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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 andoff-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 healthconcerns and 3) the quality and extent of sampling data. Also, any contaminant listed in one mediawill 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 healthcomparison values does not mean that a public health concern exists but rather signifies the needto consider the chemical further which is done in the Public Health Implications section of thepublic health assessment. The health comparison values used in this public health assessmentinclude 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 ofconcern 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 exposureto a chemical that is likely to be without a substantial risk of harmful (non-cancerous) effects overa specified duration of exposure. RMEGs are media-specific health comparison values derivedfrom EPA's reference dose (RfD) that are used when EMEGs are not available. RfDs estimate thedaily exposure to a contaminant below which adverse health effects are not anticipated. CREGsare estimated contaminant concentrations in a specific media which are anticipated to result in oneexcess cancer in one million persons exposed over a lifetime. CREGs are calculated from EPA'scancer slope factors (CSFs). CSFs are cancer potency estimates derived for chemicals shown tobe carcinogenic in either animals or humans. MCLs are contaminant concentrations in waterderived by EPA to be protective of public health (considering the availability and economics ofwater treatment technology) over a lifetime (70 years) at an ingestion exposure rate of 2 liters ofwater per day. MCLs are enforceable, regulatory values. LTHAs are non-enforceable guidelinesderived for a lifetime ingestion exposure to a contaminant in drinking water. They are calculatedfor non-carcinogenic compounds from Drinking Water Equivalent Levels (DWELs) which in turnare based on oral RfDs. LTHAs do consider the contribution of other media to the overallexposure. Human health based AWQCs are derived for both carcinogens and non-carcinogensbased on EPA's CSFs and RfDs, respectively. Two values are derived based on either ingestion ofwater (2 liters/day) or ingestion of both water and organisms (2 liters/day and 6.5 grams offish/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 eachcontaminant. This classification scheme is due to be revised in the near future but currentlyconsists of six groups: 1) Group A - Known Human Carcinogen, 2) Group B1 - Probable HumanCarcinogen with sufficient animal data and limited human data, 3) Group B2 - Probable HumanCarcinogen with sufficient animal data and inadequate or no human data, 4) Group C - PossibleHuman 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 sitefrom February, 1984 through the most recent sampling round in June, 1995. All on-sitemonitoring wells are constructed in the overburden (12). Five monitoring wells (designated "MW")installed by Soils Engineering Inc. and Groundwater Technology Inc. between August, 1983 andFebruary, 1984 do not contain surface seals and may allow surface soil contamination through thewell shaft (5). An additional 25 monitoring wells (designated "AE") were installed byEnvironmental Drilling Inc. between January and September, 1991 and monitored by AriesEngineering Inc. (AEI). Fifteen more monitoring wells (designated "SH") were installed in June,1995 during additional site characterization conducted by Sanborn, Head Associates (see Figure 2for on-site monitoring well locations).

Contaminants associated with waste oil, fuel oil and organic solvents were detected at variouslocations throughout the site. Table 1 shows the contaminants of concern (COCs) detected inon-site monitoring wells giving both overall maximum detected values as well as the maximumvalue 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 takenfrom the June, 1995 round since the December, 1995 sampling was less comprehensive. No PCBswere detected in aqueous on-site monitoring well samples taken by Haley and Aldrich Inc. in1994 (13). SHA detected PCBs in only one on-site well (AE-4) at 1.0 ppb during groundwatersampling conducted in December, 1995. This detection may be the result of free productcontamination in the sample (2).

Some of the maximum detected values are derived from the February, 1984 sampling of theoriginal, 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 notbeen retested. The high concentrations of VOCs detected in MW-2 were of particular concerndue to its proximity to several residential drinking water wells located at residences on ShadyLane (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 freeproduct samples obtained from on-site monitoring wells detected a maximum of chlorinatedVOCs at 2,570 ppm (SH-5), non-chlorinated aromatic VOCs at 16,770 ppm (SH-10) and PCBsat 80 ppm (SH-6) (2).

A total of five groundwater contaminant plumes have been identified originating from sourceareas located on Parcel 1. Data included in the SHA report indicate that the former lagoon area isthe source of a major contaminant plume moving in the overburden and impacting off-siteresidential wells. Free-product thickness associated with this plume has been measured as high as5.4 feet (SH-5). Other groundwater contaminant plumes defined in the SHA investigation includethe plume thought to be originating from the 140,000 gallon UST and nearby ASTs. Free producthas 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. Freeproduct thickness associated with the SWRP 1 and SWRP 2 plumes have been measured atdepths up to 2.1 (AE-3) and 2.8 (SH-6) feet, respectively. A fifth source consisting of a stainedsoil area around monitoring well AE-12 has been associated with a less significant plume (2). Thisplume is cause for concern, however, since the source area is towards the southern border of thesite and proximal to off-site residential wells.

