ALCOA (POINT COMFORT)/LAVACA BAY
POINT COMFORT, CALHOUN COUNTY, TEXAS
The ALCOA (Point Comfort)/Lavaca Bay National Priorities List (NPL) site is in Calhoun County, Texas, approximately 1.5 miles south of Point Comfort and four miles northeast of Port Lavaca. The site includes areas associated with current and former operations of the Aluminum Company of America (ALCOA) Point Comfort plant and a section of Lavaca Bay adjacent to ALCOA which has been contaminated with mercury. Fish sampling data indicate that levels of mercury in fish are elevated. Since eating fish contaminated with mercury at the concentrations observed at this site may potentially affect the developing fetus, and the potentially exposed population includes women of childbearing age, we have classified this site as an urgent public health hazard.
Because of the levels of mercury found in fish sampled near the ALCOA Point Comfort Operations, a portion of Lavaca Bay was closed to the taking of finfish and crabs by the Texas Department of Health in April of 1988. People who ate contaminated fish, crabs and oysters in the past as well as people who currently eat contaminated fish and crabs from the closure area may be exposed to excessive amounts of mercury.
Based on the amount of mercury in these fish, pregnant women should not eat more than 5 ounces of fish taken from the closure area per month; that is less than one meal of fish from the closure area per month. Children would experience an increased risk for adverse health effects from eating as little as 1.4 ounces of fish per month caught from the closure area.
ALCOA operated an aluminum smelter at this site from 1948 until 1980; currently, the primary activity at the site is bauxite refining. Mercury contamination originated primarily from the chlor-alkali unit at ALCOA which operated from 1965 until 1979. This unit used mercury to produce chlorine gas and sodium hydroxide. As a result, approximately 67 pounds of mercury per day were discharged into the bay prior to 1970.
Mercury has been detected throughout the site in surface soil, shallow groundwater, air, bay sediments, fish and crabs. Other contaminants, including volatile organic compounds (VOCs) and lead, have been detected in shallow groundwater. Polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) have been detected in a limited number of sediment, fish, and oyster samples; additional sampling is planned.
The Texas Department of Health (TDH) Division of Shellfish Sanitation (recently renamed Division of Seafood Safety) has sampled fish, crabs, and oysters from this area since the 1970s. In the early 1970s, mercury levels in oysters and crabs were significantly elevated. Based on these findings TDH closed parts of Lavaca Bay to the harvesting of oysters; at that time, TDH did not have the authority to prohibit crabbing or fishing. The Texas Department of Health order establishing areas which are prohibited and unsatisfactory for the taking of aquatic life that is unfit for human consumption (specifically finfish and crabs) was issued in April of 1988.
Based on reports that chlor-alkali unit workers observed pooled mercury in work areas, it is likely that exposure to mercury vapor via inhalation occurred in the past. Due to the absence of ambient air data collected while the unit was operating, we were unable to quantify this exposure. However, according to ALCOA, biological monitoring results for workers in the chlor-alkali unit were used to monitor employee exposures and make decisions about removing employees from that work unit.
Residents of the Point Comfort area have raised several questions about the potential for adverse health effects among former ALCOA workers, people engaging in recreational activities at Lavaca Bay beaches, and people consuming seafood from the closure area and other parts of Lavaca Bay. The Public Health Implications section of this Health Assessment contains detailed answers to these questions.
TDH has made the following recommendations: fish and crabs taken from the closure area should not be eaten, maintain the current crabbing and fishing closure which was issued in 1988; improve the markers which designate the closure area; publicize information on dangers of eating contaminated fish as well as the location of the closure area; and provide information to local physicians on the health effects of mercury exposure. TDH has also recommended conducting additional site characterization activities and evaluating the potential public health implications of the site as additional sampling data become available for review.
BACKGROUND
The Agency for Toxic Substances and Disease Registry (ATSDR) is a Federal agency within the Department of Health and Human Services authorized by the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) to conduct public health assessments for National Priorities List (NPL) hazardous waste sites. In cooperation with ATSDR, the Texas Department of Health (TDH) has reviewed available data to evaluate the public health significance of the ALCOA (Point Comfort)/Lavaca Bay NPL site. More specifically, ATSDR and TDH have determined whether adverse health effects from exposure to site contaminants could occur and have recommended actions to reduce or prevent such health effects.
