PCB soil levels to below 50 ppm ⁽¹⁷⁾. Soil excavated from the original Tank 22 area is apparently stored on-site in soil piles or 55-gallon drums located behind the main building on Parcel 1. Tank 22 was reportedly drained at some point during the sampling period but verification could not be found. Recent investigations revealed that some quantity of sludge, oil and water remain in this tank.

Sampling of the 86 ASTs in May, 1995 by Total Waste Management Corporation (TWM) determined that 16 of these tanks contained greater than 3,000 gallons of oil, 62 contained greater than 1 inch but less than 3,000 gallons of oil, 3 contained oil and water and 6 contained only water. The TWM sampling also included analysis for PCBs which detected 50-499 ppm in one of the 16 high volume tanks and 6 of the 62 low volume tanks. None of the 16 high volume tanks and one of the 62 low volume tanks contained oil at PCB levels greater than 500 ppm ⁽²⁾. Previous sampling of these ASTs detected a maximum PCB concentration of 6,700 ppm in Tank #51 from a sample taken on August 24, 1988. This tank was apparently leased to Dependable Waste Oil Inc. between September, 1986 and January, 1988 ⁽³⁾. As noted previously, the total contents of these tanks has been estimated by NH DPHS at approximately 820,000 gallons ⁽¹⁾.

Excavated soil taken along with the fifteen 55-gallon drums near the free product interceptor trench showed low levels of VOCs. A maximum concentration of chromium at 50 ppm was detected in the sand blast grit pile and maximum lead concentrations in surface soil of 250 ppm were found near the former AST No. 22 and in SWRP 2. ⁽⁵⁾. A surface soil sample taken by NH DES from SWRP 2 in April, 1994 detected 5.1 ppm of Aroclor-1248 along with several semi-volatile organic chemicals (SVOCs) associated with petroleum products ⁽¹⁸⁾.

Sub-surface soil samples were taken from test pits and well borings at various depths by SHA in May and June of 1995. Maximum concentrations for all contaminant categories except PCBs were found in well boring sample SH-5 taken in the area of the former surface lagoon. Maximum contaminant levels detected in the SH-5 sample include chlorinated VOCs at 205 ppm, non-chlorinated aromatic VOCs at 448 ppm, petroleum hydrocarbons (PHCs) at 30, 000 ppm and PAHs at 75 ppm. The maximum PCB level detected in SHA soil samples was 1.3 ppm taken from a test pit located near the former 140,000 gallon storage tank. Soil vapor analysis was conducted on-site at various depths by Haley & Aldrich Inc. in May, 1994 and by SHA in May, 1995. Soil vapor results were consistent with contaminants found in other on and off-site media ^{(2, 13)}.

Table 2
Contaminants of concerns in on-site surface soil at the Beede Waste Oil site, Plaistow, NH

Chemical Name EPA Cancer Group Max Concentration
(ppm) Health Comparison Value
(ppm) Source of Health Comparison Value Date

4-Methyl-2-pentanone (methyl isobutyl ketone) D 210^a NONE NONE 30-March-92

Toluene D 12^a 400 RMEG 30-March-92

Fluorene D 35 NONE NONE 25-April-94

Ethylbenzene D 180^a NONE NONE 30-March-92

Polychlorinated Biphenyls
(Aroclor-1248) B2 1,500^b 1 EMEG 9-Sept-93

Phenanthrene D 37^c NONE NONE 25-April-94

Phthalate, bis-2-ethylhexy NA 40^c NONE NONE 25-April-94

2-Methylnaphthalene NA 45^c NONE NONE 25-April-94

INORGANICS

Lead B2 250^b,c NONE NONE 30-March-92

Copper D 50^b,c NONE NONE 9-Sept-93

Chromium (VI/III) A/D 150^d 300 (VI) RMEG 9-Sept-93

See Health Comparison Value definitions.
a = Samples taken from soil excavated with 15 VOC containing 55-gallon drums.
b = Sample taken from the base of leaking Tank -22. Cleaned to below 50 ppm by EPA.
c = Sample taken from surface water runoff pit (SWRP-2) near 86 ASTs.
d = Sample taken from sand blast grit pile.
NA = not available.
ppb = parts per billion.

Surface Water

Several surface water samples have been collected from Kelley Brook along the northeast border of the site. These sample locations along with some which are upstream and downstream of the site are considered off-site since they are at or near the site border but are outside the fencing and more accessible to trespass.

A split sample taken from the interceptor trench in December, 1992 was analyzed for PCBs by two laboratories revealing a total PCB concentrations of 80 ppm (Clean Harbors) and 30 ppm (NH DES contract lab). The NH DES lab also analyzed this sample for VOCs which showed methyl ethyl ketone at 160 ppm. Total Waste Management Corp. also sampled the trench for PCBs and metals in June, 1993. Analysis of this sample by Laboratory Resources Inc. did not detect significant levels of metals but did find Aroclor-1242 and Aroclor-1260 at 33 and 51 ppm, respectively. It should be noted that these samples were taken in an effort to analyze free product and contained both water and free product from the trench. Hence, the PCBs detected are not water soluble levels ⁽¹⁹⁾.

Outdoor Air

There has been no on-site outdoor air monitoring conducted to date.

Indoor Air

There has been no on-site indoor air monitoring conducted to date. Exposure to VOCs volatilizing from indoor tap water into indoor air is considered to be similar to that of drinking the tap water. There are two on-site drinking water supply wells (bedrock) that have consistently tested negative for VOC contamination. VOC volatilization from tap water into on-site indoor air is, therefore, not a pathway of concern.

An additional source of VOCs in indoor air is through intrusion of vapors directly from contaminated groundwater through building foundations. The potential for infiltration of VOCs into indoor air from overburden groundwater was evaluated by comparing maximum on-site monitoring well (overburden) VOC levels to the GW-2 standards given in the Massachusetts Contingency Plan (MCP). The MCP GW-2 standards are levels of contaminants in groundwater below which would not contribute a significant indoor air hazard. The location of the groundwater contaminant plumes identified in the SHA report indicate that only the abandoned building is at risk for vapor intrusion from contaminated overburden groundwater since the main building is upgradient of all plumes.

The abandoned building is located directly above a free product containing plume and, therefore, vapor intrusion models that predict indoor air concentrations resulting from volatilization of VOCs in groundwater may be inappropriate. SHA sampling in June, 1995 detected non-chlorinated-VOCs at 8,010 ppm and chlorinated-VOCs at 280 ppm in free product samples from on-site monitoring well AE-9 located at the south of end of the building. Free product was also present at this time in well AE-16 between the abandoned building and the interceptor trench which contained non-chlorinated-VOCs at 4,140 ppm but did not contain chlorinated-VOCs above detection. Vinyl chloride (130 ppb) and 1,2-dichloroethane (30 ppb) detected in groundwater samples from nearby wells not containing free product (AE-5 and AE-8) exceed their respective MCP GW-2 standards of 2 ppb and 20 ppb.

VOC vapor intrusion is expected to occur directly from the floating free product and from contaminants in groundwater. The degree of this vapor intrusion and the resulting rise in indoor air VOC levels is dependant upon the contaminant, soil characteristics and the integrity of the building foundation. Considering the high levels of chlorinated-VOCs detected in free product samples from well AE-9 and the exceedance of the groundwater MCP GW-2 standards for vinyl chloride and 1,2-dichloroethane in wells AE-5 and AE-8, indoor air VOC levels in the abandoned building may be, and may have been in the past, above a level of concern. It should be noted that the abandoned building is currently secured by barbed wire fencing.

B. Off-Site Contamination

Groundwater

VOCs in Residential Wells

Overburden groundwater flow is estimated to be moving in an east-northeast direction across Parcel 1. Based on groundwater elevation and sampling of both on-site and off site wells, two contaminant plumes appear to be moving southeast in the overburden aquifer on Parcel 2. The plumes originate on Parcel 1 in the area of a former surface lagoon and a stained soil area near monitoring well AE-12. An extensive amount of free product has been detected (SH-5) on the water table in the area of the former surface lagoon. No free product has been detected in monitoring well AE-12. Table 3 summarizes the COCs for residential drinking water giving the maximum detected values in all residential wells (active and inactive) as well as the concentrations of these COCs during the most recent sampling round (MaxR) conducted in December, 1995 and January, 1996. Residential drinking water well locations are given in Appendix B - Figure 4.

Initial sampling of a nearby residential overburden well (well 14A) on Shady Lane in October, 1983 detected 1,2-DCE at 35.7 ppb, TCE at 23.8 ppb and 1,1,1-TCA at 10.3 ppb. This well is no longer in use. The resident had apparently switched to an existing bedrock well sometime during 1983. A second residential overburden well (well 6) located on Kelley Road directly abutting the site was tested in May and June of 1990 and shown to be contaminated with petroleum related VOCs including a maximum concentration of benzene at 7.9 ppb. According to the NH DES site manager, these results may be related to a petroleum surface spill which had occurred earlier in the year. This resident was subsequently connected to an on-site bedrock well later in the year which has consistently tested negative for VOC contamination.

Sampling of residential drinking water by NH DES was expanded in September, 1991 to include additional wells southeast of the site on Kelley Road, Fran Avenue and Shady Lane as well as the Howard Manor Condominiums and the Sawyer Banquet Center located on Plaistow Road. Maximum concentrations of 1,2 -DCE at 70 ppb, TCE at 51 ppb, 1,1,1 TCA at 38 ppb and 1,1-dichloroethane (1,1-DCA) at 5 ppb were detected in a single sample taken in May, 1992 from a "never used" overburden well (10C) located on Plaistow Road. Other previously undetected VOCs were found in this same sample including 1,1,2 TCA at 41.0 ppb, trichlorotriflouroethane at 2.40 ppb, chloroform at 1.10 ppb, 1,2-DCA at 5.0 ppb and tetrachloroethene (PCE) at 38.0 ppb. A bedrock well drilled on this same property and sampled shortly thereafter detected toluene at 1.0 ppb which is a common contaminant found in new bedrock wells. No other VOCs have been detected in this well.

