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PUBLIC HEALTH ASSESSMENT

ISLIP MUNICIPAL SANITARY LANDFILL
(a/k/a BLYDENBURGH ROAD LANDFILL)
HAUPPAUGE, SUFFOLK COUNTY, NEW YORK


APPENDIX A

FIGURES
Figure 1. Location of the
Blydenburgh Landfill



Figure 2. Landfilling
Phases and Acreage



Figure 3. Schematic Cross
Section of Lanfilling Phases



Figure 4.



Figure 5.



APPENDIX B

TABLES


TABLE 1.

Results of the Islip Landfill Private Well Survey Conducted by
the Suffolk County Department of Health Services
from 9/78 - 5/80.**
(All values in micrograms per liter)


Compound

Concentration Range


Chloroform 10
*Vinyl chloride 1 - 77
*1,1,1-Trichloroethane 2 - 8
*Trichloroethene 4 - 7
*Tetrachloroethene 2 - 124

1Refer to Table 8 for comparison to existing New York State and United States Environmental Protection Agency (US EPA) standards/guidelines. There were no standards for these chemicals in 1978-1980; the NYS DOH guideline for these compounds in 1980 was 50 micrograms per liter except for vinyl chloride which was 5 mcg/L.

*Contaminant selected for further evaluation.

**From NYS DOH files.




Table 2.

Islip Landfill
On-Site Soil Gas Concentrations from the Remedial Investigation1
(All values in parts per million)


Compound Average Maximum

Acetone 0.06 0.06
*1,1-Dichloroethane 6.27 32.10
*1,1,1-Trichloroethane 11.00 44.70
*Benzene 0.96 2.07
*Trichloroethene 0.30 0.75
*1,2-Dichloroethane 5.38 9.43
*Toluene 0.52 1.71
*Tetrachloroethene 0.27 0.57

VOC-HNU (ppm) 1.28 7.40
Combustible Gas (%LEL) 82 100

All samples taken inside the landfill gas collection/control system.

1Refer to Table 9 for Public Health Assessment comparison values for contaminants in ambient air.

*Contaminant selected for further evaluation.


Table 3.

Islip Landfill
No. 10 Gas Probe Cluster
Summa Canister Sampling Results from the Remedial Investigation.1
(All values in parts per million)


Compound Concentration Method Blank

*Carbon disulfide 0.09J ND
*1,1-Dichloroethene 0.2J ND
1,1,2,2-Tetrachloroethane 0.5B 0.56
Ethylbenzene 0.09J ND
Xylene (m+p) 0.09JB 0.08J
Xylene (o) 0.1JB 0.08J

Notes: ND - not detected
J - compound present below the specified detection limit
B - compound also detected in the blank

Samples were collected with the landfill gas collection/control system shut down.

1Refer to Table 9 for Public Health Assessment comparison values for contaminants in ambient air.

*Contaminant selected for further evaluation.


Table 4.

Islip Landfill
Eastern Perimeter Vent Fans
Summa Canister Gas Sampling Results
from the Remedial Investigation.1
(All values in parts per million)


Compound Fan #1 Fan #3 Method Blank

*Vinyl Chloride 2.8 ND ND
*cis-1,2-Dichloroethene 1.3 ND ND
*Benzene 0.5J 0.4J ND
Bromoform ND ND 0.16J
1,1,2,2-Tetrachloroethane ND ND 0.62
*Toluene 1.5 0.5J ND
*Chlorobenzene 0.55B 0.58B 0.2J
*Ethylbenzene 4.8 2.1 ND
*Xylene (m+p) 2.6B 1.9B 0.1J
*Xylene (o) 1.3B 0.9B 0.14J

Notes: ND - not detected
J - compound present below the specified detection limit
B - compound also detected in the blank

1Refer to Table 9 for Public Health Assessment comparison values for contaminants in ambient air.

*Contaminant selected for further evaluation.


Table 5.

Summary of Compounds Detected in On-Site Groundwater
Monitoring Wells at Islip Landfill
from the Remedial Investigation.1
(Range values are in micrograms per liter).