A. Site Description and History
The ALCOA (Point Comfort)/Lavaca Bay National Priority List (NPL) site is approximately 1.5 miles south of Point Comfort and four miles northeast of Port Lavaca in Calhoun County, Texas (Figure 1). The site includes the ALCOA (Point Comfort) plant grounds, the former smelter area part of which is owned by Formosa Plastics, Inc., the Witco dock area, the dredge spoil island west of the ALCOA plant, and a section of Lavaca Bay adjacent to ALCOA (Figure 2).
ALCOA is currently operating; bauxite ore is refined to alumina. ALCOA is in an industrial complex just south of the State Highway 35 which connects the towns of Point Comfort and Port Lavaca via a causeway over Lavaca Bay. The industrial complex is on the Bay's east central shore and includes Formosa Plastics, Inc., unloading docks used by ALCOA and Formosa, the E.S. Joslin Power Station, a railroad spur, and numerous facilities currently and formerly associated with ALCOA operations. Numerous large lakes and closed hazardous waste landfills used by ALCOA for processing, storage, and disposal of waste materials are located on the eastern side of the industrial complex.
The dredge spoil island associated with ALCOA is in the Bay approximately 1,200 feet west of the plant. The 500-acre island was constructed by ALCOA in 1950 with materials from periodic dredging of the ship channel; it includes a 91-acre lagoon and five smaller lagoons that cover approximately 50 acres which were used for disposal of gypsum wastewater from ALCOA processes [1, 2].
Lavaca Bay is part of the Matagorda Bay system on the middle Texas coast. The Bay averages 12.5 miles in length, 4.5 miles in width, and one to seven feet in depth except where it has been deepened to accommodate ship traffic. Ship channels serving ALCOA and the industrial complex are fifteen and thirty-five feet deep, respectively [3, 4].
ALCOA has been conducting operations at Point Comfort since 1948. The plant originated as an aluminum smelter. Primary activities currently include bauxite refining and production of aluminum fluoride. A carbon plant operates intermittently to produce carbon briquettes. Bauxite refining began in 1958 [5]. Other operations at ALCOA have included a cryolite (sodium aluminum fluoride) plant (1962-1979), a chrome plating operation (dates of operation unknown), and the chlorine-alkali (chlor-alkali) plant (1965-1979) [6]. ALCOA also operated the Neumin gas plant from 1957 until 1989. In 1989 the Neumin gas plant area and part of the smelter area were sold by ALCOA and are now owned by Formosa Plastics.
The ALCOA Point Comfort plant includes unloading docks, several inland dredge and wastewater disposal lakes, bauxite ore storage lots, numerous storage tanks, towers, buildings, and other structures. The industrial complex also contains a power generating station, a vacant building formerly owned by Witco Chemicals, and the site of the smelter and the disassembled chlor-alkali facility formerly operated by ALCOA. The building which housed this process is still standing [7].
Mercury contamination of the site has been attributed to wastewater discharges from the chlor-alkali unit. ALCOA estimated that prior to 1970 at least 67 pounds of mercury per day were discharged into the Bay and that an additional 89 pounds of mercury per day were released into the atmosphere. Between 1970 and 1979, mercury discharges to the Bay were reduced to approximately 13 pounds per day and releases to the atmosphere were reduced to approximately 60 pounds per day. During this period, wastewater was discharged to on-shore lakes for re-use in plant processes [4].
In addition to wastewater discharges, mercury-contaminated solids, washdown water, filter materials, and equipment were stored or disposed of in various areas of the site, including several on-shore lakes, the chlor-alkali lagoon, the dredge spoil island, and hazardous waste landfills [8]. The chlor-alkali plant was closed in 1979. In 1986 the chlor-alkali equipment was removed; however, several support buildings and the building that contained the mercury-cells from which contaminants originated remain [4].
