HEALTH CONSULTATION
Water Quality and Vapor Intrusion Assessment
RAVENSWOOD PCE
RAVENSWOOD, JACKSON COUNTY, WEST VIRGINIA
BACKGROUND AND STATEMENT OF ISSUES
The United States Environmental Protection Agency (EPA), Region III, asked the West Virginia Department of Health and Human Resources (WVDHHR) to determine whether any current or future human health risk exists from exposure to tetrachloroethylene (PCE) by drinking water supplied by the Ravenswood Public Service District (PSD). They also asked whether a risk exists from PCE vapors moving from groundwater into homes and businesses located over the contaminated groundwater. The EPA further requested that WVDHHR provide recommendations for protective public health activities and further environmental sampling, if a human health risk was identified or suspected. This health consultation was prepared under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR).
The Ravenswood PCE site (the "site") is located in the town of Ravenswood, Jackson County, West Virginia. The center of the site is the Ravenswood Maintenance Building, 329 Virginia Street, between Sycamore Street and Plaza Drive. This is in a mixed residential and commercial area. The site consists of a municipal drinking water plant with five wells clustered together near the center of the city of Ravenswood and much of the wellhead protection area southwest of the water plant. Overall the site covers approximately 30 city blocks. The site is bounded by Sandy Creek to the south, Water Street to the west, Plaza Drive to the north, and Henrietta Street to the east [1]. Grassy areas and asphalt parking lots surround the maintenance building [2]. Facilities near the maintenance building are; the Ravenswood High School and baseball field to the northeast, the Jackson County Public Library to the southeast, a public playground on the other side of the library from the maintenance building, and a bank to the south across Virginia Street. The Ohio River is 1,700 feet west of the site (Figure 1).
The water wells and water plant are operated by the Ravenswood PSD. Water from the municipal wells is blended together to produce the water sold by the Ravenswood PSD. Two of the five wells are located inside the maintenance building. The other three wells are on city property within a 3-4 acre area surrounding the maintenance building [3].
PCE is used extensively as a dry cleaning solvent and as a metal degreasing agent. The source or sources of PCE contamination at this site are unknown [2]. PCE contamination may be from one or more of three former dry cleaning establishments, from the former power plant that is now the maintenance building, or from disposal of degreasing agents used in the maintenance building [4]. In addition to tetrachloroethylene, PCE is also called perchloroethylene, perc, perclene, ethylene tetrachloride, and perchlor.
PCE was first found in the blended water in September 1989. It has been detected at levels above the EPA's Maximum Contamination Level (MCL) of 5 parts per billion (ppb) in six samples of blended water collected over a period of 14 years. The latest sample exceeding the MCL was in November of 1999 [2]. During this period, 32 samples of blended water showed PCE below the 5 ppb MCL. In more than half the samples, PCE was not detected in the blended water. The EPA's Maximum Contaminant Level is the maximum amount of a given chemical that is allowed in a public water system. The MCL level is set to protect persons who drink 2 liters of water a day over a lifetime (70 years).
Water from Well #3, the well showing the highest concentration of PCE, was not used in the blended water from the end of 1998 until June 2000. Since June 2000 water from Well #3 and Well #5 has been pumped through an air stripper, which allows some of the PCE to evaporate from the water into the air. Since the air stripper has been in operation the blended water has not exceeded the MCL limit for PCE.
EPA has awarded a $1.3 million grant to the city of Ravenswood to drill two new water wells in an area beyond where the groundwater is contaminated with PCE. The mayor of Ravenswood said he expects to have water from the new wells by the summer of 2004.
Indications are that a few private wells near the site have been used for drinking water in the past. The private well nearest to the site was located 1500 feet east [3]. Water plant personnel report that this well was taken out of service when the property changed ownership about 10 years ago. No water quality data are available from this, or other wells near this site [2]. Currently, no private wells are known to be used in the site vicinity.
