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PUBLIC HEALTH ASSESSMENT

ORGANIC CHEMICALS, INC.
GRANDVILLE, KENT COUNTY, MICHIGAN


ENVIRONMENTAL CONTAMINANTS AND OTHER HAZARDS

Contaminants of concern at this site were selected from those chemicals for which the concentration in at least one environmental medium exceeded a health-based comparison value. Lifetime exposure to chemical concentrations at or below the appropriate comparison values for a chemical should not result in more than one case of cancer in one million people exposed or any increase in non-cancer health effects. Comparison values used in this assessment include:

    ATSDR Environmental Media Evaluation Guides (EMEGs)

    ATSDR Cancer Risk Evaluation Guides (CREGs)

    Reference Dose Media Evaluation Guides (RMEGs), computed from the U.S. EPA Reference Dose (RfD) for chronic exposure of a child, assuming pica behavior for soil ingestion(2)

    U.S. EPA Drinking Water Health Advisories (Lifetime)

    U.S. EPA Safe Drinking Water Act Maximum Contaminant Levels

If no comparison values for a chemical in a medium exist, or there is no CREG available for a carcinogen, the chemical is retained for further evaluation. In addition, if the community has expressed specific concerns about exposure to a chemical, that chemical will be retained as a contaminant of concern. A list of contaminants of concern at the OCI site can be found in Table 1.

To identify facilities that might contribute to the environmental contamination at the Organic Chemicals, Inc. (OCI) site, the MDPH searched the Toxic Chemical Release Inventory (TRI) data base for 1987 through 1992. The U.S. EPA compiles the TRI from information provided by industries. The TRI contained entries for twelve facilities with the same postal zip code (49509) as the OCI site. Eight facilities listed in the zip code area are at least 2 miles or more from the site. The releases from these facilities are not likely to contribute to the environmental contamination at the site. The remaining four facilities are located within 2 miles of the site. From their addresses, the facilities listed are all located approximately one to 2 miles from the OCI site.

The Electro Chemical Finishing Company reported transfers to off-site facilities, with no environmental releases, of hydrochloric acid, nitric acid, sodium hydroxide solutions, and sulfuric acid (reports for 1987 through 1990 only). The Mid-America Potato Company reported transfers to off-site facilities, with no environmental releases, of sodium hydroxide solutions (reports for 1987 and 1988 only). A Packaging Corporation of America plant reported air releases of toluene (reports for 1987 through 1990 only). A Reynolds Metals Company plant reported releases to the air of chlorine, copper, and zinc; releases to the water in the Grand River via storm sewers and Plaster Creek of zinc; and transfers of manganese to off-site facilities, with no environmental release (reports for 1987 and 1988 only).

These facilities are all generally east of the Organic Chemicals, Inc. site. The prevailing wind in the area is from the west to southwest, though the wind might come from any direction. If the wind comes from the east, and the OCI site is downwind from the facilities, dispersion and deposition between the facilities and the site are likely to reduce the contribution from these releases to contamination present at the site. These releases are not likely to contribute significantly to the environmental contamination at the site.

For this health assessment, the site refers to the fenced OCI property, the former oil refinery operations area located north of the fenced area, and the two petroleum sludge lagoons (Figure 3). All data in this section, unless cited otherwise, were taken from the RI reports (26). Contractors conducted the RI for the U.S. EPA V team.

A. On-Site Contamination

Groundwater

During Phase I of the RI, the contractors collected two rounds of groundwater samples from six monitoring wells on the site: two at the area of the former seepage lagoon, one in the southwest corner of the OCI property, one near the center of the site southeast of the former seepage lagoon, and one at the former petroleum seepage lagoons. They analyzed the samples for volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), pesticides, polychlorinated biphenyls (PCBs), metals, and cyanide (Table 2).

Most of the organic contamination detected in the groundwater came from samples taken from locations on the OCI property. VOCs detected included (with maximum concentrations in parts per billion (ppb) (see also Table 2)): methylene chloride (9,600 ppb), benzene (an estimated 520 ppb), trichloroethylene (TCE) (33,000 ppb), chlorobenzene (an estimated 1,500 ppb), and toluene (53,000 ppb). SVOCs detected included N-nitrosodiphenylamine (1,600 ppb), benzyl alcohol (970 ppb), and 2-methyl naphthalene (55 ppb). Metals detected included arsenic (22.5 ppb), lead (21.4 ppb) and manganese (541 ppb).

From June 9 through 16, 1993, and September 20 through 25, 1993, the U.S. EPA contractors collected two rounds of on-site groundwater samples during Phase II of the RI. These samples were analyzed for VOCs, SVOCs, pesticides, PCBs, metals, and cyanide (Table 2). In addition to the on-site wells sampled during Phase I of the RI, the contractors drilled and sampled ten new on-site wells: two screened in the lower aquifer on the OCI property, two in the area of the former petroleum seepage lagoons, one in the former oil refinery operations area, and five screened in the shallow aquifer beneath the OCI property where earlier sampling results suggested that insoluble compounds heavier than water would be found.