Overburden groundwater flow is estimated to be in an east-northeast direction across Parcel 1. OnParcel 2, however, overburden groundwater is expected to flow with Kelley Brook which turns tothe southeast. Several VOCs detected in Parcel 2 monitoring wells and residential wells locatedfurther south and southeast are consistent with those detected in Parcel 1 monitoring wells closerto the suspected source areas. Common contaminants found in Parcel 1 on-site wells, Parcel 2on-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 inon-site wells may also be contributing to residential well contamination via breakdown productssuch 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
ChemicalNameEPACancerGroupConcentration
(Max/MaxR)
(ppb)
HealthComparison Value
(ppb)
Source ofHealthComparison ValueLocationaDate
(Max/MaxR)
BenzeneA 780/7801 CREG SH-6/SH-6 6-95/6-95
Chloroethane NA 540/540NONE 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
Methylenechloride B2 440/ND 5 CREG MW-3 2-84/6-95
4-Methyl-2-pentanone(methylisobutylketone) D 300/200NONE NONE AE-11S/AE-8 1-91/6-95
Naphthalene D 460/4602 LTHA SH-10/SH-10 6-95/6-95
AlkylbenzenesbNA 2,670/2,670 50 NH DPHS SH-10/SH-10 6-95/6-95
PolychlorinatedBiphenyls B2 1/1 0.005 CREG AE-4/AE-4 12-95/12-95c
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
Vinylchloride 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 ActionLevel 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 aregrouped 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 EnvironmentalProtection Agency (EPA) between September and December, 1993. Table 2 gives maximumconcentrations of COCs in on-site surface soil. Five surface soil samples taken by AEI near the 86ASTs detected PCBs (Aroclor-1242 and Aroclor-1254) in all samples at concentrations rangingfrom 2.1 to 5.4 ppm (5). Soil samples taken by EPA detected PCBs (Aroclor-1248) beneath aleaking valve of AST No. 22 at a maximum of 1,500 ppm. EPA surface soil sampling alsodetected 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 thebase 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 wasrelocated along with approximately two feet of top soil to another area on-site. Surface soilconcentrations of Aroclor-1248 around Tank 22's former location, however, remained above 50ppm with a maximum of 500 ppm. This area was further excavated and backfilled with sandreducing PCB soil levels to below 50 ppm (17). Soil excavated from the original Tank 22 area isapparently stored on-site in soil piles or 55-gallon drums located behind the main building onParcel 1. Tank 22 was reportedly drained at some point during the sampling period butverification could not be found. Recent investigations revealed that some quantity of sludge, oiland 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 greaterthan 1 inch but less than 3,000 gallons of oil, 3 contained oil and water and 6 contained onlywater. The TWM sampling also included analysis for PCBs which detected 50-499 ppm in one ofthe 16 high volume tanks and 6 of the 62 low volume tanks. None of the 16 high volume tanksand one of the 62 low volume tanks contained oil at PCB levels greater than 500 ppm (2). Previoussampling of these ASTs detected a maximum PCB concentration of 6,700 ppm in Tank #51 froma sample taken on August 24, 1988. This tank was apparently leased to Dependable Waste OilInc. between September, 1986 and January, 1988 (3). As noted previously, the total contents ofthese 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 interceptortrench showed low levels of VOCs. A maximum concentration of chromium at 50 ppm wasdetected in the sand blast grit pile and maximum lead concentrations in surface soil of 250 ppmwere found near the former AST No. 22 and in SWRP 2. (5). A surface soil sample taken by NHDES from SWRP 2 in April, 1994 detected 5.1 ppm of Aroclor-1248 along with severalsemi-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 inMay and June of 1995. Maximum concentrations for all contaminant categories except PCBswere found in well boring sample SH-5 taken in the area of the former surface lagoon. Maximumcontaminant 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 andPAHs at 75 ppm. The maximum PCB level detected in SHA soil samples was 1.3 ppm taken froma test pit located near the former 140,000 gallon storage tank. Soil vapor analysis was conductedon-site at various depths by Haley & Aldrich Inc. in May, 1994 and by SHA in May, 1995. Soilvapor 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
ChemicalName EPA CancerGroup Max Concentration
(ppm)
HealthComparison Value
(ppm)
Source ofHealthComparison Value Date
4-Methyl-2-pentanone(methylisobutylketone) D 210a NONE NONE 30-March-92
Toluene D 12a 400 RMEG 30-March-92
Fluorene D 35 NONE NONE 25-April-94
Ethylbenzene D 180a NONE NONE 30-March-92
Polychlorinated Biphenyls
(Aroclor-1248)
B2 1,500b 1 EMEG 9-Sept-93
Phenanthrene D 37c NONE NONE 25-April-94
Phthalate,bis-2-ethylhexy NA 40c NONE NONE 25-April-94
2-Methylnaphthalene NA 45c NONE NONE 25-April-94
INORGANICS
Lead B2 250b,c NONE NONE 30-March-92
Copper D 50b,c NONE NONE 9-Sept-93
Chromium(VI/III) A/D 150d 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 borderof the site. These sample locations along with some which are upstream and downstream of thesite are considered off-site since they are at or near the site border but are outside the fencing andmore accessible to trespass.

A split sample taken from the interceptor trench in December, 1992 was analyzed for PCBs bytwo 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 showedmethyl ethyl ketone at 160 ppm. Total Waste Management Corp. also sampled the trench forPCBs and metals in June, 1993. Analysis of this sample by Laboratory Resources Inc. did notdetect 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 productand contained both water and free product from the trench. Hence, the PCBs detected are notwater 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 VOCsvolatilizing from indoor tap water into indoor air is considered to be similar to that of drinking thetap water. There are two on-site drinking water supply wells (bedrock) that have consistentlytested negative for VOC contamination. VOC volatilization from tap water into on-site indoor airis, therefore, not a pathway of concern.

An additional source of VOCs in indoor air is through intrusion of vapors directly fromcontaminated groundwater through building foundations. The potential for infiltration of VOCsinto indoor air from overburden groundwater was evaluated by comparing maximum on-sitemonitoring well (overburden) VOC levels to the GW-2 standards given in the MassachusettsContingency Plan (MCP). The MCP GW-2 standards are levels of contaminants in groundwaterbelow which would not contribute a significant indoor air hazard. The location of thegroundwater contaminant plumes identified in the SHA report indicate that only the abandonedbuilding is at risk for vapor intrusion from contaminated overburden groundwater since the mainbuilding 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 ofVOCs in groundwater may be inappropriate. SHA sampling in June, 1995 detectednon-chlorinated-VOCs at 8,010 ppm and chlorinated-VOCs at 280 ppm in free product samplesfrom on-site monitoring well AE-9 located at the south of end of the building. Free product wasalso present at this time in well AE-16 between the abandoned building and the interceptor trenchwhich contained non-chlorinated-VOCs at 4,140 ppm but did not contain chlorinated-VOCsabove detection. Vinyl chloride (130 ppb) and 1,2-dichloroethane (30 ppb) detected ingroundwater samples from nearby wells not containing free product (AE-5 and AE-8) exceedtheir 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 fromcontaminants in groundwater. The degree of this vapor intrusion and the resulting rise in indoorair VOC levels is dependant upon the contaminant, soil characteristics and the integrity of thebuilding foundation. Considering the high levels of chlorinated-VOCs detected in free productsamples from well AE-9 and the exceedance of the groundwater MCP GW-2 standards for vinylchloride and 1,2-dichloroethane in wells AE-5 and AE-8, indoor air VOC levels in the abandonedbuilding may be, and may have been in the past, above a level of concern. It should be noted thatthe 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 acrossParcel 1. Based on groundwater elevation and sampling of both on-site and off site wells, twocontaminant plumes appear to be moving southeast in the overburden aquifer on Parcel 2. Theplumes originate on Parcel 1 in the area of a former surface lagoon and a stained soil area nearmonitoring well AE-12. An extensive amount of free product has been detected (SH-5) on thewater table in the area of the former surface lagoon. No free product has been detected inmonitoring well AE-12. Table 3 summarizes the COCs for residential drinking water giving themaximum detected values in all residential wells (active and inactive) as well as the concentrationsof these COCs during the most recent sampling round (MaxR) conducted in December, 1995 andJanuary, 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 nolonger in use. The resident had apparently switched to an existing bedrock well sometime during1983. A second residential overburden well (well 6) located on Kelley Road directly abutting thesite was tested in May and June of 1990 and shown to be contaminated with petroleum relatedVOCs including a maximum concentration of benzene at 7.9 ppb. According to the NH DES sitemanager, these results may be related to a petroleum surface spill which had occurred earlier inthe year. This resident was subsequently connected to an on-site bedrock well later in the yearwhich has consistently tested negative for VOC contamination.

Sampling of residential drinking water by NH DES was expanded in September, 1991 to includeadditional wells southeast of the site on Kelley Road, Fran Avenue and Shady Lane as well as theHoward 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 and1,1-dichloroethane (1,1-DCA) at 5 ppb were detected in a single sample taken in May, 1992 froma "never used" overburden well (10C) located on Plaistow Road. Other previously undetectedVOCs were found in this same sample including 1,1,2 TCA at 41.0 ppb, trichlorotriflouroethaneat 2.40 ppb, chloroform at 1.10 ppb, 1,2-DCA at 5.0 ppb and tetrachloroethene (PCE) at 38.0ppb. A bedrock well drilled on this same property and sampled shortly thereafter detected tolueneat 1.0 ppb which is a common contaminant found in new bedrock wells. No other VOCs havebeen detected in this well.

