PRELIMINARY PUBLIC HEALTH ASSESSMENT
UNITED HECKATHORN
RICHMOND, CONTRA COSTA COUNTY, CALIFORNIA
Several pathways can be identified for contaminant migration from the site.
Aerial Migration to the Residential Neighborhood of On-site Contaminants Adsorbed to Soil Particulates:
Contaminants adsorbed onto soil particulates can become airborne; some contaminants with suitably high vapor pressure may volatilize, or solvents containing pesticides may volatilize and carry the pesticide with them. Although a gravel layer was applied in 1983 as an interim cleanup measure, results from air monitoring in 1988 indicated that the action was insufficient to prevent DDT migration into air on-site and off-site (see On-Site Contamination and Off-Site Contamination). Because the gravel layer appears to have been removed from the middle area of the site, it is likely that even greater amounts of contamination are migrating into the air than were measured in 1988. The passage of large trucks drawing trailers across this area (see Site Visit) may further the aerial transport of DDT on-site and off-site.
The wind reportedly prevails from north to south, and the secondary direction is from the northeast, toward the residential area (Ecology and Environment, Inc. CERCLA Expanded Site Inspection, February 1989). An elevated freeway now occupies the area where the first block of houses once stood, possibly disturbing the air currents either to reduce contaminant deposition into the soils of the neighborhoods or to increase deposition by reducing the air flow. At this time the effect of the freeway on continued soil deposition in the residential area is unknown.
Aerial Migration into Lauritzen Canal Sediments of On-site Contaminants Adsorbed to Soil Particulates:
Contaminants from the site have migrated into the sediments of the Lauritzen Canal and the Santa Fe Channel. An EPA Emergency Removal Action in November 1990 removed portions of the canal embankments that contained up to 1,000,000 ppm total DDT (pure DDT), 146 ppm aldrin, and 1,050 ppm dieldrin (see Table 5).
Samples in 1988 of the Lauritzen Canal sediments, which were dredged in 1984-85, approximately 200 feet south of the electrical substation, have shown concentrations greater than 100 ppm total DDT (see Table 7 and Figure 3). DDT may currently migrate into the Lauritzen Canal due to tidal influences, storm water runoff, and wind. When the plant was operational, DDT was also discharged into the canal during floor washings and "overflow" from DDT settling tanks. United Heckathorn had a permitted discharge of wastewater of 3,500 gallons/day (letter to Robert Jones from Richard Lovejoy, Department of Public Works, City of Richmond, 1960, Reference 17 in EPA file).
Migration of On-Site Contaminants Through Groundwater into Lauritzen Canal Sediments:
Groundwater beneath the site contains chlorinated pesticides and lead at concentrations exceeding their MCLs. Although groundwater flow is complex due to the different types and amounts of fill material placed on the site, an average of 390 gallons/day was estimated to seep into the Lauritzen Canal (Harding Lawson Associates, 1986). This seepage carries contaminants from on-site upland locations into the Lauritzen Canal sediments where they persist, accumulate, and become constituents of benthic organisms, which are eaten by fish.
Migration Through Surface Water into Lauritzen Canal Sediments of On-site Contaminants Adsorbed to Soil Particulates :
No data were identified on contaminant concentrations in the Lauritzen Canal, Santa Fe Channel, or Richmond Inner Harbor, but surface water runoff from the embankment would be expected to carry soil containing DDT and heavy metals. Since DDT is practically insoluble in water and binds tightly to organic material, it is likely to remain in the sediment. Lead and heavy metals are insoluble in the inorganic molecular form, but bacterial action in sediments may create soluble organic compounds which could then migrate via surface water or be taken up by organisms.
Contaminants Adsorbed to Soil Particulates Migrating Through Lauritzen Canal Sediments into Biota:
Although a limited number of samples was taken (see Off-Site Contamination), data indicate that DDT has migrated from soils on-site to Lauritzen Canal sediments, and that bioaccumulation is occurring both in benthic organisms and in fish (Aqua Terra Technologies, 1984; Hayes and Phillips, 1985, 1986, and 1987; United Anglers, 1986). An indirect indication of DDT bioconcentration and bioaccumulation in fish and in benthic organisms is the significant increase in the DDT metabolite, DDE, in the livers of diving ducks called scoters during their winter stay around Richmond Harbor (Ohlendorf et al., 1991, and Off-Site Contamination Section).
Complete pathways through which human exposure has occurred and is occurring appear in Table 9 (next page) and are discussed below.
TABLE 9. COMPLETED EXPOSURE PATHWAYS
| Time | 1. Source of Contamination | 2. Environmental Media & Transport | 3. Route of Exposure | 4. Point of Exposure | 5. Receptor Population |
|
|
|||||
| 1a. Past & Present | Contaminated Upland Soil | Airborne Dust | Air On-site | Inhalation | On-site workers |
| b. Past & Present | Contaminated Upland Soil | Airborne Dust | Residential Soils | Inhalation | Adults & Children |
| 2a. Past & Present | Contaminated Upland Soil | Airborne Dust | Air On-site | Ingestion | On-site workers |
| b. Past & Present | Contaminated Upland Soil | Airborne Dust | Residential Soils | Ingestion | Adults & Children |
| 3a. Past & Present | Contaminated Upland & Embankment Soils | Airborne Dust | Lauritzen Canal Sediments | Ingestion of Shellfish and Fish | Workers, Adults, & Children |
| b. Past & Present | Contaminated Upland & Embankment Soils | Groundwater | Lauritzen Canal Sediments | Ingestion of Shellfish and Fish | Workers, Adults, & Children |
| c. Past & Present | Contaminated Upland & Embankment Soils | Tides & Surface Runoff | Lauritzen Canal Sediments | Ingestion of Shellfish and Fish | Workers, Adults, & Children |
Human beings can be exposed to chlorinated pesticides such as DDT and dieldrin and to heavy metals such as lead through more than one of these pathways simultaneously. The following paragraphs discuss the environmental pathways through which adult and child members of the community may be exposed, or through which on-site workers may be exposed.