The Ravenswood PSD supplies water to 4005 persons in Ravenswood and 1847 persons in the nearby city of Silverton. This includes 2079 students in five schools [2]. Some students are from homes supplied by the PSD and others live in areas outside the PSD [3].
The site is located on the Ohio River flood plain. Soil underlying the site consists of sand accumulated by the action of water. Clays are located near the surface. Groundwater at this site comes from rain and snow and the Ohio River [5]. Sand in the groundwater zone allow much water to move through it -- between 100 and 500 gallons per minute (gpm). Groundwater is generally found between 60 and 90 feet below the ground surface [6]. Groundwater levels under the site rise and fall with the level of water in the Ohio River [3]. Although normal groundwater flow would be from the site toward the Ohio River, the volume of water being pumped out by the wells (an average of 700,000 gallons per day) at the site has lowered the groundwater level to a point where the groundwater is believed to flow from the Ohio River toward the well field [3].
Conclusions in this document are determined by the availability and reliability of information reviewed by WVDHHR. This data review assumes that adequate quality assurance and control measures were taken during chain-of-custody, laboratory procedures, and data reporting for all data utilized in this report.
Ravenswood Public Service District Blended Water
Sample data on file in the WVDHHR offices for blended water from the Ravenswood PSD were reviewed. These samples are taken by the water system operator to determine compliance with the National Primary Drinking Water Regulations. The samples reviewed were taken between June 1989 and January 2003. The number of samples ranged from one to eleven per year. Additionally, samples of blended water collected and analyzed by the EPA from May through September 1999 were reviewed. Samples of water from individual wells were not reviewed for this report because persons are drinking blended water, not water from individual wells.
PCE was not tested in the water prior to June 1989. The first test for PCE did not detect PCE in the blended water above the detection limit of 0.1 ppb. The second test for PCE, in September 1989 detected PCE in the water at 7 ppb. The data reviewed showed that blended water distributed to the public has exceeded the MCL (5 ppb) on six occasions: September 1989 (7 ppb), January 1995 (8.2 ppb), January 1997 (7.6 ppb), March 1998 (10.8 ppb), September 1999 (6.6 ppb), and November 1999 (5.6 ppb). No data exceeding the MCL have been noted in the blended water since November 1999.
EPA's investigation determined that the groundwater containing PCE (the plume) extends southward from the area of Well #3 on Virginia Street for approximately 1,400 feet to Broadway Street (Figure 1). The plume is about 400 feet wide in the upper portion of the water-bearing zone (about 60 feet bgs) and 100 feet wide in the lower portion (about 90 feet bgs). Groundwater at about 60 feet bgs contains more PCE than does the groundwater at lower levels [2 ,7].
Concentrations of PCE between 30 ppb and 70 ppb have been found in the groundwater within approximately 50 feet of the public wells. A monitoring well at the southwest corner of the library lot (approximately 200 feet from the well field) showed PCE in the groundwater at 324 ppb. Concentrations of PCE in groundwater in other areas of the plume were measured from 70 to 150 ppb [1,2].
Vapors of a volatile chemical, such as PCE, could move through the soil and into buildings located over PCE-contaminated groundwater. The EPA collected samples to determine whether this was occurring at this site. A preliminary soil-gas survey collected 170 soil-gas samples in March and May of 1999. Samples were collected 100 feet apart in a 75-acre area around the site. This area included the location of the former dry cleaners. Most samples were taken 4 feet below ground surface (bgs). The remaining soil-gas samples were taken 6-8 ft bgs.
Soil-gas containing PCE was found in only four samples. PCE was found under the floor of the maintenance building and under a nearby paved parking lot within 100 feet of the maintenance building. The highest soil-gas result was in a sample taken from a hole bored through the concrete of the sump in the maintenance building. PCE was found here at 178 parts per billion by volume (ppbv) at 4 ft bgs and at 217 ppbv at 8 ft bgs. Two samples under the nearby parking lot contained 68 ppbv PCE [8].
