PUBLIC HEALTH ASSESSMENT
MALONE SERVICE COMPANY - SWAN LAKE PLANT
TEXAS CITY, GALVESTON COUNTY, TEXAS
The Agency for Toxic Substances and Disease Registry (ATSDR) was established under themandate of the Comprehensive Environmental Response, Compensation, and Liability Act(CERCLA) of 1980. This act, also known as the "Superfund" law, authorized the U.S.Environmental Protection Agency (EPA) to conduct cleanup activities at hazardous waste sites. EPA was directed to compile a list of sites considered hazardous to public health. This list is termedthe National Priorities List (NPL). The 1986 Superfund Amendments and Reauthorization Act (SARA) directed ATSDR to prepare a Public Health Assessment (PHA) for each NPL site.
In conducting the PHA, three types of information are used: environmental data, community healthconcerns, and health outcome data. The environmental data are reviewed to determine whetherpeople in the community might be exposed to hazardous materials from the NPL facility. If peopleare being exposed to these chemicals, ATSDR will determine whether the exposure is at levelswhich might cause harm. Community health concerns are collected to determine whether healthconcerns expressed by community members could be related to exposure to chemicals released fromthe NPL facility. If the community raises concerns about specific diseases in the community, healthoutcome data (information from state and local databases or health care providers) can be used toaddress the community concerns. Also, if ATSDR finds that harmful exposures have occurred,health outcome data can be used to determine if illnesses are occurring which could be associatedwith the hazardous chemicals released from the NPL facility.
In accordance with the Interagency Cooperative Agreement between ATSDR and the TexasDepartment of Health (TDH), ATSDR and TDH have prepared this PHA for the Malone ServiceCompany NPL site. This PHA presents conclusions about whether exposures are occurring, andwhether a health threat is present. In some cases, it is possible to determine whether exposuresoccurred in the past; however, often a lack of appropriate historical data makes it difficult toquantify past exposures. If it is found that a threat to public health exists, recommendations are made to stop or reduce the threat to public health.
The Malone Service Company (MSC) is adjacent to Galveston Bay and associated wetlands inTexas City, Galveston County, Texas. The site covers approximately 150 acres and was used as ahazardous waste storage, reclamation, and disposal facility from 1964 to 1996. The MSC site waslisted on the National Priorities List (NPL) on June 14, 2001, based on evidence that hazardoussubstances from the facility have contaminated the underlying groundwater and have migrated toGalveston Bay, a National Estuary and major fishery, and associated wetlands.
The Texas Department of Health (TDH) under a cooperative agreement with the Agency for ToxicSubstances and Disease Registry (ATSDR) reviewed available environmental information for thesite and evaluated the primary pathways through which people might come into contact withcontaminants from the site. These exposure pathways include groundwater, soil and sediment,surface water, and air. Based on available information, we have concluded that, at present, none ofthese pathways present a public health hazard. A brief review of the exposure pathways that were considered is presented below.
Although contaminants from the site were identified in the groundwater, there is no evidence that thegroundwater is being used for drinking, bathing, or other household uses. The potential for peopleto be exposed to site contaminants in the groundwater therefore is low. Since the potential forpeople to be exposed to the contaminated groundwater is low, we presently consider thecontaminants in the groundwater to pose no public health hazard.
Sediment samples collected from Galveston Bay, Campbell's Bayou and Swan Lake adjacent to thesite did not contain any contaminants above health-based screening values. Although two of thesediment samples that were collected from drainage ditches on the north and east side of the sitewere found to contain 1,3-dichlorobenzene, phenanthrene, and fluoranthene above backgroundlevels, the concentrations were not above health-based screening values. Since none of the soil orsediment samples exceeded health-based screening values and the potential for exposure to sitecontaminants in the soil and sediment is low, we have concluded that contaminants in the soil andsediment do not pose a public health hazard.
Surface water data were not available for us to evaluate for this report; however, any potentialsurface water runoff from the facility is contained within a 17-foot high hurricane protection levee. In the past, analyses for priority pollutants have detected low levels of metals in the runoff, and nodetectable levels of organic constituents. If storm water were to accumulate on the site such that itwould need to be discharged into the Bay, the TNRCC would be notified and the water would betested for "Oil and Grease" content. The only on-site surface water body with potential to beaffected by site contaminants is the fresh water pond. This pond does not connect to any othersurface water bodies and is not used as a supply for contact or potable water. As there is little or nopotential for exposure of humans to any contaminants which may be contained in the surface water,we have concluded that the surface water pathway does not pose a public health hazard.