Air monitoring performed in 1988, when the site was covered with gravel, showed that airborne dust contained DDT (Tables 1 and 2). As the data in Tables 1 and 2 show, the highest contaminant concentrations are present over a "hot spot," the former United Heckathorn Building 1. Since large trucks still traverse the area where Building 1 was located (as described in the Site Visit section), the gravel layer has been disturbed, and it might be expected that increased concentrations of airborne DDT would be measured if monitoring were done. Therefore, workers on-site may be exposed to much higher contaminant concentrations than the surrounding community. However, permissible exposure concentrations are higher for workers than the residential population since workers usually include only healthy persons who are exposed for an eight-hour workday.
Workers, however, may be exposed to site contaminants through several pathways at the same time. Airborne dust may settle on the skin of workers, allowing some DDT to be absorbed, although DDT is poorly absorbed through the skin compared to other organochlorine pesticides. There may be increased ingestion of DDT and heavy metals such as lead, and inhalation and dermal absorption of DDT, endrin, and dieldrin due to activities on the site. As described in the Site Visit section, workers appear to have been eating lunch on or near the site. In adults, inadvertent ingestion of soil may result in ingestion of about 100 mg/day of soil containing DDT, dieldrin, endrin, and lead.
Airborne dust containing contaminants was measured at a station on the boundary of residential areas north of the site when air monitoring was done (Table 6). As discussed before, at that time the site was inactive and the gravel layer was undisturbed. The airborne concentrations measured at that time were at exposure levels considered safe (see Appendix A). However, the actual airborne concentrations were undoubtedly higher when the site was used to grind DDT and other pesticides; they were likely to have been higher before the site was temporarily remediated with a gravel layer, and they may have become higher once the gravel layer was disturbed by grading and by heavy vehicles driving over upland areas that contain contaminants. Sampling of current levels of contaminants in soils, coupled with data on rates of deposition from the Ecology and Environment monitoring, may allow crude estimation of cumulative past rates of inhalation exposure.
Furthermore, inhalation of airborne dust is only one way people in the residential areas may be exposed. Airborne DDT and such heavy metals as lead, which were blown off the site, may have been deposited in the soils of the residential neighborhood. A second potential human exposure pathway of concern is ingestion of soil contaminated with those compounds by children playing in the soil around their homes, or by adults gardening. This is a particular concern because the rate of deposition may have been especially high when the United Heckathorn plant was operational; because these contaminants are persistent in soils, and because the air monitoring conducted by Ecology and Environment was performed after the site had been abandoned and had had temporary remediation. The present rate of deposition has been altered again by the activity on site, and by construction of the elevated Hoffman Freeway between Cutting Boulevard and Virginia Street, and by disturbing the gravel, which constituted part of the temporary remediation. Sixth Street and Virginia Street are now on the other side of the elevated freeway, and Virginia Street no longer extends to Fourth Street. The elevated freeway may alter air flow patterns, and thus deposition of DDT in neighborhood soils. These variables make it impossible to accurately estimate exposure concentrations without sampling soils in the residential neighborhoods.
Adults and children living in the residential neighborhoods may also be exposed to chlorinated pesticides by eating contaminated fish and seafood. The limited sampling of fish discussed in the "Off-Site Contamination" section indicates that worms and clams have high concentrations of DDT accumulated from the sediments of the Lauritzen Canal, and that fish have bioaccumulated DDT by eating these worms and clams. Although fish sampling has been insufficient, the fact that migratory scoter ducks in Richmond Harbor accumulate high concentrations of DDE after eating local fish for only about three months indicates that DDT levels in local fish are high (see Off-Site Contamination).
There are also data from the State Mussel Watch Program (see Off-Site Contamination) showing that resident and transplanted worms, mussels, and crabs in the Lauritzen Canal and in the Santa Fe Channel contained the highest levels of DDT observed along the California coast. The levels far exceeded the elevated toxic pollutant levels (ETPL) encountered in 95 percent of all mussels transplanted to bays along the western California coast as well as FDA action levels.
The shiner surf perch caught by the United Anglers from the Lauritzen and Parr Canals showed body burdens of DDT exceeding the FDA action level. Unfortunately the number of fish is too limited to accurately estimate the range of exposure by this pathway. However, life-time consumption of fish with DDT concentrations equal to that of the shiner surf perch would produce a moderate increased cancer risk (see Appendix B). Lower concentrations were found in other fish species but there was a very small total number of fish caught. Nevertheless, concern about human consumption of the marine species with similar DDT concentrations caused DHS to direct LRTC to post warning signs along the site's perimeter fence, along the canal, and at the north end of the canal in October 1986. The signs, in English and Spanish, say that channels, sediments, and shellfish are contaminated with DDT and that fish may also be contaminated with DDT (Tetra Tech, Inc., Revised Community Relations Plan LRTC Site, 1988).
It is important to note that the use of the FDA action levels as a safe level of DDT in fish for human consumption is in itself questionable. The action levels are concentrations at or above which the FDA will take legal action to remove contaminated fish or shellfish from the market. They do not represent permissible levels of contamination where it is avoidable (Hayes and Phillips, 1986). They are based on several assumptions that may not be true for members of a community who consistently catch local types of fish from a particular place. The FDA action levels are based on the assumption that a person eats fish and shellfish caught throughout the country rather than from one location, and that consumption of individual species of fish is in proportion to the percentage of that species caught in the commercial fishing industry. Therefore, the FDA action level would be too high for an individual who frequently caught and ate a particular local fish, which was not caught in large numbers commercially. Furthermore, as stated before, the FDA action levels are not intended to be considered safe levels.
Although it is unlikely that people fish in the Lauritzen Canal itself, fish are reported to migrate between Point Richmond, the Brooks Island area, the Santa Fe Channel, and the canal (Danny Reno and Keith Long, California Fish and Game, personal communication, September 1990). Chip Demerest, Coastal Resources Coordinator (NOAA), reported that he observed people apparently doing subsistence fishing in the same spot on the Santa Fe Channel during his two visits to the site within the last eight months. Fred McCollum, park ranger at Brooks Island, reported that he observes two to four boats per day fishing in an area within 300 yards of the Lauritzen Canal. He said that they appear to be repeat fishermen who launch their small boats at the Richmond Marina about five minutes from the Lauritzen Canal.