Maximum VOC concentrations ever detected in currently active wells include vinyl chloride at 2.6 ppb, cis-1,2-DCE at 19.0 ppb, TCE at 3.5 ppb, 1,1,1-TCA at 2.5 ppb, 1,1-DCA at 1.1 ppb, 1,2-DCA at 0.9 ppb, methyl-t-butyl ether (MTBE) at 38 ppb and chloroform at 3.6 ppm. The most recent sampling of active residential drinking water wells in April, 1996 detected maximum concentrations of vinyl chloride at 2.5 ppb, cis-1,2-DCE at 19.0 ppb, TCE at 3.5 ppb, 1,1-DCA at 1.1 ppb and 1,2 -DCA at 0.9 ppb and MTBE at 16.0 ppb. The "never used" residential well (10C) which had previously yielded high VOC levels was also re-sampled in April, 1996. This overburden well showed a decrease in VOC contamination but still contained TCE at 8 ppb, 1,2-DCE at 45 ppb, 1,1,1,-TCA at 17 ppb, 1,1-DCA at 4 ppb and PCE at 6 ppb. Vinyl chloride, benzene, 1,2-DCA and TCE are the only VOCs that have ever exceeded their respective health comparison values in residential wells that had been used and/or are currently used for drinking water. Vinyl chloride has consistently been detected at or near the MCL in the Howard Manor Condominium bedrock well but has not been detected in any other off-site wells. No other contaminants are currenlty exceeding their respective MCL.

Approximately thirty residential drinking water wells have been tested to date with a total of eighteen showing measurable amounts of VOCs. Seven of these contaminated wells, located southeast of Parcel 2, (10A, 10B, 10C, 11, 12, 14A and 14B) are believed to be impacted by an overburden contaminant plume moving east from the former lagoon area on Parcel 1 and southeast across Parcel 2. Three of these seven wells (10A, 10C and 14A) are not currently in use. The petroleum related VOC contamination in the currently unused well 6 located on the northern border of the site is thought to be related to a single petroleum discharge event on that border of the property rather than from the plumes identified in the SHA report. The contamination in well 6 appears to have declined significantly since initial detection.

VOC contaminants detected in the remaining ten wells are not thought to be site related. Residential well 7A located to northeast of the site was found to contain the petroleum related contaminant MTBE at a maximum of 38.0 ppb. This well is separated by Kelley Brook from the site related petroleum discharge thought to be impacting well 6 and is, therefore, assumed to be impacted by an alternate source. Wells 4 and 5 located on Kelley Road to the northwest of the site were also found to contain MTBE at a maximum of 2.4 and 2.7 ppb, respectively. MTBE is a common well contaminant found in gasoline. It should be noted that there is an auto salvage yard upgradient of Kelley Road which may be contributing to the MTBE contamination on Kelley Road. The remaining wells testing positive for VOC contamination were found to contain chloroform at a maximum concentration of 2.7 ppb. Chloroform is a common laboratory contaminant as well as a byproduct of well disinfection and its detection in these wells is not thought to be site related.

Metals in Residential Wells

Complete inorganic analysis of off-site residential well samples was limited to one sampling round in April, 1994. Inorganics detected in off-site residential wells include arsenic, lead, barium and mercury. Maximum concentrations of mercury at 2.0 ppb and arsenic at 15.0 ppb were detected in a well on Fran Avenue (well 8). Subsequent sampling and analysis of this well for mercury only in August, 1994 detected no mercury. A maximum concentration of lead at 58.0 ppb (well 7B) was detected in a sample of a treated tap. Concurrent sampling of the same well from an untreated tap showed only 10.0 ppb. Arsenic concentrations detected in both on-site and off-site media are not inconsistent with levels commonly seen in New Hampshire bedrock wells. There is no evidence of any on-site source of arsenic. Limited soil sampling suggests slightly elevated lead concentrations in on-site soil where surface discharge of waste oil is evident. Lead contamination in on-site groundwater is also elevated in monitoring wells with measurable free product. It is unlikely, however, that the contamination in the overburden well noted above is site related since it is located across Kelley Brook from the site. The discrepancy between the untreated and treated drinking water samples taken at this residence also suggests that a source exists within the home.

PCBs in Residential Wells

Residential drinking water wells were analyzed for PCBs at least once in early 1993 according to the NH DES site manager with no PCBs detected. PCBs are not very mobile within groundwater due to their low solubility in water. It is possible for PCBs to contaminate groundwater at very low levels, however, depending upon the presence of other organic compounds which might act as a solvent. The lack of PCBs in on-site groundwater suggest that this possibility is not occurring. On-site monitoring well samples taken by SHA in June 1995 detected PCBs in only one sample which was qualified as potentially contaminated with free product.

Table 3
Contaminants of concern in residential wells near Beede Waste Oil, Plaistow, NH^a

Chemical Name EPA Cancer Group Concentration
(Max/MaxR)
(ppb) Health Comparison Value
(ppb) Source of Health Comparison Value Well Type Location Date
(Max/MaxR^b)

Alkylbenzenes^c NA 20.9/6.1 50 NH DPHS OB 6 4-95/6-95

Benzene A 7.9/ND 1 CREG OB 6 6-90/4-96

Chloroform B2 3.6/ND 6 CREG OB 4 9-92/4-96

1,1-Dichloroethane C 0.7/1.1 81 STATE OB 12 1-93/4-96

1,2-Dichloroethane B2 0.9/0.9 0.4 CREG BR/BR 12/12 9-95/4-96

1,2-Dichloroethylene D 35.7/19 70 (cis) LTHA OB/BR 14A/12 10-83/4-96

Isopropylbenzene NA 4.5/3.0 280 NH DPHS OB 6 4-95/6-95

Ethylbenzene D 47.2/ND 700 MCL OB 6 6-90/6-95

Methyl-tert-butyl-ether NA 38.0/16.0 40 LTHA OB 7A/7A 2-93/4-96

Toluene D 1.0/ND 1000 MCL BR 10D 5-92/4-96

1,1,1-Trichloroethane D 10.3/ND 200 LTHA OB 14A 10-83/4-96

Trichloroethylene B2 23.8/3.5 3 CREG OB/BR 14A/12 10-83/4-96

Vinyl chloride A 2.6/2.5^d 0.2 EMEG BR/BR 10B/10B 3-95/4-96

INORGANICS

Arsenic A 15.0/NA 0.02 CREG OB 8 4-94

Lead B2 58.0/NA 15 MCL OB 7B 9-94

Mercury D 2.0/NA 2 MCL BR 8 4-94

See Health Comparison Value definitions and Figure 4 for residential well locations.

Bold indicates that this value exceeds its respective health comparison value.
a = Does not include results from "never used" overburden well 10C.
b = Results for Well 6 from June, 95 were used as MaxR since this well has not been resampled an no other wells contained these contaminants.
c = Alkybenzenes which do not have individual drinking water health comparison values are grouped and compared to an NH DPHS derived interim drinking water comparison value. This sample included n-propylbenzene, sec- butylbenzene, 1,2,4-trimethylbenzene and 1,4,5-trimethylbenzene.
d = Concentration in untreated water. POE treated water from this well has tested non-detect for VOCs.
Max = maximum value ever detected in used residential wells.
MaxR = maximum value from most recent sampling round of active residential wells conducted in April, 1996.
OB = overburden well.
ND = non-detect.
ppb = parts per billion.
BR = bedrock well.
NA = not available.

Surface Water

Kelley Brook surface water has been sampled on several occasions between January, 1991 and June, 1995. A single surface water sample (SW-1/AE) taken in Kelley Brook north of the interceptor trench by AEI in January, 1991 detected high concentrations of VOCs as is shown in Table 4. Subsequent sampling by AEI in October, 1991 at two off-site locations in Kelley Brook located upstream (KB-1) and east (KB-2) of the site revealed no VOC contamination. Surface water samples taken by NH DES from Kelley Brook at the SW-1/AE location in October, 1991 and February, 1992 detected 1,2-dichlorethylene at 3.6 ppb, 1,1-dichloroethane at 1.0 ppb, ethylbenzene at 480 ppb, xylenes at 3,600 ppb and toluene at 920 ppb. No upstream sample data was located for this sample period (see Figure 3a for sample locations) ⁽⁵⁾.

More extensive sampling and analysis of Kelley Brook surface water for VOCs, PCBs and base-neutral compounds was conducted by NH DES in April, 1994. The NH DES samples are designated as NH in Figure 3a. This sampling round included an upstream sample (SW-1) which was non-detect for VOCs and PCBs. All of these samples were taken outside the chain link fence and so will be considered off-site and from accessible areas. Several VOCs, polycyclic aromatic hydrocarbons (PAHs) and Aroclor-1260 were detected in Kelley Brook surface water during this sampling round. A maximum concentration of Aroclor-1260 at 840 ppb was found at the same location (SW-2) as the sediment/soil sample which detected Aroclor-1260. Elevated concentrations of metals were detected at location SW-2. Arsenic, barium, cadmium, chromium, lead and mercury were all found above detection limits in this sample. All other samples, including SW-1 which is upstream and assumed to be a representative background, were non-detect for metals ⁽¹⁸⁾. It should be noted that mercury was detected at 2.0 ppb in the SW-2 sample which is proximal (approximately 1,000 ft. south) to the Fran Avenue bedrock well that tested positive for mercury at the same concentration two days later. No on-site sources of mercury have been identified.

A maximum concentration of 3.3 ppm PCBs was detected in oil/water samples taken in August, 1994 by EPA in the "marsh" area near Kelley Brook ⁽²⁰⁾. EPA took an additional oil/water sample in December, 1994 from inside containment booms on Kelley Brook that contained Aroclor-1260 at 34 ppm and Aroclor-1248 at 6.0 ppm ⁽⁸⁾. The location of these EPA samples is estimated to be in the vicinity of the NH DES SW-2 location. The most recent surface water sampling of Kelley Brook was conducted by SHA in June, 1995 (samples designated SH-see Figure 3c). A maximum of 38 ppb non-chlorinated VOCs and 69 ppb chlorinated VOCs were detected in SW-4/SH. Only one sample (SW-2/SH), located in the general area of SW-2, tested positive for PCBs at 15 ppb. A maximum of 10 ppb chromium and 1 ppb cadmium were found at SW-2/SH and SW-4/SH, respectively. The lower levels of VOCs and PCBs detected in the SHA samples compared with earlier sampling may be due to a decrease in the amount of free product present in the brook ⁽²⁾.

