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PUBLIC HEALTH ASSESSMENT

SMITHTOWN GROUNDWATER CONTAMINATION
(a/k/a SMITHTOWN GROUND WATER CONTAMINATION)
SMITHTOWN, SUFFOLK COUNTY, NEW YORK


APPENDIX A: FIGURE

Smithtown Groundwater Contamination Area
Figure 1. Smithtown Groundwater Contamination Area


APPENDIX B: TABLES

Table 1. Contaminants of Concern for Smithtown Groundwater Contamination Site
All values in micrograms per liter (µg/L)

Analytes

NYS Drinking Water Standard

US EPA MCL

UNTREATED WATER
(includes pre-filter samples)

TREATED WATER
(post-filter samples)
FoD Range FoD Range
tetrachloroethene (PCE)
5
5 160/481 <0.5 - 200 4/23 <0.5 - 11
1,1,1-trichloroethane (TCA)
5
200 261/408 <0.5 - 38 3/23 <0.5 - 2.1
cis-1,2 dichloroethene
5
70 13/35 <0.5 - 6 N/A N/A
1,2-dichloropropane
5
5 4/20 <0.5 - 14 N/A N/A

Data taken from private drinking water supply well sampling results
FoD = Frequency of Detection
* All untreated water results represent concentrations at actual exposure points (historical) or eliminated but potential exposure points (wells currently filtered)

NA = Not Analyzed or Not Available


Table 2. Contaminants Detected for Smithtown Groundwater Contamination
All values in micrograms per liter (µg/L)

Analytes WELL SAMPLES
(includes pre-filtered samples)
WELL SAMPLES
(post-filtered samples)
FoD Range FoD Range
tetrachloroethene (PCE) 160/481 <0.5 - 200 4/23 <0.5 - 11
1,1,1-trichloroethane (TCA) 261/408 <0.5 - 38 3/23 <0.5 - 2.1
trichloroethene (TCE) 16/55 <0.5 - 4 N/A N/A
1,1-dichloroethene 11/55 <0.5 - 1 N/A N/A
1,1-dichloroethane 26/55 <0.5 - 3 N/A N/A
cis-1,2 dichloroethene 13/35 <0.5 - 6 N/A N/A
dichlorodifluoromethane 9/35 <0.5 - 3 N/A N/A
1,2-dichloropropane 4/20 <0.5 - 14 N/A N/A
chloroform 3/55 <0.5 - 3 N/A N/A
chlorofluoromethane 4/55 <0.5 - 2 N/A N/A
methyl tert butyl ether (MTBE) 3/55 <0.5 - 1 N/A N/A
TCPA 2/20 <10.0 - 42 N/A N/A
1,2,3-trichloropropane 1/20 <0.5 - 2 N/A N/A

Data taken from private drinking water supply well sampling results
FoD = Frequency of Detection
N/A = Not Analyzed or Not Available
TCPA is a breakdown product of the pesticide dacthal.


Table 3. Water Quality Standards/Guidelines and/or Public Health Assessment Comparison Values Exceeded by Contaminants Found in Private Drinking Water Wells at Smithtown Groundwater Contamination Site
[All values in micrograms per liter (µg/L)]

  Water Quality Standards/Guidelines  
  New York State US EPA Comparison Values*
  Range of Ground- Drinking Drinking        
Contaminant Detection Water Water Water Cancer Basis** Noncancer Basis**
                 
Untreated Water              
cis-1,2-dichloroethene 0.5 - 6 5 5 70 -- -- 70 EPA LTHA
1,2-dichloropropane 0.5 - 14 5 5 5 0.51 EPA HEAST 630 ATSDR MRL
tetrachloroethene 0.5 - 200 5 5 5 0.7 EPA HEAST 70 EPA RfD
1,1,1-trichloroethane 0.5 - 38 5 5 200 -- -- 140 EPA PV
                 
Treated Water              
tetrachloroethene 0.5 - 11 5 5 5 0.7 EPA HEAST 70 EPA RfD
                 
* Comparison values determined for a 70 kg adult who drinks 2 liters of water per day.
 