Anecdotal evidence and historical records suggest that inhalation of mercury vapor by workers may have occurred while the chlor-alkali unit was operating (1965 -1979); workers sometimes had to wash down brine and mercury from the floor of the chlor-alkali building [7, 35]. Additionally, in the past, workers reported observing pooled mercury in the chlor-alkali area. During this time, it is possible that workers in the chlor-alkali plant inadvertently transported mercury to their homes on contaminated clothing. This type of occurrence has been documented in mercury thermometer manufacture [50]. Former ALCOA employees have anecdotally reported finding mercury in their washing machine drains and traps.
Numerous state and federal agencies have conducted investigations and issued health and safety recommendations related to mercury contamination at this site. In 1970, the Texas Water Quality Board issued an Emergency Order against ALCOA finding them responsible for mercury discharged to an off-shore disposal lagoon on the dredge spoil island [4]. TDH initiated seafood sampling in Lavaca Bay in 1970, at which time samples indicated significantly high mercury levels in oysters and crabs but not in shrimp; finfish were not sampled. In July of 1970, under the authority of the Shellfish Law, TDH closed the affected areas of Lavaca Bay to the harvesting of shellfish (i.e. oysters). At that time, TDH did not have authority to close the area to the taking of crabs or finfish, but the Department continued to monitor mercury levels in seafood. The ban on oystering was lifted in October 1971 when the levels of mercury dropped below the 0.5 ppm FDA guideline. Mercury levels in blue crab remained high and TDH made a public statement warning that consumption of blue crab might be dangerous to humans [9].
Based on results of on-going sampling, TDH again issued public health warnings in 1978 and 1981 that consumption of seafood taken from parts of Lavaca Bay was dangerous to human health [10]. TDH increased sampling in 1987-88 [4]. On April 20, 1988, the Commissioner of Health issued a measure prohibiting the taking of finfish and crabs from a specific part of Lavaca Bay (Texas Department of Health Aquatic Life Order 1) [11], which remains in effect. Oystering and shrimping were not prohibited [10].
The closure area is seaward from the Highway 35 Causeway and includes the "area of Lavaca Bay inshore of a line drawn from the southwestern most point of land at Cox Point to channel marker MK #74, thence in a northwesterly direction to Channel MK #12, and thence in a northerly direction to the last part of land at the northeastern approach of the State Highway 35 Causeway, as outlined on the map dated April 21, 1988 [11]." These boundaries, shown in Figure 3, were established based on a plot map of the locations where fish samples with elevated mercury levels were caught and the use of structural landmarks that would be readily recognizable by individuals who fished the area [12].
In June of 1990, the National Oceanic and Atmospheric Administration (NOAA) requested that ATSDR investigate the potential human health threats associated with consumption of fish and shellfish harvested from Lavaca Bay. After reviewing sampling data from the TDH Division of Shellfish Sanitation Control, ATSDR concluded that the ban on finfish and crabs should be continued, access to contaminated areas of the site should be restricted, information about the dangers of mercury exposure should be disseminated, and that fish sampling in the Lavaca Bay region should be continued [3, 13]. ATSDR also recommended continuing the fishing and crabbing ban in areas that show mercury levels in fish above the revised FDA guideline of 1 ppm [10].
In October of 1990, NOAA expressed concern about elevated levels of polycyclic aromatic hydrocarbons (PAHs) in sediments, surface waters and tissues of fish and shellfish [16]. The Texas Water Commission (TWC) identified Witco Chemical Company as a likely source of creosote and its polycyclic aromatic hydrocarbon (PAH) constituents. NOAA recommended that ALCOA should be required to implement a sediment sampling plan to delineate the extent of mercury and PAH contamination, its potential for migration, and its bioavailability and toxicity. NOAA also recommended that a remedial investigation and feasibility study (RI/FS) leading to a Record of Decision (ROD) be performed to identify a remediation alternative which would be protective of the environment [16].
In 1991, TDH and ATSDR provided information on mercury toxicity to physicians in Calhoun and Victoria counties and encouraged physicians to inform pregnant patients and parents of young children about the potential health risk associated with consumption of mercury-contaminated fish [14, 15].