Compound Concentration

*acetone ND-100J
*2-butanone ND-250EJ
chloroform ND-3.9J
*methylene chloride ND-13J
chloromethane ND-4.8J
*trichlorofluoromethane ND
*dichlorodifluoromethane ND-11J
bromodichloromethane ND-1.2J
bromoethane/chloroethane ND
*vinyl chloride ND-2.3J
*1,1-dichloroethane ND-14
*1,2-dichloroethane ND-14
1,2-dibromoethane ND-1.6J
*1,1-dichloroethene ND-29
*1,2-dichloroethene (total) ND-25
trans-dichloroethene ND-5.7
*cis-dichloroethane and
2,2-dichloropropane
ND-38
*1,1,1-trichloroethane ND-170
*trichloroethene ND-71
*tetrachloroethene ND-23
1,2-dichloropropane ND-3.9J
carbon disulfide ND
*benzene ND-1.3
*toluene ND-10
o-xylene ND
1,2-dichlorobenzene ND-1.0
1,4-dichlorobenzene ND-2.8
phenol 20
benzoic acid ND
pyrene ND
fluoranthene ND
dimethylphthalate ND
*bis(2-ethylhexyl)phthalate ND-37



Table 5 (continued).

Summary of Compounds Detected in On-Site Groundwater
Monitoring Wells at Islip Landfill
from the Remedial Investigation.1
(Range values are in micrograms per liter).


Compound Concentration

Metals
*cadmium ND-6.2
*chromium ND-61.2
chromium F ND
*iron 4B-181,000
*lead ND-262
lead F ND-8.3
magnesium 1,900-60,000
*manganese 6.2B-1,850
*sodium 6,020-270,000
selenium ND
selenium F ND
zinc 8-1,030

1Refer to Table 8 for comparison to New York State and United
States Environmental Protection Agency (US EPA)
standards/guidelines.

J = an estimated value
B = that the compound was detected in the blank
F = a filtered sample

*Contaminant selected for further evaluation.


Table 6.

Range of Results from Three Rounds of Soil
Gas Samples taken near the Whippoorwill School
from the Remedial Investigation.
(All values are in micrograms per cubic meter).


Compound Concentration

Benzene2 ND-1.66
*Carbon Tetrachloride ND-.33
*Chloromethane1 ND-2.08
Ethylbenzene ND-.35
Methylene Chloride1 ND-.69
Styrene ND-.33
*Tetrachloroethene 13.19-15.60
Toluene2 ND-6.95
1,1,1-Trichloroethane ND-2.98
Trichloroethene ND-.66
Trichlorofluoromethane ND-2.78
Xylene (total m & p)2 ND-3.97
Xylene (ortho) ND-1.66

Notes: ND = Compound was not detected

*Contaminant selected for further evaluation. Refer to Table 9 for health assessment comparison values.

1Compound was detected in quality control blank during round 2.

2Compound was detected in quality control blank during round 2 and 3.


Table 7.

Summary of Compounds Detected in Off-site Groundwater
Monitoring Wells at Islip Landfill
from the Remedial Investigation.1
(Range values are in micrograms per liter).


Compound

                                Off-Site

                                Downgradient

Upgradient


*acetone ND ND
*2-butanone ND ND
chloroform ND-2.6J ND
*methylene chloride ND-51J ND
chloromethane ND-5.0J ND
*trichlorofluoromethane ND-26J ND
*dichlorodifluoromethane ND-17J ND
bromodichloromethane ND ND
bromoethane/chloroethane ND-3.1J ND
*vinyl chloride ND-21 ND
*1,1-dichloroethane ND-97 ND
*1,2-dichloroethane ND-5 ND
1,2-dibromoethane ND ND
*1,1-dichloroethene ND-9.7 ND-.8J
*1,2-dichloroethene (total) ND-130 ND
trans-dichloroethene ND-1.9 ND
*cis-dichloroethane and
2,2-dichloropropane
ND-140 ND
*1,1,1-trichloroethane ND-43 ND-3.2
*trichloroethene ND-50 ND
*tetrachloroethene ND-39 ND-5
1,2-dichloropropane ND-2.5J ND
carbon disulfide ND-5J ND
*benzene ND-28 ND
*toluene ND-29 ND
o-xylene ND-4.8 ND
1,2-dichlorobenene ND ND
1,4-dichlorobenzene ND-1.2 ND
phenol ND-40 ND
benzoic acid ND-4J ND
pyrene ND-.7J ND
fluoranthene ND-1.0J ND
dimethylphthalate ND-.3J ND
*bis(2-ethylhexyl)phthalate ND-53B ND-110



Table 7 (continued).