** ATSDR MRL = ATSDR Minimal Risk Level
EPA CPF = US EPA Cancer Potency Factor
EPA HEAST = US EPA Health Effects Assessment Summary Tables
EPA LTHA = US EPA Lifetime Health Advisory
EPA RfD = US EPA Reference Dose
EPA PV = Provisional value from US EPA Superfund Technical Support Center; National Center for Environmental Assessment


APPENDIX C: NEW YORK STATE DEPARTMENT OF HEALTH PROCEDURES FOR EVALUATING POTENTIAL HEALTH RISKS FOR CONTAMINANTS OF CONCERN

To evaluate the potential health risks from contaminants of concern associated with the Smithtown Groundwater Contamination 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 estimated increased excess lifetime cancer risk is not a specific estimate of expected cancers. Rather, it is a plausible upper bound 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 general consensus among the scientific and regulatory communities on what level of estimated excess cancer risk is acceptable. An increased lifetime cancer risk of one in one million or less is generally not considered a significant public health concern.

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. A ratio equal to or less than one is generally not considered a significant public health concern. If exposure to the contaminant exceeds the risk reference dose, there may be 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. This level of concern depends upon an evaluation of a number of factors such as the actual potential for exposure, background exposure, and the strength of the toxicologic data.


APPENDIX D: PUBLIC HEALTH HAZARD CATEGORIES

 

CATEGORY / DEFINITION DATA SUFFICIENCY CRITERIA
A. Urgent Public Health Hazard

This category is used for sites where short-term exposures (< 1 yr) to hazardous substances or conditions could result in adverse health effects that require rapid intervention.

This determination represents a professional judgement based on critical data which ATSDR has judged sufficient to support a decision. This does not necessarily imply that the available data are complete; in some cases additional data may be required to confirm or further support the decision made. Evaluation of available relevant information* indicates that site-specific conditions or likely exposures have had, are having, or are likely to have in the future, an adverse impact on human health that requires immediate action or intervention. Such site-specific conditions or exposures may include the presence of serious physical or safety hazards.
B. Public Health Hazard

This category is used for sites that pose a public health hazard due to the existence of long-term exposures (> 1 yr) to hazardous substance or conditions that could result in adverse health effects.

This determination represents a professional judgement based on critical data which ATSDR has judged sufficient to support a decision. This does not necessarily imply that the available data are complete; in some cases additional data may be required to confirm or further support the decision made. Evaluation of available relevant information* suggests that, under site-specific conditions of exposure, long-term exposures to site-specific contaminants (including radionuclides) have had, are having, or are likely to have in the future, an adverse impact on human health that requires one or more public health interventions. Such site-specific exposures may include the presence of serious physical or safety hazards.
C. Indeterminate Public Health Hazard

This category is used for sites in which "critical" data are insufficient with regard to extent of exposure and/or toxicologic properties at estimated exposure levels.

This determination represents a professional judgement that critical data are missing and ATSDR has judged the data are insufficient to support a decision. This does not necessarily imply all data are incomplete; but that some additional data are required to support a decision. The health assessor must determine, using professional judgement, the "criticality" of such data and the likelihood that the data can be obtained and will be obtained in a timely manner. Where some data are available, even limited data, the health assessor is encouraged to the extent possible to select other hazard categories and to support their decision with clear narrative that explains the limits of the data and the rationale for the decision.
D. No Apparent Public Health Hazard

This category is used for sites where human exposure to contaminated media may be occurring, may have occurred in the past, and/or may occur in the future, but the exposure is not expected to cause any adverse health effects.

This determination represents a professional judgement based on critical data which ATSDR considers sufficient to support a decision. This does not necessarily imply that the available data are complete; in some cases additional data may be required to confirm or further support the decision made. Evaluation of available relevant information* indicates that, under site-specific conditions of exposure, exposures to site-specific contaminants in the past, present, or future are not likely to result in any adverse impact on human health.
E: No Public Health Hazard

This category is used for sites that, because of the absence of exposure, do NOT pose a public health hazard.

Sufficient evidence indicates that no human exposures to contaminated media have occurred, none are now occurring, and none are likely to occur in the future  

*Such as environmental and demographic data; health outcome data; exposure data; community health concerns information; toxicologic, medical, and epidemiologic data; monitoring and management plans


APPENDIX E: ATSDR GLOSSARY OF ENVIRONMENTAL HEALTH TERMS

Absorption:
How a chemical enters a person's blood after the chemical has been swallowed, has come into contact with the skin, or has been breathed in.