Table 4 gives the maximum detected concentrations and locations of off-site surface water COCs. Although most of these COCs exceed their respective health comparison values, it should be noted that these AWQC health comparison values consider both fish and water ingestion. The water ingestion term considers an average adult drinking water intake of 2 liters/day while the fish/shellfish ingestion term assumes an intake of 6.5 grams/day. The use of AWQC health comparison values is conservative in this case as there are no drinking water intakes in Kelley Brook or the Little River within fifteen miles of the site. There is, however, anecdotal evidence that fishing does take place in both the Kelley Brook and the Little River. Kelley Brook is stocked with trout every spring by the New Hampshire Fish and Game Department.

Table 4^a
Contaminants of concern in off-site surface water at Beede Waste Oil, Plaistow, NH

Chemical Name EPA Cancer Group Max Concentration
(ppb) Health Comparison Value
(ppb) Source of Health Comparison Value Location Date

Benzene A 110 1.2 AWQC SW-1/AE^b 23-Jan-91

sec-Butylbenzene NA 2 NONE NONE SW-2/SH June-95

1,2-Dichloroethane B2 7 0.38 AWQC SW-1/AE 23-Jan-91

cis-1,2-Dichloroethylene D 140 0.03 AWQC^c SW-1/AE 23-Jan-91

trans-1,2-Dichloroethylene D 14 NONE NONE SW-1/AE 23-Jan-91

Ethylbenzene D 480 3,100 AWQC SW-1/AE 13-Feb-92

Isopropylbenzene NA 1 NONE NONE SW-4/SH June-95

Naphthalene D 150 NONE NONE SW-2 25-April-94

n-Propylbenzene NA 2 NONE NONE SW-4/SH June-95

Phenanthrene D 150 0.003 AWQC^c SW-2 25-April-94

2-Methylnapthalene NA 220 NONE NONE SW-2 25-April-94

Methylene chloride B2 2 4.7 AWQC SW-1/AE 23-Jan-91

Methyl Ethyl Ketone D 20 NONE NONE SW-2/SH June-95

PCB (Aroclor-1260) B2 840 4.4 X 10^-5 AWQC SW-2 25-April-94

Toluene D 920 6,800 AWQC SW-1/AE 13-Feb-92

1,1,1-Trichloroethane D 11 NONE NONE SW-1/AE 23-Jan-91

1,2,4-Trimethylbenzene NA 4 NONE NONE SW-4/SH June-95

Vinyl Chloride A 3.3 2 AWQC SW-4 25-April-94

INORGANICS

Arsenic A 44 0.02 AWQC SW-2 25-April-94

Cadmium D 4 10 AWQC SW-2 25-April-94

Chromium (VI/III) A/D 51 50 (III) AWQC^c SW-2 25-April-94

Lead B2 2,820 50 AWQC SW-2 25-April-94

Mercury D 2 0.14 AWQC SW-2 25-April-94

See Health Comparison Value definitions. See Figure 3 for sample locations.

a = All samples taken from Kelley Brook.
b = SW-1/AE is located on Parcel 1 but is beyond the fence.
c = Old value. No current AWQC available.
NA = not available.
ppb = parts per billion.

Soil/Sediment

Sediment samples taken by NH DES at the same time and location as the April, 1994 surface water samples were analyzed for VOCs, PCBs, base-neutral compounds and metals (see Figure 3a). Maximum concentrations of the COCs detected are shown in Table 5. Soil health comparison values are listed as surrogates since sediment specific values are unavailable. Aroclor-1260 at 25 ppm and arsenic at 51.4 ppm are the only detected contaminants which exceed their respective health comparison values. The detection of Aroclor-1260 (25 ppm) at sampling location SW-2 only, is consistent with the sole PCB detection at this same location in Kelley Brook surface water by both NH DES and SHA. Lead was detected at a maximum concentration of 126 ppm and arsenic at a maximum of 51.4 ppm. An upstream sediment sample at location SW-1 was non-detect for VOCs and PCBs except for 1.1 ppm of benzo(a)pyrene. Concentrations of lead at 10.6 ppm and arsenic at < 0.25 ppm were found in sediment sample SW-1 ⁽¹⁸⁾. Mean arsenic levels in New Hampshire soils have been estimated by NH DPHS at 4.9 ppm with a range of 1.0 to 12.0 ppm. Lead levels range from 2 to 160 ppm with a mean of 29.8 ppm ⁽²¹⁾.

Three samples of "marsh" area soil taken concurrently by EPA in August, 1995 with the oil/water samples noted above detected PCBs at 4, 9 and 20 ppm. These samples were analyzed for PCBs only and are estimated to be in the area between the interceptor trench and Kelley Brook ⁽²⁰⁾. Further sediment samples were taken by Camp, Dresser and McKee (CDM) in February, 1995 and analyzed for VOCs, semi-volatile organic chemicals (SVOCs), pesticides and PCBs (Figure 3b). Low levels of VOCs were detected at sample locations SD-03, SD-04 and SD-05. Aroclor-1260 was the only PCB congener detected at a maximum concentration of 2.8 ppm. Low levels of pesticides were found at all locations except the designated background locations. Maximum levels of pesticides detected include d-BHC at 10 ppb, 4,4'-DDD at 50 ppb, 4,4'-DDE at 120 ppb and 4,4'-DDT at 42 ppb. Maximum levels of SVOCs detected in sediment during the CDM sampling include naphthalene at 3,000 ppb, 2-methylnaphthalene at 960 ppb, di-n-butylphthalate at 7,800 and bis(2-ethylhexyl)phthalate at 2,500 ppb ⁽²²⁾.

SHA took sediment samples from Kelley Brook in June, 1995 at locations which correspond to the surface water samples taken at the same time (Figure 3c). These samples were analyzed for VOCs, PAHs, PCBs and metals. Low levels of VOCs were detected in the area near the interceptor trench at sample location SS-2/SH where free product has been visible in the past. Low levels of VOCs were also detected further downstream at location SS-4/SH. SS-2/SH was the only sediment sample collected by SHA which detected PCBs (Aroclor-1260) at a concentration of 2.2 ppm. Sample location SS-6/SH was the only location which revealed PAH contamination. Barium was the only metal detected in sediment from the SHA samples at a concentration of 80 ppb ⁽²⁾.

Table 5
Contaminants of concern in off-site sediment near Beede Waste Oil, Plaistow, NH

Chemical Name EPA Cancer Group Max Concentration
(ppm) Health Comparison Value
(ppm) Source of Health Comparison Value Location Date

Benz(a)anthracene B2 1.9 NONE NONE SS-6/SH June-95

Benzene A 0.06 20,000 CREG SW-4 25-April-94

Benzo(b)fluoranthene B2 1.9 NONE NONE SS-6/SH June-95

Benzo(a)pyrene B2 2.5 0.1 CREG SS-6/SH June-95

Benzo(g,h,i)perylene D 0.6 NONE NONE SS-6/SH June-95

sec-Butylbenzene NA 20 NONE NONE SS-2/SH June-95

Chloroethane NA 0.3 NONE NONE SW-4 25-April-94

1,1-dichloroethylene C 0.14 400 EMEG SW-4 25-April-94

1,2-dichloroethylene (cis & trans) D 0.09 1000 (trans) RMEG SW-4 25-April-94

Dimethyl disulfide NA 0.006 NONE NONE SW-6 25-April-94

Dimethyl sulfide NA 0.02 NONE NONE SW-3 25-April-94

Ethylbenzene D 30 5000 RMEG SS-4/SH June-95

Isopropylbenzene NA 10 NONE NONE SS-4/SH June-95

Naphthalene D 40 NONE NONE SS-4/SH June-95

n-Propylbenzene NA 20 NONE NONE SS-4/SH June-95

Phenanthrene D 0.4 NONE NONE SS-6/SH June-95

Methyl ethyl ketone D 1.3 30,000 RMEG SW-4 25-April-94

Polychlorinated Biphenyl
(Aroclor-1260) B2 25 0.09 EMEG SW-2 25-April-94

Tetrahydrofuran NA 0.5 NONE NONE SW-4 25-April-94

Toluene D 10 400 EMEG SS-2/SH June-95

Vinyl chloride A 0.03 1.0 EMEG SW-4 25-April-94

INORGANICS

Arsenic A 51.4 0.4 CREG SW-4 25-April-94

Cadmium D 1.7 40 EMEG SW-4 25-April-94

Chromium (VI/III) A/D 6.8 300 (VI) RMEG SW-4 25-April-94

Lead B2 126 NONE NONE SW-4 25-April-94

See Health Comparison Value definitions and Figure 3 for sample locations.
NA = not available.
ppb = parts per billion.

Outdoor Air

There has been no off-site outdoor air monitoring to date.

Indoor Air There has been no off-site indoor air monitoring conducted to date. Exposure to VOCs volatilizing from indoor tap water into indoor air is considered to be similar to that of drinking the tap water. This risk is considered significant when VOCs in residential wells that are being used as a source of tap water exceed their respective drinking water health comparison value (see Table 3). Maximum levels of benzene, 1,2-DCA, TCE and vinyl chloride exceed their respective drinking water health comparison values. The risk associated with inhalation and ingestion of these VOCs is evaluated in the Public Health Implications section of this document.

An additional source of VOCs in indoor air is through intrusion of vapors directly from contaminated groundwater through building foundations. The potential for infiltration of VOCs into indoor air from overburden groundwater was evaluated by comparing maximum residential overburden well VOC levels to the GW-2 standards given in the Massachusetts Contingency Plan (MCP). The MCP GW-2 standards are levels of contaminants in groundwater below which would not contribute a significant indoor air hazard. Vinyl chloride is the only VOC that exceeded its MCP GW-2 standard. The maximum vinyl chloride level of 2.6 ppb detected in the Howard Manor Condominium bedrock well (10A) exceeds the MCP-GW-2 standard of 2 ppb. Vinyl chloride has never been detected in residential overburden wells, however, and has often fluctuated below the 2 ppb level. NH DPHS does not consider vapor intrusion of vinyl chloride from groundwater into residential indoor air to be significant.