Surface water is not considered a human exposure pathway of concern.
Human beings may be exposed to chlorinated pesticides and heavy metals from the site by inhaling contaminated airborne dust, or by eating fish that have bioaccumulated DDT. There are insufficient data to determine the actual exposure concentration by any pathway, but any one pathway may not be high enough to warrant health concerns. However, people who live in the community may be exposed to site contaminants by several routes simultaneously, and multipathway analysis may demonstrate exposure concentrations of concern.
Actual hazards associated with exposure to chlorinated pesticides and heavy metals cannot be evaluated without data on the levels of those contaminants. The following information from the ATSDR Toxicological Profiles provides some information on the general toxicity of contaminants at the United Heckathorn site. The toxic effects described in the following section are not necessarily effects that would be expected from exposure to contaminants at the concentrations found at the United Heckathorn site.
Toxicology of Site Contaminants:
DDT, DDD, and DDE: DDT is an insecticide used for control of malaria and typhus. It is classified by EPA as a B2 carcinogen, a probable carcinogen in human beings, based on the induction of malignant liver tumors in several strains of mice. DDT produced only benign liver tumors in rats. There is no evidence from epidemiological studies that DDT causes cancer in human beings. It was banned in 1974 because of concern about the accumulation of DDT and its stable metabolites, DDD and DDE, in the environment, and its reproductive toxicity in animals, especially birds. There was also concern that it might cause reproductive toxicity in humans, because it was accumulating to high levels in human fat tissue. Ingestion of 35 mg/day, approximately 0.5 mg/kg/day, for an adult for up to 25 months showed no ill effects. However, ingestion of 10 mg/kg/day causes toxic effects in some people, but not in everyone. DDT has toxic effects on the gastrointestinal tract, the heart, and the nervous system. The effects on the nervous system are the consequence of slowing the turning-off process of sodium conductance across the nerve membrane, resulting in tremors, irritability, dizziness, apprehension, and disturbed equilibrium. At doses of 16 mg/kg, convulsions frequently occur. Inhalation of 214 ppm DDT results in headaches and nausea; at 357 ppm vomiting also occurs; at 560 ppm heart rate increases, and at 571 ppm convulsions occur (ATSDR, April, 1989).
Exposure to DDT for periods ranging from two to eight weeks has effected the immunological system in humans and in animals. Exposure to 0.07 mg/kg/day caused an increase in antigen titers in response to Salmonella typhimurium in humans, and 13mg/kg/day produced the same effects in mice. The effects were not serious. A serious immunological effect, thymus atrophy, was caused by 0.18 mg/kg/day in rabbits, and 121 mg/kg/day in rats (ATSDR, April, 1989).
Such serious developmental effects as slow development, slow learning, or decreased growth rates were observed in animals given 0.02 mg/kg/day to 26 mg/kg/day. Decreased fertility, decreased number of fetuses, or decreased numbers of litters were observed in two generations of animals given 0.02 mg/kg/day to 0.91 mg/kg/day DDT for 28 days (ATSDR, April, 1989).
Aldrin/Dieldrin: Aldrin and dieldrin are cyclodiene pesticides. Aldrin is readily converted to dieldrin in the environment. Dieldrin was banned in 1974 by EPA because of persistence in the environment and because of carcinogenic effects on animal livers. EPA classifies both aldrin and dieldrin as B2 carcinogens, or probable carcinogens in hyman beings. Studies on 235 workers exposed to 33.2 ug/kg/day aldrin and dieldrin for 12.3 years at a Shell Chemical Company plant in Holland did not show any carcinogenic effects. However, the time period for the follow-up is considered inadequate to see any appearance of cancer (ATSDR, October, 1991).
No histopathologic or carcinogenic effects were observed in rats fed 0.1 ppm (5 ug/kg/day) of dieldrin; therefore, 0.1 ppm is considered the "no observed adverse effect level" (NOAEL). However, at 1 ppm (50 ug/kg/day) dieldrin, hepatic lesions characteristic of exposure to an organochlorine insecticide were seen. Therefore, 1 ppm is the lowest observed adverse effect level (LOAEL).
Acute toxicity may occur at 20 to 70 ppm, or at blood dieldrin levels of 20 mg dieldrin/deciliter (dl) blood. The symptoms are those of central nervous system intoxication: headaches; blurred vision; dizziness; slight, involuntary muscular movements; sweating; insomnia; nausea, and bad dreams. Even higher blood dieldrin levels cause convulsions and other symptoms of severe central nervous system poisoning (ATSDR, October, 1991).
Dieldrin causes such adverse reproductive effects in animals as reduction of litter size and decreased fertility and ovulation at concentrations that do not cause maternal toxicity. There are no comparable studies in human beings.
An increase has been reported in the blood concentration of aldrin/dieldrin (33 ppb vs 5.6 ppb) in mothers of stillborn infants compared to that in mothers of liveborn infants, but the data are considered inconclusive (ATSDR, October, 1991).
Dieldrin is reported to be an active suppressor of cell mediated immunity at 5 ppm in mice, due to impairment of macrophage antigen processing. However, there are no data for human beings.
Endrin: Endrin is also a cyclodiene pesticide. It is not classified a carcinogen. Endrin has a high acute toxicity in animal studies. In dogs, the NOAEL is 1 ppm and the LOAEL is 2 ppm. Endrin is rapidly adsorbed through the skin, and it poisons the central nervous system and the liver. Endrin is also reported to produce malformations when given to mammals during pregnancy, and to have immunotoxic effects. Ingestion of 6,000 ppm of endrin, a much higher dose than generally encountered in the environment, caused convulsions and death.
An epidemiological study to examine the cause of death of workers employed in manufacturing organochlorine pesticides, including endrin, showed no statistically significant increases or decreases in the number of deaths from any specific cancer site. However, the follow-up time was only 12 years, and the latency period for appearance of cancer is considered greater than that. Increased numbers of deaths among factory workers were seen due to pneumonia and other non-malignant respiratory diseases (ATSDR, December, 1991).