In August of 1992, the Mining Safety and Health Administration (MSHA) conducted an inspection of ALCOA in response to an employee's complaint of exposure to mercury. MSHA found mercury in the soil near the chlor-alkali (R-300) building at levels between 2.6 mg/kg and 52 mg/kg. MSHA cited ALCOA for safety violations including: failure to post warning signs identifying a mercury hazard, failure to label the mercury storage containers, failure to use appropriate personal protective equipment, failure to monitor for mercury [17, 18]. MSHA also issued a Section 103(k) Accident Control Order requiring ALCOA to provide personal protective equipment, implement decontamination and mercury monitoring procedures, and to clean up the area [17, 19]. ALCOA complied with abatement actions [18A]; the 103(k) order was contested by ALCOA and was vacated.
On October 14-15 1992, investigators from the National Institute of Occupational Safety and Health (NIOSH) conducted urinalyses for workers thought to have the greatest potential for mercury exposure. These tests found that workers tested had not had mercury exposure above usual background levels within the previous two to four months [20]. ALCOA performed air sampling and urinalysis of workers. These analyses indicated that mercury exposures above usual background exposures were not occurring.
ALCOA (Point Comfort)/Lavaca Bay, Calhoun County, Texas was proposed for the Superfund National Priorities List in the Federal Register of June 23, 1993, under the Proposed update #15 [21]. The site was added to the General Superfund Section effective March 25, 1994 [2].
On January 19 and 20, 1994, Texas Department of Health representatives John F. Villanacci, Ph.D., and Kathryn A. Evans, M.P.H., of the Health Risk Assessment and Toxicology Program, along with Kirk Wiles of the Shellfish Sanitation Program, conducted a site visit at the ALCOA (Point Comfort)/Lavaca Bay National Priorities List (NPL) site. During this site visit, we met with EPA and ALCOA representatives for approximately two hours and spent three to four hours conducting a limited survey of the ALCOA facility, the nearby residential neighborhood in Point Comfort, and the surrounding areas of Point Comfort and Port Lavaca. An additional two to three hours were spent touring the Bay around ALCOA by boat. Kirk Wiles, who has worked on fish consumption safety issues in the Lavaca Bay area since the 1970s, guided the boat tour and was available to answer questions about both the physical layout and history of the site. Kirk Barringer and Patrick Cruz, representatives of the TDH Region 8 office of the Seafood Safety Division, also were available to answer questions.
The ALCOA plant complex is surrounded on the south and west by Lavaca Bay. The land northeast of the complex, adjacent to the disposal lakes, is used for cattle grazing. Huisache Creek flows from north to south across this cattle field and contains areas of ponded water. The extensive industrial facilities of Formosa Plastics Corporation are across the street from this open land, on the north side of Highway 35.
Two roads from Highway 35 connect to a main road which provides access to ALCOA. Only employees are allowed to access most areas of the industrial complex. The general public's access is limited by both the natural geography and by fences around most of the operational facilities.
Several, large, uncovered piles of bauxite ore were stored at the southern end of the site. Equipment used to unload the ore from ships in the Bay is located in this area. A large barge was being unloaded when we toured the Bay by boat on January 20, 1994. We noticed that most outdoor surfaces of the on-site buildings, fences, and equipment on and around ALCOA were coated with a layer of reddish dust similar in color to the bauxite ore.
The area of Lavaca Bay in which the taking of finfish and crabs is banned is easily accessible to the general public by boat. Part of this closed area is accessible along the south side of the State Highway 35 Causeway on the side facing the ALCOA plant; it is possible to drive a car along the old causeway at the water's edge. It was raining and very cold during our visit and we did not see anyone fishing, but we did see fishing lines, bait containers, and other evidence that people fish in this area.
We found a line of approximately ten crab traps in the Bay within the restricted area and a trap that contained live crabs. Mr. Barringer and Mr. Cruz indicated that fishing and crabbing within the restricted area is common. Mr. Wiles explained that many areas within the area closed to the taking of fish and crabs are especially attractive for winter fishing because their deep waters support extensive fish populations in cold weather. Summer is the primary season for crabbing.
