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PUBLIC HEALTH ASSESSMENT

SYOSSET LANDFILL
OYSTER BAY, NASSAU COUNTY, NEW YORK

APPENDIX A

Figure 1
Figure 1.

Figure 2
Figure 2.

Figure 3
Figure 3.

Figure 4
Figure 4.

APPENDIX B

Table 1.
Syosset Landfill.
Summary of On-Site Soil Gas (Volatile Organic Compounds) Data
Remedial Investigation.
(All values in parts per billion)


Compound Range
of
Concentration
Comparison
Value for
Ambient Air**
Source***

*vinyl chloride <1 - >400 0.005 EPA CPF
*chloroethane <2 - >400 NA
*methylene chloride <4 - 180 0.56 ATSDR CREG
trichlorofluoromethane <3 - 29 125 EPA RfC
*1,1-dichloroethene <3 - 8 0.005 ATSDR CREG
1,1-dichloroethane <3 - 55 125 EPA RfC
1,2-dichloroethene <3 - 18 18 EPA RfD
*chloroform <2 - 12 0.01 ATSDR CREG
1,1,1-trichloroethane <2 - 4 180 EPA RfC
*bromodichloromethane <2 - 2 0.005 EPA CPF
*trichloroethene <3 0.11 EPA CPF
*tetrachloroethene 2 - 11 0.26 ATSDR CREG
chlorobenzene <2 4.3 EPA RfC
*1,4-dichlorobenzene <2 0.001 EPA CPF
*benzene <2 - 180 0.031 ATSDR CREG
*toluene 23 - 240 105 EPA RfC
*ethylbenzene <2 - 250 230 EPA RfC
*m-xylene <3 - 230 161 EPA RfC
o- + p-xylene <5 - 108 161 EPA RfC


Samples analyzed using US EPA Methods 601, 602.
NA - not available
*Contaminant selected for further evaluation.
**There are no comparison values for soil gas (below soil surface). Soil gas data were compared to comparison values for ambient air (above soil surface) to select contaminants for further evaluation. Comparison values determined for a 70 kilogram adult who inhales 20 cubic meters of ambient air per day.
***EPA RfC = EPA Reference Concentration
EPA RfD = EPA Reference Dose
EPA CPF = EPA Cancer Potency Factor
ATSDR CREG = ATSDR Cancer Risk Evaluation Guide


Table 2.
Syosset Landfill.
Summary of Soil Gas Data - Passive Gas Ventilation System
March 1983
(All values except methane in parts per billion)


Compound Range of
Detection
(excluding
non-detects)
Comparison
Value for
Ambient Air**
Source***

*methane (ppm) 2 - 80,000 NA
*vinyl chloride 3 0.005 EPA CPF
trans-1,2-dichloroethene 3 - 4 18 EPA RfD
1,1,1 - trichloroethane 2 - 3 180 EPA RfC
*trichloroethene 1 - 5 0.11 EPA CPF
*tetrachloroethene 3 0.26 ATSDR CREG
*benzene 5 - >60 0.031 ATSDR CREG
*toluene 1 - 1,300 105 EPA RfC
*ethylbenzene 170 - 1,200 230 EPA RfC
*xylene 1,500 - 2,200 161 EPA RfC


ppm - parts per million
NA - not available

*Contaminant selected for further evaluation.
**There are no comparison values for soil gas (below soil surface). Soil gas data were compared to comparison values for ambient air (above soil surface) to select contaminants for further evaluation. Comparison values determined for a 70 kilogram adult who inhales 20 cubic meters of ambient air per day.
***EPA RfC = EPA Risk Reference Concentration
EPA RfD = EPA Reference Dose
EPA CPF = EPA Oral Cancer Potency Factor
ATSDR CREG = ATSDR Cancer Risk Evaluation Guide


Table 3.

Syosset Landfill.
Summary of On-Site Subsurface Soil Data
Remedial Investigation
(All values in milligrams per kilogram)


Compound Name Range of
Detection
(excluding
non-detects)
Typical
Background
Range**
Comparison
Value****
Source*****