Lead: Lead is an element that affects the nervous system, the heme-hemoprotein system, the kidneys, and the reproductive system. Developmental defects are seen at very low levels: decrements in I.Q. are seen in children of women with only 10-16 ug lead/dl of umbilical cord blood. Alterations in heme synthesis occur when concentrations of lead in blood reach 15 to 30 ug/dl. The concentration of free erythrocyte protoporphyrins is often used as an indicator of exposure. Anemia occurs at 75 ug lead/dl blood in children and at 80-85 ug lead/dl blood in adults. Calcium, phosphate, and iron may affect absorption of lead (ATSDR, October, 1991).
The risk of premature birth increases fourfold as cord or maternal blood lead levels increase from less than 8 to greater than 14 ug/dl. The range of 10 to 15 ug/dl is considered to be the LOAEL in humans, and this developmental toxicity is manifested as neurobehavioral deficits and reductions in gestational age and birth weight. Lead in humans is associated with reproductive toxicity resulting in such symptoms as miscarriages and decreased fertility, and with sperm abnormalities at 40 to 50 ug/dl. In rats, developmental reproductive defects are seen at 18 to 29 ug/dl in females and 30 ug/dl in males. There is no conclusive evidence about teratogenic effects.
Arsenic: Arsenic is an element that has been classified as a carcinogen in humans (class A) on the basis of human epidemiologic data (EPA Carcinogen Assessment Group). For non-carcinogenic effects, doses as low as about 1-4 mg/day (20 - 60 ug/kg/day) in human adults produce one or more characteristic signs of arsenic toxicity, such as gastrointestinal irritation, anemia, neuropathy, skin lesions, vascular lesions, and hepatic or renal injury.
Chromium: Chromium is found in two states, trivalent (III) and hexavalent (VI). Chromium III is considered almost innocuous, and it is an essential nutrient at 50-200 ug/day (0.7-3 ug/kg/day) in adult humans. Chromium VI, has been classified as a known carcinogen in humans due to increases in mortality from cancers of the respiratory tract in workers exposed to aerosols containing chromium. Inhalation of 0.002 mg/m3 chromium can cause nasal irritation and mild lung effects. Chromium is poorly absorbed from the digestive system of humans, and chronic oral studies in rodents are inconclusive. While some studies in rodents have not identified adverse effects on toxicological endpoints, other studies have reported that, at high oral doses in female mice, chromium attacks the digestive system by causing hemorrhaging, ulceration, and tubular necrosis of the kidneys. In order to be consistent with a policy to protect public health, chromium is assumed to be carcinogenic by ingestion as well as by inhalation, but the potencies may vary by several orders of magnitude.
B. Health Outcome Data Evaluation
Complete human exposure pathways for on-site workers and adults and children in the community do exist at the United Heckathorn site. A number of community concerns have also been identified related to the site and other hazardous waste sites in the area. However, the data are insufficient to determine the actual exposure concentration for specific pathways at this time. Additional information or data on exposure point concentrations will be necessary to determine whether it is possible or necessary to better define possible health effects using health related data.
Health data that may be relevant to the United Heckathorn site include data from the Cancer Surveillance Program and the California Birth Defects Monitoring Program. Due to recent budgetary cutbacks for these two programs, our ability to get that information is severely limited. If community concern regarding adverse health effects is expressed or additional data suggests that adverse health outcomes are plausible, we will request information from these two programs, review it, and incorporate our findings in a future public health assessment of this site.
C. Community Health Concerns Evaluation
We have addressed the community concerns about health as follows:
1. Is it safe to eat fish caught in the Lauritzen Canal?
No. DTSC has posted signs warning people not to eat fish caught in the canal. There is an indication that fish in the area of the Lauritzen Canal and nearby harbor have gradually accumulated DDT in their bodies by eating worms and clams that have high concentrations of DDT from the sediments of the canal (see discussion in the "Off-site Contamination" section). DDT enters the body when a person eats food that has been contaminated with DDT. Once inside the body, DDT is stored most readily in the fatty tissue and takes a long time to leave the body. EPA is considering having additional analyses of fish and benthic organisms included in its workplan (see Public Health Actions #1).
2. Should the nearby neighborhoods be concerned about the possibility of dust blowing off the site?
Airborne dust represents one way people in the residential areas could be exposed to contaminants. Airborne DDT and heavy metals such as lead may have blown off the site and deposited in the soils of residential neighborhoods. EPA is considering taking soil samples in residential neighborhoods and monitoring air levels for DDT and heavy metals.
Based on the available information, this site is considered a public health hazard because evidence exists that exposures to chlorinated pesticides and heavy metals have occurred, are occurring, and are likely to continue to occur through the exposure pathways described above. Although sufficient environmental sampling data are not available to estimate exposures, it appears likely that people could be simultaneously exposed to DDT and other contaminants through multiple pathways such as eating fish, inhaling soil dust, and inadvertently ingesting soil.
The upland soils where the DDT grinding and pesticide formulating operations of the United Heckathorn Company were carried out, and the embankment of the Lauritzen Canal are contaminated with chlorinated pesticides such as DDT, DDD, DDE, aldrin, endrin, dieldrin, and with heavy metals, principally lead.
The areas of the embankment that were heavily contaminated with DDT were removed as part of an Emergency Response. Because these areas appeared subject to erosion by high tides and storms, they provided a route whereby migration of contaminants into Lauritzen Canal sediments has continued. Current data on the concentrations of contaminants in the canal sediments are needed to determine the immediate and near-term effect on contaminant concentrations in sediment of excavating the embankment.
Heavy metals and chlorinated pesticides such as DDT, endrin, and dieldrin persist in the environment and in fatty tissues of organisms, so they have accumulated up to toxic levels in benthic organisms in the Lauritzen Canal. Bioaccumulation of DDT appears to be occurring in fish that may migrate into the canal to feed on the surviving benthic organisms, and then migrate to the Santa Fe Channel and Richmond Inner Harbor.