Maximum VOC concentrations ever detected in currently active wells include vinyl chloride at2.6 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. Themost recent sampling of active residential drinking water wells in April, 1996 detected maximumconcentrations of vinyl chloride at 2.5 ppb, cis-1,2-DCE at 19.0 ppb, TCE at 3.5 ppb, 1,1-DCA at1.1 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. Thisoverburden 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 healthcomparison values in residential wells that had been used and/or are currently used for drinkingwater. Vinyl chloride has consistently been detected at or near the MCL in the Howard ManorCondominium bedrock well but has not been detected in any other off-site wells. No othercontaminants are currenlty exceeding their respective MCL.

Approximately thirty residential drinking water wells have been tested to date with a total ofeighteen showing measurable amounts of VOCs. Seven of these contaminated wells, locatedsoutheast of Parcel 2, (10A, 10B, 10C, 11, 12, 14A and 14B) are believed to be impacted by anoverburden contaminant plume moving east from the former lagoon area on Parcel 1 andsoutheast across Parcel 2. Three of these seven wells (10A, 10C and 14A) are not currently inuse. The petroleum related VOC contamination in the currently unused well 6 located on thenorthern border of the site is thought to be related to a single petroleum discharge event on thatborder of the property rather than from the plumes identified in the SHA report. Thecontamination 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 relatedcontaminant MTBE at a maximum of 38.0 ppb. This well is separated by Kelley Brook from thesite related petroleum discharge thought to be impacting well 6 and is, therefore, assumed to beimpacted by an alternate source. Wells 4 and 5 located on Kelley Road to the northwest of the sitewere also found to contain MTBE at a maximum of 2.4 and 2.7 ppb, respectively. MTBE is acommon well contaminant found in gasoline. It should be noted that there is an auto salvage yardupgradient of Kelley Road which may be contributing to the MTBE contamination on KelleyRoad. The remaining wells testing positive for VOC contamination were found to containchloroform at a maximum concentration of 2.7 ppb. Chloroform is a common laboratorycontaminant as well as a byproduct of well disinfection and its detection in these wells is notthought to be site related.

Metals in Residential Wells

Complete inorganic analysis of off-site residential well samples was limited to one sampling roundin April, 1994. Inorganics detected in off-site residential wells include arsenic, lead, barium andmercury. Maximum concentrations of mercury at 2.0 ppb and arsenic at 15.0 ppb were detected ina well on Fran Avenue (well 8). Subsequent sampling and analysis of this well for mercury only inAugust, 1994 detected no mercury. A maximum concentration of lead at 58.0 ppb (well 7B) wasdetected in a sample of a treated tap. Concurrent sampling of the same well from an untreated tapshowed only 10.0 ppb. Arsenic concentrations detected in both on-site and off-site media are notinconsistent with levels commonly seen in New Hampshire bedrock wells. There is no evidence ofany on-site source of arsenic. Limited soil sampling suggests slightly elevated lead concentrationsin on-site soil where surface discharge of waste oil is evident. Lead contamination in on-sitegroundwater 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 islocated across Kelley Brook from the site. The discrepancy between the untreated and treateddrinking 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 tothe NH DES site manager with no PCBs detected. PCBs are not very mobile within groundwaterdue to their low solubility in water. It is possible for PCBs to contaminate groundwater at verylow levels, however, depending upon the presence of other organic compounds which might actas a solvent. The lack of PCBs in on-site groundwater suggest that this possibility is notoccurring. On-site monitoring well samples taken by SHA in June 1995 detected PCBs in onlyone sample which was qualified as potentially contaminated with free product.


Table 3.

Contaminants of concern in residential wells near Beede Waste Oil, Plaistow, NHa
Chemical Name EPACancerGroup Concentration
(Max/MaxR)
(ppb)
HealthComparison Value
(ppb)
SourceofHealthComparison Value WellType Location Date
(Max/MaxRb)
Alkylbenzenesc NA 20.9/6.1 50 NHDPHS OB 6 4-95/6-95
Benzene A 7.9/ND 1 CREGOB 6 6-90/4-96
Chloroform B2 3.6/ND 6 CREGOB 4 9-92/4-96
1,1-Dichloroethane C 0.7/1.181 STATE OB 12 1-93/4-96
1,2-Dichloroethane B2 0.9/0.9 0.4 CREGBR/BR 12/12 9-95/4-96
1,2-Dichloroethylene D 35.7/19 70 (cis) LTHAOB/BR 14A/12 10-83/4-96
Isopropylbenzene NA 4.5/3.0280 NHDPHS 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 LTHAOB 7A/7A2-93/4-96
Toluene D 1.0/ND 1000 MCL BR 10D 5-92/4-96
1,1,1-Trichloroethane D 10.3/ND 200 LTHAOB 14A 10-83/4-96
Trichloroethylene B2 23.8/3.5 3 CREGOB/BR 14A/12 10-83/4-96
Vinylchloride A 2.6/2.5d 0.2 EMEG BR/BR 10B/10B 3-95/4-96
INORGANICS
Arsenic A 15.0/NA 0.02 CREGOB 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 resampledan no other wells contained these contaminants.
c = Alkybenzenes which do not have individual drinking water health comparison values aregrouped and compared to an NH DPHS derived interim drinking water comparison value. Thissample 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 inApril, 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 andJune, 1995. A single surface water sample (SW-1/AE) taken in Kelley Brook north of theinterceptor trench by AEI in January, 1991 detected high concentrations of VOCs as is shown inTable 4. Subsequent sampling by AEI in October, 1991 at two off-site locations in Kelley Brooklocated upstream (KB-1) and east (KB-2) of the site revealed no VOC contamination. Surfacewater samples taken by NH DES from Kelley Brook at the SW-1/AE location in October, 1991and 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 datawas 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 andbase-neutral compounds was conducted by NH DES in April, 1994. The NH DES samples aredesignated as NH in Figure 3a. This sampling round included an upstream sample (SW-1) whichwas non-detect for VOCs and PCBs. All of these samples were taken outside the chain link fenceand so will be considered off-site and from accessible areas. Several VOCs, polycyclic aromatichydrocarbons (PAHs) and Aroclor-1260 were detected in Kelley Brook surface water during thissampling round. A maximum concentration of Aroclor-1260 at 840 ppb was found at the samelocation (SW-2) as the sediment/soil sample which detected Aroclor-1260. Elevatedconcentrations 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, includingSW-1 which is upstream and assumed to be a representative background, were non-detect formetals (18). It should be noted that mercury was detected at 2.0 ppb in the SW-2 sample which isproximal (approximately 1,000 ft. south) to the Fran Avenue bedrock well that tested positive formercury at the same concentration two days later. No on-site sources of mercury have beenidentified.

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 samplein December, 1994 from inside containment booms on Kelley Brook that contained Aroclor-1260at 34 ppm and Aroclor-1248 at 6.0 ppm (8). The location of these EPA samples is estimated to bein the vicinity of the NH DES SW-2 location. The most recent surface water sampling of KelleyBrook was conducted by SHA in June, 1995 (samples designated SH-see Figure 3c). A maximumof 38 ppb non-chlorinated VOCs and 69 ppb chlorinated VOCs were detected in SW-4/SH. Onlyone 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 withearlier 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 benoted that these AWQC health comparison values consider both fish and water ingestion. Thewater ingestion term considers an average adult drinking water intake of 2 liters/day while thefish/shellfish ingestion term assumes an intake of 6.5 grams/day. The use of AWQC healthcomparison values is conservative in this case as there are no drinking water intakes in KelleyBrook or the Little River within fifteen miles of the site. There is, however, anecdotal evidencethat fishing does take place in both the Kelley Brook and the Little River. Kelley Brook is stockedwith trout every spring by the New Hampshire Fish and Game Department.