Overburden well 6 which is located in a basement has shown consistent detection of some alkylbenzenes for which there is no MCP GW-2 standard. Alkylbenzenes for which standards do exist are not included in this group and are evaluated separately. Well 6 is in the direct path of a contaminant plume which is thought to be related to a discrete spill that occurred in early 1990. Alkylbenzenes were not detected during the first three sampling rounds of this well taken between May, 1990 and February, 1992 when the more mobile VOCs were found (i.e. benzene, ethylbenzene, xylenes and methyl tert-butyl ether). Levels of alkylbenzenes never exceeded the NH DPHS interim drinking water standard of 50 ppb and have since decreased from initial detection in October, 1993 at 35.7 ppb to 20.9 ppb in April, 1995 and 6.1 in June, 1995. NH DPHS does not consider alkylbenzenes to be a contaminant of concern in residential indoor air.

C. Quality Assurance and Quality Control

All sampling data presented in this public health assessment was conducted and analyzed according to NH DES or EPA certified methods.

D. Physical and Other Hazards

The abandoned building on Parcel 1, noted previously as being in a state of disrepair, represents a safety hazard. The building has been vandalized on more than one occasion with evidence of arson. Although significant extensions of existing chain link fencing have restricted access to both this building and the drum storage area behind the main building, the site itself remains accessible since the outer fence does not extend completely around Parcel 1. There is also access to the site via a hole in the fence on the southeastern border of Parcel 2 which has apparently been used for trespassing in the past ⁽²³⁾.

PATHWAYS ANALYSIS

The following section discusses the various ways in which contaminants of concern can come into contact with the nearby population. In order for an exposure to these contaminants to occur all the elements of a pathway must be in place. These exposure pathways are divided into completed and potential. A completed exposure pathway consists of five elements: source, environmental media and transport, point of exposure, route of exposure and receptor population. A potential exposure pathway exists when one or more of these five elements are missing.

Completed Exposure Pathways

On-Site

Trespassing represents the only current on-site completed exposure pathway at the BWO site. No businesses are currently operating on-site but as of January, 1995 the owner has submitted an application for occupancy to the town. The site is partially secured by fencing which has proven inadequate in the past as evidenced by incidences of trespassing and vandalism. Although additional fencing has been installed which should mitigate such occurrences, the site remains accessible since the fence does not extend completely around the perimeter of the site. The drum storage area and the abandoned building are both enclosed by barbed wire fencing as of September, 1994. There are no schools or recreational facilities nearby which would suggest the potential for significant and recurrent trespassing in the future. There is evidence of trespass through a hole in the fence on the southern border of Parcel 2 which is proximal to the Howard Manor Condominiums ⁽²³⁾. Trespassers on-site may be exposed to PCBs, VOCs and other petroleum hydrocarbons in soil via incidental ingestion and dermal contact. Surface water on-site is restricted to the interceptor trench and the surface lagoons which contain only minimal amounts water. The exposed population via this pathway is estimated to be less than fifty.

Past on-site completed exposure pathways to workers could date back as far as the 1920s when Parcel 1 was first used as a location for an oil storage and distribution facility. Testing of on-site drinking water wells since October, 1991 have been negative for VOCs. On-site monitoring well samples taken since February, 1984, however, indicate significant VOC contamination suggesting that past workers may have been exposed to VOCs in drinking water. Other potential pathways for past worker exposure to VOCs and other petroleum hydrocarbons include inhalation of fumes and contaminated fugitive dusts, incidental ingestion of and dermal contact with contaminated soil and direct dermal contact with waste oil. PCBs have been detected at levels as high as 6,700 ppm in waste oil and 1,500 ppm in surface soil. Potential pathways of PCB exposure to past workers include incidental ingestion of and dermal contact with PCBs in soil and waste oil. Past and current site conditions such as stained soil, leaking storage tanks and evidence of an open surface lagoon suggest careless handling of fuel and waste oil which may have resulted in significant worker exposure. The exposed population via this pathway is estimated to be no greater than 100 workers over the history of the site.

Off-Site

Groundwater

The detection of VOCs in residential drinking water wells represents a completed exposure pathway for past, present and future exposure to site related contaminants via ingestion of and dermal contact with drinking water as well as inhalation of VOCs volatilizing from the water into indoor air. Current data indicate that contaminants originating at the BWO site (source) are migrating off-site through groundwater movement (media and transport) into residential drinking water wells (point of exposure) used for drinking and washing purposes (route of exposure) by nearby residents (receptor population).

Current exposure to VOCs in residential drinking water is below a level of concern. Past exposure of Howard Manor Condominium residents (well 10B) to vinyl chloride in drinking water at or above EPA's maximum contaminant level (MCL) was limited by NH DES through the supply of bottled water (see Figure 4 for residential well locations). A point-of-entry (POE) filtration device installed on this well in February, 1995 has reduced all pathways of exposure to vinyl chloride. The effectiveness of this device has been verified by sample analyses which detected no VOCs. Ingestion, dermal and inhalation exposure to TCE and cis-1,2-DCE in drinking water is occurring at levels currently below health comparison values at two residences on Shady Lane (wells 12 and 14B) and at the Sawyer's Banquet Center (well 11). No current restrictions are recommended by NH DPHS relating to the use of these wells. Some of these residents are reportedly using bottled water at their own expense.

A completed exposure pathway exists for past exposure to VOCs in drinking water. Past exposure of Howard Manor Condominium residents to vinyl chloride via the dermal and inhalation pathways has occurred at levels exceeding the respective health comparison value. This exposure may have also included the ingestion pathway and could have occurred at higher levels than are now being detected. Past exposures to cis-1,2-DCE and TCE were also likely for users of the well at the Sawyer's Banquet Center since these compounds have consistently been detected in this well since initial sampling. VOCs detected at Sawyer's Banquet Center have never exceeded their respective health comparison values or MCLs and NH DPHS has not recommended any restrictions on the use of this well. Residents using overburden well 6 and overburden well 14A were exposed to benzene and TCE, respectively, at levels exceeding their health comparison values for an unknown length of time. These residents obtained an alternate water supply following detection of these contaminants.

Exposure to VOC contaminated groundwater represents a future completed exposure pathway for all residents in the path of the migrating contamination plume since there is no access to a municipal water supply. Residents living to the southeast of the site who are currently being exposed to VOCs as well as those not yet exposed represent a receptor population for a groundwater contamination plume moving from sources on Parcel 1 through the residentially zoned Parcel 2. It is likely that contamination will persist and possibly increase in wells already impacted. It should be noted that plumes of VOCs in groundwater can manifest themselves as breakdown products in wells further downgradient.

Contaminants detected in residential wells to the southeast of Parcel 1 are consistent with those found in on-site overburden monitoring wells. Residential well contamination also appears to be consistent with the general direction of overburden groundwater flow across the site. Although most of the maximum concentrations of VOCs have been detected in overburden wells, there has also been contamination detected in bedrock wells. The contaminants detected in residential bedrock wells are also consistent with potential sources discovered on-site.

A past, present and future completed exposure pathway exists for the ingestion of arsenic and lead in residential drinking water. Although levels of arsenic detected in residential bedrock wells are not uncommon in New Hampshire, these levels do exceed health comparison values. Ingestion of lead from a single residential drinking water well has occurred in the past at concentrations below EPA's action level. Current exposure to lead concentrations in this well above the action level may be occurring based on the most recent sampling in September, 1994. The source of this lead contamination is not clear.

Approximately fifty residents are estimated to have been or are currently exposed to site related contaminants through contact with groundwater. Residents not yet exposed but who are at risk for future exposure through this pathway are estimated to total no more than two-hundred. This does not include any persons attending events at the Sawyer's Banquet Center which reportedly host regular functions with up to two-hundred people.

Soil/ Sediment

A past, present and future completed exposure pathway exists for ingestion of and dermal contact with arsenic and PCBs in soil/sediment along Kelley Brook east of the BWO site. Off-site sampling of Kelley Brook surface water and sediment, revealed the presence of PCBs, VOCs, SVOCs and metals. The sampling points are located along the border of the site but were taken outside the fenced area along the brook and so will be considered off-site and accessible.

Of the contaminants detected in sediment, only arsenic at 51.4 ppm, PCBs at 25 ppm and benzo(a)pyrene at 2.5 ppm exceed their respective soil health comparison values. Lead was also detected in Kelley Brook sediment at 126 ppm but is not expected to cause any appreciable increase in blood lead levels of children who recreating in the area ⁽²⁴⁾. Several other contaminants are listed as COCs in sediment due to the lack of a health comparison value with which to rule them out. The maximum detected level of these COCs is very low, however, and their presence is not anticipated to contribute significantly to overall risk. The sampling area is heavily wooded and bordered by the site and private property. Exposures in this area of the brook are, therefore, expected to be limited to the abutting residents and trespassers estimated to be less than fifty persons.

Surface Water

A past, present and future completed exposure pathway exists for ingestion of and dermal contact with contaminated surface water in Kelley Brook east of the BWO site. Several contaminants detected in Kelley Brook surface water exceed their respective AWQC health comparison values. Kelley Brook does not appear to be swimmable anywhere near the site. It is also subject to seasonal variations in water content which would limit surface water contact while increasing the potential for soil/sediment contact. Since recreators/trespassers are estimated to visit the area during the low water months (i.e. summer), the off-site surface water pathway is not expected to contribute significantly to the health risk of recreators/trespassers. The exposed population through this pathway is estimated to be less than fifty.

As noted above, the use of AWQC health comparison values is conservative as these values are based on both a drinking water and fish ingestion exposure. Although there is anecdotal evidence that fishing does take place downstream of the site, there are no drinking water intakes along Kelley Brook or the Little River within 15 miles of the site. It should be noted that the Kelley Brook and the Little River are stocked with brook trout by the New Hampshire Fish and Game Department.

Potential Exposure Pathways

On-Site

Potential future exposures to on-site contamination are relevant if the site is leased for further business operations. Future workers at the BWO site could be exposed to VOCs via inhalation and PCBs via ingestion of and dermal contact with surface soil. Although both on-site drinking water wells have tested negative for VOCs, there is the potential for groundwater exposure to workers via ingestion, inhalation of vapors and dermal contact should these wells become contaminated in the future. Considering the size of the former businesses that have operated on-site, a maximum of fifty employees may be exposed at any one time if a new business were to occupy the site.