A shrimp boat was dragging a shrimp net along the bottom of the Bay in the closure area. Although shrimping is not prohibited, it was obvious that this activity was disturbing the sediment. While mercury contamination has not been found in oysters in recent years, we were told that taking oysters from the Bay is sometimes prohibited due to bacteriological contamination. The TDH Division of Shellfish Sanitation routinely monitors the bacteriological quality of the oysters in the Bay.
The channel just outside the closure area was being dredged under the authority of the Army Corps of Engineers. A barge, using a cutting tool and a system of pipes with hydraulic suction, was dredging sediment from the bottom of the channel and depositing it at the end of a pipeline approximately 300 yards away. Several spoil piles were visible at the water's surface behind the pipeline.
Large warning signs explaining the ban on taking of fish and crabs from the area were posted at four (originally five) locations near boat ramps and fishing areas. The signs state, "Catch and release for fish and crabs from the prohibited area shown on the map. Fish and crabs may be contaminated by mercury. Consumption of fish or crabs from the prohibited area may be dangerous to your health. Retaining fish or crabs from the prohibited area punishable by a fine of up to $500.00. Texas Department of Health Shellfish Sanitation Division (512) 458-7510." The Division is now called the Division of Seafood Safety and the phone number is (512) 719-0215. A large color map of the Bay designating the restricted area is posted on each sign. The warning signs are posted on state property at Chocolate Bay, Keller Bay, Port Lavaca Causeway State Park, and the northeastern end of the causeway. The sign formerly posted at the Harbor of Refuge boat ramp blew down in a storm approximately one and a half years ago and has not been replaced. Signs have not been posted at several boat ramps that provide access to the Bay, including the popular boat ramp northeast of the causeway near Formosa and the boat ramp northwest of the causeway in Port Lavaca.
Port Lavaca Causeway State Park, with facilities for approximately 30 recreational vehicles, is at the southwestern end of the causeway. The park was approximately 50% occupied by in-state and out-of-state vehicles. A long fishing pier extends from the park area into the Bay beneath the causeway next to the Noble Point boat ramp. A long boardwalk with a gazebo is situated in the Bay to the south of the state park. We saw no evidence of fishing from the pier or the boardwalk, but we were told that the pier is a popular fishing area. Neither location is in the closure area.
The Town of Point Comfort is centralized in an area approximately one mile north of ALCOA, just north of Highway 35. The town is laid out on a grid of primarily residential secondary streets with modest, single-family dwellings. We also saw a church, a school, and a day care center. A park with a swimming pool, playground, and boat ramp is on the northwest side of town within walking distance from most of the houses.
Formosa's permitted discharge point is in the Bay several hundred yards from the Point Comfort neighborhood. The discharge point is designated by two buoys (each marked with an "x").
On April 19, 1994 Kathryn Evans, M.P.H., and Susan L. Prosperie, M.S., R.S., of TDH conducted a second site visit which included a tour of ALCOA facilities and attended an Informal Open House sponsored by EPA at the Bauer Community Center in Port Lavaca. While in the area, we saw a man fishing in the closure area from the old causeway and spoke with two men who told us they had been fishing. TDH's fishing advisory warning sign was posted and readily visible at the entrance to this area.
An Environmental Professional, employed by ALCOA, guided our 2.5-hour tour of ALCOA facilities and answered questions. We drove or walked through most of the major production areas of the plant. We also observed facilities and stained areas associated with ALCOA's past production of carbon briquettes, caustic soda, chlorine gas, and other materials.
We saw the area where bauxite ore imported by ALCOA from various parts of the world is unloaded from ships onto a conveyor system. The ore is stored in huge, uncovered piles and then blended. Workers in this area were driving heavy equipment with enclosed cabs. Ore also is stored in large buildings in this area until it is processed.
The refining process includes crushing and digesting (heating to a high temperature with caustic) the bauxite mixture. The alumina is separated from mud and other undissolved residue using clarifiers or thickeners, which are large tanks with arms that turn slowly, collecting the solids. The mud waste product from this process is stored in the Mud Lakes on the eastern edge of the site. The supernatant which contains the alumina is precipitated to remove the liquid from the alumina which is then "calcined" by heating at a high temperature in a rotary kiln. Machines called shakers are used to separate the alumina fines from larger particles. We saw one shaker in a partially-enclosed building; alumina covered the concrete floor and the area was full of fine white dust. This process is partially automated and we did not see any workers.
