PUBLIC HEALTH ASSESSMENT ADDENDUM
MOTCO, INCORPORATED
TEXAS CITY, GALVESTON COUNTY, TEXAS
Environmental sampling conducted at the MOTCO site since 1981 has revealed contamination in soils, ground water, and sediments. The majority of the on-site contamination is contained in, and associated with, the waste pits. The primary contaminants of concern found both on and off the site include semi-VOCs, VOCs and heavy metals.
On-site contaminants found in soil and ground water may migrate into other environmental media such as surface water, air and biota. They may also migrate off site. Contaminants may migrate from soil with surface-water run-off, over the ground, and subsequently enter surface-water bodies. Contaminants may be transported downstream until deposited with sediments. Sediments may contribute to ground-water contamination by percolation or to contamination of the ecosystem by fish or plant uptake. Contaminants in pit waste may leach into the ground water below the pits. These contaminants will then migrate in the direction of ground-water flow until degraded by natural processes or removed by remediation. Contaminants found in surface soil may adhere to soil particles and be transported by winds or, if they are volatile, they may enter the air and migrate off site. Each of these environmental pathways is discussed below with respect to this site.
1. Soil Pathways
Analysis of top soil and subsurface soil samples defined two primary areas of soil contamination: southeast of Pit 7 and northwest of the site in the area of the abandoned trailer park. Contaminants were also detected east of the site near Pit 5. Most of the top-soil contamination was found outside the site boundary fence. In the top soil, only benzene was identified above the HAC value; the maximum level found slightly exceeded this comparison value. Subsurface contamination was detected in the area east of the site.
Top-soil contamination may migrate through surface-water run-off tracking, and in the form of airborne particulate matter. Top-soil contamination can also migrate through the soil to subsurface levels and ground water as a result of leaching. Surface water and sediment sampling data along with air quality monitoring does not support appreciable migration of top-soil contaminants through surface-water run-off or airborne dispersal. The increase in semi-VOC contaminants observed with increased depth suggests that downward migration through the soil may be occurring.
2. Ground-water Pathways
Contaminants found in ground water may migrate in the direction of ground-water flow vertically and horizontally. They may also contaminate surface-water bodies if they are fed from ground-water sources.
Ground-water samples collected from wells installed in the shallow aquifer defined two plumes of contamination, located south and northwest of the site. The first plume, located south of the site and near Pit 7, extends approximately 500 feet past the site boundary. The second plume, northwest of the site and north of Pit 2 and Pit 3, extends approximately 275 feet past the site boundary. Limited contamination was detected in the deep aquifer. Sampling data supports the current migration of contaminants through ground-water flow.
3. Surface-Water Pathways
The MOTCO site is in the Highland Bayou drainage basin. Site drainage is south and east through a series of drainage ditches and storm sewers. A large drainage ditch is located on the southwestern boundary of the site. Run-off passes through a series of storm sewers into a marsh area south of the Del Industries site. Drainage from the site ultimately reaches Jones Bay. Galveston Bay is located approximately 2.0 miles from the site and the Jones Bay/Trinity-San Jacinto estuary is approximately 1.5 miles south of the site. Surface water provides opportunity for migration of soil contaminants. As they are dispersed, these contaminants can evaporate into the air, accumulate in fish and other wildlife, and leach into the ground water.
Surface-water samples were collected primarily from drainage ditches and marsh areas around the periphery of the site. The majority of samples were taken off site. Samples taken in the initial investigation revealed low levels of the volatile compounds 1,1,2-trichloroethane and 1,2-dichloroethane. Both contaminants were from the same site, a drainage ditch on the HL&P right-of-way, west of the MOTCO site. Samples collected during the SFSI study resulted in identification of no appreciable levels of contaminants. Migration of contaminants via this pathway is unlikely.
4. Sediment Pathway
Sediment samples were taken in conjunction with surface-water samples. Sediment samples may provide several exposure pathways. Contaminants may enter sediments from surface water through dissolution and may establish an equilibrium relationship for communication of contaminants with surface-water bodies. Sediments also provide sources of contaminant contact with fish and crustaceans. Sediments in drainage ditches may also be a source of contamination of marshes and bays into which they ultimately empty. Lead was detected in sediments up to 483 ppm. No other contaminants were found at levels of concern. Data resulting from sediment sampling does not support contaminant migration through sediments as an active exposure pathway in relation to the MOTCO site.