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

Table 4.

Contaminants of concern in off-site surface water at Beede Waste Oil, Plaistow, NHa
ChemicalName EPACancerGroup Max Concentration
(ppb)
HealthComparison Value
(ppb)
Source ofHealthComparison Value Location Date
Benzene A 110 1.2 AWQC SW-1/AEb 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 AWQCc 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 AWQCc SW-2 25-April-94
2-Methylnapthalene NA 220 NONE NONE SW-2 25-April-94
Methylenechloride B2 2 4.7 AWQC SW-1/AE 23-Jan-91
MethylEthylKetone 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
VinylChloride 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) AWQCc 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 surfacewater samples were analyzed for VOCs, PCBs, base-neutral compounds and metals (see Figure3a). Maximum concentrations of the COCs detected are shown in Table 5. Soil health comparisonvalues are listed as surrogates since sediment specific values are unavailable. Aroclor-1260 at 25ppm and arsenic at 51.4 ppm are the only detected contaminants which exceed their respectivehealth comparison values. The detection of Aroclor-1260 (25 ppm) at sampling location SW-2only, is consistent with the sole PCB detection at this same location in Kelley Brook surface waterby both NH DES and SHA. Lead was detected at a maximum concentration of 126 ppm andarsenic at a maximum of 51.4 ppm. An upstream sediment sample at location SW-1 wasnon-detect for VOCs and PCBs except for 1.1 ppm of benzo(a)pyrene. Concentrations of lead at10.6 ppm and arsenic at < 0.25 ppm were found in sediment sample SW-1 (18). Mean arsenic levelsin New Hampshire soils have been estimated by NH DPHS at 4.9 ppm with a range of 1.0 to 12.0ppm. 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/watersamples noted above detected PCBs at 4, 9 and 20 ppm. These samples were analyzed for PCBsonly 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, 1995and analyzed for VOCs, semi-volatile organic chemicals (SVOCs), pesticides and PCBs (Figure3b). 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. Lowlevels 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'-DDEat 120 ppb and 4,4'-DDT at 42 ppb. Maximum levels of SVOCs detected in sediment during theCDM 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 tothe surface water samples taken at the same time (Figure 3c). These samples were analyzed forVOCs, PAHs, PCBs and metals. Low levels of VOCs were detected in the area near theinterceptor 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 wasthe only sediment sample collected by SHA which detected PCBs (Aroclor-1260) at aconcentration of 2.2 ppm. Sample location SS-6/SH was the only location which revealed PAHcontamination. Barium was the only metal detected in sediment from the SHA samples at aconcentration of 80 ppb (2).


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

Table 5.

Contaminants of concern in off-site sediment near Beede Waste Oil, Plaistow, NH
ChemicalNameEPACancerGroup Max Concentration
(ppm)
HealthComparison Value
(ppm)
Source ofHealthComparison Value Location Date
Benz(a)anthracene B2 1.9 NONE NONE SS-6/SHJune-95
Benzene A 0.06 20,000 CREG SW-4 25-April-94
Benzo(b)fluoranthene B2 1.9 NONE NONE SS-6/SHJune-95
Benzo(a)pyrene B2 2.5 0.1 CREG SS-6/SHJune-95
Benzo(g,h,i)perylene D 0.6 NONE NONE SS-6/SHJune-95
sec-Butylbenzene NA 20 NONE NONE SS-2/SHJune-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
Dimethyldisulfide NA 0.006 NONE NONE SW-6 25-April-94
Dimethylsulfide NA 0.02 NONE NONE SW-3 25-April-94
Ethylbenzene D 30 5000 RMEG SS-4/SHJune-95
Isopropylbenzene NA 10 NONE NONE SS-4/SHJune-95
Naphthalene D 40 NONE NONE SS-4/SHJune-95
n-Propylbenzene NA 20 NONE NONE SS-4/SHJune-95
Phenanthrene D 0.4 NONE NONE SS-6/SHJune-95
Methylethylketone 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/SHJune-95
Vinylchloride 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 toVOCs volatilizing from indoor tap water into indoor air is considered to be similar to that ofdrinking the tap water. This risk is considered significant when VOCs in residential wells that arebeing used as a source of tap water exceed their respective drinking water health comparisonvalue (see Table 3). Maximum levels of benzene, 1,2-DCA, TCE and vinyl chloride exceed theirrespective drinking water health comparison values. The risk associated with inhalation andingestion 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 fromcontaminated groundwater through building foundations. The potential for infiltration of VOCsinto indoor air from overburden groundwater was evaluated by comparing maximum residentialoverburden 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 wouldnot contribute a significant indoor air hazard. Vinyl chloride is the only VOC that exceeded itsMCP GW-2 standard. The maximum vinyl chloride level of 2.6 ppb detected in the HowardManor Condominium bedrock well (10A) exceeds the MCP-GW-2 standard of 2 ppb. Vinylchloride has never been detected in residential overburden wells, however, and has oftenfluctuated below the 2 ppb level. NH DPHS does not consider vapor intrusion of vinyl chloridefrom groundwater into residential indoor air to be significant.

Overburden well 6 which is located in a basement has shown consistent detection of somealkylbenzenes for which there is no MCP GW-2 standard. Alkylbenzenes for which standards doexist are not included in this group and are evaluated separately. Well 6 is in the direct path of acontaminant 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 betweenMay, 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 theNH DPHS interim drinking water standard of 50 ppb and have since decreased from initialdetection in October, 1993 at 35.7 ppb to 20.9 ppb in April, 1995 and 6.1 in June, 1995. NHDPHS 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 analyzedaccording 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 asafety hazard. The building has been vandalized on more than one occasion with evidence ofarson. Although significant extensions of existing chain link fencing have restricted access to boththis building and the drum storage area behind the main building, the site itself remains accessiblesince the outer fence does not extend completely around Parcel 1. There is also access to the sitevia a hole in the fence on the southeastern border of Parcel 2 which has apparently been used fortrespassing in the past (23).