Summary of Compounds Detected in Off-site Groundwater
Monitoring Wells at Islip Landfill
from the Remedial Investigation.1
(Range values are in micrograms per liter)



Compound
                          Off-Site
                                Downgradient                 Upgradient

*cadmium ND-20BJ ND-12
*chromium ND-76 ND-30
chromium (F) ND-32.5 ND
*iron 58B-20,200 64B-10,500
*lead ND-1,410J 3.7-187
*lead (F) 2.6J-168 ND-11.1
magnesium 1,100-38,200 1,290B-10,800
*manganese 2.0B-2,990 17-18,100
*sodium 2,600B-441,000 4,170-15,000
selenium ND-17.5B ND-16.2BJ
selenium (F) ND ND
zinc 12BJ-1,390 19BJ-6,870

1Refer to Table 8 for comparison to New York State and United
States Environmental Protection Agency (US EPA)
standards/guidelines.

J = an estimated value
B = that the compound was detected in the blank
F = a filtered sample

*Contaminant selected for further evaluation.


Table 8.

Public Health Assessment Comparison Values for Contaminants Detected in Groundwater Monitoring Wells, Private Well Water and Public Water Supply Wells.
(All values in micrograms per liter)

Compound


Comparison Values



Standards/Guidelines




New York State

US EPA



Ground
Water
Drinking
Water
Drinking
Water
Cancer* Basis** Noncancer* Basis**
benzene 0.7 5 5 0.7 EPA CPF 5 EPA RfD
benzoic acid 50 50 -- -- -- 28,000 EPA RfD
toluene 5 5 1,000;40ps -- -- 1,000 EPA LTHA
acetone 50 50 -- -- -- 700 EPA RfD
2-butanone 50 50 -- -- -- 200 EPA LTHA
chloromethane 5 5 -- 3 -- -- --
dichloromethane 5 5 5 5 EPA CPF 420 EPA RfD
1,2-dichlorobenzene 4.7e 5 600p;10ps -- -- 600 EPA LTHA
chloroform 7 100d 100d 7 EPA CPF 70 EPA RfD
dichlorodifluoromethane 5 5 -- -- -- 1,000 EPA LTHA
trichlorofluoromethane 5 5 -- -- -- 2,100 EPA RfD
1,1-dichloroethane 5 5 -- -- -- 700 EPA RfD
1,2-dichloroethane 5 5 5 0.4 EPA CPF 52 EPA RfD
1,1,1-trichloroethane 5 5 200 -- -- 200 EPA LTHA
1,1,2-trichloro-1,2,2-
trifluoroethane
5 5 -- -- -- 21,000 EPA RfD
vinyl chloride (chloroethene) 2 2 2 0.02 EPA CPF 0.7 ATSDR MRL
1,1-dichloroethene 5 5 7 0.06 EPA CPF 7 EPA LTHA
cis-1,2-dichloroethene 5 5 70 -- -- 70 EPA LTHA
trans-1,2-dichloroethene 5 5 100 -- -- 100 EPA LTHA
1,1,2-trichloroethane 5 5 5 0.6 EPA CPF 3 EPA LTHA
trichloroethene 5 5 5 3 EPA CPF 52 EPA RfD
tetrachloroethene 5 5 5 0.7 EPA CPF 70 EPA RfD
phenols 1 50 -- -- -- 4,000 EPA LTHA
pyrene 50 50 -- -- -- 210 EPA RfD
bis(2-ethylhexyl)phthalate 50 50 6 2.5 EPA CPF 140 EPA RfD
xylene, o- + p- 5n 5n 10,000i;20ps -- -- 10,000 EPA LTHA
Metals






cadmium 10 5 5 -- -- 5 EPA LTHA
chromium 50 100 100 -- -- 100 EPA LTHA
iron 300 300 300s -- -- -- --
lead 25 15*** 15*** -- -- -- --
magnesium 35,000g -- -- -- -- 35,000 NYS RfG
manganese 300 300 50s -- -- 175 EPA RfD
selenium 10 10 50 -- -- 100 ATSDR MRL
sodium 20,000 **** -- -- -- -- --
zinc 300 5,000 5,000s -- -- 2,000 EPA LTHA

Footnotes for Table 8.