Several exposure pathways are possible because of contaminated media and environmental transport at the site.
1. Top Soil:
Inhalation, dermal contact, and ingestion of contaminated off-site surface soils are possible routes of human exposure at this site. The population primarily at risk would be workers involved in remediation activities. However, trespassers gaining access to the area may be exposed to contaminated soils, as well as children who might play along the fence.
As a result of frequent hand-to-mouth activity, small children (less than 6 yrs of age) typically ingest 0.2 g of soil per day. The estimated ingestion rate for adults is 0.1 g soil per day. At the MOTCO site, physical barriers exist such that children would not be expected to readily gain access to high levels of soil contamination.
The primary location of top-soil contamination exists immediately outside site boundaries in areas not currently in active use. An overgrowth of vegetation in these areas provides protection from soil erosion as well as a mechanical barrier to reduce the risk of dermal contact. Access to the area is limited due to the presence of highways, the HL&P right-of-way, and borrow pits.
Because evidence of activities in areas of soil contamination has not been observed, exposure pathways involving top-soil contamination are considered potential rather than completed pathways. Potential for exposure to contaminated soils will increase during site remediation activities.
2. Waste Pit Contaminants:
On-site waste pit contaminants provide possible exposure, through dermal contact and inhalation (if pit contents are disturbed), particularly for on-site workers involved in remediation. Even though the site is fenced and locked, and the surrounding areas are diked, skin contact with or inhalation of contaminants may occur if persons enter the waste pits. The facility is fenced and locked reducing the possibility of trespassers becoming exposed. Areas surrounding the pits are diked reducing potential for contact, although exposure to contaminants may occur if persons were to enter the area of the waste pits. This exposure pathway is considered a potential exposure pathway for remedial workers and trespassers, and will be eliminated following site remediation.
3. Ground Water:
Contaminated ground water may lead to human exposure through ingestion, dermal contact, and inhalation (during showers, bathing, etc.). People may become exposed to contaminants when they drink contaminated water, but exposure also occurs during use of contaminated water for domestic chores such as washing clothes, taking baths and showers, and washing dishes. Exposure occurs not only as a result of dermal contact and ingestion, but inhalation of contaminants may be attributed to the natural evaporation occurring during these activities.
Surrounding neighborhoods obtain their water from public water supplies that are not directly affected by aquifer contamination in this area. Existing area private wells are abandoned or are used for nonpotable purposes.
Existing on-site ground-water contamination is present at the MOTCO site, but on-site wells are currently not in operation. Presently, there is no indication of contaminant migration to the Del Industries or Central Freight process wells. Current area water use does not support the classification of ground-water contamination as a past or present exposure pathway. However, if inactive or nonpotable sources of water are used for potable purposes in the future, a complete exposure pathway would exist.
4. Surface-water Sediments:
Off-site surface-water sediments present in drainage ditches and marsh areas provide possible human exposure to low level contamination through ingestion and dermal contact. The primary contaminant of concern is lead. Specific populations at risk include workers involved in remediation activities as well as workers employed in activities along the HL&P right-of-way. Trespassers and children gaining access to the area may also be exposed.
5. Biota:
The data in this Addendum indicate that fish and shellfish are not contaminated with site-related chemicals; therefore, persons consuming these biota will not be exposed to site-related contaminants. However the pond adjacent to Del Industries and Central Freight was not sampled. This area is not restricted and fishing may occur. In the event that fishing would occur, the human exposure potential has not been defined.
6. Air:
Air exposure pathway analyses were conducted on the basis of monitoring data collected in 1981. At that time, no elevated levels of air contaminants were found. Nevertheless, with the implementation of incineration, air sampling activities has resumed and air quality is being monitored around the periphery of the site.
The primary site contaminants consisted of three groups: volatile organics, semivolatile organics, and metals. The following discussion used the ATSDR Toxicological Profiles for 1,1,2-trichloroethane, 1,2-dichloroethane, vinyl chloride, benzene, bis(2-chloroethyl)ether, arsenic, and lead (7-11, 13, 16).