Acute Exposure:
Contact with a chemical that happens once or only for a limited period of time. ATSDR defines acute exposures as those that might last up to 14 days.


Additive Effect:
A response to a chemical mixture, or combination of substances, that might be expected if the known effects of individual chemicals, seen at specific doses, were added together.


Adverse Health Effect:
A change in body function or the structures of cells that can lead to disease or health problems.


Antagonistic Effect:
A response to a mixture of chemicals or combination of substances that is less than might be expected if the known effects of individual chemicals, seen at specific doses, were added together.


ATSDR:
The Agency for Toxic Substances and Disease Registry. ATSDR is a federal health agency in Atlanta, Georgia that deals with hazardous substance and waste site issues. ATSDR gives people information about harmful chemicals in their environment and tells people how to protect themselves from coming into contact with chemicals.


Background Level:
An average or expected amount of a chemical in a specific environment. Or, amounts of chemicals that occur naturally in a specific environment.


Biota:
Used in public health, things that humans would eat - including animals, fish and plants.


CAP:
See Community Assistance Panel.


Cancer:
A group of diseases which occur when cells in the body become abnormal and grow, or multiply, out of control


Carcinogen:
Any substance shown to cause tumors or cancer in experimental studies.


CERCLA:
See Comprehensive Environmental Response, Compensation, and Liability Act.


Chronic Exposure:
A contact with a substance or chemical that happens over a long period of time. ATSDR considers exposures of more than one year to be chronic.


Completed Exposure Pathway:
See Exposure Pathway.


Community Assistance Panel (CAP):
A group of people from the community and health and environmental agencies who work together on issues and problems at hazardous waste sites.


Comparison Value (CVs):
Concentrations or the amount of substances in air, water, food, and soil that are unlikely, upon exposure, to cause adverse health effects. Comparison values are used by health assessors to select which substances and environmental media (air, water, food and soil) need additional evaluation while health concerns or effects are investigated.


Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA):
CERCLA was put into place in 1980. It is also known as Superfund. This act concerns releases of hazardous substances into the environment, and the cleanup of these substances and hazardous waste sites. ATSDR was created by this act and is responsible for looking into the health issues related to hazardous waste sites.


Concern:
A belief or worry that chemicals in the environment might cause harm to people.


Concentration:
How much or the amount of a substance present in a certain amount of soil, water, air, or food.


Contaminant:
See Environmental Contaminant.


Delayed Health Effect:
A disease or injury that happens as a result of exposures that may have occurred far in the past.


Dermal Contact:
A chemical getting onto your skin. (see Route of Exposure).


Dose:
The amount of a substance to which a person may be exposed, usually on a daily basis. Dose is often explained as "amount of substance(s) per body weight per day".


Dose / Response:
The relationship between the amount of exposure (dose) and the change in body function or health that result.


Duration:
The amount of time (days, months, years) that a person is exposed to a chemical.


Environmental Contaminant:
A substance (chemical) that gets into a system (person, animal, or the environment) in amounts higher than that found in Background Level, or what would be expected.


Environmental Media:
Usually refers to the air, water, and soil in which chemical of interest are found. Sometimes refers to the plants and animals that are eaten by humans. Environmental Media is the second part of an Exposure Pathway.


U.S. Environmental Protection Agency (EPA):
The federal agency that develops and enforces environmental laws to protect the environment and the public's health.


Epidemiology:
The study of the different factors that determine how often, in how many people, and in which people will disease occur.


Exposure:
Coming into contact with a chemical substance.(For the three ways people can come in contact with substances, see Route of Exposure.)


Exposure Assessment:
The process of finding the ways people come in contact with chemicals, how often and how long they come in contact with chemicals, and the amounts of chemicals with which they come in contact.


Exposure Pathway:
A description of the way that a chemical moves from its source (where it began) to where and how people can come into contact with (or get exposed to) the chemical.

ATSDR defines an exposure pathway as having 5 parts:
  1. Source of Contamination,

  2. Environmental Media and Transport Mechanism,

  3. Point of Exposure,

  4. Route of Exposure; and,

  5. Receptor Population.

When all 5 parts of an exposure pathway are present, it is called a Completed Exposure Pathway. Each of these 5 terms is defined in this Glossary.