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.
e = applies to total of 1,2- and 1,4- isomers
g = guidance value
i = total xylenes
n = applies to each isomer separately unless isomers are analytically indistinguishable
p = proposed maximum contaminant level (MCL)
ps = proposed secondary MCL
s = secondary MCL

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

**EPA CPF = EPA Cancer Potency Factor
EPA RfD = EPA Reference Dose
EPA LTHA = EPA Lifetime Health Advisory
ATSDR MRL = ATSDR Minimum Risk Level
NYS RfG = NYS Risk Reference Guideline

***There is a maximum contaminant level goal (MCLG) of zero for lead and an action level of 15 mcg/L at the tap.

****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.

Table 9.

Public Health Assessment Comparison Values for Contaminants in Ambient Air.
(All values in parts per million [ppm] and/or micrograms per cubic meter [mcg/m3]).

Compound

Typical Background
Range*



Comparison Values


Cancer**


Noncancer**


ppm mcg/m3 ppm mcg/m3 Basis*** ppm mcg/m3 Basis***
Acetone 0.003-0.006 7.5-15.4 -- -- -- 0.148 350 EPA RfD
Benzene 0.0002-0.002 0.53-5.9 0.00003 0.1 EPA CPF 0.0008 2.5 NYS RfG
Carbon disulfide 0.000041-0.000065 0.13-0.2 -- -- -- 0.0032 10 EPA RfG
Carbon tetrachloride 0.00013-0.00019 0.8-1.2 0.00001 0.07 EPA CPF 0.0004 2.5 EPA RfD
Chlorobenzene 0.00063 3 -- -- -- 0.0004 20 EPA HEAST
Chloromethane 0.0006-0.0007 1.3-1.5 0.0003 0.6 EPA CPF 0.4 800 ATSDR MRL
1,1-Dichloroethane 0.000055 0.22 -- -- -- 0.125 500 EPA HEAST
1,2-Dichloroethane 0.00012-0.0015 0.5-6 -- -- EPA CPF 0.0065 26 NYS RfG
1,1-Dichloroethene 0.000005-0.00003 0.02-0.12 0.000005 0.02 EPA CPF 0.008 32 EPA RfD
cis-1,2-Dichloroethene 0.000068 0.27 -- -- -- 0.009 35 EPA RfD
Ethylbenzene 0.00017-0.0015 0.7-6.5 -- -- -- 0.230 1,000 EPA HEAST
1,1,2,2-Tetrachloroethane 0-0.057 0-398 0.000003 0.02 EPA CPF -- -- --
Tetrachloroethene 0.00003-0.00163 0.2-11.2 0.0003 2 EPA CPF 0.015 100 NYS RfG
Toluene 0.0007-0.037 3-142 -- -- -- 0.165 400 EPA RfC
1,1,1-Trichloroethane 0.0001-0.0004 0.6-2.3 -- -- -- 0.180 1,000 EPA HEAST
Trichloroethene 0.00003-0.00059 0.2-3.2 0.00011 0.59 EPA CPF 0.005 26 NYS RfG
Vinyl chloride ND ND 0.000005 0.01 EPA CPF -- -- --
Xylene (total m + p) 0.00009-0.0028 0.38-12 -- -- -- 0.069 300 EPA RfC
Xylene (ortho) 0.00009-0.0012 0.41-5.2 -- -- -- 0.161 700 EPA RfC

ND = not detected

*References: ATSDR (1989a,e; 1990b,c,i); Brodzinsky and Singh (1982); Singh et al. (1981, 1982); Wallace et al. (1984)

**Comparison value determined for a 70 kilogram adult who breathes 20 cubic meters per day.

***EPA RfC = EPA Reference Concentration
EPA CPF = EPA Cancer Potency Factor
EPA HEAST = EPA Health Effects Assessment Summary Tables
NYS RfG = NYS Risk Reference Guideline


APPENDIX C

PROCEDURE FOR EVALUATING POTENTIAL HEALTH RISKS
FROM CONTAMINANTS OF CONCERN

To evaluate the potential health risks from contaminants of concern associated with the Islip Landfill site, the New York State Department of Health assessed the risks for cancer and noncancer health effects.