A past potential exposure pathway exists for former workers through inhalation of VOCs while working in the abandoned building. An extensive amount of free product associated with the UST/AST groundwater plume has been detected in monitoring wells adjacent to this building. This plume and free product body is predicted to move directly under the building and contains significant amounts of non-chlorinated and chlorinated VOCs. The free product identified throughout the site is characterized as a light non-aqueous phase liquid (LNAPL) that is floating on the water table. The VOC component is, therefore, available to volatilize directly from the free product. The amount of VOC gas which might penetrate into the building is dependant upon the characteristics of the buildings foundation which are unknown. It is also unclear whether employees worked extensive hours in this building and, if so, whether the plume and free product existed during such periods. The exposed population via this pathway is estimated to be no greater than 100 workers over the history of the site.

Off-Site

Groundwater

Mercury detected in a residential drinking water well on Fran Avenue (well 8) represents a past potential exposure pathway via ingestion of drinking water. The users of this well which tested positive for mercury at the MCL in April, 1994 were advised by NH DPHS at this time to cease drinking the water and minimize washing use. These residents are apparently drinking only bottled water and their well has tested negative for mercury since the initial detection. The lack of confirmation of the initial mercury detection puts this past exposure in doubt. NH DPHS has kept the recommended restriction on drinking, however, and the residents have indicated that they will continue to use bottled water.

Residents who may have been exposed in the past to site related contaminants in groundwater include those who are now being exposed as well as those who have wells as close or closer to the site not currently showing contamination. Also, any person living at these residences prior to the residential well sampling may have been exposed in the past. This population is estimated to be no more than two-hundred persons.

Soil/Dust

Although the major pathway already exposing the surrounding community is via groundwater, concern for the migration of fugitive dust from the many as yet uncharacterized soil piles has been raised by the community. Of particular concern is the presence of polychlorinated biphenyls (PCBs) in on-site soil. Limited on-site surface soil sampling has detected significant amounts of PCBs in areas proximal to the 86 ASTs. PCBs are very stable compounds with low volatility and solubility causing them to be very persistent in soils. Should further soil characterization show significant and widespread PCB soil contamination, then the soil migration pathway will then need to be investigated for those residences proximal to the contaminated areas. The presence of volatiles in the soil is not anticipated to pose a hazard via off-site soil migration. The population at risk from this potential exposure pathway is limited to abutting residents estimated to be no more than fifty persons.

Fish Ingestion

A potential exposure pathway exists for the ingestion of fish containing PCBs. Anecdotal evidence suggests that fishing does take place in Kelley Brook and the Little River both of which are stocked with Brook Trout. PCBs have been detected in Kelley Brook surface water and both are known to bioaccumulate in fish. PCBs have also been detected in sediment at a maximum concentration of 25 ppm. Further characterization of Kelley Brook contamination by both CDM in February, 1995 and SHA in June, 1995 suggests that free product discharging into the brook near the interceptor trench is a significant source of PCBs in sediment and surface water. The CDM data showed low levels of PCBs further downstream which may indicate transport of sediment from the noted area of high concentration or a more widespread area of discharge from the heavily contaminated overburden on Parcel 1.

Mercury is another contaminant detected in Kelley Brook surface water that can bioaccumulate in fish. Mercury was detected in only one sample, however, taken from Kelley Brook. Considering that this surface water sample contained mercury at the detection limit of 2 ppb and that mercury was not found in any other samples from Kelley Brook (surface water or sediment), mercury bioaccumulation in Kelley Brook fish is not expected to be impacted by the site. It should be noted, however, that a fish ingestion advisory is in effect for all inland water bodies located in New Hampshire due to elevated levels of mercury in fish. Please contact the Bureau of Health Risk Assessment at 800-852-3345 for the latest information on this advisory.

NH DES plans to sample and analyze macro invertebrates (summer 1996) and fish (fall 1996) for PCBs. The New Hampshire Fish and Game Department has indicated that it will continue to stock the Kelley Brook pending recommendations from NH DPHS and NH DES. The amount of fishing in the Kelley Brook and Little River is difficult to estimate but is not likely to exceed more than one-hundred persons fishing in areas near the site.

PUBLIC HEALTH IMPLICATIONS

A. Toxicological Evaluation

The following section discusses and attempts to quantify the adverse health effects which may result from exposure to the contamination described previously. Contaminants which exceeded their media-specific health comparison values are evaluated below for both carcinogenic and non-carcinogenic health effects. This evaluation is based on current data and is subject to change should more data become available relative to the site and/or the toxic potential of the contaminants.

In order to evaluate the potential for non-carcinogenic adverse health effects resulting from exposure to contaminated media (i.e. air, water, soil and sediment), a dose was estimated for each contaminant. These doses were calculated for situations (scenarios) in which nearby residents or on-site workers might come into contact with the contaminated media. The estimated dose for each contaminant under each scenario was then compared to ATSDR's minimal risk level (MRL) or EPA's oral reference dose (RfD). MRLs and RfDs are doses below which no non-carcinogenic adverse health effects are anticipated (so called "safe" doses) and are derived from toxic effect levels obtained from human population and laboratory animal studies. These toxic effect levels can be a no-observed adverse effect level (NOAEL) or the lowest observed adverse effect level (LOAEL). In order to account for the uncertainty in this data, the toxic effect level is divided by "safety" factors giving the more lower and more protective MRL or RfD. Exceedance of the MRL or RfD indicates only the potential for adverse health effects. The magnitude of this potential can be inferred from the degree to which this value is exceeded. If the estimated exposure dose is only slightly above the MRL or RfD, then that dose will fall well below the toxic effect level. The higher the estimated dose is above the MRL or RfD, the closer it will be to the toxic effect level.

Some chemicals have the ability to cause cancer. Cancer risk is estimated by calculating a dose similar to that described above and multiplying it by the cancer potency factor, also known as the cancer slope factor. Some cancer potency factors are derived from human population data. Others are derived from laboratory animal studies involving doses much higher than are usually encountered in the environment. Use of animal data requires extrapolation of the cancer potency obtained from these high dose studies down to real world exposures which carries much uncertainty. Current thinking suggests that there is no "safe" dose of a carcinogen and that a very small dose of a carcinogen will give a very small cancer risk. Cancer risk estimates are, therefore, not yes/no answers but measures of chance (probability). Such measures, however uncertain, are useful in determining the significance of a cancer threat since any level of a carcinogenic contaminant carries an associated risk. It should be noted that mechanistic studies are underway to assess the validity of the "no threshold" assumption for cancer causing chemicals.

VOCs in Residential Drinking Water

Volatile organic compounds (VOCs) in drinking water have three routes of exposure: ingestion, inhalation of vapors and dermal contact. Exposure estimates for ingestion of VOC tainted drinking water can be readily calculated using some generally accepted parameters. Dermal uptake and inhalation of vapor resulting from washing activity is harder to estimate. Based on the most recent sampling data from residential drinking water wells still in use, it is apparent that exposure to several VOCs is presently occurring. In some cases, this exposure has been minimized by the use of bottled water. It should be noted that exposure to VOCs via drinking water has likely occurred in the past and will likely occur in the future should use of contaminated water not be eliminated. Future increases in VOC drinking water concentrations along with past exposure could increase the potential for the adverse health effects discussed below. It should also be noted that many chlorinated VOCs have similar target organs (e.g. liver) and should several appear at individually acceptable levels, the potential for adverse health effects may still exist due to their combined presence.

Table 3 gives the VOCs detected in active and previously used residential drinking water wells that have been determined to be contaminants of concern. Of the VOCs listed, only benzene, 1,2-DCA, TCE and vinyl chloride have ever exceeded their respective health comparison values. VOCs currently being detected in active residential drinking water wells include cis-1,2-DCE, 1,2 -DCA, MTBE, TCE and vinyl chloride. Of these, vinyl chloride, 1,2-DCA and TCE are the only contaminants exceeding their media specific health comparison value. Vinyl chloride is the only VOC currently exceeding its respective MCL and continues to fluctuate above and below this level in the untreated water from the Howard Manor Condominium well (10B).

Vinyl Chloride

Exposure to the maximum concentration of vinyl chloride (2.6 ppb) yet detected in drinking water poses no acute or intermediate health hazards. Based on a chronic adult ingestion and inhalation exposure scenario, a daily intake of vinyl chloride 4-fold higher than ATSDR's chronic oral minimal risk level (MRL) was estimated. This MRL was obtained from a lowest observed adverse effect level (LOAEL) divided by a "safety" factor of 1,000. The LOAEL for vinyl chloride is based on liver effects in rats ⁽²⁵⁾. It is not certain how much damage these effects would do to liver function. The estimated exposure of residents to vinyl chloride is expected to result in a very low potential for chronic non-carcinogenic adverse health effects since the estimated dose is 250-fold below the toxic effect level (i.e. the LOAEL).

The carcinogenic status of vinyl chloride is currently under review by an EPA risk assessment workgroup. A quantitative estimate of the cancer risks associated with the ingestion of this amount of vinyl chloride in drinking water was made, however, based on its previous classification as a Group A known human carcinogen ⁽²⁶⁾. The classification of a substance as a known human carcinogen signifies that sufficient evidence exists linking that chemical to cancer in humans. The dose estimate for cancer endpoints is based on a chronic 30-year adult ingestion and inhalation exposure averaged over a 70-year lifetime. Quantitation of cancer risk resulting from vinyl chloride exposure, however, is reliant on extrapolation of high dose tumor incidence in laboratory animals to real world low dose exposures. Such extrapolation carries much uncertainty and can only approximate the increase in cancer risk to humans. The cancer risk associated with a thirty year ingestion exposure to the maximum levels of vinyl chloride detected in residential drinking water wells represents a low increase in cancer risk.

The exposure to vinyl chloride evaluated above was limited by the supply of bottled water from July, 1994 to May, 1995 to the users of the only water supply in which vinyl chloride has been detected. Recent installation of a POE treatment device on this well in February, 1995 has decreased both ingestion and inhalation exposures below a level of concern. Although the dermal pathway was not evaluated quantitatively, it is not thought to contribute significantly to the overall exposure. It should be noted that the potential exists for vinyl chloride contamination to increase in this well and in other active wells near the site which are currently below detection. The POE system is expected to maintain VOCs below a level of concern despite any fluctuations in concentration. The performance of the POE has been verified by two rounds of sampling following installation which detected no VOCs.