Volatile Organics

chloromethane .01J ND 50 EPA CPF
bromomethane .005J-.009J ND NA
vinyl chloride .008J ND 0.4 EPA CPF
chloroethane .009J ND NA
methylene chloride .006-.074B ND 93 ATSDR CREG
acetone .013-.75B ND 5,000 EPA RfD
carbon disulfide .003J-.022J ND 5,000 EPA RfD
1,1-dichloroethane .004J ND 5,000 EPA RfD
chloroform .003J-.013 ND 110 ATSDR CREG
1,2-dichloroethane .006 ND 7.7 ATSDR CREG
2-butanone .014-.032 ND 2,500 EPA RfD
1,1,1-trichloroethane .005J-.006 ND 4,500 EPA RfD
carbon tetrachloride .004J ND 5.4 ATSDR CREG
bromodichloromethane .002J-.006 ND 5.4 ATSDR CREG
1,2-dichloropropane .007 ND 11 EPA CPF
trans-1,3-dichloropropene .004J ND NA
trichloroethene .005J ND 65 EPA CPF
dibromochloromethane .002J-.006 ND 1,000 EPA RfD
1,1,2-trichloroethane .008 ND 12 ATSDR CREG
benzene .006-.008 ND 24 ATSDR CREG
cis-1,3-dichloropropene .006 ND 15 EPA RfD
bromoform .003J-.006 ND 89 ATSDR CREG
4-methyl-2-pentanone .005J ND NA
tetrachloroethene .005J-.009 ND 14 EPA CPF
1,1,2,2-tetrachloroethane .009 ND 3.5 ATSDR CREG
toluene .006-.009 ND 10,000 EPA RfD
chlorobenzene .01-.18 ND 1,000 EPA RfD
ethylbenzene .008-.016 ND 5,000 EPA RfD
styrene .006 ND 24 EPA CPF
1,4-dichlorobenzene .23 ND 30 EPA CPF
total xylenes .016B-.069 ND 100,000 EPA RfD

Polychlorinated Biphenyls (PCBs)

*Aroclor 1016 .11-3.1 <0.01-0.04a 0.092 EPA CPF
*Aroclor 1254 .061-1.5 <0.01-0.04a 0.092 EPA CPF

Semi-Volatile Organics

1,2-dichlorobenzene .02J ND 4,500 EPA RfD
naphthalene .014J-24J ND 200 EPA RfD
dimethyl phthalate 4.4J ND NA
acenaphthylene .25J *** NA
acenaphthene .019J-7.2J *** 3,000EPA RfD
diethylphthalate .012J-.38J ND 40,000 ATSDR EMEG
fluorene .029J-2.2J *** 2,000 EPA RfD
n-nitrosodiphenylamine1 .18J ND 140 ATSDR CREG
phenanthrene .019J-9.7J *** NA
anthracene .042J-2.3J *** 15,000 EPA RfD
di-n-butylphthalate .013JB-.61J ND 5,000 EPA RfD
fluoranthene .027J-9 *** 2,000 EPA RfD
pyrene .016J-3.9J *** 1,500 EPA RfD
butylbenzylphthalate .16J ND 10,000 EPA RfD
chrysene .064J-3.3J *** NA
benzo(a)anthracene .059J-3.3J *** NA
bis(2-ethylhexyl)phthalate .84B-47B ND 50 EPA CPF
di-n-octylphthalate .008J-27J ND 1,000 EPA RfD
benzo(b)fluoranthene .71-3.8J *** NA
benzo(a)pyrene .027J-2.5J <1-1.3 0.12 ATSDR CREG
benzo(g,h,i)perylene .18J-2.2J *** NA
indeno(1,2,3-c,d)pyrene .022J-2J *** NA

Metals

*antimony 12-64 0.6-10 20 EPA RfD
arsenic 2-20 10-20 15 EPA RfD
cadmium 2 <0.5-1 10 ATSDR EMEG
copper 20-30 <1-25 6,500 EPA RfD
silver 10-20 0.1-5 250 EPA RfD
zinc 30-700 50-100 10,000 EPA RfD

Note: Only those compounds which were detected, including estimated values, are listed in this table.

Soil Sampling Depths: Volatile Organics - 15 ft. to 183 ft.
Semi-Volatile Organics - 15 ft. to 110 ft.
PCBs and Metals - 15 ft. to 110 ft.

1During the standard analysis, n-nitrosodiphenylamine typically decomposes to diphenylamine. The analysis used cannot distinguish between the two compounds.

2Total PCBs

B - analyte detected in the blank as well as in the sample
J - estimated value

NA - not available
ND - not determined

*Contaminant selected for further evaluation.

**References: Adriano (1986); Clarke et al. (1985a,b); Connor et al. (1957); Davis and Bennett (1983); Frank et al. (1976); McGovern (1988); Shacklette and Boerngen (1984)

***Based on reported background levels for total polycyclic aromatic hydrocarbons of <1 to 13 milligrams per kilogram in soil (ATSDR, 1990f; Edwards, 1983)

****These values are for a nonresidential setting and assume a lifetime exposure through incidental ingestion. Cancer comparison values determined for a 70 kilogram adult who ingests 100 milligrams soil per day; noncancer comparison values determined for a 10 kilogram child who ingests 200 milligrams soil per day.

*****ATSDR EMEG = ATSDR Environmental Media Evaluation Guide
      ATSDR CREG = ATSDR Cancer Risk Evaluation Guide
      EPA CPF = EPA Cancer Potency Factor
      EPA RfD = EPA Reference Dose


Table 4.