Air sampling data were not available for us to evaluate for this report; however, the site is in aremote location with limited access and is no longer operating. The contaminants are contained inan oily sludge and are not likely to volatilize. Because the likelihood that people could come into contact with any contaminants in the air is low, we have concluded that the air pathway does not pose a public health hazard.
|CATEGORY A. |
URGENT PUBLIC HEALTH HAZARD1
This category is used for sites where short-term exposures (<one yr) to hazardous substances or conditions could result in adverse health effects that require rapid intervention.
|CATEGORY B. |
PUBLIC HEALTH HAZARD1
This category is used for sites that pose a public health hazard due to the existence of long-term exposures (>one yr) to hazardous substances or conditions that could result in adverse health effects.
|CATEGORY 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.
|CATEGORY D. |
NO APPARENT PUBLIC HEALTH HAZARD 1
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.
|CATEGORY 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.
2 Such as environmental and demographic data; health outcome data; exposure data; community health concerns information; toxicologic, medical, and epidemiologic data.
The Malone Service Company (MSC) is adjacent to Galveston Bay and associated wetlands inTexas City, Galveston County, Texas. There are numerous industrial facilities in Texas City,including the Tex-Tin Superfund site within two miles of the site. The MSC site was a commercialstorage, processing and disposal facility permitted by the Texas Natural Resource ConservationCommission (TNRCC) to store, process, and to dispose of liquid hazardous and non-hazardouswaste by means of deep well injection.
The facility occupies a 150-acre tract of land, of which 75 acres have been developed for the wastemanagement operations. On-site structures include numerous above ground storage tanks, a largeearthen surface impoundment, concrete lined separators, two underground injection wells, and rolloff bins. The entire waste management facility is surrounded by a flood protection-levee with a crestelevation of 17 feet . Surface water runoff is discharged from the facility through two culvertsinto Campbell's Bayou. Operations at the MSC site began in 1964 and continued until 1996, whenthe last scheduled waste shipment was received and processed. Waste materials remain on-site andare managed in surface impoundments, separators, roll-off bins, and above ground tanks (Figs 1-7).
The MSC site is bordered on the northeast and east by swamp/marsh lands which extend to the shoreof Swan Lake and Galveston Bay, the seventh largest estuary in the United States. The site isbordered on the northwest and north by the closed Texas City Landfill and on the south by ruralundeveloped land (Fig 8). The closest residential areas are approximately 1.5 miles from the facilityto the west. According to the baseline risk assessment it is improbable that there will be anyresidential development within the existing 1.5 mile buffer of the site .
The two sources of contamination on the site are known as the "settling basin surfaceimpoundment/earthen impoundment" (Fig. 1) and the "oil pit" (Fig. 2). These areas were used forthe management of industrial solid waste. The earthen impoundment covers approximately fiveacres with an average depth of 37 feet. The oil pit is lined with concrete and covers approximately28,000 square feet. Both areas are surrounded by earthen dikes which are approximately 17 feetabove ground level. These impoundments, which have been inactive since 1996, were used forseparation of solids and oils from aqueous wastes with the solids remaining in the excavation. Theoils were recovered from the impoundments, and the aqueous phase was disposed of by deep wellinjection. Since 1996, the only significant activity regarding the impoundments has been to removeaccumulated stormwater for subsequent management. Currently, the material contained in theseareas consists of oily solids, oil, and water .
In 1986 and 1989, the TNRCC collected samples of material in the earthen impoundment and theoil pit as part of compliance inspections. TNRCC returned to the site in 1997 to evaluate potentialcontamination of groundwater and sediment at the site. Groundwater samples collected in 1997indicated the presence of contaminants originally found in the earthen impoundment and oil pit inthe 1980s. The contaminants found in the groundwater included phenol, chlorobenzene, 1,1-dichloroethane, 1,2-dichloroethane, 1,1-dichloroethylene, 1,2-dichloroethylene, 1,1,2-trichloroethane, and vinyl chloride, and metals (arsenic, barium, chromium, copper, and lead). Chromium and lead were found in sediment samples collected from Galveston Bay during the 1997inspection .