Trichloroethylene (TCE)

TCE was detected above its respective health comparison value in a currently inactive but formerly used residential drinking water well. A daily intake more than 100-fold lower than ATSDR's intermediate oral MRL was estimated based on a chronic ingestion and inhalation exposure to TCE at the maximum detection level of 23.8 ppb. This comparison indicates that no acute or intermediate adverse health effects are anticipated at this level of exposure. Although a chronic oral MRL or RfD is not available, the limited chronic exposure animal studies available indicate that LOAELs and NOAELs are well above the estimated intake given for this exposure scenario ⁽²⁷⁾.

TCE was previously classified by the EPA as Group B2 probable human carcinogen based on adequate animal data and insufficient human data. This classification has been removed, however, by EPA and is pending further review. Although EPA has withdrawn its former classification of TCE as a probable human carcinogen, evidence does exist showing TCE to be carcinogenic in animals. As a result, quantitative cancer assessment was performed based on animal data provided by EPA prior to the ongoing review. TCE is currently being detected at a maximum of 3.5 ppb in an active residential drinking water well. No significant cancer risk is expected to result from exposure to current levels of TCE in drinking water. The maximum level of TCE detected in a formerly used well (23.8 ppb) would result in a slight increase in cancer risk assuming a 30 year exposure duration at this concentration.

Benzene

A maximum of 7.9 ppb benzene was detected in a formerly used overburden well believed to be impacted by a discrete surface spill in early 1990 that occurred along the northern border of the site. Use of this well as a drinking water source was discontinued in June, 1990 following detection of the benzene and other petroleum related VOCs. Since this contamination is thought to be related to this specific and discrete spill, the exposure duration in this scenario is thought to be less than one year. Assuming a worst case scenario of a child exposed for 5 years at the maximum detected level of 7.9 ppb in drinking water, no non-carcinogenic adverse health effects are anticipated to result from this exposure. Although no MRL or RfD is currently available for benzene, the estimated dose calculated from the scenario noted above does not exceed a chronic RfD adapted from the background documentation for the Massachusetts Contingency Plan ⁽²⁸⁾.

Benzene is classified as a Group A known human carcinogen by the EPA based on adequate human and animal data. Long-term exposure of workers to benzene in air has resulted in an increased incidence of leukemia. High dose laboratory animal testing has shown increases in various tumors including lymphomas and leukemias ⁽²⁹⁾. No significant increase in cancer risk is anticipated as a result of this past exposure under the scenario noted above.

1,2-Dichloroethane (1,2-DCA)

The past three sampling rounds of residential wells detected maximum concentrations of 1,2-DCA at 0.9, 0.8 and 0.9 ppb in the same active well. A daily intake more than 1000-fold lower than ATSDR's intermediate oral MRL was estimated based on a chronic ingestion and inhalation exposure to 1,2-DCA at a maximum of 0.9 ppb. This comparison indicates that no acute or intermediate adverse health effects are anticipated at this level of exposure. Although a chronic oral MRL or RfD is not available, the limited chronic exposure animal studies available indicate that LOAELs and NOAELs are well above the estimated intake given for this exposure scenario ⁽³⁰⁾. No non-carcinogenic adverse health effects are anticipated to result from exposure to 1,2-DCA at these levels in drinking water.

1,2-DCA is classified by EPA as a Group B2 probable human carcinogen based on adequate animal evidence and no human data. Rats given high oral doses of 1,2 -DCA showed increases in lung and blood vessel tumors ⁽²⁹⁾. No significant increase in cancer risk is anticipated to result from a lifetime exposure at the maximum level of 1,2-DCA detected in residential drinking water wells.

Metals in Residential Drinking Water

Arsenic

A maximum concentration of arsenic at 15.0 ppb was detected in a single residential drinking water well on Fran Avenue. Based on a chronic adult ingestion only pathway, a daily intake of arsenic slightly higher than ATSDR's chronic MRL was estimated. The MRL is based on a NOAEL observed in a large Taiwanese population exposed primarily through drinking water. This dose was divided by an uncertainty factor of 3 for human variability to yield the MRL ⁽³¹⁾. The lowest observed adverse effect level (LOAEL) noted in this same study was 35 times higher than the NOAEL and was based on hyperkeratosis (dermal) and hyperpigmentation (ocular). Considering the fact that the estimated dose is approximately equal to the NOAEL and 35-fold lower than the LOAEL, no non-carcinogenic adverse health effects are anticipated. The contribution of the dermal pathway is expected to be insignificant in comparison to ingestion. Since arsenic is relatively non-volatile, the inhalation pathway will not contribute significantly to exposure.

A low increase in cancer risk is associated with a 30-year adult exposure to arsenic at the levels detected. Arsenic is classified by EPA as a Group A known human carcinogen. This classification is based on two studies. One study involved the inhalation exposure of smelter workers who exhibited an increased incidence in lung cancer mortality. More relevant studies examined populations in Taiwan (same population used to derive the MRL discussed above), Chile and Mexico in which the exposure occurred through the ingestion of drinking water. Increases in skin cancer were observed in these drinking water exposed populations when compared to an appropriate control population. Studies done on populations within the United States have showed no evidence of carcinogenicity at drinking water levels well above the MCL of 50 ppb. The exposed populations in the U.S. studies were not large enough, however, to detect the cancer rates found in those done outside the U.S. ⁽²⁹⁾. It is important to note that skin cancer is often successfully treated and does not usually result in death. There is some evidence, however, which indicates that internal tumors may also be associated with arsenic ingestion.

Mercury

Mercury was detected only once at 2.0 ppb in the same well on Fran avenue as was the maximum level of arsenic. The sample analysis for mercury represents a measure of total mercury. Most of this total is expected to be inorganic as opposed to organic mercury (e.g. methyl mercury) ⁽³²⁾. In general, inorganic mercury is less bioavailable and less toxic than organic mercury. The target organ for inorganic mercury toxicity is the kidney while the most sensitive toxic endpoint for methyl mercury exposure is the nervous system. A chronic exposure to the maximum amount of mercury detected in residential drinking water (15 ppb) is not estimated to exceed oral RfD's derived by EPA for the organic forms phenyl mercuric acetate and methyl mercury or the inorganic form mercuric chloride. Since the estimated dose at the maximum detected level of mercury does not exceed RfDs for neither the inorganic nor organic forms, no adverse health effects are anticipated from exposure to mercury in drinking water at this level.

There is no data available to indicate that elemental mercury causes cancer and it is classified as a Group D (not classifiable) carcinogen by the EPA ⁽²⁹⁾. Limited data indicates an increase of renal tumors in rats fed high levels of methylmercury and there is limited evidence that mercuric chloride (an inorganic form) is carcinogenic in animals. It is likely that the form of mercury present in drinking water is inorganic. Considering the low level of mercury detected and that it has been detected only once in one residential well, no significant increase in cancer risk is anticipated from exposure to mercury in drinking water drawn from this well.

It should be noted that mercury was detected in only one sample of one drinking water well which has since tested negative. The residents of this household have reported that they are drinking only bottled water and will continue to do so despite a recent negative sampling result. NH DPHS has maintained a recommendation that these residents not drink their well water pending further negative testing for mercury. The dermal pathway was not considered but is not expected to contribute significantly to overall exposure. The contribution of the inhalation pathway for mercury volatilizing from drinking water is indeterminate but is not expected to be significant.

Lead

Lead was detected in two samples taken from different outdoor taps, one treated and one untreated, at a residence on Kelley Road. Lead concentrations of 58.0 ppb and 10.0 ppb were detected in samples taken from the treated and untreated samples, respectively. This sampling represents the only lead detected in residential wells near the BWO site and is not thought to be site related. Young children (ages 0-6 years) represent a very sensitive exposure population for the neurotoxic effects of lead. Low levels of lead in the blood of children have been associated with a decrease in IQ and other behavioral effects. It is unknown whether any children live at this residence. EPA has set an action level of 15.0 ppb which was exceeded by the lead concentration in the treated tap. The treatment system associated with this tap is unknown but is thought to be a mineral removal system (i.e. water softener). Although the action level is exceeded in this case, adverse health effects are not anticipated in children exposed at this level ⁽²⁴⁾. This evaluation assumes that other routes of lead exposure (i.e. lead in dust, paint, food and soil) are at average background levels. If other sources of lead are present above background, then the contribution of this amount of lead in drinking water may be significant.

Lead is currently classified by EPA as a Group B2 probable human carcinogen. There is very little human data to substantiate the kidney tumors noted in high dose rat studies ⁽²⁹⁾. Although no quantitative analysis of the cancer potential of lead was made, evaluation of the non-carcinogenic effects of lead is assumed be protective of health. The non-carcinogenic effects of lead can occur at very low levels of exposure and are thought to be the most sensitive and important toxic endpoint of lead exposure.

PCBs in Kelley Brook Sediment and Surface Water

PCBs are mixtures of various chemicals of similar structure (congeners) identified by their trade name, Aroclor, followed by a four digit number. The first two digits represent the number of carbon atoms (12) while the second two digits give the percent by weight of chlorination for the congeners in that mixture. In general, PCB toxicity increases with the degree of chlorination in the mixture ⁽³³⁾. Aroclor-1260 was the PCB detected in Kelley Brook sediment.

No non-carcinogenic adverse health effects are anticipated to result from exposure to PCBs in the Kelley Brook area. An estimated daily intake via incidental ingestion of and dermal contact with a maximum of 25 ppm PCBs found in soil/sediment along Kelley Brook did not exceed ATSDR's relatively conservative chronic MRL. This estimated dose considered a trespassing/recreating older child exposed for 36 days per year over a 10-year period. The MRL is based on a LOAEL for immunological effects relating to decreased IgG and IgM response following chronic oral exposure of Aroclor-1254 via oil gavage to female rhesus monkeys ⁽²⁵⁾. The MRL for Aroclor-1254 was used as surrogate to estimate the potential for non-carcinogenic adverse health effects as there is no MRL or RfD for Aroclor-1260 ⁽³³⁾.