PATHWAYS ANALYSIS

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

Completed Exposure Pathways

On-Site

Trespassing represents the only current on-site completed exposure pathway at the BWO site. Nobusinesses are currently operating on-site but as of January, 1995 the owner has submitted anapplication for occupancy to the town. The site is partially secured by fencing which has proveninadequate in the past as evidenced by incidences of trespassing and vandalism. Althoughadditional fencing has been installed which should mitigate such occurrences, the site remainsaccessible since the fence does not extend completely around the perimeter of the site. The drumstorage area and the abandoned building are both enclosed by barbed wire fencing as ofSeptember, 1994. There are no schools or recreational facilities nearby which would suggest thepotential for significant and recurrent trespassing in the future. There is evidence of trespassthrough a hole in the fence on the southern border of Parcel 2 which is proximal to the HowardManor Condominiums (23). Trespassers on-site may be exposed to PCBs, VOCs and otherpetroleum hydrocarbons in soil via incidental ingestion and dermal contact. Surface water on-siteis restricted to the interceptor trench and the surface lagoons which contain only minimal amountswater. 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 whenParcel 1 was first used as a location for an oil storage and distribution facility. Testing of on-sitedrinking water wells since October, 1991 have been negative for VOCs. On-site monitoring wellsamples taken since February, 1984, however, indicate significant VOC contamination suggestingthat past workers may have been exposed to VOCs in drinking water. Other potential pathwaysfor past worker exposure to VOCs and other petroleum hydrocarbons include inhalation of fumesand contaminated fugitive dusts, incidental ingestion of and dermal contact with contaminated soiland direct dermal contact with waste oil. PCBs have been detected at levels as high as 6,700 ppmin waste oil and 1,500 ppm in surface soil. Potential pathways of PCB exposure to past workersinclude incidental ingestion of and dermal contact with PCBs in soil and waste oil. Past andcurrent site conditions such as stained soil, leaking storage tanks and evidence of an open surfacelagoon suggest careless handling of fuel and waste oil which may have resulted in significantworker exposure. The exposed population via this pathway is estimated to be no greater than 100workers over the history of the site.

Off-Site

Groundwater

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

Current exposure to VOCs in residential drinking water is below a level of concern. Pastexposure of Howard Manor Condominium residents (well 10B) to vinyl chloride in drinking waterat or above EPA's maximum contaminant level (MCL) was limited by NH DES through thesupply 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 tovinyl chloride. The effectiveness of this device has been verified by sample analyses whichdetected no VOCs. Ingestion, dermal and inhalation exposure to TCE and cis-1,2-DCE indrinking water is occurring at levels currently below health comparison values at two residenceson Shady Lane (wells 12 and 14B) and at the Sawyer's Banquet Center (well 11). No currentrestrictions are recommended by NH DPHS relating to the use of these wells. Some of theseresidents are reportedly using bottled water at their own expense.

A completed exposure pathway exists for past exposure to VOCs in drinking water. Pastexposure of Howard Manor Condominium residents to vinyl chloride via the dermal andinhalation pathways has occurred at levels exceeding the respective health comparison value. Thisexposure may have also included the ingestion pathway and could have occurred at higher levelsthan are now being detected. Past exposures to cis-1,2-DCE and TCE were also likely for usersof the well at the Sawyer's Banquet Center since these compounds have consistently beendetected in this well since initial sampling. VOCs detected at Sawyer's Banquet Center have neverexceeded their respective health comparison values or MCLs and NH DPHS has notrecommended any restrictions on the use of this well. Residents using overburden well 6 andoverburden well 14A were exposed to benzene and TCE, respectively, at levels exceeding theirhealth comparison values for an unknown length of time. These residents obtained an alternatewater supply following detection of these contaminants.

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

Contaminants detected in residential wells to the southeast of Parcel 1 are consistent with thosefound in on-site overburden monitoring wells. Residential well contamination also appears to beconsistent with the general direction of overburden groundwater flow across the site. Althoughmost of the maximum concentrations of VOCs have been detected in overburden wells, there hasalso been contamination detected in bedrock wells. The contaminants detected in residentialbedrock wells are also consistent with potential sources discovered on-site.

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

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

Soil/ Sediment

A past, present and future completed exposure pathway exists for ingestion of and dermal contactwith arsenic and PCBs in soil/sediment along Kelley Brook east of the BWO site. Off-sitesampling 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 takenoutside 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 andbenzo(a)pyrene at 2.5 ppm exceed their respective soil health comparison values. Lead was alsodetected in Kelley Brook sediment at 126 ppm but is not expected to cause any appreciableincrease in blood lead levels of children who recreating in the area (24). Several other contaminantsare listed as COCs in sediment due to the lack of a health comparison value with which to rulethem out. The maximum detected level of these COCs is very low, however, and their presence isnot anticipated to contribute significantly to overall risk. The sampling area is heavily wooded andbordered 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 fiftypersons.

Surface Water

A past, present and future completed exposure pathway exists for ingestion of and dermal contactwith contaminated surface water in Kelley Brook east of the BWO site. Several contaminantsdetected 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 toseasonal variations in water content which would limit surface water contact while increasing thepotential for soil/sediment contact. Since recreators/trespassers are estimated to visit the areaduring the low water months (i.e. summer), the off-site surface water pathway is not expected tocontribute significantly to the health risk of recreators/trespassers. The exposed populationthrough this pathway is estimated to be less than fifty.

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

Potential Exposure Pathways

On-Site

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

A past potential exposure pathway exists for former workers through inhalation of VOCs whileworking in the abandoned building. An extensive amount of free product associated with theUST/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 containssignificant amounts of non-chlorinated and chlorinated VOCs. The free product identifiedthroughout the site is characterized as a light non-aqueous phase liquid (LNAPL) that is floatingon the water table. The VOC component is, therefore, available to volatilize directly from the freeproduct. The amount of VOC gas which might penetrate into the building is dependant upon thecharacteristics of the buildings foundation which are unknown. It is also unclear whetheremployees worked extensive hours in this building and, if so, whether the plume and free productexisted during such periods. The exposed population via this pathway is estimated to be nogreater 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 pastpotential exposure pathway via ingestion of drinking water. The users of this well which testedpositive for mercury at the MCL in April, 1994 were advised by NH DPHS at this time to ceasedrinking the water and minimize washing use. These residents are apparently drinking only bottledwater and their well has tested negative for mercury since the initial detection. The lack ofconfirmation of the initial mercury detection puts this past exposure in doubt. NH DPHS has keptthe recommended restriction on drinking, however, and the residents have indicated that they willcontinue to use bottled water.

Residents who may have been exposed in the past to site related contaminants in groundwaterinclude those who are now being exposed as well as those who have wells as close or closer tothe site not currently showing contamination. Also, any person living at these residences prior tothe residential well sampling may have been exposed in the past. This population is estimated tobe 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 beenraised 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 ofPCBs in areas proximal to the 86 ASTs. PCBs are very stable compounds with low volatility andsolubility causing them to be very persistent in soils. Should further soil characterization showsignificant and widespread PCB soil contamination, then the soil migration pathway will then needto be investigated for those residences proximal to the contaminated areas. The presence ofvolatiles in the soil is not anticipated to pose a hazard via off-site soil migration. The population atrisk from this potential exposure pathway is limited to abutting residents estimated to be no morethan fifty persons.

Fish Ingestion

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

Mercury is another contaminant detected in Kelley Brook surface water that can bioaccumulate infish. Mercury was detected in only one sample, however, taken from Kelley Brook. Consideringthat this surface water sample contained mercury at the detection limit of 2 ppb and that mercurywas not found in any other samples from Kelley Brook (surface water or sediment), mercurybioaccumulation in Kelley Brook fish is not expected to be impacted by the site. It should benoted, however, that a fish ingestion advisory is in effect for all inland water bodies located inNew Hampshire due to elevated levels of mercury in fish. Please contact the Bureau of HealthRisk 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) forPCBs. The New Hampshire Fish and Game Department has indicated that it will continue to stockthe Kelley Brook pending recommendations from NH DPHS and NH DES. The amount of fishingin the Kelley Brook and Little River is difficult to estimate but is not likely to exceed more thanone-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 mayresult from exposure to the contamination described previously. Contaminants which exceededtheir media-specific health comparison values are evaluated below for both carcinogenic andnon-carcinogenic health effects. This evaluation is based on current data and is subject to changeshould more data become available relative to the site and/or the toxic potential of thecontaminants.