According to the baseline risk assessment, MSC plans to remove excess liquids, stabilize andencapsulate the sludge, construct a protective cover, construct a subsurface cutoff wall, and restoregroundwater quality at the facility . The site was proposed to the Environmental ProtectionAgency's (EPA's) National Priority List (NPL) in August of 2000 and was listed on the NPL onJune 14, 2001. The NPL is a list of the most serious uncontrolled or abandoned hazardous wastesites identified for possible long-term remedial action under Superfund .
Although TDH has not had any direct involvement with this site, the TDH Seafood Safety Division,as part of their routine monitoring of fish from water bodies in Texas has extensively sampledseafood from Galveston Bay and has not found cause to issue any fish consumption advisories associated with chemical contaminants in the Bay .
We toured the MSC site in February, 2001 along with personnel from the TNRCC regional office. The site is located close to a major highway but is not visible from the highway because of the 17foot high hurricane levee that surrounds the property. To reach the site we had to turn off thehighway and drive approximately one mile over a rough dirt road to a coded access gate just beyondthe levee. A code was required for entry. We had to drive another ½ mile over dirt roads to a trailerwhich served as an office. Along the way, we observed wetlands, flat unused pasture land, and aduck pond with numerous bird species. The property was fenced with a sign stating "AuthorizedPersonnel Only - Do Not Enter."
There were two employees on the site during our visit. We toured the site by vehicle since we wereadvised that rattlesnakes and mosquitos were rampant on the property. We saw numerous tanks andthe oil pit next to the trailer. The oil pit contained a black tar-like liquid with a strong chemicalodor. The earthen impoundment was filled with sludge and waste materials that had a mildchemical odor. In order to observe the impoundment, we had to climb up a dike. Because of itslocation, it did not appear that the liquid would run off from the impoundment. We observed thatthe freshwater duck pond is approximately 200 feet from the impoundment.
We saw two pipes that, according to TNRCC, discharge storm water from the site into the GalvestonBay wetlands and Swan Lake; however, we were told that it would take a very large hurricane togenerate enough water to cause a release of storm water.
The site was extremely difficult to access, and we did not see any evidence that people other thanauthorized personnel had gained access to the site. According to the site manager, only properlytrained personnel are allowed near the earthen impoundment and oil pit.
The 1990 U.S. Bureau of Census data reports that there are ten housing units and two residentswithin a one-half mile radius of the MSC site . There are no schools or daycare facilities withinone-mile of the site. The nearest residential areas are approximately 1.5 miles from the facility tothe west . Because of the industrial nature of this area, it is improbable that there will be anyresidential development within the existing 1.5 mile buffer surrounding the site (Fig. 9). The site isin Texas City, which has a population of 41,521.
In an effort to collect community health concerns, we contacted the Galveston County HealthDistrict and the Galveston County Pollution Control District. The Galveston County Health Districtreported that, although there is general public health concern regarding the numerous industrialfacilities in Texas City, they were not aware of specific health concerns regarding the MSC site. There were no residents living near the site for us to contact.
The presence of chemical contaminants in the environment does not always result in exposure to orcontact with the chemicals by people. Since chemicals only have the potential to cause adversehealth effects when people actually come into contact with them, it is exposure, or the contact thatpeople have with the contaminants that drives the public health assessment process.
People may be exposed to chemicals in different ways; usually by breathing, eating, drinking, orcoming into direct contact with a substance containing the contaminant. This section reviewsavailable information to determine whether people in the community have been, currently are, ormay in the future be exposed to contaminants associated with this site.
To determine whether people are exposed to contaminants associated with the site, we evaluate theenvironmental and human components that lead to human exposure. This analysis consists ofevaluating the five elements of an exposure pathway: a source of contamination, transport throughan environmental medium, a point of exposure, a route through which the contaminant can enter thebody, and an exposed population. Exposure pathways can be complete, potential, or eliminated. For a person to be exposed to a contaminant, the exposure pathway must be complete. An exposurepathway is considered complete when all five elements in the pathway are present and exposure hasoccurred, is occurring, or will occur in the future. A potential pathway is missing at least one of thefive elements and may be completed in the future. Eliminated pathways are missing one or moreelements and will never be completed. Table 3 identifies the pathways that we identified for thissite. The following discussion incorporates only those pathways which are relevant and important tothe site.