Many of the other processes also are automated and most of the process areas were noisy, dusty, and hot. We observed several workers in the outdoor areas, most of whom were using earplugs and eye protection. We also went into one of the control rooms where workers monitor plant processes; this room was quiet, cool, and free of dust.
We drove along roads atop the berms of Mud Lakes #1, #2, #3, and #4. We were able to see the Mud Lakes as well as Clear Lake, Recycle Lake, and Dredge Lake, which also have been used in ALCOA processes. The lakes had varying water levels with reddish mud visible at the bottom of some of the drier lakes. The berms are above the 100-year flood plain, but the lakes are unlined. The ALCOA representative noted that at least one closed hazardous waste landfill is located near the lakes.
We drove through the area formerly associated with the chlor-alkali facility. The only remaining building was R-300, which formerly housed the mercury cathodes. The entrances to this building were barricaded and marked with signs stating "NOTICE: Mercury can collect at this location. If observed, notify supervisor." We walked around this area and did not notice any mercury. (We have viewed a videotape prepared during the September 27, 1993 site visit by NOAA and EPA that shows visible droplets of mercury on concrete in the chlor-alkali area). We saw two men working to break up the concrete pad adjacent to the building. One man was using a forklift, the other was using a backhoe with an open cab; neither man was using respiratory protection. ALCOA indicated that surveillance monitoring conducted in accordance with the Health and Safety plan indicated there was no need for respiratory protection during these activities.
We drove by the old Witco dock area where raw materials came in for production of carbon briquettes from coal tar pitch and coke. The carbon was used for smelting pots once operated by ALCOA at the site.
From 5:30 to 7:00 pm, we attended EPA's Informal Open House at the Bauer Community Center in Port Lavaca. Representatives from EPA, Texas Natural Resource Conservation Commission (TNRCC), NOAA, and TDH attended. Approximately 35 people from the community including Port Lavaca city officials, a county judge, and former ALCOA employees also attended. One retired ALCOA employee, who attended the open house, reported that he had been diagnosed with a neurological disorder of unknown cause.
C. Demographics, Land Use and Natural Resources Use
Demographics
According to the 1990 census [22], 19,053 individuals live in Calhoun County in 7,666 households. The two major population areas are the towns of Port Lavaca and Point Comfort. Sixty-one percent of the population have lived in the same house since 1985. Persons 18 years of age and under comprise 29.5% of the population; persons 65 years and over comprise 11.0% of the population. Approximately 4,002 women (41.6%) are of childbearing age (15-45 years). The racial make up of Calhoun County is 77.8% white, 2.9% African American, 0.2% Indian, 2.9% Asian or Pacific Islander, and 16.2% other races. Persons of Hispanic origin make up 36.2% of the total population.
Port Lavaca, which is four miles southwest of the site, has a population of 10,886 people who live in 3,783 households. Approximately 31% of the total population are 18 years of age and younger; approximately 10% are 65 years and over. The racial make up of Port Lavaca is 71.3% white, 4.7% African American, 0.2% Indian, 3.0% Asian or Pacific Islander, 20.8% other races. Approximately 47% of the total population are of Hispanic origin.
Point Comfort, which is 1.5 miles northeast of the site, has a population of 956 people who live in 360 households. Approximately 27% of the total population is comprised of people 18 years of age and younger; approximately 12% of the total population is made up of people 65 years of age and older. The racial make up of the Point Comfort population is 92.7% White, 0.2% African American, 0.1% Indian, 1.8% Asian or Pacific Islander, and 5.2% other races. Approximately 12% of the total population are of Hispanic origin.
In Calhoun county eight percent of employed persons age 16 and over are employed in agriculture and fisheries. Approximately 19% of the population lives in a household with an income below the federal poverty level. The ALCOA plant has 1,080 employees, not all of whom live in Calhoun county.
Point Comfort has two licensed day care centers, the United Methodist Church (licensed for 40 children, with 26 enrolled as of August 1993) and Village Daycare (licensed for 12 children, with 10 enrolled as of March 1993). The county has one nursing home, which is across the Bay from Formosa Plastics in the City of Port Lavaca [23].