A water sample from a shallow well near the former seepage lagoon contained high concentrations of VOCs (2,523 ppb total VOCs). The contaminants included: 1,2-DCE (565 ppb), TCE (195 ppb), benzene (155 ppb), toluene (660 ppb), chlorobenzene (205 ppb), and ethylbenzene (310 ppb). The sample from this well also contained the highest concentrations of total SVOCs, pesticides and PCBs, including naphthalene (13 ppb), 2-methylnaphthalene (25 ppb), N-nitrosodiphenylamine (160 ppb), carbazole (150 ppb), and aldrin (0.033 ppb). Concentrations of inorganic compounds found in Phase II samples were generally comparable to Phase I results.

Surface Soil

The U.S. EPA contractors collected surface soil samples from the site during both phases of the RI field work. Surface soil samples were taken from between 2-6 inches below the ground surface and analyzed for VOCs, SVOCs, pesticides, PCBs, metals, and cyanide (Table 3). Surface soil samples were collected from areas of known or suspected waste spillage, drum storage, stained soil, or locations where previous investigations had detected soil contamination.

The highest concentrations of VOCs and SVOCs found during Phase I of the RI were in a surface soil sample from the former seepage lagoon area. The contaminants found included methylene chloride (1,100 parts per million (ppm)), ethyl benzene (950 ppm), xylene (7,300 ppm), PCE (66 ppm), toluene (6,700 ppm), and N-nitrosodiphenylamine (17 ppm). Surface soil samples taken from stained soil in a ditch west of the OCI chemical building contained phenanthrene (6.2 ppm), benzo(a) pyrene (7.6 ppm), and PCB (15 ppm).

All surface soil samples contained inorganic chemicals at varying concentrations. A soil sample collected approximately 1,500 feet southwest of the OCI facility near a residential area was used to represent naturally occurring background levels for the area. Nine inorganic contaminants were detected in on-site soil samples at maximum concentrations significantly above (that is, more than five times) background levels. Included were the following metals: arsenic (7 ppm), barium (262 ppm), cadmium (10.6 ppm), chromium (228 ppm), cobalt (31.3 ppm), copper (189 ppm), lead (1,160 ppm), and mercury (1.6 ppm). These concentrations were also more than five times the statewide background levels found by an MDNR survey (15).

Three surface soil samples were collected from the former petroleum sludge lagoons. The contractors collected a fourth surface soil sample from an area between the two lagoons as a localized background sample. The contractors collected five surface soil samples from the former oil refinery operations area. Except for benzo(a)pyrene (21 ppm), chrysene (39 ppm) and phenanthrene (33 ppm) detected in surface soil samples taken from the former petroleum sludge lagoons, the concentrations of contaminants of concern from samples collected from both areas were below the maximum concentrations of compounds detected in other on-site surface soil samples.

The maximum concentrations of principal contaminants of concern detected during Phase II were all found in soils near the former tanker loading areas on or next to the main driveway of the site. These included xylene (73 ppm), toluene (74 ppm), ethyl benzene (25 ppm), and 1,2-DCE (13 ppm).

The highest levels of SVOCs in surface soils were found in samples from the lacquer thinner spill area. The compound showing the highest concentration was bis(2-ethylhexyl)phthalate (66 to 220 ppm). The highest PCB levels (74 ppm) in surface soil samples were found just north of the northern tank farm area.

The highest inorganic contaminant concentrations were found in samples from the lacquer thinner spill area. Cadmium, chromium, cyanide, and lead were significantly higher (that is, more than five times) than background concentrations. The maximum concentrations detected for each were: cadmium (44.8 ppm), chromium (1,590 ppm), cyanide (136 ppm), and lead (13,100 ppm).

The contractors collected seven surface soil samples from the area of the former oil refinery operations. Organic contaminants and metals detected did not exceed or were comparable to the levels detected during the Phase I sampling of the same area.

Subsurface Soil

During Phase I of the RI, U.S. EPA contractors collected subsurface soil samples from the borings for four monitoring wells on the site, three on the OCI property and one at the former petroleum seepage lagoons. The contractors analyzed these samples for VOCs, SVOCs, pesticides, PCBs, metals, and cyanide (Table 4).

The highest organic contaminant concentrations were found in samples from borings on the OCI property located at the former seepage lagoon. These samples were collected at 10 and 20 feet below ground surface. Compounds detected included TCE (100 ppm), toluene (1,800 ppm), chlorobenzene (94 ppm), xylene (360 ppm), N-nitrosodiphenylamine (240 ppm), bis(2-ethylhexyl)phthalate (47 ppm), and naphthalene (an estimated 12 ppm) (Table 4). Other compounds were detected in high concentrations in a soil boring located near the center of the OCI fenced area.