1. Volatile Organics
Appreciable levels of VOCs were found both on and off site in the shallow ground water. The primary VOCs detected were 1,1,2- trichloroethane, 1,2-dichloroethane, vinyl chloride and benzene. In general, these chemicals are toxic to the liver as the result of their metabolic conversion to highly-reactive chemical intermediates. Exposures of VOCs related to MOTCO are expected to be low level and short term, with remediation workers considered the primary population at risk.
Limited information is available concerning health effects related to short term low level exposure to VOCs. Short-term effects resulting from high levels of vinyl chloride exposure include dizziness, ataxia, and headache. In addition, long-term, low-dose exposures have resulted in "vinyl chloride disease". This syndrome is characterized by liver, circulatory, integumentary and hematopoietic involvement. The exposed person develops poor circulation in the fingers, thickening of the skin, and changes in the blood. Epidemiologic evidence has indicated that occupational inhalation exposure to vinyl chloride can induce tumors of the liver (hepatic angiosarcoma) and other organs in exposed workers. However, vinyl chloride levels associated with the MOTCO site are considerably lower than expected in standard occupational settings (9).
Benzene was found as a contaminant in soil and ground water both on and off site and in waste materials in the pits on site. The primary consideration for health risk with benzene are effects on bone marrow which can result in blood abnormalities and leukemia. Benzene is also a known human carcinogen. Epidemiologic studies of occupational exposure have indicated that exposure to benzene can cause bone marrow toxicity. Occupational exposures have also been associated with an increased incidence of blood dyscrasia, aplastic anemia, and leukemia (10).
Due to site location and proximity of highways, it is unlikely that children or trespassers will gain contact to the shallow ground water at the MOTCO site or surrounding vicinity.
3. Bis(2-chloroethyl)ether
A semi-VOC found in appreciable concentrations both on and off site is bis(2-chloroethyl)ether.
Inhalation exposure to bis(2-chloroethyl)ether is a pathway of concern. At the MOTCO site, the primary areas of contamination are off-site subsurface soil and on-site and off-site shallow ground water. Inhalation exposure resulting from contact with contaminants associated with subsurface soil and ground water might occur during remediation activities, but would be considered highly unlikely. Inhalation of contaminants may occur during water use if contaminated ground water is used as a potable water source.
Potential exposure to bis(2-chloroethyl)ether may also occur from ingestion and dermal contact with contaminated soils or water. Although remediation activities are not designed to disturb large amounts of soil or release appreciable quantities of ground water, workers involved in remediation activities should be considered at potential risk for exposure.
This compound has been primarily shown to cause pulmonary damage. Inhalation of the compound results in pulmonary congestion, edema, and hemorrhage. Animal studies have exhibited no histologic evidence of residual injury resulting from isolated exposures. Bis(2-chloroethyl)ether causes central nervous system depression in animals and skin irritation in both animals and man after dermal contact. Limited human exposure data on carcinogenicity exists; however, there are some animal data linking bis(2-chloroethyl)ether and hepatic cancer.
4. Arsenic
Elevated levels of arsenic were noted in off-site subsurface soil samples (3 to 50 feet depth). Ingestion of arsenic is the primary exposure pathway of concern. If excavation of off-site contaminated areas would occur, unprotected workers, children and trespassers gaining access to excavated areas would be at risk of exposure. Arsenic is quickly absorbed through the stomach and intestines and enters the blood stream but does not tend to bioaccumulate. Local effects of ingested arsenic include irritation to the digestive tract that results in nausea, vomiting, and diarrhea. Systemic effects include cardiac, circulatory, and neurologic damage. The most characteristic systemic effect is a pattern of skin abnormalities. These include dark and light spots on skin and small "corns" on the palms, soles, and trunk. Dermal contact frequently results in mild to severe irritation of the skin. Arsenic has been reported to increase risk of cancer, especially of the lung, through inhalation and the skin through ingestion.