Since exposure does not always result in adverse health effects, we also evaluate whether theexposure could be sufficient to pose a hazard to people in the community. The factors that influencewhether exposure to a contaminant or contaminants could or would result in adverse health effectsinclude; (1) the toxicologic properties of the contaminant; (2) how much of the contaminant theindividual is exposed to; (3) how often and/or how long exposure is allowed to occur; (4) themanner in which the contaminant enters or contacts the body (breathing, eating, drinking, orskin/eye contact); and, (5) the number of contaminants to which an individual is exposed(combinations of contaminants). Once exposure occurs, characteristics such as age, sex, nutritionalstatus, genetics, life style, and health status of the exposed individual influence how the individualabsorbs, distributes, metabolizes, and excretes the contaminant.
When we identify plausible potential exposure scenarios, we begin assessing the potential publichealth significance of the exposure by comparing contaminant concentrations to health assessmentcomparison (HAC) values for both non-carcinogenic and carcinogenic endpoints. HAC values aremedia-specific contaminant concentrations that are used to screen contaminants for furtherevaluation. While exceeding a HAC value does not necessarily mean that a contaminant represents apublic health threat, it does suggest that the contaminant warrants further consideration.
Non-cancer comparison values are called environmental media evaluation guides (EMEGs) orreference dose media evaluation guides (RMEGs) and are respectively based on ATSDR's minimalrisk levels (MRLs) and EPA's reference doses (RfDs). MRLs and RfDs are estimates of dailyhuman exposure to a contaminant that is unlikely to cause adverse non-cancer health effects over alifetime. Cancer risk comparison values are called carcinogenic risk evaluation guides (CREGs)and are based on EPA's chemical specific cancer slope factors and an estimated excess lifetimecancer risk of one-in-one-million persons exposed for a lifetime. We use standard assumptions tocalculate appropriate HAC values .
The environmental data used in this public health assessment were obtained from the 1997 TNRCCsite screening inspection report. Data were available for groundwater, soil, and sediment. Thesamples were analyzed for volatile and semi-volatile organic compounds, PCBs, pesticides, andmetals. All samples were collected according to EPA-approved Quality Assurance Project Plans,and the sample locations were approved by the EPA prior to sample collection. The analysis andconclusions in this report are valid only if the referenced information is valid and complete.
To assess the public health significance of this site we considered potential exposure to sitecontaminants in groundwater, soil and sediment, surface water, and air (Table 3).
In 1997, the TNRCC collected ten groundwater samples, including two background and oneduplicate sample from the MSC site (Table 1a). Background samples were obtained upgradient ofthe sources at the MSC site from groundwater monitoring wells at depths of 7-20 feet.
The samples collected from monitoring wells adjacent to the earthen impoundment and the oil pitcontained chlorobenzene, 1,1-dichloroethane, 1,2-dichloroethane, 1,1-dichloroethene, 1,2-dichloroethene, phenol, 1,1,2-trichloroethane, vinyl chloride, arsenic, barium, and chromium atconcentrations greater than their respective HAC values (Table 1b). Although 1,2-dichloroethyleneand vinyl chloride were not documented in the source, they are degradation products of othercompounds found on the site.
The major hydrologic units in the MSC site area include two major aquifers, the Chicot andEvangeline. The Chicot aquifer ranges in thickness from approximately 700 to 1,200 feet andunderlies the site from just below the surface to approximately 1,000 feet. Groundwater flowappears to be northwest to southeast, toward Galveston Bay; however, studies indicate that saltwaterintrusion from Galveston Bay continues to degrade water quality in this aquifer, which indicates thatit also is tidally influenced by the Bay. The shallow Chicot aquifer is isolated from the deeperEvangeline aquifer by a massive clay formation approximately that is 150 feet thick. The top of theEvangeline aquifer is about 1,200 feet deep and its thickness averages 2,300 feet. Downwardmigration of groundwater from the Chicot to the usable parts of the Evangeline, through the clayformation, is not likely to occur .
Although not used in the vicinity of the MSC site, the Evangeline aquifer is the major source ofgroundwater in the nearby Houston area. The shallower Chicot aquifer, a source of drinking waterin some parts of Galveston County, is not used in and around the MSC site because of its highchloride and total dissolved solids content. There are no public supply or domestic drinking waterwells completed in the Chicot Aquifer within one mile of the Malone site .