Frequency:
How often a person is exposed to a chemical over time; for example, every day, once a week, twice a month.


Hazardous Waste:
Substances that have been released or thrown away into the environment and, under certain conditions, could be harmful to people who come into contact with them.


Health Effect:
ATSDR deals only with Adverse Health Effects (see definition in this Glossary).


Indeterminate Public Health Hazard:
The category is used in Public Health Assessment documents for sites where important information is lacking (missing or has not yet been gathered) about site-related chemical exposures.


Ingestion:
Swallowing something, as in eating or drinking. It is a way a chemical can enter your body (See Route of Exposure).


Inhalation:
Breathing. It is a way a chemical can enter your body (See Route of Exposure).


LOAEL:
Lowest Observed Adverse Effect Level. The lowest dose of a chemical in a study, or group of studies, that has caused harmful health effects in people or animals.


Malignancy:
See Cancer.


MRL:
Minimal Risk Level. An estimate of daily human exposure - by a specified route and length of time -- to a dose of chemical that is likely to be without a measurable risk of adverse, noncancerous effects. An MRL should not be used as a predictor of adverse health effects.


NPL:
The National Priorities List. (Which is part of Superfund.) A list kept by the U.S. Environmental Protection Agency (EPA) of the most serious, uncontrolled or abandoned hazardous waste sites in the country. An NPL site needs to be cleaned up or is being looked at to see if people can be exposed to chemicals from the site.


NOAEL:
No Observed Adverse Effect Level. The highest dose of a chemical in a study, or group of studies, that did not cause harmful health effects in people or animals.


No Apparent Public Health Hazard:
The category is used in ATSDR's Public Health Assessment documents for sites where exposure to site-related chemicals may have occurred in the past or is still occurring but the exposures are not at levels expected to cause adverse health effects.


No Public Health Hazard:
The category is used in ATSDR's Public Health Assessment documents for sites where there is evidence of an absence of exposure to site-related chemicals.


PHA:
Public Health Assessment. A report or document that looks at chemicals at a hazardous waste site and tells if people could be harmed from coming into contact with those chemicals. The PHA also tells if possible further public health actions are needed.


Plume:
A line or column of air or water containing chemicals moving from the source to areas further away. A plume can be a column or clouds of smoke from a chimney or contaminated underground water sources or contaminated surface water (such as lakes, ponds and streams).


Point of Exposure:
The place where someone can come into contact with a contaminated environmental medium (air, water, food or soil). For examples:
the area of a playground that has contaminated dirt, a contaminated spring used for drinking water, the location where fruits or vegetables are grown in contaminated soil, or the backyard area where someone might breathe contaminated air.


Population:
A group of people living in a certain area; or the number of people in a certain area.


PRP:
Potentially Responsible Party. A company, government or person that is responsible for causing the pollution at a hazardous waste site. PRP's are expected to help pay for the clean up of a site.


Public Health Assessment(s):
See PHA.


Public Health Hazard:
The category is used in PHAs for sites that have certain physical features or evidence of chronic, site-related chemical exposure that could result in adverse health effects.


Public Health Hazard Criteria:
PHA categories given to a site which tell whether people could be harmed by conditions present at the site. Each are defined in the Glossary. The categories are:
- Urgent Public Health Hazard
- Public Health Hazard
- Indeterminate Public Health Hazard
- No Apparent Public Health Hazard
- No Public Health Hazard


Receptor Population:
People who live or work in the path of one or more chemicals, and who could come into contact with them (See Exposure Pathway).


Reference Dose (RfD):
An estimate, with safety factors (see safety factor) built in, of the daily, life-time exposure of human populations to a possible hazard that is not likely to cause harm to the person.


Route of Exposure:
The way a chemical can get into a person's body. There are three exposure routes:
- breathing (also called inhalation),
- eating or drinking (also called ingestion), and
- or getting something on the skin (also called dermal contact).


Safety Factor:
Also called Uncertainty Factor. When scientists don't have enough information to decide if an exposure will cause harm to people, they use "safety factors" and formulas in place of the information that is not known. These factors and formulas can help determine the amount of a chemical that is not likely to cause harm to people.