The amount of arsenic required for adverse human health effects varies with the chemical and physical form of the arsenic. Data as to the specific form of arsenic recovered at this site was not available. It may be noted, however, that inorganic forms tend to be more toxic than organic forms. In addition, more-soluble forms of arsenic tend to have a higher toxicity than less-soluble forms.
5. Lead
Elevated lead levels were detected on-site and off-site in the shallow aquifer and off-site in subsurface soil samples. Lead is absorbed through the lungs, gastrointestinal tract, and skin. Lead exposure is of greatest concern in children and pregnant women.
Due to more frequent hand-to-mouth activity, young children have a higher exposure potential through ingestion and are more susceptible to lead toxicity. Lead has been shown to decrease intelligence scores, slow growth, and cause hearing problems. At high levels, lead exposure can cause brain and kidney damage.
Present contact with contaminated soil and ground water is minimized because of the depth of soil contamination and nonuse of the shallow ground water. However, if this ground water was used for potable purposes in the future, lead exposure may result from ingestion of contaminated ground water. Exposure to remedial workers may occur during remediation activities if adequate personal protective measures are not used.
B. Health Outcome Data Evaluation
Community concerns have been focused on the incineration of wastes on site and the possible air emissions into surrounding communities. We have not received any reports of concerns of adverse health outcomes related to the MOTCO site and surrounding communities. Based on the evaluation of environmental data, no past or present pathways of exposure to site contaminants have been identified for the surrounding communities.
Galveston County contains numerous refining and petrochemical plants that are located primarily in Texas City. Texas City lies adjacent to La Marque. Therefore, it would be difficult to attribute any county level or city level (La Marque) differences in birth outcomes or cancer mortality to the MOTCO site without having additional information on occupational exposures or residential histories. Based on the lack of past or present community exposure pathways to MOTCO site contaminants and the close proximity of the nearest city (La Marque) to various chemical industries, we did not evaluate the available Galveston County or La Marque health outcome data.
Since there is no evidence of current or past human exposure to hazardous substances and because access to the site is restricted, this site is currently classified as no public health hazard. The site could pose a future public health hazard if not remediated, current site conditions change, or remediation workers fail to follow personal protection guidelines. On-site pit waste provides physical hazards as well as a health risk due to possible inhalation of and dermal contact with contents of the pits. The primary population of concern is on-site workers.
Although both on-site and off-site shallow ground water is contaminated, public utilities provide drinking water to homes in the MOTCO area. Available information indicates that there are no existing area wells used for potable purposes. There is currently no known human consumption of contaminated ground water and since the contaminated ground water is a Class III aquifer, it is unlikely that the water will be used for human consumption in the future. If the site is not remediated, however, the contamination could migrate to the Upper Chicot Aquifer, which is a Class II aquifer. Therefore, the site represents a potential source of contamination to deep groundwater and needs to be remediated. On-site and off-site shallow groundwater is heavily contaminated with volatile organic compounds. During remediation of groundwater, volatilization of these compounds might occur. Remedial workers could be exposed to these contaminants through inhalation without the appropriate personal protective equipment.
In the documents reviewed, no surface water or biota sampling from the Del Industries' pond were done. Therefore, the risk potential of this area could not be characterized in the Addendum.
The test burn for the liquids incinerator was completed October 1990, and the test burn for the solids incinerator was completed July 1991. No air samples, however, were available to evaluate during the preparation of this Addendum. Stack sampling protocols have been developed to determine release of potential contaminants during the incineration process. Due to the absence of data, the incineration process is an indeterminate public health hazard.
Present contact with soil and sediment contaminants is limited. Current physical boundaries decrease human contact with the MOTCO site and peripheral areas. However, during remediation activities and in the event of future excavation or public use of areas adjacent to the MOTCO site, exposure to site-related contaminants could cause adverse health effects in the exposed population.
Present remediation activities do not involve excavation of subsurface soil. However, in the event of future excavation or public use of the site and its peripheral areas of identified contamination, workers and neighboring populations would be at increased risk of exposure to contaminants through inhalation, dermal absorption, and ingestion.
