PETITIONED HEALTH CONSULTATION
BREWTON IRON WORKS
TR MILLER MILL,
BREWTON, ESCAMBIA COUNTY, ALABAMA
The Lisbon aquifer is the sole source of water for the town of Brewton . Wells developed in the Lisbon aquifer yield large quantities of water to public supply, industrial and irrigation wells, as much as 350 gallons per minute . The municipal wells that service the Brewton vicinity are 600-700 feet deep. Most private well depths vary between 100-400 feet. The regional groundwater flow in the Brewton area is generally south to southwest, but varies with geographic location .
ATSDR reviewed groundwater monitoring data from the municipalities supplying drinking water to the public surrounding the six industrial facilities in Brewton (Brewton Water Works and McCall Water System) to determine if the quality of municipal water supply has been adversely impacted. ATSDR also reviewed groundwater monitoring data from a privately operated public well that supplies potable water exclusively to employees of Container Corporation (Jefferson Smurfit).
Private wells are located sporadically throughout the Brewton area, however, there was not a current private well inventory that provided an accurate number or location. Private wells are not regulated in the state of Alabama, therefore, records on individual private wells are sparse. The Geological Survey of Alabama conducted a well survey of Escambia County in 1963 . Although the information from the existing well survey is dated, it was incorporated into the assessment of groundwater quality and potential for contamination. Groundwater characterization data from private wells were not available for ATSDR to review.
McCall Water System, Inc.
McCall Water System has four municipal wells located outside of the Brewton town limits and services 1500 customers in the area around Brewton. The groundwater is drawn from the Lisbon aquifer at a depth of approximately 700 feet and each of the four wells are treated for bacteria via chlorination before drinking water is distributed to the customers . This municipality is regulated under the Safe Drinking Water Act which requires ADEM to monitor organic, inorganic, synthetic organic, and radiological components in the groundwater biannually. McCall Water System has been in compliance with ADEM's regulations since the municipality began operating in 1969. There were no chemical components detected above ATSDR's health comparison values(1) in McCall Water System municipal wells. Therefore, ATSDR has determined the use of the municipal water supplied by McCall Water System is a No Public Health Hazard in the past and present.
Brewton Water Works
Brewton Water Works Municipality entails four municipal wells located within the town limits of Brewton and serves 3100 customers in an area of approximately nine square miles. The groundwater is drawn from the Lisbon aquifer at a depth of approximately 700 feet and is treated for bacteria via chlorination at each of the four wells before it is distributed to customers . This municipality is regulated under the Safe Drinking Water Act which requires ADEM to monitor organic, inorganic, synthetic organic, and radiological components in the municipal water biannually.
Three chemical compounds were sporadically detected in Brewton Water Works public supply wells above ATSDR's health guidelines beginning in 1995. Dibromochloromethane has been detected in all Brewton Water Works municipal wells since 1995 at concentrations ranging of 0.5-1.8 part per billion (ppb) and averaging 0.86 ppb. Bromodichloromethane has been detected in all Brewton Water Works municipal wells since 1995 at concentrations ranging 0.6 - 5.4 ppb and averaging 2.1 ppb. Ethylene dibromide (EDB) was detected in one sample taken from a Brewton Works municipal well (Industrial Park) in May of 1995 at a concentration of 0.9 ppb. EDB was sampled again in July, September and December of 1995 and was not detected. Prior to 1995, EDB was not detected in the Brewton Water municipality. These compounds are discussed further in Public Health Implication Section of this document and listed in Appendix C - Table 1.
Container Corporation (a/k/a: Jefferson Smurfit)
Container Corporation has a privately operated public well on-site that is 585 feet deep which draws water from the Lisbon aquifer to service approximately 560 employees of the company. This well is regulated under the Safe Drinking Water Act which requires the groundwater to be continuously chlorinated before distribution and analyzed biannually for inorganic, organic, synthetic organic, and radiological components. To this date, ethylene dibromide is the only chemical component that was detected at a concentration above ATSDR's comparison values in May of 1995 at a maximum concentration of 0.3 ppb (See Appendix C - Table 2). Another groundwater sample was taken in July 1995 specifically for ethylene dibromide analysis, however, no ethylene dibromide was detected. Ethylene dibromide has not been detected in the annual samples taken from Container Corporation's private well prior to May 1995. This compound is discussed further in the Public Health Implication Section of this document.