Increased cancer risks were estimated by using site-specific information on exposure levels for the contaminant of concern and interpreting them using cancer potency estimates derived for that contaminant by the US EPA or, in some cases, by the NYS DOH. The following qualitative ranking of cancer risk estimates, developed by the NYS DOH, was then used to rank the risk from very low to very high. For example, if the qualitative descriptor was "low", then the excess lifetime cancer risk from that exposure is in the range of greater than one per million to less than one per ten thousand. Other qualitative descriptors are listed below:

Excess Lifetime Cancer Risk

Risk Ratio Qualitative Descriptor
equal to or less than one per million very low
greater than one per million to less
than one per ten thousand
low
one per ten thousand to less than one
per thousand
moderate
one per thousand to less than one per ten high
equal to or greater than one per ten very high

An increased excess lifetime cancer risk is not a specific estimate of expected cancers. Rather, it is an estimate of the probability that a person may develop cancer sometime in his or her lifetime following exposure to that contaminant.

There is insufficient knowledge of cancer mechanisms to decide if there exists a level of exposure to a cancer-causing agent below which there is no risk of getting cancer, namely, a threshold level. Therefore, every exposure, no matter how low, to a cancer-causing compound is assumed to be associated with some increased risk. As the dose of a carcinogen decreases, the chance of developing cancer decreases, but each exposure is accompanied by some increased risk.

There is no general consensus within the scientific or regulatory communities on what level of estimated excess cancer risk is acceptable. Some have recommended the use of the relatively conservative excess lifetime cancer risk level of one in one million because of the uncertainties in our scientific knowledge about the mechanism of cancer. Others feel that risks that are lower or higher may be acceptable, depending on scientific, economic and social factors. An increased lifetime cancer risk of one in one million or less is generally considered an insignificant increase in cancer risk.

For noncarcinogenic health risks, the contaminant intake was estimated using exposure assumptions for the site conditions. This dose was then compared to a risk reference dose (estimated daily intake of a chemical that is likely to be without an appreciable risk of health effects) developed by the US EPA, ATSDR and/or NYS DOH. The resulting ratio was then compared to the following qualitative scale of health risk:

Qualitative Descriptions for
Noncarcinogenic Health Risks

Ratio of Estimated Contaminant
Intake to Risk Reference Dose
Qualitative
Descriptor
equal to or less than the risk
reference dose
minimal
greater than one to five times
the risk reference dose
low
greater than five to ten times
the risk reference dose
moderate
greater than ten times the
risk reference dose
high

Noncarcinogenic effects unlike carcinogenic effects are believed to have a threshold, that is, a dose below which adverse effects will not occur. As a result, the current practice is to identify, usually from animal toxicology experiments, a no-observed-effect-level (NOEL). This is the experimental exposure level in animals at which no adverse toxic effect is observed. The NOEL is then divided by an uncertainty factor to yield the risk reference dose. The uncertainty factor is a number which reflects the degree of uncertainty that exists when experimental animal data are extrapolated to the general human population. The magnitude of the uncertainty factor takes into consideration various factors such as sensitive subpopulations (for example, children or the elderly), extrapolation from animals to humans, and the incompleteness of available data. Thus, the risk reference dose is not expected to cause health effects because it is selected to be much lower than dosages that do not cause adverse health effects in laboratory animals.

The measure used to describe the potential for noncancer health effects to occur in an individual is expressed as a ratio of estimated contaminant intake to the risk reference dose. If exposure to the contaminant exceeds the risk reference dose, there is major concern for potential noncancer health effects, because the margin of protection is less than that afforded by the reference dose. As a rule, the greater the ratio of the estimated contaminant intake to the risk reference dose, the greater the level of concern. A ratio equal to or less than one is generally considered an insignificant (minimal) increase in risk.