SARA:
The Superfund Amendments and Reauthorization Act in 1986 amended CERCLA and expanded the health-related responsibilities of ATSDR. CERCLA and SARA direct ATSDR to look into the health effects from chemical exposures at hazardous waste sites.


Sample Size:
The number of people that are needed for a health study.


Sample:
A small number of people chosen from a larger population (See Population).


Source (of Contamination):
The place where a chemical comes from, such as a landfill, pond, creek, incinerator, tank, or drum. Contaminant source is the first part of an Exposure Pathway.


Special Populations:
People who may be more sensitive to chemical exposures because of certain factors such as age, a disease they already have, occupation, sex, or certain behaviors (like cigarette smoking). Children, pregnant women, and older people are often considered special populations.


Statistics:
A branch of the math process of collecting, looking at, and summarizing data or information.


Superfund Site:
See NPL.


Survey:
A way to collect information or data from a group of people (population). Surveys can be done by phone, mail, or in person. ATSDR cannot do surveys of more than nine people without approval from the U.S. Department of Health and Human Services.


Synergistic effect:
A health effect from an exposure to more than one chemical, where one of the chemicals worsens the effect of another chemical. The combined effect of the chemicals acting together are greater than the effects of the chemicals acting by themselves.


Toxic:
Harmful. Any substance or chemical can be toxic at a certain dose (amount). The dose is what determines the potential harm of a chemical and whether it would cause someone to get sick.


Toxicology:
The study of the harmful effects of chemicals on humans or animals.


Tumor:
Abnormal growth of tissue or cells that have formed a lump or mass.


Uncertainty Factor:
See Safety Factor.


Urgent Public Health Hazard:
This category is used in ATSDR's Public Health Assessment documents for sites that have certain physical features or evidence of short-term (less than 1 year), site-related chemical exposure that could result in adverse health effects and require quick intervention to stop people from being exposed.

APPENDIX F: RESPONSE TO PUBLIC COMMENTS

This summary was prepared to address comments and questions on the public comment draft of the Smithtown Groundwater Contamination Site Public Health Assessment. The public was invited to review the draft during the public comment period, which ran from December 18, 2001 through January 17, 2002. We received four responses, two of which were from public agencies. Some comments were addressed by minor changes in the text of this public health assessment. These comments are not reproduced in this summary. Some statements were reworded for clarity. If you have any questions about this summary, you can contact the New York State Department of Health's (NYS DOH) Outreach Unit at the toll-free number: 1-800-458-1158, extension 27530.

Comment #1 - Is the contamination in general getting worse, less, or is it the same as when the investigation started?

Response #1 - The degree of groundwater contamination in the area seems to be about the same as it was when the investigation started. The United States Environmental Protection Agency (US EPA) is conducting a Remedial Investigation to look for sources for the groundwater contamination. The results so far suggest that the contamination is not a single defined plume but rather a number of small "slugs" of contaminated groundwater. When the investigation is complete, a Remedial Investigation Report will be published. The report will be available to the public at the document repository for the site, which is the Smithtown Library, 1 North Country Road, Smithtown, NY 11787.

Comment #2 -Have any individuals been indicted or convicted of causing the contamination?

Response #2 - No. Investigations to date have not determined the source of the contamination detected in private wells in Smithtown. As the Remedial Investigation continues, potential source areas will be investigated. Those found to be contributing to groundwater contamination will be addressed under an appropriate remedial program by the US EPA or the New York State Department of Environmental Conservation (NYS DEC).

Comment #3 - Will the monitoring effort continue? If so, for how long?

Response #3 - The monitoring of private water supplies will continue until a remedy for the contamination is in place. The US EPA has been monitoring private water supplies about once a year for the past several years as part of the Remedial Investigation, and they will continue to do so. Residents who continue to use private wells and wish to have their water tested more frequently may contact the Suffolk County Department of Health Services (SCDHS) Laboratory, which provides this service for a fee. As of this writing, the cost of the analysis is $65 per sample. A number of private laboratories can also test water samples, but the cost will likely be higher. For more information about having a private water supply tested, please contact the NYS DOH at the number listed above or the SCDHS at (631) 853-2250.