Migratory ducks that winter on Brooks Island, which is just outside the Richmond harbor, are known to bioaccumulate DDE, a metabolite of DDT, during their stay from January to March, apparently from feeding on fish in Richmond harbor, which contain DDT and DDE. Therefore, people who eat fish that migrate into the Lauritzen Canal to feed may also accumulate DDT or its persistent metabolites.
Recent activity on the site appears to have disturbed the top layer of gravel, and may be generating dust containing DDT and heavy metals. That may result in increased generation of soil dust containing DDT and heavy metals with subsequent deposition on the skin, and inhalation and ingestion of contaminated dust by on-site workers who were observed eating lunch on site. Chlorinated pesticides and heavy metals accumulate in tissues of exposed persons and in other organisms. Previous air monitoring was performed when the site was inactive; therefore, the levels measured may not reflect current conditions.
DDT, endrin, dieldrin, and heavy metals such as lead may have migrated off site in airborne dust to the residential community north of the site. The dust containing DDT and heavy metals may have been deposited in the soils of the neighborhood where children may play and adults may garden.
The data available for review at this time are insufficient to fully characterize potential health risks.
Health Activities Recommendation Panel (HARP) Recommendation
The United Heckathorn site has been evaluated by ATSDR's HARP for follow-up health activities. Although exposure to site contaminants is believed to have occurred in the past and may be occurring currently, environmental sampling data are not available to assess the magnitude and public health significance of the exposure. Therefore, this site is not being considered at this time for follow-up health activities. However, when these data become available, ATSDR and the California Department of Health Services will re-evaluate this site for any indicated follow-up activities.
Public Health Actions Planned
Based on the recommendation of HARP, ATSDR is not planning any follow-up health activities at this time. However, CDHS will cooperate with appropriate state agencies to post warnings in different languages and with pictograms against fishing on the Lauritzen Canal and water side of the channel. Community relations staffmembers within CDHS and EPA will continue community relations activities with the Richmond community, sharing information about the site and warning people against fishing in the area. Additionally, EPA has indicated that they plan to take the actions listed below, which are related to the recommendations in the preliminary health assessment.
1. EPA will consider including in the workplan for the Remedial Investigation/Feasibility Study additional analyses of fish and benthic organisms from the Lauritzen Canal, Santa Fe Channel, Richmond Harbor, and waters around Brooks Island for DDT, other chlorinated pesticides, and heavy metals.
2. EPA will consider taking samples of soil in the residential neighborhood and monitoring air levels for DDT, other chloriated pesticides, and heavy metals.
3. EPA will continue working with potentially responsible parties to fully characterize the site and to decrease exposures for on-site workers.
CDHS and ATSDR will coordinate with the appropriate agencies regarding actions to be taken in response to those recommendations provided in this preliminary health assessment, and for which no plan of action has yet been developed.
Environmental and Health Effects Assessors:
Susan Ann Knadle, Ph.D., DABT
Staff Toxicologist
Hazardous Waste Toxicology Section*
Office of Health Hazard AssessmentJennifer Rous, B.S.
University of California at Davis
Student Intern in the Hazardous Waste Toxicology SectionDiana M. Lee, M.P.H
Research Scientist
Environmental Epidemiology and Toxicology Branch
California Department of Health ServicesJane Riggan, M.S.W.
Community Relations Coordinator
Impact Assessment
ATSDR Regional Representatives
Gwendolyn Eng
Regional Services, Region IX
Office of the Assistant AdministratorWilliam Nelson
Regional Services, Region IX
Office of the Assistant Administrator
ATSDR TECHNICAL PROJECT OFFICER
Burt J. Cooper, M.S.
Environmental Health Scientist
Division of Health Assessment and Consultation
Remedial Programs Branch, State Programs Section*Before 7/19/91, the Hazardous Waste Toxicology Section was a section under the Environmental Epdemiology and Toxicology Branch within the California Department of Health Services.
This preliminary public health assessment was prepared by the California Department of Helath Services 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.
Burt J. Cooper
Technical Project Officer, SPS, RPB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this preliminary public health assessment, and concurs with the findings contained in it.
Director, DHAC, ATSDR
APPENDIX A: INHALATION OF CONTAMINATED AIRBORNE DUST IN THE RESIDENTIAL NEIGHBORHOOD NEAR UNITED HECKATHORN
A calculation has been performed to determine if excess risks from inhalation of DDT in dust exists at the levels reported in Ecology and Environment's "Determination of Organochlorine Pesticides and Polychlorinated Biphenyls in Ambient Air," 1989. The following equation was used: Risk = CDI x SF
where risk is a unitless probability of a person developing cancer. It is expressed as the "Life-time excess cancer risk per million people."
CDI is the chronic daily intake or exposure averaged over 70 years, expressed as mg/kg-day. SF is the slope factor, expressed in (mg/kg-day)-1.
Since test animals receive high doses compared to usual environmental exposures, a linear dose-response slope is extrapolated down to low-doses using a multistage model for cancer development. The SF, or q1*, is an estimate of the potency of the compound based on the number of tumors induced in animals. It is the 95 percent upper confidence level of the value obtained by calculating the slope from the number of tumors observed at each dose level in the animal studies. It is specific for each compound and is found in the EPA's Integrated Risk Management System (IRIS). The potency values of the two compounds classified as probable carcinogens are 3.4 x 10-1 for DDT, and 1.6 (mg/kg-day)-1 for Dieldrin.
Chronic Daily Intake is calculated from measured or estimated environmental media concentrations, physiological and physical factors that influence exposure, and duration of exposure. The calculation and the factors used in the calculations of Chronic Daily Intake are discussed below.
where CA is the contaminant concentration in the air in mg/m3. The air monitoring data given in the sections on On-Site Contaminants and Off-Site Contaminant concentration were converted from ng/m3 to mg/m3 by the factor 1 mg /1 x 106 ng. The exposure values for DDT are the averages for DDD, DDE, and DDT, which were summed to derive the Total DDT concentration (Table 6).