APPENDIX D

RESPONSE TO PUBLIC COMMENTS


Islip Landfill Public Health Assessment

Response to Public Comments

This responsiveness summary was prepared to answer the public's comments on the Islip Landfill draft Public Health Assessment. The public was invited to comment during the public comment period which ran from November 30, 1994, to February 20, 1995. Some comments were consolidated or grouped together to incorporate similar concerns raised by more than one person. If you have any questions, please contact the New York State Department of Health's Health Liaison Program at the toll-free number 1-800-458-1158, extension 402.

Comment #1 - The public health assessment (PHA) should include detailed information about: private well sampling, indoor air sampling for methane and vinyl chloride, ambient air modeling using the Industrial Source Complex (ISC) dispersion model, groundwater monitoring conducted during the remedial investigation (RI), and the figures and tables presented in the PHA.

Response #1 - The purpose of a PHA is to evaluate if exposure to chemicals from a hazardous waste site has occurred, or can occur, and whether exposure to these chemicals might cause harm to the public. A PHA is prepared by summarizing information about the site, including environmental data, health data and community health concerns. The detailed information requested is in the documents referenced in the PHA.

Comment #2 - The historical private well sample results should be compared to the standards in place at the time the samples were collected.

Response #2 - There were no standards for the chemicals in 1978-80 although the New York State Department of Health (NYS DOH) did have guidelines. That information has been added to Table 1. When evaluating the health effects which may be associated with existing or historical exposure to chemical contaminants, the most current health based standards and/or guidelines are used. Standards/guidelines are based on current toxicological data and are up-dated as new information becomes available.

Comment #3 - Sampling for vinyl chloride was never performed in any household basement on Woods Edge Court.

Response #3 - On May 17, 1980, the NYS DOH sampled for vinyl chloride in the basement of a home on Woods Edge Court. This information is presented in Appendix B of the June 3, 1983 Woodward-Clyde Phase I Investigation Report (PHA reference #38).

Comment #4 - Statements in the PHA concerning the detection of vinyl chloride in the Whippoorwill School are inappropriate and may not be factual.

Response #4 - Our records indicate that on May 13-14, 1980, the Town's consultant (H2M) detected 0.26 milligrams per square meter (mg/m3) of vinyl chloride in the Whippoorwill School cafeteria. Subsequent air sampling in the school by the NYS DOH and US EPA never confirmed the presence of vinyl chloride. This information is presented in Appendix B of the June 3, 1983 Phase I investigation. The PHA has been changed to indicate that the H2M sample results are questionable.

Comment #5 - Due to lack of documentation, it is inappropriate to conclude that the landfill represented a public health hazard in the past.

Response #5 - The public health categories used in preparing a PHA are defined by the Agency for Toxic Substances and Disease Registry (Appendix E). A site is categorized as a public health hazard if there are confirmed exposures to site-related contaminants in concentrations which would represent a public health concern. At the Islip Landfill, site-related contaminants were detected in private drinking water wells downgradient from the site and in the indoor air of at least two homes bordering the landfill. These homes were purchased by the Town due to the elevated levels of methane detected in the basements. Exposure to site-related contaminants in drinking water and air have since been eliminated by the extension of public water to affected homes and the construction and operation of the landfill gas control systems. Based on this information, the landfill represented a public health hazard in the past, but currently poses no apparent public health hazard.

Comment #6 - Disposal of the drums containing waste solvent in June of 1978 was never confirmed.

Response #6 - The PHA has been changed to address this concern.

Comment #7 - The Town's consultant (H2M), the NYS DOH and the United States Environmental Protection Agency (US EPA) were not involved in sampling private wells between 1978 and 1980.

Response #7 - Results of private well sampling conducted by H2M, the NYS DOH, the Suffolk County Department of Health Services and the US EPA are found in Appendix B of the June 3, 1983 Woodward-Clyde Phase I Investigation Report (PHA reference #38).

Comment #8 - The land surrounding the landfill is not flat.

Response #8 - The PHA has been changed to address this comment.

Comment #9 - Figure 3 does not show the location of the alleged solvents and the depth of drum burial is not consistent with the document.

Response #9 - The PHA has been changed to address this comment.

Comment #10 - The Nichols Road public supply wells are the only public wells downgradient from the landfill.