During the inorganic analysis, five metals were detected in concentrations significantly above background levels according to the MDNR Michigan Background Soil Survey (that is, more than five times higher) (15). These were barium (163 ppm), chromium (194 ppm), copper (46.4 ppm), lead (959 ppm), and nickel (62.8 ppm).

During Phase II of the RI, subsurface soil samples were collected from nine soil borings and four monitoring wells located on the OCI property. In addition, subsurface soil samples were taken from three locations associated with the former oil refinery operations area. All samples were analyzed for VOCs, SVOCs, pesticides, PCBs, metals, and cyanide (Table 4). The locations where VOC concentrations were the highest were associated with the former seepage lagoon and the northwest corner of the OCI property, ranging in depths from 6 to 8 feet and 26 to 28 feet.

The subsurface soil samples with the highest concentrations of SVOCs were collected from the former seepage lagoon, the north chemical building, the north tank farm, and the south tank farm. Ten samples (out of a total of approximately 100) contained detectable concentrations of PCBs (up to 5.6 ppm). PCBs were mainly found in samples collected from the former seepage lagoon, the south chemical building, and the south tank farm.

The highest concentrations of inorganic contaminants detected in subsurface soil samples were found in the area associated with the former seepage lagoon. Barium (an estimated 120 ppm), copper (76 ppm), lead (631 ppm), and mercury (7.8 ppm) were found in excess of 10 times their associated background concentrations. Arsenic was detected at a significantly high level (that is, more than five times background) in the former oil refinery operations area (9.9 ppm).

B. Off-Site Contamination

Groundwater

    Monitoring Wells

During Phase I of the RI, the contractors collected 21 groundwater samples from monitoring wells located outside the immediate area surrounding the 5-acre OCI property and as far as 2,000 feet away. The samples were analyzed for VOCs, SVOCs, pesticides, PCBs, metals, and cyanide (Table 5). As mentioned earlier, inorganic concentrations in water from two monitoring wells located approximately 500 feet southeast (upgradient) of the OCI site in a residential setting were assumed to represent naturally occurring background levels for the area.

Much of the groundwater contamination has been found in the shallow aquifer, however, samples from three wells screened in the lower aquifer -- two located within 200 feet west of the OCI property and one approximately 1,500 feet northwest of the OCI property -- contained between 10 ppb and 100 ppb of total organic contaminants. The well furthest away from the site contained 3 ppb (estimated, laboratory blank contamination) methylene chloride, 6 ppb (estimated, laboratory blank contamination) bis(2-ethylhexyl)phthalate, and 1 ppb (estimated) di-n-octyl phthalate. All three of these chemicals are common laboratory contaminants. The two wells closer to the site contained other organic contamination (Table 5). The contaminants in these wells were similar to those in adjacent wells screened in the upper aquifer.

In addition to the monitoring wells sampled during Phase I, 17 additional off-site monitoring wells were installed during Phase II of the RI. Nine wells were screened in the shallow aquifer; seven wells were screened in the deep aquifer; and one well was screened in the shallow aquifer in an area where the presence of insoluble compounds heavier than water was indicated.

The highest VOC and SVOC concentrations in the groundwater were found just north of the fenced area. VOCs found included methylene chloride (26 ppb), benzene (21 ppb) and ethyl benzene (39 ppb). The principal SVOC contaminants found were naphthalene and 2-methylnaphthalene. In addition, a sample from a well just west of the OCI property contained 1,1,2-trichloroethane (TCA) (18 ppb), benzene, toluene, chlorobenzene, and ethylbenzene. A sample from an off-site monitoring well located approximately 600 feet west of the OCI property contained 1.6 ppb PCBs.

    Private Wells

The RI contractors collected samples from four private wells (two [PW-1 and PW-2 in Figure 1] serving commercial establishments and two [PW-3 and PW-7 in Figure 1] serving residences) approximately 2,000 feet west to northwest of the site in September 1989. The samples from PW-1, PW-2, and PW-3 were analyzed for VOCs, SVOCs, pesticides, PCBs, metals, and cyanide; the sample from PW-7, only for VOCs. As mentioned earlier, concentrations of inorganic chemicals in water from two monitoring wells located approximately 500 feet southeast (upgradient) of the OCI site in a residential setting were assumed to represent naturally occurring background levels for the area.