IR is the inhalation rate, 20 m3/day for adults normally, 30 m3/day during heavy work or jogging.
ET is exposure time in hours/day, assumed to be 24 hours/day for residents and 8 hours/day for workers.
EF is the exposure frequency. In the case of residents it may be 365 days/year, while workers may be exposed for only 5 days/week, or 260 days/year.
ED is the exposure duration, usually estimated as 70 years.
BW is body weight, given as 70 kg for an adult, and 15 kg for a child.
AT is the averaging time, which for carcinogenic effects is 70 years x 365 days/year
The standard equation for risk calculations is used here to estimate the lifetime risk for residents in the neighborhoods north of the site who may have inhaled or who may inhale airborne contaminants. This is only an estimate, since the exposure levels are assumed to remain constant over a 70 year lifetime, and a standard adult weight of 70 kg is used.
CALCULATIONS OF INHALATION RISK IN RESIDENTIAL AREA:
Air monitoring 7/18/88 - 8/8/88 at 6th and Virginia Streets:
Risk = SF x Chronic Daily Intake
Therefore, the combined excess risk from DDT and dieldrin associated with inhalation in residential area near the United Heckathorn is 3 X 10-7.
APPENDIX B: EXCESS RISKS ASSOCIATED WITH EATING FISH CAUGHT NEAR UNITED HECKATHORN
A calculation has been performed to estimate if excess risks from ingesting fish containing DDT exist at the levels reported in the limited samples caught by United Anglers and analyzed by the California Department of Fish and Game. The following equation was used: Risk = CDI x SF
where risk is a unitless probability of a person developing cancer. It is expressed as the "Life-time excess cancer risk per million people".
CDI is the chronic daily intake or exposure averaged over 70 years, expressed as mg/kg-day;
SF is the slope factor, expressed in (mg/kg-day)-1. Since test animals receive high doses compared to usual environmental exposures, a linear dose-response slope is extrapolated down to low-doses using a multistage model for cancer development. The SF, or q1*, is an estimate of the potency of the compound based on the number of tumors induced in animals. It is the 95 percent upper confidence level of the value obtained by calculating the slope from the number of tumors observed at each dose level in the animal studies. It is specific for each compound and is found in the EPA's Integrated Risk Management System (IRIS). The value for the potency of DDT is 3.4 x 10-1.
Chronic daily intake is calculated from measured or estimated environmental media concentrations, physiological and physical factors that influence exposure, and duration of exposure. The calculation and the factors used in the calculations of chronic daily intake are discussed below.
where CA is the contaminant concentration in the fish and/or shellfish in mg/kg.
IR is the ingestion rate which varies with lifestyle factors, geographic location and socio-ethnic origin. CDHS has used 22 g/day for the average Californian, but this value is considered low for current fish consumption because it allows only one small fish meal per week. Thirty-eight g/day is the 50th percentile daily intake and 132 g/day is the 95th percentile for daily intake according to the EPA Risk Assessment Guidance for Superfund, 1989.
FI is the fraction ingested from the contaminated source, which is estimated to be 50 percent of the fish in this risk assessment.
EF is the exposure frequency. It is pathway specific and should consider local population patterns if such information is available. The 1989 EPA TOlerance Assessment System estimates 48 days/year to be the average amount per capita for fish and shellfish consumption. The exposure frequency is 365 days/year if daily intake values of 23 g/day to 132 g/day are used.
ED is the exposure duration, usually estimated as 70 years.
BW is body weight, given as 70 kg for an adult, and 15 kg for a child.
AT is the averaging time, which for carcinogenic effects is 70 years x 365 days/year.
The standard equation for risk calculations is used here to estimate the lifetime risk for neighborhood residents who may catch and eat fish and shellfish from the Richmond Harbor area. This estimate is based on very limited data on DDT contamination levels in fish. This is only an estimate, because the exposure levels are assumed to remain constant over a 70 year lifetime, and a standard adult weight of 70 kg is used.
Therefore, the excess risk associated with eating fish near United Heckathorn is 3.7 X 10-3.
APPENDIX C: RESPONSES TO PUBLIC COMMENTS ON THE SEPTEMBER 1991 DRAFT PRELIMINARY HEALTH ASSESSMENT
1. Comment: The Preliminary Health Assessment (PHA) relies upon inaccurate data, and contains inappropriate speculation, incorrect information, and irrelevant comments. It fails to provide information necessary to draw conclusions regarding public health hazard.
Response: The California Department of Health Services (CDHS) has prepared this Preliminary Health Assessment for the United Heckathorn site under a cooperative agreement with the Agency for Toxic Substances Disease Registry (ATSDR). Under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) and the 1986 Superfund Amendments and Reauthorization Act (SARA), ATSDR must evaluate the public health significance of hazardous waste sites by performing specific public health activities associated with actual or potential exposure to hazardous substances released into the environment. ATSDR must conduct health assessments on all sites added to the National Priorities List (NPL) since October 17, 1986, within one year of a listing (or being proposed for listing).
As with the United Heckathorn site, CDHS and ATSDR will designate as "preliminary" those health assessments prepared on sites for which site characterization is incomplete, or for which there is no summary of relevant health outcome data or environmental data. For the United Heckathorn Preliminary Health Assessment, CDHS and ATSDR evaluated data primarily available when the site was initially proposed for inclusion on the NPL. Information utilized was obtained from state administrative files, federal agency reports, site visits, and consultations with involved agencies and with the public. Designating a health assessment as preliminary conveys to EPA, the state, and the public that CDHS and ATSDR have conducted the assessment based upon limited data. For sites receiving a preliminary health assessment, a further health assessment will be performed, if considered appropriate, when the full environmental characterization is completed, usually in the form of a Remedial Investigation Feasibility Study and Baseline Risk Assessment, and provided to ATSDR for consideration.
To assist with the development of health assessments, ATSDR has developed guidance materials, including a Health Assessment Guidance Manual, decision statements, and toxicological profiles. States preparing health assessments under cooperative agreement with ATSDR must utilize the format and include appropriate content as outlined in these guidance materials. All health assessments undergo a rigorous review by scientists and technical people within CDHS, ATSDR, EPA, and other appropriate agencies before being released for public comment. CDHS and ATSDR welcomes additional infomation from any party who wishes to submit it to us and will make revisions as we deem appropriate.