Response #10 - We agree with the comment. Please refer to the "Environmental Contamination and Other Hazards" section, subsection B "Off-site Contamination", "Groundwater (Public Supply Wells)" of the PHA.

Comment #11 - An elaboration of why the Nichols Road and Liberty Street wellfields were taken out of service in January 1989 should be given and the source of this information should be referenced.

Response #11 - The PHA has been changed to address this comment.

Comment #12 - The use of historical data without documentation of quality assurance/quality control (QA/QC) measures is questionable.

Response #12 - Historical environmental sampling data cited in the PHA include private well water and indoor air samples. Although documentation of actual QA/QC procedures followed at that time may not be available, the analyses were performed by reputable laboratories. The detection of site-related contaminants in private drinking water wells between 1978 and 1980 by four different laboratories supports the validity of these sampling results. The NYS DOH and US EPA laboratories were not able to confirm the presence of vinyl chloride in the air of the Whippoorwill School cafeteria which indicates that the results, initially reported by H2M, may be invalid.

Comment #13 - Concerns over the use of the term "any waste disposal area" in the second paragraph of the "Pathways Analyses" section of the PHA, will given the impression that the entire landfill, including the double lined portion of the filled area, is the source of the contamination.

Response #13 - The statement of concern is used in the introduction of the "Pathways Analysis" section to define, in general terms, "source of contamination," and does not refer specifically to the Islip Landfill.

Comment #14 - The PHA should evaluate the potential health effects associated with the exposure to contaminants in the Oval Drive public water supply well for residents living around the landfill.

Response #14 - As stated in the "Environmental Contamination and Other Hazards" section, subsection B "Off-site Contamination," "Groundwater (Public Water Supply Wells)" of the PHA, the Oval Drive public water supply wellfield is about 1.25 miles southwest of the landfill, and was taken out of service in 1977. The contamination in the Oval Drive wells is believed to have originated from the Jancyn Cesspool Cleaner manufacturers and not from the landfill. Groundwater flow from the site is to the southeast. Prior to 1980, the homes near the landfill were serviced by private wells, some of which were contaminated by solvents migrating from the site. Based on this information, the people living near the landfill were not exposed to contaminants from the Oval Drive wellfield.

Comment #15 - People living near the landfill have septic tanks which may contribute to the groundwater contamination.

Response #15 - While septic tanks can contribute to groundwater contamination, the extensive investigation of groundwater quality upgradient and downgradient from the site, indicate that the landfill is a major source of groundwater contamination downgradient from the site.

Comment #16 - A discussion of the Industrial Source Complex (ISC) dispersion model is not appropriate without reference or documentation.

Response #16 - Information about the ISC dispersion model is in the RI report (PHA reference #26) and the Malcolm Pirnie "Blydenburgh Road Landfill Air Quality Study" (PHA reference #27) which were prepared for the Town in 1991.

Comment #17 - Two homes, not nine, were purchased by the Town due to the detection of high levels of methane in basements.

Response #17 - The PHA has been changed to address this comment.

Comment #18 - One comment indicates that some of the information in the PHA is not referenced.

Response #18 - We are unaware of any information in the PHA that was not obtained from the references. If anyone has a question about a specific statement, please call Nina Knapp of the NYS DOH at the toll free number 1-800-458-1148, extension 402, and we will identify the reference and page numbers.

Comment #19 - Concerns have been raised about groundwater quality upgradient from the landfill and the frequency of groundwater monitoring at the site.

Response #19 - During the RI, several upgradient monitoring wells were developed north of the site to evaluate the quality of groundwater which is unaffected by the site. Metals and low levels of solvents were detected in some of the upgradient groundwater monitoring wells (see Table 7 in PHA). Some of the groundwater monitoring wells at the landfill are currently monitored on an annual basis as per NYS DEC regulations for a solid waste facility. Once pumping and treatment of groundwater begins in the near future, groundwater will be monitored on a quarterly basis for two years, and then annually thereafter.

Comment #20 - Concerns have been raised about the lack of on-site ambient air sampling.