Water from PW-3 and PW-7 contained no organic chemicals. Water from PW-1 and PW-2 contained methylene chloride, toluene, bis(2-ethylhexyl)phthalate and benzoic acid, at maximum concentrations of 8 ppb, 0.5 ppb, 3 ppb, and 2 ppb respectively. Only two metals were detected at levels significantly above background (that is, more than five times): lead and zinc. Lead was detected in water from PW-1 at a concentration of 173 ppb and zinc was detected in PW-1, PW-2, and PW-3, with a maximum concentration of 1,180 ppb (Table 6).

During Phase II of the RI, the contractors collected water samples from two of the private wells sampled in Phase I (PW-2 and PW-3) and a commercial well near PW-1 (PW-5 in Figure 1). The samples were only analyzed for VOCs. The following VOCs were detected in water from PW-2, located 1,500 feet west of the OCI property: acetone (14 ppb), carbon disulfide (1 ppb), chloroethane (0.3 ppb), chloromethane (13 ppb), 1,2-DCA (17 ppb), and 1,2-dichloropropane (0.4 ppb). Water from PW-3 contained no VOCs, and water from PW-5 contained 0.1 ppb toluene (Table 6). Water from PW-2 had contained low concentrations of methylene chloride and toluene in Phase I, and water from PW-3, located 300 feet from PW-2, contained in no detectable VOCs in either Phase I or Phase II sampling.

Surface Soil

During Phase I of the RI, the contractors collected six surface soil samples from locations just north of the OCI property and south of the former oil refinery operations area, and a background surface soil sample approximately 1,350 feet southwest of the OCI property. Various organic compounds were detected in the samples including polycyclic aromatic hydrocarbons (PAHs) and PCBs (0.52 ppm).

Off-site surface soil samples collected just north of the OCI property contained the following metals at concentrations significantly (that is, more than five times) above their background levels: arsenic (5.3 ppm), barium (an estimated 1,070 ppm), lead (1,680 ppm), nickel (33.5 ppm), and zinc (853 ppm).

During Phase II of the RI, the contractors collected 65 off-site surface soil samples. The samples were taken from various locations, which included areas immediately east (adjacent), north (within 150 feet) and west (within 300 feet) of the OCI property. Other areas included those further away from the OCI property to the west (up to 1,500 feet away) and north (near former petroleum lagoons). Nine of the off-site surface soil samples were taken along the railroad siding east of the OCI fenced area. Eight of the nine samples collected along the railroad siding contained high levels of SVOCs. The most extensive contamination occurred in this area, which is closest to the OCI property.

Maximum concentrations of contaminants detected in off-site surface soil sampling during Phases I and II of the RI can be found in Table 7.

Subsurface Soil

During Phase I of the RI, off-site subsurface soil samples were collected and analyzed for VOCs, SVOCs, pesticides, PCBs, metals, and cyanide (Table 8). The most extensive contamination detected was located approximately 50 feet north of the OCI facility. Samples were taken from test pits at the 4 to 6 foot depth and indicated the presence of VOCs and SVOCs. Contaminants detected included acetone (0.38 ppm), 2-methyl naphthalene (an estimated 3.1 ppm), naphthalene (2.4 ppm), and low levels of chlorinated solvents.

A soil boring collected at the 3 to 5 feet depth, approximately 2,000 feet west-northwest from the OCI facility directly across from a truck service station showed VOC and SVOC contamination. Analysis of the sample indicated the presence of methylene chloride (0.031 ppm), phenanthrene (3 ppm), 2-methylphenol (0.67 ppm), and 4-methylphenol (0.63 ppm). Other contamination source areas included an area located approximately 50 feet west of the OCI facility.

The highest concentrations of inorganic chemicals were found in samples form two areas. One area is located approximately 2,000 feet west-northwest of the OCI property across from a truck service station. A sample taken from 3 to 5 feet deep contained antimony (79.1 ppm), barium (284 ppm), cadmium (10.4 ppm), chromium (1,510 ppm), cobalt (36.3 ppm), copper (139 ppm), and nickel (827 ppm). The other area is located approximately 850 feet west of the OCI property. A sample from a soil boring taken from the 7 to 8 feet depth contained arsenic (14.6 ppm), beryllium (109 ppm), lead (11,000 ppm), and manganese (15,300 ppm).

During Phase II of the RI, subsurface soil samples were taken from 36 soil boring locations and seven monitoring wells and analyzed for VOCs, SVOCs, pesticides, PCBs, metals, and cyanide (Table 8). The majority of organic contamination was found in soil borings and monitoring wells located near the former oil refinery operations area, just west of the OCI property and approximately 1,000 feet north west of the OCI property. Maximum concentrations of VOCs and SVOCs found included an estimated 0.004 ppm PCE, 0.049 ppm pentachlorophenol, 0.85 ppm benzo(a)anthracene, 0.31 ppm carbazole, and an estimated 0.48 ppm benzo(a)pyrene.