Texas City, the nearest populated area, purchases treated surface water from the Gulf Coast WaterAuthority; this water comes from the Brazos River. No public supply wells or domestic drinkingwater wells exist within a one mile radius of the site . Records obtained from the HoustonGalveston County Subsidence District indicate that there are several wells in the nearby BayouVista Subdivision which are used as a domestic water supply. These wells were reported to beapproximately 100 to 200 feet deep and are isolated from the Chicot aquifer. There is nodocumentation indicating that drinking water wells in the vicinity of the site have been contaminatedby hazardous substances attributable to the site. Although contaminants from the site wereidentified in the groundwater beneath the site, there is no evidence that the groundwater is beingused for drinking, bathing, or other household uses. The potential for people to be exposed to sitecontaminants in the groundwater therefore is low. Since the potential for people to be exposed to thecontaminated groundwater is low, we presently consider the contaminants in the groundwater topose no public health hazard.
In order to assess soil and sediment contamination, the TNRCC collected 14 sediment and three soilsamples, including three duplicate and five background samples (all samples collected at 0-6" depth)(Table 2a). Sediment samples collected from Galveston Bay, Campbell's Bayou and Swan Lakeadjacent to the site did not contain any contaminants above HAC values (Table 2b and 2c). Two ofthe sediment samples that were collected from drainage ditches on the north and east side of the sitewere found to contain 1,3-dichlorobenzene, phenanthrene, and fluoranthene above backgroundlevels, but not above HAC values (Table 2c).
Since none of the soil or sediment samples exceeded HAC values and the potential for exposure tosite contaminants in the soil and sediment is low, we have concluded that contaminants in the soil and sediment do not pose a public health hazard.
Surface water data were not available for us to evaluate for this report. The surface water runofffrom undeveloped areas of the facility is contained within a 17-foot high hurricane protection levee. Surface water runoff is discharged from the facility through two culverts into Campbell's Bayou. These culverts have gates (which act like valves) that can be closed to prevent accumulated stormwater within the MSC site from discharging to the Bayou. While we are unable to comment on thehistoric practices of MSC in regard to management of these gates, the current practice asimplemented by EPA includes keeping the gates closed. In the past, if storm water were toaccumulate on the site such that it would need to be discharged into the Bay, the TNRCC would benotified, and the water would be tested for "Oil and Grease" content and for the "Target AnalyteList" to ensure it is free of unacceptable levels of contamination prior to discharge. The role ofmanaging storm water at the MSC site was transferred from TNRCC to EPA effective September 1,2001. Past analysis for priority pollutants have detected low levels of metals in the runoff and nodetectable levels of organic constituents .
The only on-site surface water body with potential to be affected by site contaminants is the freshwater pond. This pond does not connect to any other surface water bodies and is not used as asupply for contact or potable water.
As there is little or no potential for exposure of humans to any contaminants which may be containedin the surface water, we have concluded that the surface water pathway does not pose a public healthhazard.
Air sampling data were not available for us to evaluate for this report; however, the contaminants onthis site are contained in an oily sludge and are not likely to volatilize . The site also is in aremote location with limited access and is no longer operating. Because the likelihood that peoplecould come into contact with any contaminants in the air is low, we have concluded that the air pathway does not pose a public health hazard.
Health outcome data (HOD) record certain health conditions that occur in populations. These datacan provide information on the general health of communities living near a hazardous waste site. Italso can provide information on patterns of specified health conditions. Some examples of healthoutcome databases are tumor registries, birth defects registries, and vital statistics. Information fromlocal hospitals, and other health care providers also may be used to investigate patterns of disease ina specific population. TDH and ATSDR look at appropriate and available health outcome datawhen there is a completed exposure pathway or community concern. Due to a lack of completedexposure pathways and no identified community concerns, a review of health outcome data was not required for this site.
TDH has prepared this consult under a cooperative agreement with the Agency for Toxic Substancesand Disease Registry (ATSDR). TDH has included the following information in accordance withthe ATSDR's Child Health Initiative.
ATSDR's Child Health Initiative recognizes that the unique vulnerabilities of infants and childrendemand special emphasis in communities faced with contamination of their water, soil, air, or food. Children are at greater risk than adults from certain kinds of exposures to hazardous substancesemitted from waste sites and emergency events. They are more likely to be exposed because theyplay outdoors and they often bring food into contaminated areas. They are shorter than adults,which means they breathe dust, soil, and heavy vapors close to the ground. Children also aresmaller, resulting in higher doses of chemical exposure per body weight. The developing bodysystems of children can sustain permanent damage if toxic exposures occur during critical growthstages. Most importantly, children depend completely on adults for risk identification andmanagement decisions, housing decision, and access to medical care.