Syosset Landfill

Summary of Groundwater Data
(On-Site Monitoring Wells) Remedial Investigation
(All values in micrograms per liter)


Compound Name Range of
Detection
(excluding
non-detects)
NYS and Federal Standards
and Guidelines

Comparison
Value****
Source*****
New York State

U.S. EPA

Groundwater Drinking
Water
Drinking
Water

Volatile Organics

acetone 7J 50 50 -- 700 EPA RfD
*vinyl chloride 1 2 2 2 0.02 EPA CPF
1,1-dichloroethane 2J-4J 5 5 -- 700 EPA RfD
*1,2-dichloroethene 7-9 5 5 7 70 EPA LTHA
chloroform 2-18J 7 100d 100d 6 EPA CPF
1,1,1-trichloroethane 1-2J 5 5 200 200 EPA LTHA
*trichloroethene 2J-7J 5 5 5 3 NYS CREG
*tetrachloroethene 3J-19J 5 5 5 0.7 NYS CREG
*chlorobenzene 2J-8 5 5 100 140 EPA RfD
benzene 1J-2J 0.7 5 5 0.7 NYS CREG
toluene 2J 5 5 1,000 1,000 EPA LTHA
2-butanone 1J 50 50 -- 200 EPA LTHA

Semi-Volatile Organics

1,3-dichlorobenzene 0.4J-0.6J -- 5 600 600 EPA LTHA
1,4-dichlorobenzene 0.5J-3J 4.7e 5 75 1.5 EPA CPF
1,2-dichlorobenzene 0.5J-2J 4.7e 5 600 600 EPA LTHA
benzoic acid 5J-8J 50 50 -- 28,000 EPA RfD
naphthalene 0.8J-2J 10g 50 -- 20 EPA LTHA
2-methylnaphthalene 0.4J 50 50 -- -- --
diethylphthalate 0.3J-0.4J 50 50 -- 5,000 EPA LTHA
fluorene 0.4J 5050 -- 280 EPA RfD
n-nitrosodiphenylamine1 0.5J-2J -- 50 -- 7 ATSDR CREG
fluoranthene 0.2J 50 50 -- 280 EPA RfD
butylbenzylphthalate 0.2J-3J 50 50 -- 1,400 EPA RfD
bis(2-ethylhexyl)phthalate 2JB-34B 50 50 4p 2.5 EPA CPF
di-n-octylphthalate0.7J-39B 50 50 -- 140 EPA RfD
4-methylphenol 1J-2J 1 50 -- 360 EPA RfD

Metals Filtered Unfiltered

*antimony 5J-15 5J-18J 3g -- 6 3 EPA LTHA
*arsenic 2-60J 4-180 25 50 50 11 EPA RfD
beryllium 2J-3.5 1J-3J 3g -- 1p 180 EPA RFD
cadmium 1-2.5 1 5 10 5 5 EPA LTHA
chromium ND 6J-38J 50 50 100 100 EPA LTHA
copper 20-130J 30-310 200 1,000 1,300 1,300 EPA MCLG
*lead ND 5J-130J 25 50 15*** -- --
selenium ND 2J -- -- -- 30 ATSDR EMEG
silver ND 2J 50 50 50;100ps 100 EPA LTHA
*thallium 5J-27J 5 4g -- 2 0.4 EPA LTHA
*zinc 20-4,000 30-5,200 5,000 5,000 5,000s 2,100 EPA LTHA
*sodium 28,000-770,000 26,000J-530,000J 20,000 ** -- -- --
potassium 2,000J-210,000 2,000J-140,000J -- -- -- -- --
*barium 50J-3,800 50-1,000 1,000 2,000 2,000 2,000 EPA LTHA
*iron 60J-58,000J 60J-190,000J 300 300 300s -- --

Note: Only those compounds that are detected including estimated values are listed in this table.

1During the standard analysis, n-nitrosodiphenylamine typically decomposes to diphenylamine. The analysis used cannot distinguish between the two compounds.

ND - not detected
B - analyte detected in the blank as well as in the sample
J - estimated value

d - drinking water standard for total trihalomethanes produced as a result of disinfection with chlorine. This standard is inappropriate for evaluating environmental contamination not associated with disinfection practices.
g - guidance value
p - proposed maximum contaminant level (MCL)
s - secondary MCL

*Contaminant selected for further evaluation.

**no designated limit; water containing more than 20,000 mcg/L should not be used for drinking by people on severely restricted sodium diets; water containing more than 270,000 mcg/L should not be used for drinking by moderately restricted sodium diets.

***The maximum contaminant level goal (MCLG) for lead is zero, and the action level is 15 mcg/L at the tap.

****Comparison value determined for a 70 kilogram adult who ingests 2 liters of water per day.

*****ATSDR CREG = ATSDR Cancer Risk Evaluation Guide
     ATSDR EMEG = ATSDR Environmental Media Evaluation Guide
     EPA CPF = EPA Cancer Potency Factor
     EPA LTHA = EPA Drinking Water Lifetime Health Advisory
     EPA RfD = EPA Reference Dose
     EPA MCLG = EPA Maximum Contaminant Level Goal
     NYS CREG = NYS Cancer Risk Evaluation Guideline

APPENDIX C

RESPONSE TO PUBLIC COMMENTS

Syosset Landfill

This summary responds to the public's comments on the draft Public Health Assessment for the Syosset Landfill site. The public comment period ran from April 1, 1993, to May 5, 1993. Some comments were consolidated or grouped together to incorporate similar concerns raised by more than one person. If you have any questions about this summary, contact the NYS DOH's Health Liaison Program at the toll free number 1-800-458-1148, extension 402.