All samples collected contained varying concentrations of inorganic chemicals. The maximum concentrations found were primarily in soil boring samples taken from 2 to 4 feet in depth from an area approximately 1,250 feet northwest of the OCI property. Metals detected from this soil boring at significant levels (that is, more than five times background) included: arsenic (an estimated 47.6 ppm), chromium (1,550 ppm), cobalt (57.6 ppm), copper (an estimated 343 ppm), manganese (5,450 ppm), and nickel (1,260 ppm).

C. Quality Assurance and Quality Control

In preparing this public health assessment, the MDPH relied on the information provided in the referenced documents and assumed that adequate quality assurance and quality control measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. The validity of the analysis and conclusions drawn for this public health assessment is determined by the reliability of the referenced information.

Many analytical results for organic chemicals in the RI report were flagged with a "J" qualifier. This qualifier represents an estimated value for the concentration detected due to limitations identified in the Quality Assurance Review. The RI report also included results with a "B" qualifier attached meaning that the compound detected was also found in the blank.

During the Phase I soil investigation, the remedial investigation contractor used a surface soil sample that was collected from an area between two former petroleum sludge lagoons located 100 yards apart as a local background sample. Due to the proximity of the two lagoons, the background sample does not appear to be representative of background conditions and will not be considered so in this health assessment.

D. Physical and Other Hazards

During the MDPH site visits of July 8 and November 1, 1994, it was observed that structures still exist on the OCI property, however, access to this area is completely restricted and there was no evidence of trespass (1011).


PATHWAYS ANALYSES

To determine whether nearby residents are exposed to contaminants migrating from the site, ATSDR evaluates the environmental and human components that lead to human exposure. An exposure pathway contains five major elements:

  1. A source of contamination (source of contaminant release into the environment or the environmental media responsible for causing contamination at a point of exposure if the original source of contamination is unknown).
  2. A transport process of contamination through an environmental medium which serves to move contaminants from the source to points where human exposure can occur.
  3. A point of exposure at which people contact a contaminated medium.
  4. A route of human exposure (means by which the contaminant actually enters or contacts the body).
  5. A receptor population (population that is exposed).

An exposure pathway is considered a completed pathway if there is evidence that all five of these elements are or have in the past been present. A pathway is considered a potential pathway if one or more of these elements is not known to be or have been present, but could be or have been. An exposure pathway can be eliminated from consideration if one of the elements is not present and could never be present. The following sections discuss the most important exposure pathways at this site.

A. Completed Exposure Pathways

Surface Soils

Based on the history of past operations undertaken at the OCI site and elevated contaminant levels found in surface and subsurface soils, anyone coming onto the site could be exposed to contaminated surface soils via dermal contact, through incidental ingestion or inhalation of fugitive dust particulates. Workers on-site during operations at Organic Chemicals could have been exposed to chemicals that had gotten onto the surface soils of the site as a result of accidental spills or handling of chemicals. Access to the OCI property is completely restricted and there is no evidence of trespass onto the fenced site.

Operations that took place outside the OCI property but in close proximity (just north) included waste disposal of petroleum products and a former oil refinery. Off-site surface soil and subsurface soil sampling has shown contamination to exist outside the OCI property. Access to these areas is not restricted and anyone coming into the area could have been exposed or could be exposed to contaminated surface soils via dermal contact, through incidental ingestion or inhalation of fugitive dust particulates at levels of health concern. The representatives from the MDPH and MDNR did not observe any signs of trespass in these areas during the site visit, however, these areas were heavily vegetated, making it difficult to determine whether trespass had occurred.

Air

Air sampling was not conducted as a part of the RI for the OCI site, however, extensive surface soil contamination has been documented during the RI. VOCs in contaminated soils could volatilize into the air. In addition, fugitive dust particles distributed from contaminated soil could also be transported by the wind. Persons trespassing in areas with extensive soil contamination could have been or could be exposed to VOCs at levels of concern.

Because the site and surrounding site area are heavily vegetated, the risk of humans inhaling contaminated dust particles outside the site area is minimal. Residences closest to the site are located approximately 0.5 miles west of the site. The closest business (west and adjacent), Haven Busch Co., is defunct. It is unlikely that VOCs would volatilize into the air at levels of concern away from the site.

Groundwater

Due to previous operations conducted at the OCI site, contamination of the groundwater has occurred. Rainwater percolating through the on and off-site contaminated areas has leached contaminants into the groundwater beneath the site, as indicated by analysis of groundwater samples collected during Phase I and Phase II of the RI.

Residential wells that were sampled did show contamination that may be site-related. However, there is no indication to date that these private wells are or were in household potable use. Residences in the site area are connected to a municipal water supply, but private wells may be used for watering lawns and washing cars. Residents using the contaminated wells for non-potable uses would be exposed to contaminants by incidental ingestion, by dermal exposure, or by inhalation of VOCs secondary to household use.