TDH evaluated the potential for children living in the vicinity of Malone Service Company to beexposed to site contaminants at levels of health concern. Although contaminants in groundwaterexceed the health based comparisons for children, exposure to site contaminants is not occurring and is not likely to occur in the future.
Based on available information, we were not able to identify any pathways through which peoplewould be likely to come into contact with site contaminants. We have concluded that, at present, the MSC site does not pose a public health hazard.
There are no public health recommendations for the site
TNRCC/EPA plan to proceed with the remedial investigation of the site.
- U.S. EPA, United States Environmental Protection Agency. Baseline Risk Assessment for Closure of the Settling Basin. Malone Service Co. Swan Lake Facility. Oct. 1994
- TNRCC, Texas Natural Resource Conservation Commission. Screening Site Inspection Report for Malone Service Company, TXD980864789, Texas City, Galveston County, Texas. Prepared in cooperation with the U.S. EPA. Oct. 1998.
- U.S. EPA, United States Environmental Protection Agency. National Priorities List (NPL). Malone Service Company, Texas City, Texas. August, 2000.
- Texas Department of Health, Seafood Safety Division. Health Consultation(s) forconsumption of fish from Galveston Bay. 1999-2001.
- U.S. Census Bureau. Census of the population. Demographic Statistics Source: 1990 U.S. Census. U.S. Government Printing Office, Washington, D.C., 1985.
- ATSDR, Agency for Toxic Substances and Disease Registry. Public Health AssessmentGuidance Manual. Lewis Publishers, 1992.
Lisa R. Williams, M.S.
Health Risk Assessment and Toxicology Program
Susan Prosperie, M.S., R.S.
Health Risk Assessment and Toxicology Program
John F. Villanacci, Ph.D.
Health Risk Assessment and Toxicology Program
ATSDR REGIONAL REPRESENTATIVE
George Pettigrew, P.E.
Senior Regional Representative
ATSDR - Region 6
ATSDR TECHNICAL PROJECT OFFICER
Alan W. Yarbrough
Environmental Health Scientist
Division of Health Assessment and Consultation
Superfund Site Assessment Branch
This Public Health Assessment was prepared by the Texas Department of Health 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 Public Health Assessment was initiated.
Alan W. Yarbrough
Technical Project Officer, SPS, SSAB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this Public Health Assessment and concurs with its findings.
Lisa C. Hayes
for Chief, State Programs Section, SSAB, DHAC, ATSDR
|ATSDR||Agency for Toxic Substances and Disease Registry|
|CERCLA||Comprehensive Environmental Response, Compensation and Liability Act of 1980|
|CREG||Carcinogenic Risk Evaluation Guide|
|EMEG||Environmental Media Evaluation Guide|
|EPA||Environmental Protection Agency|
|HAC Value||Health Assessment Comparison Value|
|MRL||Minimal Risk Level|
|MSC||Malone Service Company|
|NPL||National Priorities List|
|PHA||Public Health Assessment|
|SARA||Superfund Amendments and Reauthorization Act of 1986|
|SVOCs||Semi-Volatile Organic Compounds|
|TDH||Texas Department of Health|
|TNRCC||Texas Natural Resource Conservation Commission|
|Sample Location and depth||Rationale|
|GW-01||Monitoring well (BW-28A) at Gulf Coast Waste Disposal Authority (west of the site) [7-26']||establish background levels of contaminants uprgradient in sand channel|
|GW-02||Monitoring well (BW-24) at Gulf Coast Waste Disposal Authority (west of the site) [8-28']||establish background levels of contaminants uprgradient in sand channel|
|GW-03||Duplicate of GW-02||quality assurance / quality control|
|GW-08||Background sample (MW-15U) taken from South end of MSC facility [9-16']||assess groundwater contamination migrating along the pathway to the southeast|