In order to evaluate the potential for non-carcinogenic adverse health effects resulting fromexposure to contaminated media (i.e. air, water, soil and sediment), a dose was estimated for eachcontaminant. These doses were calculated for situations (scenarios) in which nearby residents oron-site workers might come into contact with the contaminated media. The estimated dose foreach 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-carcinogenicadverse health effects are anticipated (so called "safe" doses) and are derived from toxic effectlevels obtained from human population and laboratory animal studies. These toxic effect levels canbe 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 MRLor RfD indicates only the potential for adverse health effects. The magnitude of this potential canbe inferred from the degree to which this value is exceeded. If the estimated exposure dose is onlyslightly above the MRL or RfD, then that dose will fall well below the toxic effect level. Thehigher 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 dosesimilar to that described above and multiplying it by the cancer potency factor, also known as thecancer slope factor. Some cancer potency factors are derived from human population data. Othersare derived from laboratory animal studies involving doses much higher than are usuallyencountered in the environment. Use of animal data requires extrapolation of the cancer potencyobtained from these high dose studies down to real world exposures which carries muchuncertainty. Current thinking suggests that there is no "safe" dose of a carcinogen and that a verysmall 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, areuseful in determining the significance of a cancer threat since any level of a carcinogeniccontaminant carries an associated risk. It should be noted that mechanistic studies are underwayto 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 tainteddrinking water can be readily calculated using some generally accepted parameters. Dermaluptake and inhalation of vapor resulting from washing activity is harder to estimate. Based on themost recent sampling data from residential drinking water wells still in use, it is apparent thatexposure to several VOCs is presently occurring. In some cases, this exposure has been minimizedby the use of bottled water. It should be noted that exposure to VOCs via drinking water haslikely occurred in the past and will likely occur in the future should use of contaminated water notbe eliminated. Future increases in VOC drinking water concentrations along with past exposurecould increase the potential for the adverse health effects discussed below. It should also be notedthat many chlorinated VOCs have similar target organs (e.g. liver) and should several appear atindividually acceptable levels, the potential for adverse health effects may still exist due to theircombined presence.

Table 3 gives the VOCs detected in active and previously used residential drinking water wellsthat 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 onlycontaminants exceeding their media specific health comparison value. Vinyl chloride is the onlyVOC currently exceeding its respective MCL and continues to fluctuate above and below thislevel 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 waterposes no acute or intermediate health hazards. Based on a chronic adult ingestion and inhalationexposure scenario, a daily intake of vinyl chloride 4-fold higher than ATSDR's chronic oralminimal risk level (MRL) was estimated. This MRL was obtained from a lowest observed adverseeffect level (LOAEL) divided by a "safety" factor of 1,000. The LOAEL for vinyl chloride isbased on liver effects in rats (25). It is not certain how much damage these effects would do to liverfunction. The estimated exposure of residents to vinyl chloride is expected to result in a very lowpotential for chronic non-carcinogenic adverse health effects since the estimated dose is 250-foldbelow the toxic effect level (i.e. the LOAEL).

The carcinogenic status of vinyl chloride is currently under review by an EPA risk assessmentworkgroup. A quantitative estimate of the cancer risks associated with the ingestion of thisamount of vinyl chloride in drinking water was made, however, based on its previousclassification as a Group A known human carcinogen (26). The classification of a substance as aknown human carcinogen signifies that sufficient evidence exists linking that chemical to cancer inhumans. The dose estimate for cancer endpoints is based on a chronic 30-year adult ingestion andinhalation exposure averaged over a 70-year lifetime. Quantitation of cancer risk resulting fromvinyl chloride exposure, however, is reliant on extrapolation of high dose tumor incidence inlaboratory animals to real world low dose exposures. Such extrapolation carries much uncertaintyand can only approximate the increase in cancer risk to humans. The cancer risk associated with athirty year ingestion exposure to the maximum levels of vinyl chloride detected in residentialdrinking water wells represents a low increase in cancer risk.

The exposure to vinyl chloride evaluated above was limited by the supply of bottled water fromJuly, 1994 to May, 1995 to the users of the only water supply in which vinyl chloride has beendetected. Recent installation of a POE treatment device on this well in February, 1995 hasdecreased both ingestion and inhalation exposures below a level of concern. Although the dermalpathway was not evaluated quantitatively, it is not thought to contribute significantly to theoverall exposure. It should be noted that the potential exists for vinyl chloride contamination toincrease 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 fluctuationsin concentration. The performance of the POE has been verified by two rounds of samplingfollowing installation which detected no VOCs.

Trichloroethylene (TCE)

TCE was detected above its respective health comparison value in a currently inactive butformerly used residential drinking water well. A daily intake more than 100-fold lower thanATSDR's intermediate oral MRL was estimated based on a chronic ingestion and inhalationexposure to TCE at the maximum detection level of 23.8 ppb. This comparison indicates that noacute or intermediate adverse health effects are anticipated at this level of exposure. Although achronic oral MRL or RfD is not available, the limited chronic exposure animal studies availableindicate that LOAELs and NOAELs are well above the estimated intake given for this exposurescenario (27).

TCE was previously classified by the EPA as Group B2 probable human carcinogen based onadequate 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 ofTCE as a probable human carcinogen, evidence does exist showing TCE to be carcinogenic inanimals. As a result, quantitative cancer assessment was performed based on animal data providedby EPA prior to the ongoing review. TCE is currently being detected at a maximum of 3.5 ppb inan active residential drinking water well. No significant cancer risk is expected to result fromexposure to current levels of TCE in drinking water. The maximum level of TCE detected in aformerly used well (23.8 ppb) would result in a slight increase in cancer risk assuming a 30 yearexposure duration at this concentration.

Benzene

A maximum of 7.9 ppb benzene was detected in a formerly used overburden well believed to beimpacted by a discrete surface spill in early 1990 that occurred along the northern border of thesite. Use of this well as a drinking water source was discontinued in June, 1990 followingdetection of the benzene and other petroleum related VOCs. Since this contamination is thoughtto be related to this specific and discrete spill, the exposure duration in this scenario is thought tobe less than one year. Assuming a worst case scenario of a child exposed for 5 years at themaximum detected level of 7.9 ppb in drinking water, no non-carcinogenic adverse health effectsare anticipated to result from this exposure. Although no MRL or RfD is currently available forbenzene, the estimated dose calculated from the scenario noted above does not exceed a chronicRfD 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 adequatehuman and animal data. Long-term exposure of workers to benzene in air has resulted in anincreased incidence of leukemia. High dose laboratory animal testing has shown increases invarious tumors including lymphomas and leukemias (29). No significant increase in cancer risk isanticipated 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-DCAat 0.9, 0.8 and 0.9 ppb in the same active well. A daily intake more than 1000-fold lower thanATSDR's intermediate oral MRL was estimated based on a chronic ingestion and inhalationexposure to 1,2-DCA at a maximum of 0.9 ppb. This comparison indicates that no acute orintermediate adverse health effects are anticipated at this level of exposure. Although a chronicoral MRL or RfD is not available, the limited chronic exposure animal studies available indicatethat 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 to1,2-DCA at these levels in drinking water.