Response #20 - Ambient air samples collected during the RI did not adequately evaluate on-site and off-site ambient air quality due to the lack of upwind (background) samples and significant contamination in the instrumentation quality control blanks. As an alternative to ambient air sampling, an air modeling program estimated on-site and off-site exposure to site-related compounds in air. The excess lifetime cancer risk associated with exposure to air contaminants was low for on-site workers and the residents living at the closest off-site location. Since the RI, a cap was constructed on the landfill. The landfill cap includes a gas collection/treatment system which significantly reduces the possibility of exposure to site-related air contaminants at both on-site and off-site locations.

Comment #21 - Concerns have been raised about the rate of methane migration from the landfill.

Response #21 - The production of methane in a municipal landfill is due to the bacterial decomposition of garbage in the absence of oxygen. Methane generation varies depending upon the ever changing conditions of the landfill, such as available food for the bacteria and moisture content of the fill. In the late 1970's to early 1980's, methane was migrating through the soil, beyond the landfill border. To prevent the migration of methane, the Town constructed a landfill gas collection/treatment system, which effectively eliminated methane migration beyond the site borders. The effectiveness of this system will be continually evaluated and, if necessary, upgraded to prevent methane migration.

Comment #22 - Several community members have complained about a "sewage-like" odor coming from the landfill.

Response #22 - In early 1995, the NYS DOH received calls from several people living near the landfill about a sewage-like odor coming from the site. Based on information from NYS DEC, the odor was originating from the "clean fill" section of the landfill. The clean fill section of the landfill is a lined, active section of the site permitted by the NYS DEC to receive fill absent of household garbage and any hazardous materials. The NYS DEC indicated that the odor was possibly due to the decomposition of gypsum wallboard disposed in the "clean fill" cell. The bacterial decomposition of gypsum wallboard in the absence of oxygen produces hydrogen sulfide (H2S) gas. H2S gas has a "rotten egg" or "sewage-like" odor and can be detected by many people at very low concentrations. In the spring of 1995, the Town constructed a gas collection/control system on the "clean fill" section of the site which is effectively controlling the odor problem.

Comment #23 - Concerns have been raised about the safety of the public water supply wells 2,500-3,000 feet east of the landfill.

Response #23 - The Liberty Street public drinking water supply well is approximately 3,000 feet due east of the landfill. The RI has established that groundwater flow in the area of the site is toward the southeast. Since groundwater contaminants from the landfill are migrating in a south/southeasterly direction, the Liberty Street well is unlikely to be affected by site-related contaminants. Based on recent discussion with the SC DHS, the Liberty Street supply well meets all NYS DOH public drinking water supply standards. To reduce the possibly of exposure to site-related contaminants in drinking water, contaminated groundwater near the landfill will be pumped out of the ground and treated. Treated groundwater will then be discharged to on-site groundwater recharge basins.

Comment #24 - Concerns have been raised about the existence of private wells on Evergreen Avenue.

Response #24 - Evergreen Avenue is northeast of the site and is unlikely to be affected by groundwater contaminants migrating from the landfill (see response #23). However, the NYS DOH will request that the SC DHS sample these wells.

Comment #25 - Some residents living near the landfill are concerned that their specific medical problems may be associated with exposure to site-related contaminants.

Response #25 - Specific medical concerns were referred to the NYS DOH Division of Occupational Health and Environmental Epidemiology (DOHEE). DOHEE staff will contact those individuals to discuss their concerns.

Comment #26 - How many flares are on the landfill, when were samples of the flared gas collected and what work has been done or is recommended to remediate the landfill?

Response #26 - Currently there are two flare systems, each with two stacks, on the northern and southern end of the landfill. The flare system on the southern end of landfill also receives gas from the clean fill cell. An Energy Generation Facility (EGF) is on the northwestern section of the site. The EGF uses internal combustion engines to convert landfill gas to electricity and includes seven exhaust stacks. Gas from a municipal landfill is composed predominantly of methane gas, the major component of natural gas. Although samples of flared gas have not been collected at the landfill, the burning of landfill gas is a generally accepted method of treating it. Burning the gas will reduce odors and other contaminants possibly present in the gas. A discussion of remedial activities for the landfill is in the Conclusions and Recommendations sections of the PHA.


APPENDIX E
Public Health Hazard Categories

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