Land Use and Natural Resources Use
The nearest residential area from the site is the City of Point Comfort with a population of 956 people. The nearest recreational areas are the beaches along the western side of Lavaca Bay at Port Lavaca. In addition there is a boat ramp to the Bay in Point Comfort. The area in the immediate vicinity of the site is industrial. ALCOA employs approximately 1,080 people [25]; Formosa Plastics Corporation employs at least 1,000 people. Rice and cotton farming, cattle grazing, and commercial fishing also are economic factors in the county [24]. The climate in Calhoun county is warm and humid with a total rainfall of approximately 39.4 inches per year; temperatures range from 47 to 92oF [24].
In the past the City of Point Comfort and ALCOA obtained drinking water from water wells located eight miles east of Point Comfort. These wells are screened in the Chicot aquifer at depths of approximately 500 to 1,200 feet. According to the Hazard Ranking System, these wells are the closest potable groundwater wells to the NPL site [10]. In February of 1995 the City of Point Comfort began using surface water from Lake Texana (Lavaca-Navidad River Authority). The City of Port Lavaca obtains drinking water downstream of the confluence of the Guadalupe and San Antonio Rivers [10]. A well inventory is available; however, current well usage should be determined.
Shallow groundwater is approximately 14 to 20 feet below the surface in most areas of Calhoun county, but is of poor quality primarily due to high levels of sodium (3,000-6,000+ ppm) and chlorides (6,500 to 40,500 ppm) [6]. Groundwater generally flows from east to west from the site into Lavaca Bay, but also may flow south and east into Cox Bay and Cox (Huisache) Creek [6].
People fish the area both commercially and for recreation. Commercial seafood dealers (who may have their own fleet of fishing boats or who may buy fish from independent fishermen) are required to submit a monthly marine products report of pounds of seafood harvested from coastal bays to Texas Parks & Wildlife Department (TPWD) [26]. For 1991, reports to TPWD for all parts of Lavaca Bay included no finfish, 308,754 pounds of blue crabs, and 20,109 pounds of oysters. In 1992, TPWD records included reports of no blue crabs, no finfish, and 56,562 pounds of oysters.
During the Expanded Site Inspection sampling event conducted in April 1993, EPA's contractor observed both recreational and commercial fishing near the ALCOA plant and near the area restricted to the taking of fish and crabs [6].
TDH staff reviewed historical records and made numerous requests to determine whether human biological monitoring had been conducted among individuals who may have been exposed to mercury from this site. TDH staff obtained and reviewed records from TNRCC, EPA, MSHA, ALCOA, and the Texas General Land Office, as well as TDH's Bureau of Epidemiology and Division of Shellfish Sanitation. In addition, TDH staff conducted a library literature search for information related to this site and requested information from the local health department and the medical officer for Calhoun county.
The only available medical data include TDH records of serological surveys conducted in 1978 and 1979 [27, 28; ALCOA's historical records of employee urine mercury tests [29]; and ALCOA's recent quarterly reports of employee urine mercury test results to their Mercury Surveillance Program [30, 31, 32]. These limited data and their relevance to the site will be presented and discussed in the Health Outcome Data Evaluation section of this report.
COMMUNITY HEALTH CONCERNS
In an effort to determine community health concerns, we contacted ATSDR, Region VI, United States Environmental Protection Agency (U.S. EPA), the Texas Natural Resource Conservation Commission (TNRCC), the Calhoun County Health Department, Texas Parks and Wildlife Department, Mining Safety and Health Administration, and the Texas General Land Office. We spoke with the principal of the Point Comfort Elementary School, representatives from ALCOA, a Sierra Club member, a representative from the Calhoun County Resource Watch group, the City Manager of the City of Port Lavaca, the Marine agent for the Texas Agricultural Extension Service, staff from the TDH Divisions of Occupational Health and Shellfish Sanitation (Seafood Safety), a former worker at ALCOA, and citizens attending the EPA Open House on April 19, 1994.
The following health-related concerns, which will be addressed in the Public Health Implications section of this health assessment, were obtained:
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