B. Potential Exposure Pathways

Surface Water and Sediments

Contaminated groundwater at the site is moving to the north toward Roy's Creek and the Grand River. Contaminants from the groundwater could mix with the water in the creek and river. Some contaminants could adhere to the sediments in the river. People using the creek or river for recreation could come into contact with the water or sediments and be exposed to the contaminants by dermal contact or incidental ingestion. Fish living in the creek or river could absorb contaminants from the water or sediments, and people who eat fish caught from the creek or river could ingest the contaminants. The RI that took place for the OCI site did not address surface water, sediments, or fish sampling from the creek or river. These pathways are not known to be complete. Most of the contaminants associated with this site do not typically accumulate to significant levels in fish tissue.


PUBLIC HEALTH IMPLICATIONS

A. Toxicological Evaluation

The risk of contracting cancer after exposure to a carcinogen or potential carcinogen is estimated from the extent of the exposure and a cancer potency (slope) factor derived from experimental or epidemiologic studies. The estimated risk is stated in terms of the number of additional cases of cancer that could develop in a large population that undergoes the exposure compared to an equal-size population which is not exposed. The slope factors are calculated as upper bounds, with appropriate safety factors, and the actual risk may in fact be zero. For this health assessment, a significant additional risk is taken to be one additional case of cancer in a population of one million people experiencing the exposure over a 70 year period (lifetime).

Exposure doses for the various chemicals at this site are evaluated by comparison with health-related guidelines. The guidelines used for evaluation of non-cancer adverse health effects are the Minimal Risk Levels (MRLs) established by the ATSDR and Reference Doses (RfDs) and Reference Concentrations (RfCs), established by the U.S. EPA. If an exposure dose does not exceed the MRL, RfD, or RfC, it is generally accepted that there would be little risk of adverse non-cancer health effects occurring. These MRLs, RfDs, and RfCs may not be sufficiently protective for especially susceptible individuals, such as the very young, the elderly, those whose immune systems have been weakened by other causes (immunocompromised), or those with a heightened sensitivity to a specific chemical (hypersensitive).

Exposure doses for this assessment are computed assuming the following standard individuals: an adult weighing 70 kilograms (154 pounds) who incidentally ingests 100 milligrams of soil per day; a child weighing 10 kilograms (22 pounds) who incidentally ingests 200 milligrams of soil per day, or, if subject to pica behavior, deliberately ingests 5 grams of soil per day. Pica is an abnormal urge to consume non-food substances, such as soil. Pica behavior most commonly occurs between the ages 2 and 5.

The OCI property is heavily contaminated with a number of VOCs and SVOCs. In addition, inorganic compounds have been detected at levels significantly above background levels. The media affected include groundwater, surface soil and subsurface soil. In addition, areas outside the fenced area are also contaminated. Such areas include the former oil refinery operations directly north of the property and former sludge lagoons to the north of the former refinery operations area. Both have also impacted groundwater, surface soil and subsurface soil.

Documented completed exposure pathways at the site according to this assessment include past exposure to former workers that worked on-site during operations at OCI and remedial workers conducting work on the site. The exposure levels are unknown. There has been no evidence of trespass onto the OCI property area, where access is restricted, however, the former oil refinery operations area and former petroleum seepage lagoons have no physical restrictions against access in place. Most of the contamination that exists at the site was found in the soil and in areas where sludge lagoons were used. Groundwater has also been impacted as a result of contaminated soils and seepage from lagoons and spills. Water in nearby residential wells contain contaminants of concern, but the wells are reportedly not used for potable purposes.

Much of the organic chemical contamination found at the site consists of benzene, toluene, ethylbenzene, and xylene (BTEX), which are common constituents of gasoline, other fuels, and oil (16, 17, 18, 19). Past oil refinery operations and past operations at the OCI site account for this contamination. The likelihood of high exposures as a result of inhalation to persons outside the site area is not likely, however, high exposures could be occurring or could occur for those who trespass on the site area. Because of heavy vegetation in the area, exposure levels would be dependent on the type of activity. The vegetation will decrease the amount of volatilization of VOCs from the soil. If trespassers play extensively in the contaminated areas, then exposures would be greater than for those who might walk through the site area. Benzene has been classified as a human carcinogen by the U.S. EPA (U.S. EPA Class A). No one is likely to ingest enough benzene from the surface soil on the site to incur a significant increased risk of cancer or to attain the doses at which adverse health effects have been observed (16). A child might incidentally ingest enough toluene from the surface soil on the site to exceed the MRL for intermediate-term exposure for non-cancer adverse health effects. A child subject to pica behavior might deliberately ingest enough contaminated surface soil to exceed the MRL for acute-term exposure and the RfD for toluene, the RfD for ethylbenzene, and the MRL for intermediate-term exposure and the RfD for xylenes. No child is likely to ingest enough toluene, ethylbenzene, or xylenes from the surface soil on the site to attain the doses at which adverse health effects have been observed in laboratory animals or human epidemiological studies (171819). Children, particularly those of the ages subject to pica behavior, are not likely to be on the site under current conditions.