Comments 1 through 45 summarize several similar comments received from the Town of Oyster Bay.

Comment 1

The Town points out that the United States Environmental Protection Agency (US EPA) performed an in depth Health and Endangerment Assessment (CDM, 1990) using the site-specific data obtained during the on-site remedial investigation to quantify the potential risk from the site to the community, the Town of Oyster Bay workers and the people at the South Grove School. Although the site related risks are within the US EPA acceptable range, the US EPA has set a site-specific acceptable risk for this site. Since the site risks are in excess of this designation, the US EPA recommended that the site be remediated to reduce these risk levels even further. The site remediation is currently in the engineering design phase and an off-site remedial investigation is currently being performed by the Town. The off-site remedial investigation was separated from the on-site remediation in order to expedite the on-site remediation. Separating these two programs enabled the Town to begin the on-site remediation before completing the off-site remedial investigation and feasibility study process.

The health assessment also indicates that adequate data or information is not available for all environmental media. The Town has performed an on-site remedial investigation and and collected soil, gas, and groundwater data which were utilized to characterize the site and determine the proper site remediation. These data were then adequate enough to be used by the US EPA to develop a Health and Endangerment Assessment to evaluate on-site and off-site health risks associated with the site.

Response 1

The Health and Endangerment Assessment performed by CDM used only on-site environmental data and as such, evaluated risks to on-site levels of contaminants only. A complete health assessment would require the evaluation of off-site soil gas (and the potential for impact on indoor air), off-site ambient air and potential exposures to contaminated groundwater.

Comment 2

The health assessment indicates that there may have been contamination from a public water supply well prior to the development of volatile organic compounds (VOCs) detection technology. It is the responsibility of the New York State Department of Health (NYS DOH) and the Nassau County Department of Health (NC DOH) to ensure that the drinking water supplied to the public meets drinking water standards. Well N4133 was closed due to taste and odor reasons, which are secondary drinking water quality parameters (aesthetic standards). The Town has addressed the health concerns related to the site by performing the on-site remedial investigation, feasibility study and remedial design and the off-site remedial investigation. The remediation work has been and continues to be performed with oversight by the US EPA, NYS DEC and the NYS DOH. The health assessment also suggests that while there is no data to indicate the well was contaminated with VOCs, there is also no data to indicate that is wasn't. While the on-site remedial investigation detected some VOCs in the groundwater beneath the landfill, the conclusion of the remedial investigation report was that the concentrations and locations of VOCs on-site were not indicative of a VOC plume emanating from the landfill. One explanation given in the on-site Remedial Investigation for the lack of a VOC plume is that controlled ongoing landfill fires were common during site operation. These fires may have destroyed organic material which otherwise might have contributed to VOC contamination. In addition, during the operation of Well N4133, two industrial supply wells wee operated on the Cerro Wire site adjacent to the landfill. While Well N4133 operated at a flow of 1,000 gallons per minute (GPM) at a distance of over 1,000 feet from the northern landfill boundary, the two Cerro wells operated at a flow of 1,000 gpm each at a distance of 422 feet and 580 feet from the southern landfill boundary. These two wells could have temporarily influenced the hydrologic patterns in the area, directing the groundwater flow from the landfill away from Well N4133. Operation of these two wells ceased when operations at the Cerro Wire site were discontinued in the 1980's.

Response 2

The health assessment has been clarified to reflect that the well closure was due to taste and odor problems. Also, while VOC contamination of the public water supply well was possible, the current on-site groundwater monitoring data do not indicate a significant VOC plume emanating from the site.

Comment 3

The health assessment states that a public health concern exists for the Town of Oyster Bay employees at the site, nearby residents and people at the South Grove School due to the levels of VOCs and methane in the site soil gas. The Town installed a gas venting trench along the property line adjacent to the South Grove School following the identification of gas in the soil on the school grounds in 1981. This trench continues to be monitored and maintained by the Town. The trench was rehabilitated last in 1988. Monitoring was initially performed at the trench on a daily basis for the first few years after trench installation. As the gas conditions at the trench improved, monitoring continued on a weekly basis. The monitoring results are submitted to the NYS DEC and the NC DOH for review. The school also has methane meters in its buildings which have not encountered methane to date. The Town monitored methane in the Town buildings in 1983 and none was detected. A series of ten additional gas monitoring wells were also installed along the site's northern property line adjacent to the residential community and the school. The Town will be sampling these wells under the on-site remedial design program.

Response 3

The health assessment discusses the gas venting trench in appropriate sections within the document. The trench has been effective in preventing methane intrusion into the South Grove School as evidenced by the methane meters in the building; however, percent levels of methane have been detected on the school side of the gas venting trench, indicating the trench has not entirely cut off the migration of methane. Where appropriate, additional discussion of the gas venting trench has been added to the health assessment.