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

Metals in Residential Drinking Water

Arsenic

A maximum concentration of arsenic at 15.0 ppb was detected in a single residential drinkingwater well on Fran Avenue. Based on a chronic adult ingestion only pathway, a daily intake ofarsenic slightly higher than ATSDR's chronic MRL was estimated. The MRL is based on aNOAEL 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 higherthan 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-foldlower than the LOAEL, no non-carcinogenic adverse health effects are anticipated. Thecontribution 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 toexposure.

A low increase in cancer risk is associated with a 30-year adult exposure to arsenic at the levelsdetected. Arsenic is classified by EPA as a Group A known human carcinogen. This classificationis based on two studies. One study involved the inhalation exposure of smelter workers whoexhibited an increased incidence in lung cancer mortality. More relevant studies examinedpopulations in Taiwan (same population used to derive the MRL discussed above), Chile andMexico in which the exposure occurred through the ingestion of drinking water. Increases in skincancer were observed in these drinking water exposed populations when compared to anappropriate control population. Studies done on populations within the United States haveshowed 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 cancerrates found in those done outside the U.S. (29). It is important to note that skin cancer is oftensuccessfully treated and does not usually result in death. There is some evidence, however, whichindicates 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 maximumlevel of arsenic. The sample analysis for mercury represents a measure of total mercury. Most ofthis total is expected to be inorganic as opposed to organic mercury (e.g. methyl mercury) (32). Ingeneral, inorganic mercury is less bioavailable and less toxic than organic mercury. The targetorgan for inorganic mercury toxicity is the kidney while the most sensitive toxic endpoint formethyl mercury exposure is the nervous system. A chronic exposure to the maximum amount ofmercury detected in residential drinking water (15 ppb) is not estimated to exceed oral RfD'sderived by EPA for the organic forms phenyl mercuric acetate and methyl mercury or theinorganic form mercuric chloride. Since the estimated dose at the maximum detected level ofmercury does not exceed RfDs for neither the inorganic nor organic forms, no adverse healtheffects 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 aGroup D (not classifiable) carcinogen by the EPA (29). Limited data indicates an increase of renaltumors in rats fed high levels of methylmercury and there is limited evidence that mercuricchloride (an inorganic form) is carcinogenic in animals. It is likely that the form of mercurypresent in drinking water is inorganic. Considering the low level of mercury detected and that ithas been detected only once in one residential well, no significant increase in cancer risk isanticipated 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 whichhas since tested negative. The residents of this household have reported that they are drinkingonly bottled water and will continue to do so despite a recent negative sampling result. NH DPHShas maintained a recommendation that these residents not drink their well water pending furthernegative testing for mercury. The dermal pathway was not considered but is not expected tocontribute significantly to overall exposure. The contribution of the inhalation pathway formercury 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 oneuntreated, at a residence on Kelley Road. Lead concentrations of 58.0 ppb and 10.0 ppb weredetected in samples taken from the treated and untreated samples, respectively. This samplingrepresents the only lead detected in residential wells near the BWO site and is not thought to besite related. Young children (ages 0-6 years) represent a very sensitive exposure population forthe neurotoxic effects of lead. Low levels of lead in the blood of children have been associatedwith a decrease in IQ and other behavioral effects. It is unknown whether any children live at thisresidence. EPA has set an action level of 15.0 ppb which was exceeded by the lead concentrationin the treated tap. The treatment system associated with this tap is unknown but is thought to be amineral 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 evaluationassumes that other routes of lead exposure (i.e. lead in dust, paint, food and soil) are at averagebackground levels. If other sources of lead are present above background, then the contribution ofthis 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 littlehuman data to substantiate the kidney tumors noted in high dose rat studies (29). Although noquantitative analysis of the cancer potential of lead was made, evaluation of the non-carcinogeniceffects of lead is assumed be protective of health. The non-carcinogenic effects of lead can occurat very low levels of exposure and are thought to be the most sensitive and important toxicendpoint of lead exposure.

PCBs in Kelley Brook Sediment and Surface Water

PCBs are mixtures of various chemicals of similar structure (congeners) identified by their tradename, Aroclor, followed by a four digit number. The first two digits represent the number ofcarbon atoms (12) while the second two digits give the percent by weight of chlorination for thecongeners in that mixture. In general, PCB toxicity increases with the degree of chlorination in themixture (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 inthe Kelley Brook area. An estimated daily intake via incidental ingestion of and dermal contactwith a maximum of 25 ppm PCBs found in soil/sediment along Kelley Brook did not exceedATSDR's relatively conservative chronic MRL. This estimated dose considered atrespassing/recreating older child exposed for 36 days per year over a 10-year period. The MRL isbased on a LOAEL for immunological effects relating to decreased IgG and IgM responsefollowing chronic oral exposure of Aroclor-1254 via oil gavage to female rhesus monkeys (25). TheMRL for Aroclor-1254 was used as surrogate to estimate the potential for non-carcinogenicadverse 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 thisclassification was determined to be adequate by EPA while available human data was deemedinsufficient. Several high dose animal studies have demonstrated the ability of PCBs to induceliver carcinomas. Cancer risk was quantified using and EPA derived cancer slope factor based onan animal bioassay of rats fed Aroclor-1254 (29). Levels of PCBs detected in soil/sediment near theKelley 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 andincidental 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 thesediment sample which showed the maximum level of PCBs. It should be noted that surface watersampling, especially in a shallow, running stream, is subject to sediment contamination whichcould explain the PCB levels in this surface water sample and not in any others. Although somesurface water exposure could occur to trespassers/recreators in the brook, this exposure is notexpected to result in any significant ingestion of surface water. The brook is not swimmable in anyarea adjacent to the site and is apparently very low during the summer when exposures areestimated to be occurring. Also, the contribution of surface water ingestion would be insignificantcompared to the soil/sediment pathway. Dermal contact with PCBs in surface water could occurin this scenario but has not been quantified due to the lack of an acceptable method. Although thispathway was not evaluated, dermal contact with surface water in this scenario is expected to beminimal.