HEALTH ACTIVITIES RECOMMENDATION PANEL (HARP) RECOMMENDATIONS
In accordance with the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) of 1980, as amended, the MOTCO site has been evaluated for appropriate follow-up with respect to health activities. Because there is no indication that human exposure to site contaminants at levels of public health concern is occurring or has occurred, this site is not being considered for follow-up health activities at this time. However, if emissions from the incineration process or other environmental data become available suggesting that human exposure to significant levels of hazardous substances is currently occurring or has occurred in the past, ATSDR and TDH will reevaluate this site for any indicated follow-up. In addition, TDH recommends community education to residents concerning the emissions from the incinerator pilot test.
To respond to community concerns and based on the HARP recommendations, the following actions have been or will be performed to meet the needs expressed by the Recommendations of this Health Assessment Addendum.
TDH in cooperation with the ATSDR will conduct the following public health actions:
Suzanne D. Hahn, D.V.M.
Staff Epidemiologist
Health Assessment Coordinator
Texas Department of Health
Michelle Kelly, M.M.Sc.
Environmental Quality Specialist
Texas Separtment of Health
Jean D. Brender, R.N., Ph.D.
Director, Environmental
Epidemiology Program
Texas Eepartment of Health
Nancy B. Ingram
Administrative Technician
Texas Department of health
ATSDR REGIONAL REPRESENTATIVES
Carl Hickam, R.S.
Senior Regional Consultant
ATSDR - Region 6
George Pettigrew, P.E.
Regional Representative
ATSDR - Region 6
ATSDR TECHNICAL PROJECT OFFICER
William Greim, M.S., M.P.H.
Environmental Health Scientist
Division of Health Assessment and Consultation
Remedial Programs Branch
State Programs Section
This Public Health Assessment Addendum 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 Addendum was initiated.
William J. Greim
Technical Project Officer, SPS, RPB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this Public Health Assessment Addendum and concurs with its findings.
Director, DHAC, ATSDR
APPENDIX A: EXISTING HEALTH ASSESSMENT, JULY, 1984
July 20, 1984
George Buynoski
Public Health Advisor, CDC
Remedial Alternatives - MOTCO
Don Porter,
Operations Section, Superfund Branch
As requested, staff at the Center for Environmental Health , at the Centers for Disease Control, have the document that you provided entitled "Summary of Remedial Alternative Selection MOTCO". Through our analysis we have attempted to answer two questions. Does the site constitute a significant potential threat to public health? Do the remedial alternatives proposed sufficiently reduce and/or eliminate the possibilities of human exposure to hazardous substances?
For the Centers for Disease Control to consider a site as a potential/actual threat to the public's health several conditions must be satisfied.
The data contained in the report documents the presence of numerous organic volatiles and, base neutrals at concentrations into the thousands of parts per million (ppm). Current standards for air and ground water could very conceivably be acutely or chronically exceeded. Several of the contaminants are designated carcinogens, therefore chronic exposure to even very low levels would be a serious health concern.
The report states that two residential subdivisions are located near the site: Omega Bay is approximately 1500 feet to the west-southwest and Bayou Vista is 1500-2000 feet the south-southwest. There is a private residence 2000 feet to the northwest. Since public health concerns involve possible long-term exposure future development in the area could very likely increase the size of the potentially exposed population.
While we have seen no evidence that indicates that actual exposure is presently occurring, the report states that contamination is migrating from the waste pits.
Releases from the pits have occurred in the past, and several immediate remedial actions have been carried out at the site. There is evidence that the shallow ground water is also contaminated. Since the wastes are found in elevated unlined pits future releases should be anticipated. Climatic conditions, (eg. rainfall, temperature, air currents etc.) would also affect site conditions. Because of the numerous volatiles present, air emissions could also occur. Since the site is secured by a chain link fence with a locked gate exposure by direct contact is a less probable occurrence.
The MOTCO site in its present condition would constitute a significant potential threat to public health and remedial action that would reduce/eliminate potential exposure would be advisable from a public health perspective.
The remedial alternatives designated as "retained" would apparently all adequately address the issue of gross contamination and thereby lessen the potential risk to the public. Selection of a particular alternative can be based on cost and engineering considerations. Waste destruction rather than waste containment is preferable from a public health viewpoint because it alleviates the concern we would have regarding assurances that the integrity of the containment will be maintained and future land utilization will be restricted.