Comment 4

The summary should also indicate that all of the NYS DOH recommendations are in fact currently underway except for additional ambient monitoring since it was agreed in June 1991 that no further testing would be required if the NC DOH ambient air monitoring did not exceed typical ambient air levels.

Response 4

The summary has been changed to reflect the ongoing activities which will satisfy the recommendations made by NYS DOH. While the preliminary on-site air sampling conducted by the NC DOH in July of 1991 suggested that the compounds detected in on-site ambient air were not in excess of typical urban/suburban background air, NYS DOH recommended additional air monitoring to confirm the preliminary results.

Comment 5

The Town was not aware that the NYS DOH performed a preliminary health assessment of the site in June 1989. The Town requests that the NYS DOH submit a copy of this report to the Town for review.

Response 5

NYS DOH will send a copy of the report to the Town.

Comment 6

The October 1989 Health and Endangerment Assessment prepared by CDM for the US EPA was identified in the fourth paragraph of this section. The final version of this report was issued in July 1990. The October 1989 version of the Health and Endangerment Assessment contained some mathematical errors which were corrected in the July 1990 report. The conclusions from this report should be identified in the NYS DOH Health Assessment. These conclusions are summarized in the second paragraph of this comment document on page 1.

Response 6

The health assessment has been changed to reflect the final version of the Health and Endangerment Assessment. The conclusions from this report are incomplete in that the report does not address potential exposures to contaminants that have migrated off-site.

Comment 7

The health assessment should note that, to date, there has been no indication of contamination in currently active supply wells.

Response 7

The health assessment has been changed to reflect this comment.

Comment 8

The health assessment should also indicate that in addition to the NYS DOH, NC DOH and the US EPA, the Town has also been involved in the site remediation and continues to provide education and information to the public. The Town has conducted several public meetings and continues to discuss site conditions with the public as questions arise.

Response 8

The health assessment has been changed to reflect this comment.

Comment 9

The fourth bullet in the site visit section discusses the Town of Oyster Bay Animal Shelter. This sentence should indicate that this facility is not located on the landfill site.

Response 9

The health assessment has been changed to reflect this comment.

Comment 10

The fifth bullet under the site visit section should also mention that the southwestern portion of the landfill site is used for the Town's leaf composting operations. The leaf composting operations have been approved by the US EPA and are permitted by the NYS DEC.

Response 10

Information in this comment has been added to the site description.

Comment 11

The health assessment mentions that the Cerro Wire site adjacent to the landfill contained soil and groundwater contamination. The Town is aware of the reported remediation which consisted of excavating portions of the site to remove contaminated soil, but no mention of groundwater remediation has been made. Is any groundwater remediation planned for that site?

Response 11

No groundwater remediation is planned for the Cerro Wire site since samples of on-site groundwater indicate that only three contaminants (iron, manganese and lead) are present at concentrations slightly above drinking water standards and exposure to site-related contaminants in drinking water is unlikely to occur since the surrounding area is supplied with public water.

Comment 12

The health assessment reports that the NYS DOH has not evaluated the health outcome data specific for the Syosset Landfill site. Does the NYS DOH plan on evaluating this data in the future? The community surrounding the site indicated in the April 1, 1992 Public Meeting for the site that they would like to have an evaluation performed. The Town concurs that a study of this nature should be performed by the appropriate agency.

Response 12

The NYS DOH is currently conducting a study of cancer incidence near a number of New York State landfills (ATSDR Grant #H75/ATH298290-01). This study is examining characteristics of each site and levels of methane and other organic chemicals in soil gas to determine potential impacts. NYS DOH has included this site in the study.

Comment 13

The term "RI/FS" in the on-site contamination section should be replaced by the term "RI". Site investigations are conducted during the RI phase of the RI/FS process.

Response 13

This change has been made in the health assessment.

Comment 14

The first sentence in the soil gas/ambient air section should be modified to indicate that the 19 monitoring wells were monitored monthly "during the Remedial Investigation".

Response 14

This change has been made in the health assessment.

Comment 15

The health assessment indicates that methane and non-methane VOCs were found on-site during the on-site remedial investigation ranging from 0 to greater than 100,000 parts per million (ppm). This sentence should be corrected to indicate that methane was found on-site at levels of 0 to greater than 100,000 ppm (0 to 10%), and that non-methane VOCs were encountered at levels of 0 to greater than 400 parts per billion (ppb).

Response 15

This change has been made in the health assessment.

Comment 16

In the last paragraph of the on-site soil gas/ambient air section, the results of the NC DOH ambient air sampling program are discussed, however, no data results are reported until the "Off-site Contamination" section of the health assessment. The results should be included in a table in the Appendix and discussed further in this section.

Response 16

The health assessment was changed to include the ambient air sampling discussion in the On-site Contamination section.

Comment 17

If some of the VOC air sampling data had to be rejected, then the VOC data which were not rejected during the NC DOH air sampling events in 1991 should be included in a table in the appendix of the health assessment.

Response 17

The limited ambient air data are now discussed in the On-site Contamination section and all detectable results are listed. Inclusion of a table in the appendix would provide no additional information.