|GW-05||MSC property, approximately 150 feet west of the earthen impoundment (MW-4) [6-26']||assess groundwater contamination related to release from the earthen impoundment|
|GW-07||MSC property, between earthen impoundment and API separator (MW-12U) [8-16']||assess groundwater contamination related to release from the earthen impoundment|
|GW-09||MSC property, approximately 800 feet north of the earthen impoundment (MW-7U) [9-16']||assess groundwater contamination migrating north toward Campbell's Bayou|
|GW-06||MSC property, monitoring well (MW-5D) on northern side of property||assess groundwater migrating along the northern pathway|
|GW-10||MSC property, monitoring well (MW-7D)||assess groundwater contamination migrating north toward Campbell's Bayou|
|Background Samples||On-site Samples|
|GW-01||GW-02||GW-03||GW-08||GW-05||GW-07||GW-09||GW-06||GW-10||HAC values (ug/L)*||Exceeds HAC values?|
|chlorobenzene||ND**||ND||ND||ND||ND||200||ND||ND||ND||RMEG 200 child/700 adult |
MCL 100; LTHA 100; CLHA2,000
|1,2-dichloroethane||ND||ND||ND||ND||150,000||210||ND||ND||ND||EMEG (intermediate) |
2,000 child/7,000 adult
MCL 5; CLHA 700; CREG 0.4
|1,1-dichloroethene||ND||ND||ND||ND||ND||360||ND||ND||ND||RMEG/EMEG 90 child/300 adult |
MCL 7; LTHA 7; CLHA 1,000; CREG 0.06
|1,2-dichloroethene||ND||ND||ND||ND||ND||2,700||ND||ND||ND||RMEG 200 child/700 adult |
MCL 100; LTHA 100; CLHA 2,000
|phenol||ND||ND||ND||ND||26,000||4,600||ND||ND||ND||RMEG 6,000 child/20,000 adult |
LTHA 4,000; CLHA 6,000
|1,1,2-trichloroethane||ND||ND||ND||ND||ND||280||ND||ND||ND||RMEG 40 child/100 adult |
MCL 5; LTHA 3; CLHA 400;
|vinyl chloride||ND||ND||ND||ND||ND||11,000||ND||ND||ND||RMEG 30 child/100 adult |
EMEG 0.2 child/0.7 adult
MCL 2; CLHA 10; CREG 0.03
*RMEG=reference dose media evaluation guide and is based on EPA's RfD for chronic exposure (unless otherwise specified), EMEG=environmental media evaluation guide and is based on ATSDRs MRL for chronic exposure (unless otherwise specified), CREG=cancer risk evaluation guide and is based on an excess cancer risk of one in one-million persons exposed over a lifetime. Health based comparison values are based on an assumed ingestion rate of one liter water for children (body weight 10 kg) and an ingestion rate of two liters water for adults (body weight 70 kg). MCL is the maximum contaminant level for drinking water (EPA); LTHA is the lifetime health advisory for drinking water (EPA); and CLHA is the child longer term health advisory for drinking water (EPA).
|Background Samples||On-site Samples|
|GW-01||GW-02||GW-03||GW-08||GW-05||GW-07||GW-09||GW-06||GW-10||HAC values (µg/L)*||Exceeds HAC values?|
|arsenic||4.1||10.3||ND**||3.7||4,070||6,000||80||7.6||3.2||RMEG/EMEG 3 child/10 adult |
MCL 10 (proposed); CREG 0.02
|barium||61.6||55.4||ND||74.6||1,050||1,900||438||67.1||72..3||RMEG 700 child/2,000 adult |
MCL 2,000; LTHA 2,000
|chromium||2||ND||ND||ND||472||46.2||ND||ND||ND||MCL 100; LTHA 100; CLHA 200||yes|
*RMEG=reference dose media evaluation guide and is based on EPA's RfD for chronic exposure (unless otherwise specified), EMEG=environmental media evaluation guide and is based on ATSDRs MRL for chronic exposure (unless otherwise specified) , CREG=cancer risk evaluation guide and is based on an excess cancer risk of one in one-million persons exposed over a lifetime. Health based comparison values are based on an assumed ingestion rate of one liter water for children (body weight 10 kg) and an ingestion rate of two liters water for adults (body weight 70 kg). MCL is the maximum contaminant level for drinking water (EPA); LTHA is the lifetime health advisory for drinking water (EPA); and CLHA is the child longer term health advisory for drinking water (EPA).