A child subject to pica behavior might ingest enough tetrachloroethylene (PCE) from the soil on the site to exceed the RfD for non-cancer adverse health effects. The pica child would not be likely to attain the dose of PCE at which adverse health effects have been observed in laboratory experiments on animals or epidemiological studies of humans. Children of the age subject to pica behavior are not likely to be on the site. The U.S. EPA had classified PCE as a probable human carcinogen (U.S. EPA Class B2) but is reconsidering the classification (20). No one is likely to ingest enough PCE from the soil on the site to incur a significant increased cancer risk.

None of the other chlorinated hydrocarbons found at the site, including chloroform, 1,1-DCA, 1,2-DCA, 1,1-DCE, 1,2-DCE, methylene chloride, 1,1,1-TCA, TCE, and vinyl chloride, have been found in surface soil samples at concentrations where anyone would be likely to ingest enough to attain the MRLs, RfDs, or levels at which adverse non-cancer health effects have been observed.

Exposure to high concentrations of any chlorinated hydrocarbon can cause central nervous system depression, liver damage, and kidney damage (20, 21, 22, 23, 24, 25, 26, 27). Someone digging into the site where contamination is present might encounter these chemicals at very high concentrations. Vinyl chloride has been classified by the U.S. EPA as a proven human carcinogen (U.S. EPA Class A) (21). 1,2-DCE and methylene chloride are classified as probable human carcinogens (U.S. EPA Class B2), and 1,1-DCA and 1,1-DCE are classified as possible human carcinogens (U.S. EPA Class C) (22232425). The U.S. EPA had classified TCE as a probable human carcinogen (U.S. EPA Class B2), but the agency is reconsidering the classification (26). Much of this contamination is within the fenced area and high exposures to these chemicals are unlikely. However, remedial workers could be exposed to levels above health concern if proper precautions are not taken.

Polycyclic aromatic hydrocarbons (PAHs) are a group of SVOCs that are dispersed during the incomplete burning of coal, oil and gas, garbage, or other organic substances. In all, there are over one hundred PAH compounds (28). PAHs that were found during Phases I and II of the RI are listed in Table 1. The most significant route of exposure for PAHs is through the lungs when breathed from air containing them. Several PAHs listed have been shown to cause cancer in humans who have been exposed to them by breathing or skin contact for long periods of time. Based on the exposure assessment done as a part of this health assessment, it is possible that persons trespassing in the unrestricted-access areas outside of the OCI facility could be exposed at levels of health concern. The concentrations of PAHs found in surface soil on or near the site are comparable to those found in urban area surface soil (Reference 28, Table 5-1).

PCBs are a group of man-made chemicals that contain 209 individual compounds (congeners) with varying possible adverse health effects. In humans, PCB toxicity affects the skin and liver, and may also cause developmental effects in the fetus and young children. Metabolic, reproductive, endocrine, and immunosuppressive effects have been documented in animals studied, but these health effects have not been adequately studied in humans. Although data from animal studies show that PCBs can cause cancer in animals, evidence of PCBs as human carcinogens is limited. The U.S. EPA has classified all PCBs as probable human carcinogens (29). A child might incidentally ingest enough PCBs from the surface soil on the site to exceed the MRL for non-cancer adverse health effects, but children are not likely to be on the site. No one is likely to spend enough time on the site that he or she would ingest enough PCBs to incur a significant increased risk of contracting cancer.

Some inorganic compounds were present at elevated levels, particularly in the surface and subsurface soils on the OCI property (former seepage lagoon), just north of the OCI property, in an area approximately 2,000 feet northwest of the OCI property. Metals found include arsenic, barium, beryllium, cadmium, chromium, copper, lead, manganese, mercury, and nickel. Cyanide is also present. An older child or an adult who occasionally visits the site would not be likely to incidentally ingest enough surface soil from the site to be exposed to enough of any of these inorganic chemicals to exceed the MRLs, RfDs, or doses at which adverse non-cancer health effects have been observed (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40).

Ingestion of arsenic is linked to cancer of the skin, liver, bladder, kidney, and lung (30). The U.S. EPA has classified arsenic as a human carcinogen (U.S. EPA Class A). The U.S. EPA has determined that beryllium is a probable human carcinogen (U.S. EPA Class B2). Occasional exposure to the surface soil at the site is not likely to result in a significant increased risk of contracting cancer from the arsenic and beryllium present (3031).