PCBs are classified as a B2 probable human carcinogen by EPA. Animal data used for this classification was determined to be adequate by EPA while available human data was deemed insufficient. Several high dose animal studies have demonstrated the ability of PCBs to induce liver carcinomas. Cancer risk was quantified using and EPA derived cancer slope factor based on an animal bioassay of rats fed Aroclor-1254 ⁽²⁹⁾. Levels of PCBs detected in soil/sediment near the Kelley Brook pose no significant increase in cancer risk to trespassers/recreators in this area. This estimate is based on a 10-year exposure of an older child via dermal contact with and incidental ingestion of soil/sediment averaged over a 70-year lifetime.

Aroclor-1260 was also detected in Kelley Brook surface water in the same location as the sediment sample which showed the maximum level of PCBs. It should be noted that surface water sampling, especially in a shallow, running stream, is subject to sediment contamination which could explain the PCB levels in this surface water sample and not in any others. Although some surface water exposure could occur to trespassers/recreators in the brook, this exposure is not expected to result in any significant ingestion of surface water. The brook is not swimmable in any area adjacent to the site and is apparently very low during the summer when exposures are estimated to be occurring. Also, the contribution of surface water ingestion would be insignificant compared to the soil/sediment pathway. Dermal contact with PCBs in surface water could occur in this scenario but has not been quantified due to the lack of an acceptable method. Although this pathway was not evaluated, dermal contact with surface water in this scenario is expected to be minimal.

The movement of PCB contaminated fugitive dusts from on-site surface soil to nearby residential yards also poses a potential pathway for PCB exposure. Exposure via this pathway is indeterminate due to the lack of off-site and insufficient on-site soil sampling data. Exposure via PCB contaminated fish ingestion also represents a potential exposure pathway. Although PCB sediment contamination appears to be localized to the area of Kelley Brook where free product is being discharged, some sampling has indicated low levels of PCBs in sediment downstream of this area. The NH DES Biology Bureau will be sampling Kelley Brook macro invertebrates (summer 1996) and fish (fall 1996) for PCB analysis. NH DPHS will await the results of this sampling and analysis prior to determining the significance of this pathway.

Metals in Kelley Brook Sediment and Surface Water

No non-carcinogenic adverse health effects are anticipated as a result of ingestion and dermal uptake from arsenic in soil/sediment along the Kelley Brook. The trespasser/recreator exposure scenario outlined above was used to estimate a daily intake well below ATSDR's MRL for arsenic. This dose estimate was based on incidental ingestion and dermal contact with a maximum of 51.4 ppm arsenic in soil/sediment from the Kelley Brook area. As noted above, the MRL is based on a NOAEL observed in a large Taiwanese population exposed primarily through drinking water. Adverse health effects noted at doses above the NOAEL included hyperkeratosis (dermal) and hyperpigmentation (ocular) ⁽³¹⁾.

There is a very low increase in cancer risk associated with trespassing/recreation in this area and levels of arsenic in the soil/sediment. Arsenic is classified by EPA as a Group A known human carcinogen. This classification is based on human exposures through both inhalation and ingestion ⁽²⁹⁾. As noted above , the relevant studies for this scenario involved exposures of large populations to arsenic in drinking water.

As in the PCB scenario, the dermal and ingestion pathways were excluded for surface water. Although surface water concentrations of arsenic at 44.0 ppb and mercury at 2.0 ppb were detected in one sample along the brook, both the lack of significant exposure to surface water as well as the low concentrations result in a comparatively small contribution to the overall risk.

Interpreting Cancer Risk

The meaning of low, very low, slight and no significant increase in cancer risk, can be better understood by considering the population size required for such an estimate to result in a single cancer case. For example, a low increase in cancer risk indicates an estimate of one cancer case per ten thousand persons exposed over a lifetime, a very low estimate might result in one cancer case per several tens of thousands exposed over a lifetime and a slight estimate would require a lifetime exposed population of several hundreds of thousands. NH DPHS considers cancer risk to be not significant when the estimate results in one cancer per one million or more people exposed over a lifetime.

B. Health Outcome Data Evaluation

Site specific cancer incidence data gathered for the town of Plaistow between July, 1987 and June, 1993 was obtained from the NH DPHS Chronic Disease Epidemiology Program. Cancer incidence rates were not available for Plaistow and the number of cases were too few to be age-adjusted which precluded a comparison with the age-adjusted rates generated by the state. A comparison between Plaistow and the state was made, however, for site specific percentages of total cancers. Of the total 134 cancer cases recorded from Plaistow during this period, breast cancer accounted for 21.6% (29 cases), non-Hodgkin's lymphoma for 6.7% (9 cases) and leukemia for 3.7% (5 cases). These percentages are higher than those of the state which recorded 16.8% breast cancer, 3.3% non-Hodgkin's lymphoma and 1.8% leukemia out of a total of 16,421 cancer cases between 1987 and 1990. There were no other remarkable differences noted for other cancer sites.^{(10, 11)}

It is important to note that this comparison does not correct for potential population differences between Plaistow and the state. Differences in population characteristics could slant the numbers presented above. For example, a higher Plaistow female population between the ages of 40 and 50 years could generate a higher percentage of breast cancer than the state suggesting a higher incidence. This could be misleading since the state value may be lower simply because the state population contained a lower percentage of women at risk for breast cancer. Also, the data is not presented as an incidence rate but as a percentage of cancers diagnosed over a 7 year period and therefore, is not sensitive to population changes during this period. This data also has obvious limitations relative to linking the BWO site to these increases.

C. Community Health Concerns Evaluation

Several community health concerns were related to NH DPHS at a recent public availability session held at the Plaistow Town Hall on September 15, 1994. These concerns are listed and responded to below.

1. Citizens from two nearby residences not included in the current drinking water well sampling program were concerned about the quality of their well water. They are both using their wells (bedrock) for washing purposes only and have been drinking bottled water for several years. Each of these residents would like to have their well tested but not at their own expense.

Since the wells have not been tested no recommendations on use could be given. The NH DPHS suggests that these residents have their water tested for VOCs. Requests for well tests should be directed to the New Hampshire Department of Environmental Services (NH DES) site manager at the Groundwater Protection Bureau (603-271-2941).

2. Several residents expressed concern over soil which had been trucked onto the site from an outside source. A related concern over apparent "late night" shipments onto the site and other "unknown activities" was also voiced.

These concerns will be forwarded to NH DES for appropriate follow-up. Such concerns can only be addressed by proper characterization of all on-site media and potential sources of contamination. NH DPHS recommended in the Draft for Public Comment version of this public health assessment that sources of contamination previously identified be further characterized. This document contains further site characterization data. Recommendations remain, however, for further PCB soil and fish sampling. NH DES plans to conduct sampling of macro invertebrates (summer 1996) and fish (fall 1996) in Kelley Brook for PCB analysis.

3. A resident from a nearby property (~ 200 ft. from BWO) expressed concern over the health of her daughter. She said that they had stopped drinking the water from her bedrock well approximately ten years ago but has been using it for bathing and showering. This resident wants to know why her well water has not been tested. She feels her rights have been violated.

Since her well has not been tested, discussion of potential health effects for the resident or her daughter is not possible. NH DPHS did advise the woman that by not drinking the well water the potential for exposure to herself and her daughter was significantly reduced. This resident was advised to have her well tested for VOCs. Requests for well tests should be directed to the New Hampshire Department of Environmental Services (NH DES) site manager at the Groundwater Protection Bureau (603-271-2941).

4. Several residents expressed concern over the potential for fires or explosions on the site.

This building has been the target for arson in the past. Imminent explosive hazards were not identified in preliminary investigations by the state or EPA. There are, however, obvious explosive hazards associated with fuel storage and the past vandalism and attempted arson which has been reported on-site. This building has been secured under NH DES authority by a barbed wire fence as of September, 1994

5. A concern related to dermal contact during washing and bathing with mercury contaminated well water was expressed by a resident.

The well in question has tested positive for mercury at the MCL (2 ppb). This resident was advised by NH DPHS not to drink this water and to minimize washing uses. These recommendations were accompanied by health effects information pertinent to the exposure. Subsequent testing of this well has not detected mercury. Mercury exposure via drinking water through non-ingestive pathways is difficult to quantify. Exposure can be greatly reduced by not drinking the water and minimizing hot water use. Mercury in its inorganic form is known to be toxic to the kidneys while organic mercury is primarily a neurotoxicant.

6. A couple noted a "gasoline-like sheen" in a wetlands area of their property which borders the site. The residents wished to know whether this could be site related. Concern for the surrounding ecology was also expressed by this couple who noticed a squirrel on their property which "looked as if it had mange".

This couple lives near the site and has wetlands on her property bordering Kelley Brook. The "sheen" could be site related petroleum products. NH DPHS will relay this observation to NH DES which has taken surface water samples along Kelley Brook. It should be noted that certain bacteria commonly associated with wetlands can produce a similar sheen. The local ecology may well be impacted by site related contaminants but the squirrel's problem is not readily definable.

7. A resident inquired as to whether the state has probed the site with metal detectors to determine if any more unaccounted for 55-gallon drums exist on the site. Another resident claimed that drums have been disposed of on the site.

The site has been probed on three occasions with ground penetrating radar (GPR). GPR is an effective method for detecting underground metallic structures such as pipes, drum and storage tanks due to the strong electrical contrasts of the metal with surrounding media. The most recent GPR survey was performed in May, 1995 by Kick Geoexploration as part of a site characterization conducted by Sanborn, Head & Associates for NH DES. Five areas were selected for this survey based on ground surface disturbances, reported dumping and environmental sampling data. Crushed tanks, metal pipes, re-bar and a hot water heater were excavated near the southwest corner of the site. A large underground storage tank (UST) was uncovered in the wooded area towards the southern border of the site. This tank did not contain hazardous waste. A large amount of metal debris was also excavated along with a crushed drum near the area of the interceptor trench where 15 55-gallon drums were previously unearthed.

8. The proprietor of a nearby multiplex which has shown drinking water well contamination (probably site related) wished to know if he can be held legally liable for any adverse health effects which could be attributed to the contaminants.

