PUBLIC HEALTH ASSESSMENT
CLARKE ROAD MUNICIPAL SOLID WASTE LANDFILL
WAYNESBORO, BURKE COUNTY, GEORGIA
The Burke County Clarke Road Municipal Solid Waste Landfill (MSWL) opened in 1975 and is still in operation. This landfill has two areas which accept waste, one cell for municipal and the other for construction and demolition waste (1). Several residences exist along the southern border of the site and were reported to have been built around 1978.
The Georgia Environmental Protection Division (EPD) and the consultant for Burke County, Tribble and Richardson, Inc. (T&R) collected drinking-water well samples on May 12, 1997, at seven residences in the vicinity of the landfill. A sample was also taken from the one potable well on the landfill property. One private well test indicated the presence of contamination in both the split samples. The county valved off the contaminated well and connected the residence to an alternative supply of water on May 30, 1997.
EPD asked the Georgia Division of Public Health (GDPH) to conduct a public health investigation at the Clarke Road MSWL in Waynesboro, Georgia. EPD is concerned about possible adverse health effects caused by past, present, and future exposures to environmental contamination from the landfill. The cooperation between EPD and GDPH was initiated through a memorandum of agreement for GDPH to address public health hazards at any Georgia sites when EPD is concerned about environmental contamination releases from a site it regulates.
GDPH classifies this site as no apparent public health hazard. Discussions of exposure pathways, specific contaminants, and conclusions about the risk posed to residents near the landfill are included in this document.
GDPH recommends that: (1) To insure that residents are not exposed to contaminants present in the single impacted private well, EPD should continue to recommend that this water source not be used for consumption or any other use where humans may come into contact with it; (2) because other private wells could be impacted by groundwater contamination, EPD should continue to require monitoring private wells in the area at least yearly until the area is remediated; and (3) because the source of contamination is unclear and private wells could be contaminated in the future, EPD should continue to require that the extent of off-site groundwater contamination is sufficiently delineated and that the risk site contamination poses to area private wells is determined.
The purpose of this public health assessment is to answer several questions which were posed by the Georgia Department of Natural Resources, Environmental Protection Division (EPD), which relate to the health of residents in the vicinity of the Clarke Road Municipal Solid Waste Landfill (MSWL)in Waynesboro, Georgia. These questions are:
The discussion of health effects will be limited to those which may result from exposure to contaminants released from this particular source. This document specifically discusses any potential routes of exposure that have existed in the past, that may currently exist, and that may exist in the future. The discussion of exposure issues focuses on any impacts that releases from the landfill may have on private wells in areas surrounding the site. Because this is a public health document, it does not address issues of liability, remediation alternatives, future land use, and other non-health issues. Ultimately, this document provides conclusions on the public health issues relevant to this site and states recommendations to protect the health of the residents in the area.
EPD asked GDPH to conduct a public health investigation at the Clarke Road MSWL in Waynesboro, Georgia. EPD is concerned about possible adverse health effects caused by past, present, and future exposures to environmental contamination from the landfill. The cooperation between EPD and GDPH was initiated through a memorandum of agreement for GDPH to address public health hazards at any Georgia sites when EPD is concerned about environmental contamination releases from a site it regulates.
The landfill opened in 1975 and is still in operation. This landfill has two areas which accept waste, one cell for municipal and the other for construction and demolition waste (1). The homes along the southern border were reportedly built around 1978.
EPD and the consultant for Burke County, Tribble and Richardson, Inc. (T&R) collected drinking-water well samples on May 12, 1997, at seven residences near the landfill. A sample was also taken from the one potable well on the landfill property. One private well test indicated the presence of contamination in both the split samples. The county valved off the contaminated well and connected the residence to an alternative supply of water on May 30, 1997.
After further efforts by T&R to characterize the direction of flow and the extent of off-site contamination, GDPH and EPD asked that all residences be retested for private well-water contamination. These samples were taken on January 2, 1999, and only the private well which was previously affected showed measurable levels of contamination.