The cancer risks from ingesting cadmium, chromium(VI), lead, and nickel are not well enough understood to evaluate them at this site (32333435). Chromium-containing compounds usually contain the metal in one of two valence states, trivalent or hexavalent. Hexavalent chromium is generally much more toxic than the trivalent form. For inhalation exposures, hexavalent chromium compounds are classified as human carcinogens (U.S. EPA Class A). There is not enough information available to classify the carcinogenicity of this form of the chemical by other routes. Trivalent chromium is a necessary trace element, though at high levels of exposure, it can be toxic. Hexavalent chromium tends to be reduced to the trivalent species in the environment (32).

For inhalation exposures only, cadmium is classified as a probable (U.S. EPA Class B1) carcinogen. There is not enough information available to classify the carcinogenicity of the element by other routes of exposure (33).

Lead is classified as a probable human carcinogen (U.S. EPA Class B2). This metal is a cumulative poison, affecting the nervous system (34).

The International Agency for Research on Cancer (IARC) has determined that some nickel compounds are carcinogenic to humans and that metallic nickel is possibly carcinogenic to humans. The U.S. EPA has determined that nickel refinery dust and nickel subsulfide are human carcinogens (35).

Contaminants in private well water

The concentrations of contaminants found in water from private wells near the site are low enough that no one is likely to be exposed to enough of the contaminants to exceed MRLs, RfDs, RfCs, or levels at which adverse health effects have been observed, or to incur a significantly increased risk of contracting cancer, except upon using the water as their primary drinking water source. Since none of these private wells is reportedly used as a drinking water supply, no one is currently likely to suffer adverse health effects from current use of the water.

If one of the private wells should be used as a residential household water supply, a child might ingest enough lead from the water to exceed the doses at which the activity of enzymes involved in the synthesis of important blood components was observed to decrease in people who were dosed with lead for periods of several weeks. Lead tends to accumulate in the body, and the effects from any given lead exposure depends on the previous exposure of the person involved. The U.S. EPA has classified lead as a probable human carcinogen (U.S. EPA Class B2), because some laboratory animals whose food or water contained lead developed kidney cancer. There is not enough information available to evaluate the cancer risk from an exposure to lead (34).

A child might ingest enough manganese from the water from the private wells to exceed the RfD, but he or she would not attain the dose at which adverse health effects have been observed. Manganese compounds are not known to cause cancer (36). No one using the private well water for their drinking water supply is likely to ingest enough mercury to exceed the available acute- or intermediate-term MRLs for ingestion of any mercury compound, nor the doses at which adverse health effects have been observed from exposure to any mercury compound. Exposure to mercury is not known to cause cancer (37).

There is no information available on the health effects from ingestion of chloroethane. The air concentration of chloroethane from volatilization during use of the water is not likely to attain the MRLs, RfCs, or levels at which adverse health effects have been observed. Some laboratory animals who breathed air containing chloroethane developed cancer of the uterus, liver or lungs. The U.S. EPA has not classified chloroethane as a carcinogen, nor is there enough information available to evaluate the cancer risk from exposure to chloroethane (41).

There is no information available on the health effects from ingestion of chloromethane. The air concentration of chloromethane from volatilization during use of the water from the private wells is not likely to attain the MRLs, RfCs, or levels at which adverse health effects have been observed. Some animals who breathed chloromethane developed kidney cancer. The U.S. EPA had classified chloromethane as a possible human carcinogen (U.S. EPA Class C), but the classification is under review. Lifetime use of water from the private wells for drinking and showering might result in a low increased risk of contracting cancer (42).

Lifetime use of water from the private wells might result in a low increased risk of cancer from the bis(2-ethylhexyl)phthalate, 1,2-DCA, or methylene chloride present (25, 27, 43). Cadmium is classified as a probable human carcinogen (Class B1) by inhalation. There is not enough information available to evaluate the cancer risk from exposure to cadmium (33).

B. Health Outcome Data Evaluation

Based on the evaluations performed as part of this public health assessment, there are no indications that humans had significant exposure to site-related contaminants. In addition, there were no community health concerns identified, therefore, an evaluation of health outcome data is not indicated.

C. Community Health Concerns Evaluation

As mentioned earlier, a public comment period was held for the ROD from July 22 through August 20, 1991. During this time, no community health concerns were expressed. No community health concerns have been expressed to the MDPH, MDNR or Kent County Health Department regarding the OCI Superfund site (131444). Once the FS for Phase II of the RI has been completed, further public comments will be solicited by the U.S. EPA. The MDPH will continue to seek out any community health concerns regarding the site.

The MDCH released a draft of this assessment for public comment on November 6, 1996. The comment period lasted until December 6, 1996. Comments received and MDCH responses are listed in the Responsiveness Summary at the end of the document.


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