The EPA did not take any indoor air samples at this site.
An exposure pathway consists of five elements: (1) a source of contamination, (2) movement of the contaminant(s) into and through the environment, (3) a place where humans could be exposed to the contaminant(s), (4) a way for humans to be exposed to the contaminant(s)(such as by drinking the water or breathing the air), and (5) the existence of one or more persons who may have been in contact with the contaminant(s). An exposure pathway is considered "complete" when all five elements are present.
Estimated exposure doses were calculated for all completed pathways. These doses were evaluated to determine whether exposures might have caused or are likely to cause adverse health effects.
Drinking water from the Ravenswood Public Service District
Although the source of PCE is unknown, this man-made chemical is in the groundwater under a portion of the city of Ravenswood. PCE is present at least some of the time in the drinking water of the Ravenswood PSD. As long as PCE is present in blended water used by the public, people drinking the water would be exposed and the exposure pathway will be complete. In the past and present, a completed pathway has been present for exposures to PCE in drinking water.
This analysis of potential exposures to PCE used the highest level of PCE found in the blended water (10.8 ppb or 0.0108 milligrams per liter [mg/liter]) to calculate the exposure doses. Because the amount of PCE in water did not stay at 10.8 ppb all the time, estimated exposure doses will be higher than actual exposures to this chemical. Estimated exposure dose was calculated by multiplying the amount of water ingested every day by the amount of chemical in the water and dividing by body weight. This estimates of the amount of chemical (mg) ingested for each kilogram (kg) of body weight each day (mg/kg/day).
Assuming that a child weighing 10 kilograms (about 22 lb.) drinks 1 liter of water a day containing 0.0108 milligrams (mg) of PCE per liter, the estimated exposure dose for PCE is 0.0011 mg/kg/day. If an adult weighing 70 kilograms (about 154 lbs.) drinks 2 liters of water a day containing 0.0108 mg of PCE per liter, the estimated exposure dose for PCE would be 0.0003 mg/kg/day.
EPA's Chronic Reference Dose (RfD) is an estimate of the amount of chemical that a person would have to be exposed to over a lifetime before any observable health effects (excluding cancer) would be expected. The estimated exposure dose of PCE for a child drinking the water is 10 times less than the RfD of 0.01 mg/kg/day. The estimated exposure dose of PCE for an adult drinking the water is 35 times less than the RfD for PCE. The data reviewed and assumptions made show that the levels of PCE in water of the Ravenswood PSD have not been high enough for any adverse, noncarcinogenic, health effects to have occurred.
Studies give some indication that PCE causes cancer. Data shows that long term exposure to PCE causes liver cancer in mice and monocellular leukemia and kidney cancers in rats. However, humans respond to PCE differently than mice and rats do. PCE is suspected, but not proven, to cause cancer in humans. No significant increases in cancers in mice and rats have been observed at the low level of PCE exposure noted at this site [9].
Drinking water from private wells in the plume area
A few residents of Ravenswood may have used water contaminated with PCE from their private water wells. All exposures would have occurred in the past because no one is known to currently use private water sources within the groundwater plume. No data are available to assess the potential for exposure to PCE from these wells.
Vapor Intrusion
PCE is a volatile chemical that it evaporates easily into the air and becomes a gas. PCE in the groundwater can potentially evaporate into soil above the groundwater table. PCE vapors could move through the soil and into buildings located over PCE contaminated groundwater. This process is called vapor intrusion. Persons inside buildings with PCE-contaminated air could be exposed to the chemical by breathing the air.
Soil-gas data shows that PCE is not in the soil over most of the PCE-contaminated groundwater. PCE was located only under the maintenance building and an adjacent parking lot. PCE soil-gas at 4 feet bgs under the maintenance building was measured at 178 ppb.
PCE has been found in soil-gas below one occupied building in Ravenswood. A completed pathway for PCE exposure exists through the vapor intrusion pathway. Exposures have been possible in the past and present and will be possible in the future if groundwater remains contaminated with PCE.