Comment 18

The sentence in the second paragraph of the off-site soil gas/ambient air section should have the following phrase added: "since it was an on-site investigation."

Response 18

The health assessment has been changed to reflect this comment.

Comment 19

Standard US EPA QA/QC protocol requires that trip blanks only be sampled for VOCs to identify any possible sample contamination from the air which the samples are exposed to. If the trip blank contains VOCs, then some amount of the VOCs found in the soil samples may be attributable to the air that the sample came in contact with and not the landfill as a source. If a trip blank is not analyzed during a sampling event, then any VOCs found in the soil samples must be attributed to the landfill, making the sample results more conservative rather than less conservative.

Response 19

The health assessment has been changed to reflect this comment.

Comment 20

Although the Toxic Release Inventory (TRI) section discusses other facilities in the area which may contribute to groundwater, soil or air contamination, no mention is made of the Cerro Wire site which was discussed earlier in the health assessment as a site which has contributed soil and groundwater contamination. In addition, there is no mention of the Long Island Expressway or Long Island Rail Road contributions to air quality. These other sources should be identified and their contributions quantified.

Response 20

The TRI section discusses only those facilities on the TRI inventory. As indicated in the PHA, based on TRI modeling, the facilities inventoried do not effect ambient air in the vicinity of the Syosset Landfill at levels exceeding a screening criterion of 1 microgram per cubic meter.

Comment 21

The second paragraph in the potential exposure Pathways/Groundwater exposure pathways section indicates that the uncapped landfill is a continuing source of contamination. A sentence should be added to indicate that site remediation is ongoing and that once the landfill is capped it will no longer be a source of contamination.

Response 21

The health assessment has been changed to reflect this comment.

Comment 22

The health assessment indicates that the water supply water quality is routinely monitored. Shouldn't this monitoring remove any potential for current and future groundwater exposure pathways? If so, it should be explicitly stated. If not, the reason should be explained.

Response 22

Routine monitoring ensures that contamination and thus exposures do not go undetected for long periods, but short-term exposures to contaminants could occur between monitoring periods.

Comment 23

It should be noted in the health assessment that all public supply wells are routinely monitored and therefore this potential pathway will never become a completed pathway.

Response 23

Routine monitoring of public drinking water supplies minimizes, but does not entirely eliminate the potential for exposure to chemical contaminants. The health assessment has been changed to indicate that "routine monitoring of public water supply wells minimizes the potential for exposure to occur."

Comment 24

Although the levels of iron found in the groundwater on-site are in excess of water quality standards, the standard for iron is based on water appearance and taste, not on health related data. High levels of iron are avoided in water supply systems because they stain fixtures and clothing in the laundry.

Response 24

The health assessment refers to the high iron levels as an aesthetic water quality problem.

Comment 25

The health outcome data section mentions that the NYS DOH has not evaluated health outcome data specific to the Syosset Landfill. Will this be done in the near future as mentioned in comment 16?

Response 25

The NYS DOH is currently conducting a study of cancer incidence near a number of New York State landfills (ATSDR Grant #H75/ATH298290-01). This study is examining characteristics of each site and levels of methane and other organic chemicals in soil gas to determine potential impacts. NYS DOH has included this site in the study.

Comment 26

In the health outcome data section there is a typo in the years quoted for the breast cancer study. It should be 1978-1987.

Response 26

The health assessment has been changed to reflect this comment.

Comment 27

The community health concerns evaluation section should also indicate that the Town has developed a Health and Safety Plan (HASP) for this site which will be followed during the on-site field investigations and during the cap construction. This HASP was developed following all US EPA and federal occupational health guidelines to protect on-site workers and the general public.

Response 27

The health assessment has been changed to reflect this comment.

Comment 28

Conclusion 1 - The first paragraph also indicates that there is no health outcome data for this site. The community surrounding the site indicated in the April 1, 1992 Public Meeting for the site that they would like to have an evaluation performed. The Town concurs that a study of this nature should be performed by the appropriate agency. Does the NYS DOH plan on evaluating these data in the future?

Response 28

The NYS DOH is currently conducting a study of cancer incidence near a number of New York State landfills (ATSDR Grant #H75/ATH298290-01). This study is examining characteristics of each site and levels of methane and other organic chemicals in soil gas to determine potential impacts. NYS DOH has included this site in the study.

Comment 29

Conclusion 1 - The second paragraph of this conclusion discusses the possibility of past, current and future exposure pathways for ambient air. Although it is noted that the planned remediation will eliminate potential health risks, it should also be noted that the Town and the South Grove School have implemented mitigation measures to reduce the risk of off-site gas migration. (See comments 26, 30 and 31) In addition, the NC DOH conducted ambient air sampling which indicated that ambient air at the down wind portion of the landfill in the vicinity of the gas venting trench did not exceed typical urban/suburban ambient air quality. (See comments 24 and 28) More over, the health assessment stated earlier that there are no completed exposure pathways, which should be repeated here.

Response 29

The conclusion is changed to indicate that evaluation of the limited ambient air data that are available does not indicate an impact on ambient air quality.