ATSDR believes that municipal water characteristics from Brewton Water Works and McCall Water System may not be representative of all private wells in the Brewton vicinity. Private well water in this area may be drawn from the same aquifer as Brewton Water Works and McCall Water System; however, the depths of private wells tend to be more shallow, averaging 200 feet. ATSDR contacted the Brewton Health Department, Alabama Department of Environmental Management (ADEM), and the Alabama Geological Survey to locate an inventory on existing private wells in Brewton and Escambia County. A well survey that was conducted in 1963 identified several private wells throughout Escambia County, however, there is no information on the current production status of these wells . The Brewton Health Department also has sparse and dated well drilling records from Escambia County and some bacteriological analyses on individually requested private wells. This information is inconclusive to determine private well water quality since the chemical components of groundwater from private wells are unaccounted for in the Brewton vicinity.
ATSDR reviewed the existing well survey information to determine if there were private wells hydrologically downgradient of TR Miller, the only site with known groundwater contamination. No private wells were recorded hydrologically downgradient of TR Miller Mill in Brewton. Although, the well survey is dated 1963 and may not be accurate, ATSDR has reviewed maps of Brewton and does not see any residential property in the area near the TR Miller Mill groundwater contamination plume. The groundwater plume flows southeast toward Murder Creek on TR Miller Mill property and the closest residential area is approximately 0.5 mile across the creek. The groundwater contamination at TR Miller Mill is contained on-site and is currently being treated and monitored for migration. This localized contamination currently does not represent a threat to potable water supplies in Brewton. ATSDR recommends that future private well drilling practices in the immediate vicinity of TR Miller Mill should contact ADEM to check the groundwater remediation status of TR Miller Mill. Therefore, the private well water quality impact from TR Miller Mill and the other five surrounding facilities mentioned in this document is currently a No Apparent Public Health Hazard.
ATSDR reviewed data for each public water supply well. At the completion of the data review and analysis, ATSDR selected the following chemicals as contaminants of concern (COCs): dibromochloromethane, bromodichloromethane and ethylene dibromide (EDB) detected in Brewton Water Works, and EDB detected in Container Corporation's well. Additional environmental and toxicological evaluation was required for each of these chemicals. In preparing this analysis, ATSDR staff members have used established methodologies for determining how people may be exposed to hazardous substances and what harmful effects, if any, may result from such exposure. For a complete discussion of quality assurance considerations, human exposure pathways analyses, ATSDR's health comparison values, and the methods of selecting contaminants of concern, please refer to Appendix B and C.
Dibromochloromethane and bromodichloromethane are part of a chemical group called trihalomethanes. Trihalomethanes (dibromochloromethane, bromodichloromethane, chloroform, and bromoform) are chlorination by-products formed by the reaction of free chlorine with certain organic compounds in water. As a result of the chlorine disinfection process, these compounds are frequently detected in municipal water systems.
The maximum contaminant level (MCL) for total trihalomethanes in drinking water is 100 part per billion (ppb) and the goal is 10 to 25 ppb . The MCL, an enforceable standard, is the maximum permissible level of a contaminant in water delivered to any user of a public water supply. Due to concerns about potential health effects resulting from exposures to trihalomethanes, the current MCL is under review. In response to these concerns, EPA proposed to reduce the MCL to 80 ppb in the 1994 Proposed Rule for Disinfectants and Disinfection By-Products .
The total concentration of trihalomethanes detected in the public water systems in Brewton are well below the current and proposed MCL. Actually, the concentrations of total trihalomethanes (THMs) detected are less than 10 ppb, the lower limit of the goal for total THMs. Adverse health effects are not expected as a result of exposure to these low concentrations of THMs (including dibromochloromethane and bromodichloromethane). Therefore, ATSDR classifies the use of the municipal water supplied by Brewton Water Works as a No Apparent Public Health Hazard in the past and present.