CDHS and ATSDR have revised the September 1991 Draft Preliminary Health Assessment based on public comments that supported with adequate documentation. CDHS and ATSDR appreciate the time and effort spent by citizens and organizations who commented on the assessment. Many of the comments resulted in revisions that improved the document. In preparation for conducting a full health assessment, ATSDR will continue to consider information that the public may wish to send us regarding community health issues associated with the United Heckathorn site. In the meantime, the conclusions expressed in the September 1991 Draft Preliminary Health Assessment represent CDHS and ATSDR's position on the information available at the time. CDHS and ATSDR stand by the conclusions presented in the September 1991 document.
2. Comment: The PHA ignores current data on pesticide concentrations on the site following remedial actions taken in Fall 1990 and April 1991.
Response: CDHS and ATSDR have evaluated data currently available in state administrative files, in federal agency reports, and in information submitted to CDHS during the public comment period. Staffers consider information gathered during site visits or during meetings or contacts with involved agencies and with the public.
Only information regarding pre-remediation concentrations was available to us during the development of the preliminary health assessment. This information is important to include from a historical perspective, especially in characterizing past exposures which may have past, current or future public health implications. ATSDR and CDHS thank all those who offered comments or who provided additional information. We will review all additional information not available at the time of the development of this preliminary health assessment when a full health assessment is prepared. (see response to Comment #1.)
3. Comment: PHA does not contain an adequate analysis of toxicity, dose, and exposure.
Response: CDHS and ATSDR agree that further information is required to determine potential health risks. However, based on the information available, CDHS and ATSDR evaluated the potential public health risks from short-term, intermediate-term, and long-term exposure to site-related contaminants found in different media, and we do not agree with the commentator. Our conclusions are based on published studies in the fields of epidemiology and toxicology, and on recommended environmental exposure levels endorsed by the Agency.
4. Comment: Available research does not support the CDHS conclusion that DDT, aldrin and dieldrin pose serious threats to human health.
Response: CDHS and ATSDR appreciate the additional information provided. As stated previously, our conclusions are based on published studies in the fields of epidemiology and toxicology, and on recommended environmental exposure levels endorsed by the Agency. These studies show that EPA classifies DDT, aldrin, and dieldrin as probable carcinogens in human beings based on animal studies (B2 carcinogen). IARC and NTP similarly classify DDT as "reasonably anticipated carcinogen." Additionally, there are documented non-carcinogenic health effects associated wtih DDT, aldrin, and dieldrin, and which must be considered, as described in the Public Health Implications section.
5. Comment: Assuming that persons are exposed to DDT from the site, existing data suggest any such exposure is not sufficient to pose a health risk.
Response: CDHS and ATSDR agree that additional data are necessary in order to better characterize exposures and related health risks, and appreciates receiving additional information. However, information available for development of the September 1991 draft indicates exposures to site-related contaminants have occurred in the past and may currently be occurring through multiple exposure pathways at levels that may pose health concerns. The assumptions made in the PHA are consistent with the procedures outlined in ATSDR's Health Assessment Guidance Manual. Additional information will be considered as appropriate during development of a full health assessment.
6. Comment: DDT poses little risk as an air-borne source. The 1988 air data show levels below OSHA's Permissible Exposure Levels (PELs).
Response: DDT as a parent compound and DDT's metabolites may be transported through several media by the processes of adsorption, bioaccumulation, solubilization or volatilization. Volatilization of DDT and DDE accounts for their considerable losses from soil surfaces and water. Estimates of rates of DDT, DDE, and DDD losses from water ranging from several hours to 50 hours (Hazardous Substances Data Base 1988) have been documented. DDT and its metabolites also bioaccumulate in fresh water and marine plankton, insects, mollusks, other invertebrates, fish and other organisms, according to the ATSDR 1989 Toxicological Profile for DDT, DDE and DDD. DDT and its metabolites may also be transported by wind as fugitive dust.
OSHA's Permissible Exposure Levels (PELs) apply to healthy adult employees working 40-hour weeks and do not apply to the general population (including children, the sick and the elderly) who may have been subjected to continuous exposure to environmental contaminants from United Heckathorn. Consequently, air levels below OSHA's PELs may still pose a health concern for certain population groups. Additionally OSHA's PEL value for DDT is not based on carcinogenicity. The National Institute of Occupational Safety and Health (NIOSH) identifies DDT as an occupational carcinogen and recommends that exposure be limited to the lowest feasible concentration.
7. Comment: There are errors in the risk calculations for inhalation of air by off-site receptors, and for fish ingestion. Additionally, the PHA inappropriately uses input values based on "worst case" scenario, which differs from EPA's Risk Assessment Guidelines for Superfund.
Response: The references and calculations on the inhalation of airborne dusts and excess risks associated with eating fish caught near United Heckathorn have been checked and corrected where appropriate. The data used for calculations on excess risk due to ingestion of fish came from the Department of Fish and Game and were reviewed by the state staff from the Pesticide Epidemiology and Toxicology Section. The calculations were based on ATSDR's Health Assessment guidelines and/or EPA's Risk Assessment Guidance for Superfund. DDT and its metabolites concentrate in lipids. Some population groups, however, eat raw fish and fish organs as part of their regular diet. Consequently, using the "worst case" scenario and other averaging values about fish consumption, the excess risk associated with eating fish was computed. The use of "worst case" and average concentrations based on site-specific information as scenarios for the analyses are valid and consistent with ATSDR's health assessment procedures. Following are the corrected risk estimate values identified in Apendices A and B. For the inhalation of contaminated airborne dust in the residential neighborhood near United Heckathorn, the DDT excess risk = 1.9 X 10 -7 and the combined average excess risk from DDT + Dieldrin = 3.1 X 10-7. The excess risk associated with eating fish contaminated only with DDT and caught near the United Heckathorn site = 2.2 X 10-4. The actual risk may actually be higher for contaminated fish ingestion if the added risk from dieldrin contamination is considered. According to the state's Mussel Watch Program, the highest dieldrin levels in fish in the state are found in fish caught in the Lauritzen Canal.