Comment 30

Conclusion 2 - This conclusion indicates that there are data inadequacies for off-site groundwater, soil, soil gas and ambient air. It should be noted that (1) investigations to date were on-site investigations and, therefore, no off-site data was required to be taken. The off-site remedial investigation was separated from the on-site remediation in order to expedite the on-site remediation. Separating these two programs enabled the Town to begin the on-site remediation before completing the off-site remedial investigation and feasibility study process; (2) there is currently an off-site remedial investigation ongoing; and (3) the NC DOH performed ambient air testing at the site's down wind location at the gas venting trench to determine off-site ambient air conditions (see comment 38). The results of this sampling event were reported by the NYS DOH to be within the limits of typical urban/suburban air quality. An additional statement is made that the on site soil gas and ambient air data were insufficient. The on-site remedial investigation was performed to characterize the site. As part of this investigation, soil gas sampling was performed throughout the site. The Town has also been sampling the gas venting system adjacent to the school for over ten years. Ambient air sampling was performed by the NC DOH on-site as previously discussed. With all these data obtained, the Town does not understand the conclusion that the on-site data were insufficient for soil gas and ambient air.

Response 30

VOC soil gas monitoring was not performed during the remedial investigation for all gas monitoring wells on both sides of the gas venting trench. NC DOH sampled ambient air on both sides of the trench and sampled soil gas monitoring wells in the vicinity of the trench. The soil gas data were invalid because high moisture levels in the soil gas interfered with the analysis. Our conclusion that the ambient air data are insufficient is because the only valid data consist of only one sampling round of usable data by NC DOH.

Comment 31

Conclusion 3 - This conclusion should also contain a statement that the on-site remedial investigation concluded that VOCs found in the on-site groundwater sampling were not indicative of a plume migrating off-site. In addition, the water districts are required to monitor the water supply wells and report the data to the NC DOH and the NYS DOH who regulate the water quality.

Response 31

The health assessment has been changed to reflect this comment.

Comment 32

Conclusion 4 - Soil gas monitoring has been, and continues to be, monitored regularly at the site's gas venting trench and within the South Grove School. The Town does not understand how the soil gas sampling can be inadequate as mentioned in conclusion number 4?

Response 32

The conclusion is based upon elevated levels of methane detected on the school side of the trench and the lack of soil gas data at depths comparable to the depth of the fill.

Comment 33

Recommendation 1 - It has been the Town's understanding that the NYS DOH and the NC DOH regulations require the water districts to monitor all drinking water supply wells regardless of their location (i.e., upgradient or downgradient) with respect to the site. Therefore, this recommendation is already being performed.

Response 33

The health assessment has been changed to reflect this comment.

Comment 34

Recommendation 2 - This recommendation is already being performed by the Town. It should be noted that the Town is currently conducting the off-site groundwater investigation. The off-site remedial investigation began in 1990 and is currently in the monitoring well installation phase which began in October 1992. The off-site remedial investigation was separated from the on-site remediation in order to expedite the on-site remediation. If these two programs were not performed separately, the Town would have to wait until the off-site remedial investigation and feasibility study program was completed before beginning the on-site remediation.

Response 34

The health assessment has been changed to reflect this comment.

Comment 35

Recommendation 3 - The Town does routinely inspect the site's fence to ensure its condition.

Response 35

The health assessment has been changed to reflect this comment.

Comment 36

The Town feels that the recommendations made in the health assessment under the "Recommendations Section" #4 have already been undertaken by the Town, the US EPA, the NYS DOH and the NC DOH.

Response 36

To date, the potential for methane migration to affect nearby buildings has not been adequately characterized by the Town or any of the agencies mentioned by the Town. However, at the request of the NYS DOH, the Town will develop soil gas monitoring well clusters where residential yards and the South Grove Elementary School border the landfill.

Comment 37

Recommendation 5 - As previously mentioned in comment 49, the Town has developed a Health and Safety Plan (HASP) for this site which will be followed during the on-site field investigations and during the cap construction. This HASP was developed following all US EPA and federal occupational health guidelines to protect on-site workers and the general public. A site safety officer will be on-site during the construction period to enforce the requirements of the HASP. The HASP anticipates that the construction will be performed using Level D protection (coveralls, hard hat, and work boots) which does not require respirators as recommended in this paragraph. However, the HASP does have provisions for monitoring the site conditions and upgrading to Level C (Level D with the addition of a respirator), if necessary.

Response 37

The health assessment has been changed to reflect this comment.

Comment 38

This paragraph indicates that the NYS DOH has performed community health education for this site. The Town is unaware of the education performed by the NYS DOH and would like to obtain a copy of this material for their records along with any other public notices or fact sheets prepared and distributed by the NYS DOH.

Response 38

The public health education referenced to in the health assessment was in the form of public meetings.

Comment 39

The Health and Endangerment Assessment report referenced on page 28 is not the final report. Since the draft report contained some mathematical errors, the final report should be referenced and utilized for any site health data.