This question should be referred to a law professional.

9. Several residents expressed concern over a "documented" injection well installed by a previous owner of the site.

The NH DES site manager is aware of this documentation but has no evidence that such a well exists.

10. Several residents expressed concern over apparent dumping of battery acids on-site.

Contaminants which might pose a health concern in battery acid would include heavy metals. Heavy metals have been detected in on-site soil and have been tested for in residential wells. Low levels of arsenic and mercury were found in one well but are not thought to be site related and are not metals associated with car battery acid. Lead is the primary contaminant of concern in car battery acid and has been found in elevated concentrations in on-site groundwater samples containing free product. Lead detected in a single well north of the site across from Kelley Brook is not thought to be site related, however, since it is in the overburden groundwater which is expected to discharge into the brook.

11. Several residents expressed concern related to migration of soil contaminants from on-site soil piles to off-site residences. PCBs (polychlorinated biphenyls) were noted as particular contaminant of concern in on-site soil. One resident noted that a "black powdery substance" has blown into his yard from the site.

This potential exposure pathway is difficult to quantify. Further characterization of on-site soil contamination at least is needed in order to determine if this pathway poses a health threat to nearby residences. Of the contaminants detected on-site to date, PCBs are the only contaminant of concern for this exposure pathway due to low volatility, strong soil sorption and extreme environmental persistence. PCBs can concentrate in fat tissue, are thought to be hormone disruptive and are classified by the EPA (Environmental Protection Agency) as a Group B2 probable human carcinogen. NH DPHS is exploring options for off-site soil sampling to better assess this potential exposure pathway.

12. Several residents expressed concern related to the opening of another business on-site. These residents suggested that the site be closed to any future operations. They also expressed concern that a potential new tenant on-site is affiliated with the present owner. A related question was raised as to whether another on-site business would add to the existing hazard.

The Town of Plaistow holds the authority to restrict business operations within the borders of the town. Whether another business would add to existing hazards, depends upon how that business is operated. Fuel oil distribution operations need not be more environmentally damaging than the end use of their product.

13. One resident stated that on-site monitoring well data was promised to be made available to him at 3-month intervals. He stated that he has not seen any data in over a year.

On-site data is not generated at these intervals but requests for data can be referred to the NH DES site manager. The NH DES site manager for the BWO site can be reached at the Groundwater Protection Bureau 603-271-2491.

14. One resident claimed that waste was being discharged through hoses into surface runoff pits.

Many surface discharges are expected to have occurred on this site. Deliberate discharges have not been documented at the site. There is considerable evidence, however, that large quantities of waste oil have been discharged to a former surface lagoon thought to be the source of significant groundwater contamination. There is also evidence of surface discharges to two surface water runoff pits located on the site.

15. Concern over a leaking AST (Above-ground Storage Tank) was expressed. Documented leaks have occurred in on-site ASTs. Tank No. 22 which has since been removed had a history of valve leaks which apparently contaminated the soil beneath with PCBs. Tank No. 11 also had a leak which was discovered by NH DES and sampled for PCBs by EPA on November 30, 1993. No PCBs were detected in Tank No. 11. There have apparently been large surface discharges of waste oil throughout the site.

16. One resident expressed concern about the health hazards of antifreeze which has apparently been disposed on-site.

The vacant building which is now enclosed by chain-link fencing was reportedly used for antifreeze recycling. Although there is no evidence of any disposal of automobile antifreeeze/coolant on the site, some discharge may have occurred into drains or onto the site grounds. The main component of most automobile antifreeze/coolant is ethylene glycol. Ethylene glycol has not been detected on-site to date but as mentioned previously, NH DPHS is recommending further characterization of the site. Further characterization of the site is needed to evaluate this health concern. Ethylene glycol is known to affect the heart when used in drug therapy.

Next Section Table of Contents

Agency for Toxic Substances and Disease Registry, 1825 Century Blvd, Atlanta, GA 30345
Contact CDC: 800-232-4636 / TTY: 888-232-6348

Department of Health and Human Services

Chemical Name	EPA Cancer Group	Concentration (Max/MaxR) (ppb)	Health Comparison Value (ppb)	Source of Health Comparison Value	Location^a	Date (Max/MaxR)
Benzene	A	780/780	1	CREG	SH-6/SH-6	6-95/6-95
Chloroethane	NA	540/540	NONE	NONE	AE-16	6-95/6-95
Chloroform (trichloromethane)	B2	17/2	6	CREG	AE-12/AE-12	1-91/6-95
1,1-Dichloroethane	C	3,000/3,000	81	STATE	SH-6/SH-6	6-95/6-95
1,2-Dichloroethane	B2	78/30	0.4	CREG	MW-3/AE-8	2-84/6-95
1,1-Dichloroethylene	C	140/40	0.06	CREG	MW-3/SH-5	2-84/6-95
cis-1,2-Dichloroethylene	D	2,200/2,200	70	LTHA	SH-5/SH-5	6-95/6-95
trans-1,2-Dichloroethylene	D	1,100/110	100	LTHA	MW-2/SH-6	2-84/6-95
Ethylbenzene	D	1,300/1,300	700	MCL	SH-10/SH-10	6-95/6-95
Isopropylbenzene (cumene)	NA	80/80	280	NH DPHS	SH-10/SH-10	6-95/6-95
p-Isopropyl toluene	NA	80/80	NONE	NONE	SH-10/SH-10	6-95/6-95
Methylene chloride	B2	440/ND	5	CREG	MW-3	2-84/6-95
4-Methyl-2-pentanone (methyl isobutyl ketone)	D	300/200	NONE	NONE	AE-11S/AE-8	1-91/6-95
Naphthalene	D	460/460	2	LTHA	SH-10/SH-10	6-95/6-95
Alkylbenzenes^b	NA	2,670/2,670	50	NH DPHS	SH-10/SH-10	6-95/6-95
Polychlorinated Biphenyls	B2	1/1	0.005	CREG	AE-4/AE-4	12-95/12-95^c
Tetrachloroethylene	B2	96/30	0.7	CREG	AE-15/SH-10	1-91/6-95
Toluene	D	1,500/1,500	1000	MCL	AE-9B/AE-9B	6-95/6-95
1,1,1-Trichloroethane	D	1,800/1,800	200	LTHA	SH-5/SH-5	6-95/6-95
Trichloroethylene	B2	2,000/2,000	3	CREG	SH-5/SH-5	6-95/6-95
Vinyl chloride	A	2,200/2,200	0.2	EMEG	SH-6/SH-6	6-95/6-95
INORGANICS
Arsenic	A	90/90	0.02	CREG	AE-3/AE-3	6-95/6-95
Cadmium	D	27/27	5	RMEG	AE-3/AE-3	6-95/6-95
Chromium (VI/III)	A/D	74/12	50 (VI)	RMEG	AE-3/SH-7	5-94/6-95
Lead	B2	2,600/2,600	15	Action Level	SH-7/SH-7	6-95/6-95

Chemical Name	EPA Cancer Group	Max Concentration (ppm)	Health Comparison Value (ppm)	Source of Health Comparison Value	Date
4-Methyl-2-pentanone (methyl isobutyl ketone)	D	210^a	NONE	NONE	30-March-92
Toluene	D	12^a	400	RMEG	30-March-92
Fluorene	D	35	NONE	NONE	25-April-94
Ethylbenzene	D	180^a	NONE	NONE	30-March-92
Polychlorinated Biphenyls (Aroclor-1248)	B2	1,500^b	1	EMEG	9-Sept-93
Phenanthrene	D	37^c	NONE	NONE	25-April-94
Phthalate, bis-2-ethylhexy	NA	40^c	NONE	NONE	25-April-94
2-Methylnaphthalene	NA	45^c	NONE	NONE	25-April-94
INORGANICS
Lead	B2	250^b,c	NONE	NONE	30-March-92
Copper	D	50^b,c	NONE	NONE	9-Sept-93
Chromium (VI/III)	A/D	150^d	300 (VI)	RMEG	9-Sept-93

Chemical Name	EPA Cancer Group	Max Concentration (ppb)	Health Comparison Value (ppb)	Source of Health Comparison Value	Location	Date
Benzene	A	110	1.2	AWQC	SW-1/AE^b	23-Jan-91
sec-Butylbenzene	NA	2	NONE	NONE	SW-2/SH	June-95
1,2-Dichloroethane	B2	7	0.38	AWQC	SW-1/AE	23-Jan-91
cis-1,2-Dichloroethylene	D	140	0.03	AWQC^c	SW-1/AE	23-Jan-91
trans-1,2-Dichloroethylene	D	14	NONE	NONE	SW-1/AE	23-Jan-91
Ethylbenzene	D	480	3,100	AWQC	SW-1/AE	13-Feb-92
Isopropylbenzene	NA	1	NONE	NONE	SW-4/SH	June-95
Naphthalene	D	150	NONE	NONE	SW-2	25-April-94
n-Propylbenzene	NA	2	NONE	NONE	SW-4/SH	June-95
Phenanthrene	D	150	0.003	AWQC^c	SW-2	25-April-94
2-Methylnapthalene	NA	220	NONE	NONE	SW-2	25-April-94
Methylene chloride	B2	2	4.7	AWQC	SW-1/AE	23-Jan-91
Methyl Ethyl Ketone	D	20	NONE	NONE	SW-2/SH	June-95
PCB (Aroclor-1260)	B2	840	4.4 X 10^-5	AWQC	SW-2	25-April-94
Toluene	D	920	6,800	AWQC	SW-1/AE	13-Feb-92
1,1,1-Trichloroethane	D	11	NONE	NONE	SW-1/AE	23-Jan-91
1,2,4-Trimethylbenzene	NA	4	NONE	NONE	SW-4/SH	June-95
Vinyl Chloride	A	3.3	2	AWQC	SW-4	25-April-94
INORGANICS
Arsenic	A	44	0.02	AWQC	SW-2	25-April-94
Cadmium	D	4	10	AWQC	SW-2	25-April-94
Chromium (VI/III)	A/D	51	50 (III)	AWQC^c	SW-2	25-April-94
Lead	B2	2,820	50	AWQC	SW-2	25-April-94
Mercury	D	2	0.14	AWQC	SW-2	25-April-94