Because of the acknowledged ground water contamination problem, we recognize that the alternatives detailed do not represent the final solution for the MOTCO site. While no evidence has been presented that suggest that potable water sources are being impacted, the probabilities of such an occurrence must be addressed. The site cannot be certified as completely safe by the public health authorities until this issue is resolved. We would be willing to work with you and TDWR on this problem.
Because of the presence of volatiles we are concerned about possible emissions when the site remedial work is undertaken. Appropriate measures to suppress possible releases and an effective site monitoring program would be essential. If requested the Center for Environmental Health would be willing to provide consultation in this area. If it is desired our consultation could also include review and comment on the site safety plan.
I hope these comments will be of some use. If you have any questions please call me.
APPENDIX C: MOTCO WELL AND BORING SITES
Appendix C. Motco Well and Boring Sites
APPENDIX D: LIST OF LABORATORY ANALYZED CHEMICAL COMPOUNDS
| METALS: | |
| arsenic barium cadmium chromium copper |
lead mercury selenium silver |
| VOLATILES: | |
| chloromethane bromomethane vinyl chloride chloroethane methylene chloride acetone carbon disulfide 1,1 dichloroethene 1,1 dichloroethane total 1,2-dichloroethene chloroform 1,2-dichloroethane 2-butanone 1,1,1-trichloroethane carbon tetrachloride vinyl acetate bromodichloromethane 1,2-dichloropropane |
cis-1,3-dichloropropene trichloroethene dibromochloroethane 1,1,2-trichloroethane benzene trans-1,3-dichloropropene bromoform 4-methyl-2 pentanone 2-hexanone tetrachloroethene 1,1,2,2-tetrachloroethane toluene chlorobenzene ethylbenzene styrene total xylenes total volatiles (calculated by adding all values except values denoted as U or B) |
| PESTICIDES/PCB: | |
| alpha-BHC beta-BHC delta-BHC gamma-BHC (lindane) heptachlor aldrin heptachlor epoxide endosulfan I dieldrin 4,41-DDE endrin endosulfan II 4,41-DDD endosulfan sulfate |
4,41-DDT methoxychlor endrin ketone alpha-chlordane gamma-chlordane toxaphene aroclor-1016 aroclor-1221 aroclor-1232 aroclor-1242 aroclor-1248 aroclor-1254 aroclor-1260 |
| SEMI-VOLATILES: | |
| phenol bis(2-chloroethyl)ether 2-chlorophenol 1,3-dichlorobenzene 1,4-dichlorobenzene benzyl alcohol 1,2-dichlorobenzene 2-methylphenol bis(2-chloroisopropyl)ether 4-methylphenol n-nitroso-di-n-propylamine hexachloroethane nitrobenzene isophorone 2-nitrophenol 2,4-dimethylphenol benzoic acid bis(2-chloroethoxyl)methane 2,4-dichlorophenol 1,2,4-trichlorobenzene naphthalene 4-chloroaniline hexachlorobutadiene 4-chloro-3-methylphenol 2-methylnaphthalene hexachlorocyclopentadiene 2,4,6-trichlorophenol 2,4,5-trichlorophenol 2-chloronaphthalene 2-nitroaniline dimethyl phthalate acenaphthylene 2,6-dinitrotoluene 3-nitroaniline |
acenaphthene 2,4-di-nitrophenol 4-nitrophenol dibenzofuran 2,4-dinitrotoluene diethyl phthalate 4-chlorophenyl phenylether fluorene 4-nitroaniline 4,6-dinitro-2-methylphenol n-nitroso diphenylamine 4-bromophenyl phenylether hexachlorobenzene pentachlorophenol phenanthrene anthracene di-n-butylphthalate fluoranthene pyrene butylbenzyl phthalate 3,3-dichlorobenzidine benzo(a)anthracene chrysene bis(2-ethylhexyl)phthalate di-n-octyl-phthalate benzo(b)fluoranthene benzo(k)fluoranthene benzo(a)pyrene indeno(1,2,3-cd)pyrene dibenzo(a,h)anthracene benzo(g,h,i)perylene total semi-volatiles (calculated by adding all values, except values denoted as U or B) |