NATURE AND EXTENT OF CONTAMINATION
All four contaminants detected in the private well sample were volatile organic compounds (VOCs), including methylene chloride, 1,1-dichloroethane, tetrachloroethene, and cis-1,2-dichloroethene. Two compounds were detected at levels above the appropriate maximum contaminant levels (MCL): methylene chloride recorded at 7.5 parts per billion (ppb) and tetrachloroethene at 7 ppb (Table 1) (2). The second round of samples on this well indicated that both these contaminants were still present but at slightly lower levels (3). Whether the contamination is directly associated with the landfill or with another source has not been clearly determined.
PUBLIC HEALTH CONCERNS AND DEMOGRAPHICS
Several residences are in the area near the landfill, including seven homes which border the site along the southern border. The nearest residence is the home where contamination was detected in the private well. This home is about 1,500 feet from the border of the landfill. At least seven private wells are within a mile of the landfill. The number of individuals who reside in the area around the landfill has also been investigated (Table 4).
City officials, representatives from GDPH, and the Burke County Health Department conducted a site visit and resident interviews. No specific concerns relating to health were reported by residents who were interviewed, but a level of concern exists about contamination of the private well and the potential that other wells could be contaminated in the future (4).
This public health assessment was released for public comment on May 3, 1999. GDPH received no comments.
Discussing the potential for adverse health effects due to exposure to environmental chemicals is best done by evaluating human exposure pathways. Pathways are generally evaluated as on site and off site and by the media which are contaminated. Because on-site exposures are not a concern at this site, only off-site exposure pathways are discussed. The only environmental medium shown to be contaminated off site is groundwater. A completed exposure pathway was found at one residence, and potential exposure pathways may exist in the future.
Off-site Groundwater
A completed exposure pathway to contaminated groundwater at one residence, which is the nearest property to the landfill, was found (Table 2). This residence has been occupied since 1978 and has housed four people over that time. The two contaminants detected in this residence's well were above the MCL and are listed in Table 1. The comparison values used in this document are meant only to screen for contaminants that should be further evaluated and do not represent thresholds of toxicity. Levels of exposure above these values do not indicate that adverse health effects can be expected. Because past exposures may have occurred, the contaminants require discussion. Even though some of these compounds exist at levels above comparison values, including MCLs, the contaminants can only affect someone who is actually exposed and if the exposure results in high enough doses for adverse effects to occur. For that reason, we focus on contamination for which exposure may have occurred off site and discuss only chemicals that may pose a threat to public health if exposure was high enough to possibly cause adverse health effects. We reviewed the scientific literature, comparison values, and possible health effects associated with the contaminants selected for evaluation. The results of our review are presented in this section.
Methylene Chloride: The highest recorded level of methylene chloride in private well water was 7.5 ppb. The MCL for this contaminant is 5 ppb, and the ATSDR comparison value is 5 ppb. This comparison value has been set for carcinogenic substances. The Department of Health and Human Services (DHHS) has determined that methylene chloride may reasonably be anticipated to be a carcinogen (5).
We estimated the dose to children and adults for this compound through ingestion of drinking water and compared this value to the health guideline (Table 5) (Appendix A). The estimated exposure to children and adults did NOT exceed this guideline. The cancer risk due to exposure to this contaminant was estimated for 19 years and was NOT found to pose a significant increase in cancer risk (Table 5) (Appendix A).
Tetrachloroethene: The highest recorded level of tetrachloroethene in private well water was 7 ppb. The MCL for this contaminant is 5 ppb, and the ATSDR comparison value is 0.7 ppb. This comparison value has been set for carcinogenic substances. DHHS has determined that tetrachloroethene may reasonably be anticipated to be a carcinogen (6).
We estimated the dose to children and adults for this compound through ingestion of drinking water and compared this value to the health guideline (Table 5) (Appendix A). The estimated exposure to children and adults did NOT exceed this guideline. The cancer risk due to exposure to this contaminant was estimated for 19 years and was NOT found to pose a significant increase in cancer risk (Table 5) (Appendix A).
A potential exposure pathway exists in the future through ingestion of groundwater if contamination present near the currently contaminated well migrates to other wells in the area (Table 3). Further characterization by T&R of the nature and extent of groundwater contamination in the vicinity of the landfill will provide better insight into the possibility that other private wells in the area could be impacted.
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