8. Comment: The toxicity information presented in the assessment is incomplete and/or unreferenced and, in a number of instances, plainly erroneous.
Response: CDHS and ATSDR appreciate receiving the additional information provided by the commentators. Where appropriate, we have clarified references to concentrations and doses. Carcinogenicity information regarding aldrin and dieldrin is taken from EPA, which classifies dieldrin and aldrin, too, as probable carcinogens in humans (B2) based on animal data. Additionally we use toxicity information obtained from ATSDR's Toxicological Profiles, EPA's Integrated Risk Information System (IRIS), and other published studies.
9. Comment: The PHA identifies airborne particulate emissions and ground water seepage into the Lauritzen Canal as apparently significant contaminant transport pathways. However, the available data indicate that these migration routes are not very significant and would not lead to significant chemical exposures. The PHA also identifies inhalation and ingestion exposure to residential soils as being complete exposure pathways, despite the presence of little or no data to confirm that human exposures have occured or are currently occuring.
Response: CDHS and ATSDR include as a recommendation in the PHA gathering additional data in order to better characterize exposure pathways. However, based on the information we have reviewed, inhalation of airborne contaminants and ingestion of contaminants through consumption of contaminated fish could pose significant exposure pathways.
10. Comment: Why didn't the state clean the site, given that the site has been a serious health hazard since 1949?
Response: Available site information we have shows that several agencies have been active in attempts to clean up the site, but the complex history of the site and the inadequate environmental sampling are some of the factors that have led to delays in site clean-up. Currently EPA is carrying out a detailed sampling plan that will allow for a number of clean-up alternatives to be considered.
11. Comment: Residents, neighborhood groups, and all agencies involved should meet to discuss concerns and clarify issues.
Response: CDHS and ATSDR agree that ongoing communication is necessary, and have shared this concern with staff at EPA and the Cal EPA Department of Toxic Substances Control and asked the community relations staff at EPA to consider this request.
12. Comment: Was the community notified of soil removal on the site? What precautionary measures were taken to provide public safety? What means were used to insure that no ingestion of the soil would occur?
Response: Different government agencies have been involved with soil removal activities on the site. A number of fact sheets were developed and distributed by the different regulatory agencies to inform the community of the proposed activities. Questions about soil removal activities that took place under the direction of the California Regional Water Quality Control Board should be directed to their Community Relations Coordinator in Oakland at (510) 464-1255. Questions about removal activities that occurred under the direction of the California Department of Toxic Substances Control can be directed to their Community Relations Coordinator at (510) 540-2122. Questions about clean-up activities under EPA, the regulatory agency now in charge of the site's clean-up, can be directed to Norman Calero, Community Relations Coordinator, US EPA, 75 Hawthorne St. (H-1-1), San Francisco, CA 94105, phone (415) 744-2183 or 1-800-231-3075. EPA also maintains an administrative record including all documents upon which EPA bases the decision for a removal action a site. Copies of the administrative record are available for public review at the Richmond Public Library, 325 Civic Center Plaza, Richmond, CA 94804. EPA prepares a Health and Safety Plan for all emergency removal actions. (See response to #16 below.)
Questions about this CDHS/ATSDR preliminary health assessment, or health assessments in general, can be directed to Ms. Jane Riggan or Diana Lee at the Environmental Epidemiology and Toxicology Program, CA Department of Health Services, 5900 Hollis Street, Suite E, Emeryville, CA 94608, phone (510) 540-3657.
13. Comment: Have the communities been screened for possible coronary diseases or respiratory diseases as a result of the contaminated material being in the community?
Response: To our knowledge, no health screenings related to the site contaminants have been conducted for the communities. The Health Activities Recommendation Panel within ATSDR has reveiwed the draft preliminary health assessment and is not currently recommending follow-up health activities. As environmental sampling data become available to assess the magnitude and public health significance of the exposure, ATSDR and CDHS will reevaluate the site for any indicated follow-up health activities.
14. Comment: What can be done about other airborne particles that pollute the air, and which might be coming from some of the existing activities around the site?
Response: Routine air monitoring to determine overall air quality is the responsibility of the Bay Area Air Quality Management District and is not usually considered part of the Superfund clean-up process. If required by health and safety procedures, air monitoring can be conducted during investigation and clean-up.
Recommendations were included in the preliminary health assessment for conducting air monitoring to better quantify site-related contaminants. Current air monitoring results may not reflect air contaminant concentrations that may have resulted from past site operations.
15. Comment: The community should have top priority with regards to safety, public health, long term prognosis, air sampling, community awareness, preventive measures, and health risks associated with whatever amount of exposure. If evacuation is advised, effects on the community (housing costs, additional travel to work and school) need to be considered.
Response: As the agency overseeing current clean-up activities, EPA is developing a community relations plan. For all emergency removal actions, EPA requires the preparation of a health and safety plan to ensure no releases of contaminants to the surrounding community occur during the removal. The community will also be given the opportunity to comment on the proposed clean-up plan. Recommendations and findings from CDHS and ATSDR regarding the pulbic health significance of the site are routinely shared with the community, EPA, and other appropriate agencies to assist with development of clean-up procedures.
16. Comment: The health assessment should take into account any and all potential health effects caused by the site on the community and biota.
Response: CDHS and ATSDR have described past and present complete human exposure pathways in Table 9 of the preliminary health assessment. Past exposures may result in present or future health effects. More data are needed to determine the actual exposure concentrations. When these data become available, better characterization of health effects will be possible, and the public health significance of the site can be better defined.
17. Comment: The contaminated material and clean-up at United Heckathorne should be handled with great care and the material kept track of, including where it gets disposed of.
Response: Federal regulations require that clean-up measures protect human health and the environment, and will include procedures for and documentatation of proper handling and disposal of contaminated material. (See response to comments #11 and #14, above.)