Ethylene Dibromide (1,2-dibromoethane)
Ethylene dibromide has been widely detected in groundwater samples collected in the United States. Contamination of groundwater with ethylene dibromide (EDB) principally occurred as a result of its use in the past as a soil and grain fumigant to kill insects and worms and, secondarily, from spills or leaks of leaded gasoline in which EDB is added to produce better fuel efficiency. Due to the ban on the use of EDB as a fumigant in 1984 and increased regulation of leaded gasoline, the use of EDB has been substantially reduced .
In May 1995, EDB was detected at a concentration of 900 part per trillion (ppt) in one well in the Brewton Works municipal well system and at a concentration of 300 ppt in the on-site public well at Container Corporation. These wells are not located near agricultural areas or fueling stations. EDB has not been detected in other wells of the municipal systems in Brewton.
The environmental sampling data for the wells in Brewton suggests the detections of EDB are likely an analytical anomaly (laboratory error). EDB was detected on only one occasion (May 1995). Analysis of samples collected in October 1993 had no detections of EDB and EDB was not detected in samples collected in July, September, and December 1995. Environmental chemistry and monitoring data for other sites contaminated with EDB indicate that EDB contamination of groundwater can be a long term environmental problem. EDB released to soil is sorbed strongly to soil micropores where it persists for long periods of time, resistant to mobilization and degradation. This residual EDB slowly leaches over a period of years to contaminate the groundwater . In addition, EDB is resistant to hydrolysis. As a result of EDB's hydrolytic stability and the limited degradation in subsurface soils, EDB contamination of groundwater is expected to persist for years.
Due to the chemical properties of EDB, one would expect EDB detections for several years in the wells in Brewton if the groundwater was contaminated with EDB. Since EDB was detected in May 1995 and was not detected in the next three sampling rounds, it is likely that the reported detection is an analytical anomaly. Therefore, it is unlikely that people were exposed to EDB at levels of health concern.
However, because ATSDR cannot conclusively determine that the reported detection of EDB is a laboratory error, a discussion of the potential exposure follows:
ATSDR determined that the maximum potential exposure duration to EDB was approximately two years. Exposure would not have occurred prior to October 1993 when sampling reported no detection of EDB and exposure would not have occurred after July 1995 when again sampling reported no detection of EDB. A person drinking two liters of water a day with 900 ppt of EDB would receive an estimated exposure of 0.026 g/kg/day (micrograms per kilogram per day). The lowest concentration associated with adverse health effects from exposure to EDB is 4000 g/kg/day . The potential exposures to EDB in Brewton are approximately 150,000 times less than this level. In general, adverse health effects that have been associated with exposure to EDB (those reported in the scientific literature) have resulted from exposure to higher concentrations than the concentrations detected in Brewton . Adverse health effects are not expected as a result of potential exposure to EDB in the Brewton water supply. It appears likely that any possible exposures never reached this level and may have not actually occurred. Therefore, ATSDR has determined the use of the potable water supplied by Brewton Water Works and the privately owned public well at Container Corporation as a No Apparent Public Health Hazard in the past and present.
As part of ATSDR's Child Health Initiative, a section is included in all ATSDR health based documents to address potential exposures of children to contaminants. Children are at greater risk than adults from certain kinds of exposure to hazardous substances emitted from waste sites and emergency events. They are more likely to be exposed for several reasons; children play outside more often than adults, increasing the likelihood that they will come into contact with chemicals in the environment. Since they are shorter than adults, they breathe more dust, soil, and heavy vapors close to the ground. Children are also smaller, resulting in higher doses of chemical exposure per body weight. The developing body systems of children can sustain damage if toxic exposures occur during certain growth stages.
During the evaluation of quality of the municipal groundwater supplies, ATSDR used the Environmental Media Evaluation Guidelines (EMEG) for children who are considered the most sensitive segment of the population. ATSDR did not identify any chemical contaminants at levels of health concern to children.