|SE-01||Swan Lake across Campbell Bayou||establish background levels of contaminants in Swan Lake|
|SE-02||duplicate of SE-01||quality assurance / quality control|
|SE-03||Island separating Swan Lake and Galveston Bay||establish background levels of contaminants in Galveston Bay|
|SE-04||Virginia Point shoreline, south of the MSC site||establish background levels of contaminants in Galveston Bay|
|SE-05||south shoreline of Campbell Bayou, connecting Swan Lake and Galveston Bay||assess sediment contamination migrating along the groundwater to surface water pathway into Swan Lake/Galveston Bay|
|SE-06||south shoreline of Campbell Bayou, connecting Swan Lake and Galveston Bay||assess sediment contamination migrating along the groundwater to surface water pathway into Swan Lake/Galveston Bay|
|SE-07||confluence of drainage channel and Swan Lake||assess contaminant migration from Campbell Bayou to Swan Lake|
|SE-08||drainage channel adjacent to MSC site||assess contaminant migration along the surface water and/or groundwater to surface water pathway into drainage channel|
|SE-09||inlet of Swan Lake adjacent to Campbell Bayou||assess contaminant migration along the groundwater to surface water pathway into Swan Lake|
|SE-10||drainage channel adjacent to MSC site and connecting to Swan Lake||assess contaminant migration along surface water and/or groundwater to surface water pathway in drainage channel and/or discharge point at probable point of entry|
|SE-11||duplicate of SE-10||quality assurance / quality control|
|SE-12||downstream end of drainage channel adjacent to the MSC site and connecting to Swan Lake||assess contaminant migration along surface water and/or along the groundwater to surface water pathway in drainage channel to Swan Lake|
|SE-13||drainage ditch along north side of MSC||assess contaminant migration on north side of MSC|
|SE-14||drainage ditch along east side of MSC||assess contaminant migration on east side of MSC|
|SO-01||adjacent to west side of the earthen impoundment||document waste characterization and release of hazardous substances to the surface soil by leakage through the surface impoundment levee|
|SO-02||southwest of MSC along access road||background sample|
|SO-03||duplicate of SO-02||quality assurance / quality control|
|Background Samples (mg/kg)||On-site Samples|
|SE-01||SE-02||SE-03||SE-04||SE-05||SE-06||SE-07||HAC Values (mg/kg)*||Exceeds HAC values?|
|barium||28.3||17.9||49.8||267||96.2||51.2||39||RMEG 4,000 child/50,000 adult||no|
|chromium||8.4||5.9||6.1||9.0||47.6||9.5||20.9||RMEG 200 child/2,000 adult||no|
|On-Site Samples (mg/kg)|
|SE-08||SE-09||SE-10||SE-11||SE-12||SE-13||SE-14||HAC values (mg/kg)*||Exceeds HAC Values?|
|fluoranthene||ND||ND||ND||ND||ND||1,400||600||RMEG 2,000 child/30,000 adult||no|
|barium||57.6||21||52.3||63.7||120||121||149||RMEG 4,000 child/50,000 adult||no|
|chromium||47||8.3||3.9||5.2||79.2||18.3||37.4||RMEG 200 child/2,000 adult||no|
*RMEG=reference dose media evaluation guide and is based on EPA's RfD for chronic exposure (unless otherwise specified), EMEG=environmental media evaluation guide and is based on ATSDRs MRL for chronic exposure (unless otherwise specified) , CREG=cancer risk evaluation guide and is based on an excess cancer risk of one in one-million persons exposed over a lifetime. Health based comparison values are based on an assumed ingestion rate of 200 mg of soil for children (body weight 10 kg) and an ingestion rate of 100 mg of soil for adults (body weight 70 kg).
|PATHWAY NAME||PRIMARY CONTAMINANTS OF CONCERN||EXPOSURE PATHWAY ELEMENTS||TIME||CONCLUSIONS|
|SOURCE||ENVIRONMENTAL MEDIA||POINT OF EXPOSURE||ROUTE OF EXPOSURE||EXPOSED POPULATION|
|Potential Exposure Pathways|
|wastewater discharge from local industry / site operations||groundwater||drinking water||ingestion||residents||past |
|no public health hazard; drinking water is supplied by the City|
|water wells||ingestion||residents||past |
|no public health hazard; all wells are upgradient of the site|
|Surface water||not sampled||wastewater discharge from local industry / site operations||surface water||swimming, |
|dermal, incidental ingestion||workers |
|no public health hazard; sufficient evidence indicates that residents do not use the site for recreational purposes or drinking water|
|wastewater discharge from local industry / site operations||sediment||on-site, |
|no public health hazard; sufficient evidence indicates that people would not be likely to come in contact with sediment on a frequent basis|
|Air||not sampled||wastewater discharge from site operations||air||on site||inhalation||on-site workers||past |
|no apparent public health hazard; site no longer operating|