The movement of PCB contaminated fugitive dusts from on-site surface soil to nearby residentialyards also poses a potential pathway for PCB exposure. Exposure via this pathway isindeterminate due to the lack of off-site and insufficient on-site soil sampling data. Exposure viaPCB contaminated fish ingestion also represents a potential exposure pathway. Although PCBsediment contamination appears to be localized to the area of Kelley Brook where free product isbeing discharged, some sampling has indicated low levels of PCBs in sediment downstream of thisarea. The NH DES Biology Bureau will be sampling Kelley Brook macro invertebrates (summer1996) and fish (fall 1996) for PCB analysis. NH DPHS will await the results of this sampling andanalysis 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 dermaluptake from arsenic in soil/sediment along the Kelley Brook. The trespasser/recreator exposurescenario outlined above was used to estimate a daily intake well below ATSDR's MRL forarsenic. This dose estimate was based on incidental ingestion and dermal contact with a maximumof 51.4 ppm arsenic in soil/sediment from the Kelley Brook area. As noted above, the MRL isbased on a NOAEL observed in a large Taiwanese population exposed primarily through drinkingwater. 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 andlevels of arsenic in the soil/sediment. Arsenic is classified by EPA as a Group A known humancarcinogen. 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 populationsto 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 weredetected in one sample along the brook, both the lack of significant exposure to surface water aswell 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 betterunderstood by considering the population size required for such an estimate to result in a singlecancer case. For example, a low increase in cancer risk indicates an estimate of one cancer caseper ten thousand persons exposed over a lifetime, a very low estimate might result in one cancercase per several tens of thousands exposed over a lifetime and a slight estimate would require alifetime exposed population of several hundreds of thousands. NH DPHS considers cancer risk tobe not significant when the estimate results in one cancer per one million or more people exposedover a lifetime.

B. Health Outcome Data Evaluation

Site specific cancer incidence data gathered for the town of Plaistow between July, 1987 andJune, 1993 was obtained from the NH DPHS Chronic Disease Epidemiology Program. Cancerincidence rates were not available for Plaistow and the number of cases were too few to beage-adjusted which precluded a comparison with the age-adjusted rates generated by the state. Acomparison between Plaistow and the state was made, however, for site specific percentages oftotal cancers. Of the total 134 cancer cases recorded from Plaistow during this period, breastcancer accounted for 21.6% (29 cases), non-Hodgkin's lymphoma for 6.7% (9 cases) andleukemia for 3.7% (5 cases). These percentages are higher than those of the state which recorded16.8% breast cancer, 3.3% non-Hodgkin's lymphoma and 1.8% leukemia out of a total of 16,421cancer cases between 1987 and 1990. There were no other remarkable differences noted for othercancer sites.(10, 11)

It is important to note that this comparison does not correct for potential population differencesbetween Plaistow and the state. Differences in population characteristics could slant the numberspresented above. For example, a higher Plaistow female population between the ages of 40 and 50years could generate a higher percentage of breast cancer than the state suggesting a higherincidence. This could be misleading since the state value may be lower simply because the statepopulation contained a lower percentage of women at risk for breast cancer. Also, the data is notpresented as an incidence rate but as a percentage of cancers diagnosed over a 7 year period andtherefore, is not sensitive to population changes during this period. This data also has obviouslimitations 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 availabilitysession held at the Plaistow Town Hall on September 15, 1994. These concerns are listed andresponded to below.

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

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

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

These concerns will be forwarded to NH DES for appropriate follow-up. Such concerns can onlybe addressed by proper characterization of all on-site media and potential sources ofcontamination. NH DPHS recommended in the Draft for Public Comment version of this publichealth assessment that sources of contamination previously identified be further characterized.This document contains further site characterization data. Recommendations remain, however, forfurther 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 thehealth of her daughter. She said that they had stopped drinking the water from herbedrock 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 rightshave been violated.

Since her well has not been tested, discussion of potential health effects for the resident or herdaughter is not possible. NH DPHS did advise the woman that by not drinking the well water thepotential for exposure to herself and her daughter was significantly reduced. This resident wasadvised to have her well tested for VOCs. Requests for well tests should be directed to the NewHampshire Department of Environmental Services (NH DES) site manager at the GroundwaterProtection 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 notidentified in preliminary investigations by the state or EPA. There are, however, obvious explosivehazards associated with fuel storage and the past vandalism and attempted arson which has beenreported on-site. This building has been secured under NH DES authority by a barbed wire fenceas of September, 1994

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

The well in question has tested positive for mercury at the MCL (2 ppb). This resident wasadvised by NH DPHS not to drink this water and to minimize washing uses. Theserecommendations were accompanied by health effects information pertinent to the exposure.Subsequent testing of this well has not detected mercury. Mercury exposure via drinking waterthrough non-ingestive pathways is difficult to quantify. Exposure can be greatly reduced by notdrinking the water and minimizing hot water use. Mercury in its inorganic form is known to betoxic 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 whichborders the site. The residents wished to know whether this could be site related. Concernfor the surrounding ecology was also expressed by this couple who noticed a squirrel ontheir 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 NHDES which has taken surface water samples along Kelley Brook. It should be noted that certainbacteria commonly associated with wetlands can produce a similar sheen. The local ecology maywell 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 todetermine if any more unaccounted for 55-gallon drums exist on the site. Another residentclaimed that drums have been disposed of on the site.

The site has been probed on three occasions with ground penetrating radar (GPR). GPR is aneffective method for detecting underground metallic structures such as pipes, drum and storagetanks due to the strong electrical contrasts of the metal with surrounding media. The most recentGPR survey was performed in May, 1995 by Kick Geoexploration as part of a sitecharacterization conducted by Sanborn, Head & Associates for NH DES. Five areas wereselected for this survey based on ground surface disturbances, reported dumping andenvironmental sampling data. Crushed tanks, metal pipes, re-bar and a hot water heater wereexcavated near the southwest corner of the site. A large underground storage tank (UST) wasuncovered in the wooded area towards the southern border of the site. This tank did not containhazardous waste. A large amount of metal debris was also excavated along with a crushed drumnear 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 wellcontamination (probably site related) wished to know if he can be held legally liable for anyadverse 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 aprevious owner of the site.

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

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. Lowlevels of arsenic and mercury were found in one well but are not thought to be site related and arenot metals associated with car battery acid. Lead is the primary contaminant of concern in carbattery acid and has been found in elevated concentrations in on-site groundwater samplescontaining free product. Lead detected in a single well north of the site across from Kelley Brookis not thought to be site related, however, since it is in the overburden groundwater which isexpected to discharge into the brook.

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

This potential exposure pathway is difficult to quantify. Further characterization of on-site soilcontamination at least is needed in order to determine if this pathway poses a health threat tonearby residences. Of the contaminants detected on-site to date, PCBs are the only contaminant ofconcern for this exposure pathway due to low volatility, strong soil sorption and extremeenvironmental persistence. PCBs can concentrate in fat tissue, are thought to be hormonedisruptive and are classified by the EPA (Environmental Protection Agency) as a Group B2probable human carcinogen. NH DPHS is exploring options for off-site soil sampling to betterassess 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 alsoexpressed concern that a potential new tenant on-site is affiliated with the present owner. Arelated question was raised as to whether another on-site business would add to the existinghazard.

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

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

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

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

Many surface discharges are expected to have occurred on this site. Deliberate discharges havenot been documented at the site. There is considerable evidence, however, that large quantities ofwaste oil have been discharged to a former surface lagoon thought to be the source of significantgroundwater contamination. There is also evidence of surface discharges to two surface waterrunoff pits located on the site.

15. Concern over a leaking AST (Above-ground Storage Tank) was expressed. Documentedleaks have occurred in on-site ASTs. Tank No. 22 which has since been removed had a history ofvalve leaks which apparently contaminated the soil beneath with PCBs. Tank No. 11 also had aleak 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 ofwaste oil throughout the site.

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

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



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