Response 39

The health assessment has been changed to reflect this comment.

Comment 40

The remedial investigation report referenced on page 28 is a final report.

Response 40

The health assessment has been changed to reflect this comment.

Comment 41

The reports prepared by LKB referenced on pages 28 and 29 should all indicate that the reports were prepared under contract to the Town for Oyster Bay who prepared them for the US EPA (with the exception of the Gas Control Evaluation report).

Response 41

The health assessment has been changed to reflect this comment.

Comment 42

The figures in Appendix marked "draft" should be updated to incorporate all the monitoring wells.

Response 42

Draft Figures 1 and 2 have been updated.

Comment 43

Table 2 compares subsurface soil gas data with ambient air comparison values. A note should be added to clarify the distinction between the soil gas data which were obtained from on-site gas monitoring wells (at various depths below land surface) and the comparison values which are for ambient air above the ground surface.

Response 43

The health assessment has been changed to reflect this comment.

Comment 44

A table should be included for the ambient air data obtained by the NC DOH in 1991 along with comparison values.

Response 44

The limited ambient air data were sufficiently discussed in the text.

Comment 45

Table 5 - Why are comparison values for some contaminants (i.e., vinyl chloride, chloroform, trichloroethene, tetrachloroethene, 1,4-dichlorobenzene, N-nitrosodiphenylamine, bis(2-ethylhexl)-phthalate, arsenic, thallium, and zinc) less than the NYS and US EPA standards for groundwater?

Response 45

The US EPA does not have standards for groundwater. In regard to NYS groundwater standards, the comparison value for chloroform should be the same as the standard (7 micrograms/liter) for this chemical. The groundwater standard of 5,000 micrograms/liter (mcg/L) for zinc is incorrect; the correct value is 300 mcg/L which is less than the comparison value for zinc. Corrections have been made to the revised public health assessment.

Groundwater standards and guidelines for vinyl chloride, trichloro-ethene, tetrachloroethene, 1,4-dichlorobenzene, N-nitrosodi-phenylamine, bis(2-ethylhexyl)phthalate, arsenic and thallium do not reflect recent health effects data and may be higher than comparison values for these chemicals because these standards and guidelines were developed in the past and either have not yet been revised to represent more recent toxicological data or current methodology that is used to promulgate regulations. Some drinking water standards may be higher than comparison values or groundwater standards because drinking water standards also take into consideration practical analytical capability, water treatment capabilities, economic impacts and, in the case of chloroform (a chlorine-containing disinfecting product), the benefits of disinfection versus the risks from exposure to low levels of chloroform in drinking water.

Summary of Comments from a resident:

Comment:

The resident's primary concern is the potential for the health assessment to cause undue concern and resultant panic among the public due to the "classification" of the landfill as a "indeterminate public health hazard" even though the health assessment concludes that past and current exposures/risks have not been identified. In addition, the health assessment concludes that a potential risk exists; however, no data are available to demonstrate any current of future risk to the South Grove School or surrounding homes.

Response:

The "indeterminate public health assessment" classification is based strictly on the risks associated with the potential for exposures to occur in the future. While the likelihood for future exposures is small, without additional soil gas and ambient air data it is not possible to totally eliminate concerns regarding future exposures, and thus the "indeterminate public health hazard." Wherever possible, the Health Assessment has been changed to better explain the health classification so as not to needlessly alarm the public.

Other questions/comments from residents:

Comment:

A cancer survey of homeowners surrounding the landfill since 1960 would be very enlightening.

Response:

The NYS DOH is currently conducting a study of cancer incidence near a number of New York State landfills (ATSDR Grant # H75/ATH298290-01). This study is examining characteristics of each site and levels of methane and other organic chemicals in soil gas to determine potential impacts. NYS DOH has included this site in the study.

Comment:

Do the residents understand the danger of ingesting less than 5 ppb of PCE (tetrachloroethene) and TCE (trichloroethene) over time?

Response:

The NYS DOH and US EPA believe that drinking water with less than 5 ppb of TCE or PCE does not pose a significant threat to public health.

Comment:

Has a rate of flow or advance of groundwater in the upper glacial horizontally and vertically been measured, and has migration of this groundwater horizontally through the Magothy been measured? How long will it take (theoretically) to reach the public drinking water wells.

Response:

Based on the first phase of the remedial investigation (RI), the Magothy Aquifer in the study area is directly (hydraulically) connected to the Upper glacial formations which is unsaturated in the vicinity of the site. Horizontal groundwater flow in the site area is reported to be about 400 gallons per day per square foot (gpd/ft2), however, a significant amount of variation in flow is known to occur throughout this formation. Although not specifically measured, the vertical direction of groundwater flow was observed to be consistently downward across the site and is reported to be more pronounced than the horizontal groundwater flow component. The second Phase RI will provide additional information on groundwater flow rates, direction and quality. This information will help in evaluating potential contamination of public drinking water supply wells with site related contaminants. All public drinking water supply wells near the site are monitored on a quarterly basis as required by New York State Department of Health and Nassau County Health Department regulations.


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