Comment #4 - Each homeowner should be connected by state and federal means to the Suffolk County Water Authority water supply immediately.

Response #4 - The US EPA is able to provide public water supply connections (where available) or private water supply treatment for homes where contamination in private water supplies exceeds Federal drinking water standards, also called Maximum Contaminant Levels or MCLs. To date, the US EPA has connected 29 homes and provided water treatment systems for 9 homes where public water supply was not available. The supply wells for all of these homes were contaminated with tetrachloroethene (PCE) at concentrations greater than the MCL of five  micrograms per liter (5 µg/L).

There are some private water supplies in the area in which contaminant concentrations (primarily 1,1,1-trichloroethane [1,1,1-TCA]) exceed New York State drinking water standards but do not exceed Federal drinking water standards. The US EPA cannot provide connections or treatment for wells where concentrations do not exceed Federal standards. The New York State Superfund Program is set up to remediate contamination that originates from a known source. Because no source has yet been found for the Smithtown Groundwater Contamination, the NYS DEC cannot use Superfund monies to provide public water supply connections or treatment for private wells impacted by the contamination.

Residents whose private water supplies are contaminated at levels below Federal standards and who wish to reduce their exposure to those contaminants may take actions on their own. These actions may include connecting to the public water supply system where it is available or installing and maintaining a water treatment system where public water is not available. The NYS DOH and the SCDHS can provide guidance on the selection, installation and maintenance of a treatment system for a private water supply.

Comment #5 - I am very concerned about the slow reaction to the problem. Little has been done in the 6-7 years since the contamination has been recognized.

Response #5 - This investigation and others like it take a considerable amount of time. However, much has been accomplished.

The existence of relatively widespread groundwater contamination in the area was recognized during the SCDHS's private well sampling effort, which took place between 1996 and 1998. The initial responses to the discovery were focused on reducing exposures to the contamination. By July 1998, US EPA had begun to provide public water supply connections or treatment systems to residences where private water supplies exceeded the US EPA MCL for one or more volatile organic compounds. This effort continues. If ongoing monitoring at the site shows that a private well has exceeded the US EPA MCL for one or more volatile organic compounds, the US EPA will provide a water supply connection, if possible, or a treatment system if public water is unavailable.

The SCDHS investigated a number of potential sources of contamination - primarily existing or former dry cleaners - in 1997 and 1998. The SCDHS found contamination in onsite wastewater disposal systems (such as septic tanks and leaching pools) at several of these establishments. The contaminated systems were cleaned with oversight from the SCDHS. Whether any of these systems were sources of the contamination detected in private wells in Smithtown is not known.

In 1999, the US EPA developed a work plan for a Remedial Investigation to fully characterize the extent of groundwater contamination in the area. The plan called for two phases of investigation: Phase 1 would determine the extent of contamination in the impacted residential area, and Phase 2 would focus on the apparent sources of the contamination suggested by Phase 1.

The US EPA had difficulty negotiating access to conduct the field work for Phase 1 of the investigation, which delayed the investigation for nearly a year. The Phase 1 work began in 2001 and was completed by the spring of 2002. As of this writing, the US EPA is evaluating the results of Phase 1 and planning the scope of work for Phase 2. The results of the investigations will be documented in Remedial Investigation Reports, which will be placed in the document repositories for the site. The Phase 1 Report should be available during the calendar year 2002.

The Remedial Investigation will be followed by a Feasibility Study in which options for remediating the contamination will be evaluated. Based on this evaluation, the US EPA will present its proposed remedy to the public in a Proposed Remedial Action Plan. The public will have the opportunity to comment on the proposed remedy, and the US EPA will consider those comments in selecting the final remedy for the contamination.

Comment # 6 - Page 14, Last Paragraph: The text focuses on exposure via ingestion. The text should also address potential exposure through inhalation of aerosols and vapors from drinking water. This evaluation can be either quantitative or qualitative.

Response # 6 - Although the term "drinking water" is used in the text, it is not meant to suggest that ingestion is the only route of exposure to contaminants in a drinking water supply. As stated on page 11, exposure to contaminants in drinking water supplies can occur via ingestion, dermal contact and inhalation from water uses such as showering, bathing or other household uses.


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