The EPA has published guidance for estimating the risk of vapor intrusion into residential homes with basements [10]. Application of this model to the maintenance building would overestimate potential health effects because the model first assumes that vapors were confined to a space, such as a home, that is smaller than the maintenance building. Secondly, the model assumes that persons in such homes are exposed for longer period of time than a person would be in the maintenance building. This model determined that the potential for PCE vapors to enter the maintenance building from the PCE plume was so minimal that no indoor air samples need to be taken.
Children are at greater risk than adults from certain kinds of exposure to hazardous substances. Several reasons account for this. Children are smaller than adults, which results in higher doses of chemical exposure per body weight. Children are often more sensitive to the effects of chemical exposures than are adults and can sustain permanent damage if toxic exposures occur during critical growing stages. Children play outside more often than adults, which increases the likelihood that they will come into contact with chemicals in the environment. Children are shorter than adults and breathe air closer to the ground. Finally, children depend on adults for risk identification and avoidance. For these reasons, this health consultation considered possible child exposure scenarios related to this site.
Because exposure to PCE is at concentrations below amounts that would be expected to cause any adverse health effects, this site is classified as posing No Apparent Public Health Hazard. Persons served by the Ravenswood PSD have been and are being exposed to PCE, at least intermittently, in drinking water. However, data reviewed show that the amount of PCE in drinking water would not be expected to cause adverse health effects for children or adults.
New wells will be drilled to supply water that has not been contaminated with PCE, further reducing potential exposure to PCE in the future. The Ravenswood PSD will work with state and federal agencies to determine whether water from the wells containing PCE will still be used. A previous attempt to take these wells out of service showed that the PCE plume would be pulled into other wells in the system.
Current soil-gas data indicate that potential exposure to PCE in air inside occupied buildings is confined to the Ravenswood Maintenance Building. Data reviewed show that the potential for exposure to PCE from this source is so low that no indoor air samples are recommended.
The Ravenswood PSD should continue to monitor concentrations of PCE in individual wells and blended water and take appropriate action to maintain PCE in the water below the EPA regulatory limit of 5 ppb.
WVDHHR will review new data collected at this site upon request. If data becomes available suggesting that exposures to PCE at this site are at levels of public health concern, the WVDHHR will reevaluate the need for additional actions at this site.
WVDHHR will provide community education activities for any group or individual who would like the findings of this health consultation explained.
Barbara J. Smith MS
Epidemiologist II
Public Health Sanitation Division
Office of Environmental Health Services
Bureau for Public Health, WV DHHR
Reviewers of Report
Joseph A. Wyatt, RS
Acting Director
Public Health Sanitation Division
Office of Environmental Health Services
Bureau for Public Health, WV DHHR
Fred R. Barley, RS
Health Educator
Public Health Sanitation Division
Office of Environmental Health Services
Bureau for Public Health, WV DHHR
ATSDR Technical Project Officer
LCDR Alan G. Parham, REHS, MPH
Technical Project Officer
Agency for Toxic Substances and Disease Registry
1600 Clifton Road, N.E. MS-E32
Atlanta, GA 30333
ATSDR Regional Representative
Lora Siegmann-Werner
ATSDR Region III Regional Representative
1650 Arch Street Mail Stop 3HS00
Philadelphia, PA 19103
The Health Consultation on the Ravenswood PCE Site, in Ravenswood, Jackson County, West Virginia was prepared by the West Virginia Department of Health and Human Resources under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the Health Consultation was begun.
Alan G. Parham, REHS, MPH
Technical Project Officer
Division of Health Assessment and Consultation (DHAC)
ATSDR
The Division of Health Assessment and Consultation, ATSDR, has reviewed this Health Consultation and concurs with its findings.
Roberta Erlwein
Section Chief, SPS, SSAB, DHAC, ATSDR
Figure 1. Site Vicinity and Estimated Extent of the PCE Plume (Upper Zone)
