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Johnson Iron Industries Ecological Risk Assessment

Site Description/History

Environmental Setting

In this section, the history of the site, along with endangered species known (or suspected) to be at the site, is described. Information about the historical and current land-use, as well as types of habitats, and known or suspected sources of contamination.

Site Description

Johnson Iron Industries (JII), Charlotte, Michigan, manufactured gray iron counterweights and castings from scrap iron between 1947 and 1986. Onsite hazardous waste disposal included foundry sand and slag, deposited in three piles (northwest, southwest, and southeast); sludge from air pollution control operations, deposited in a sludge basin from which it was periodically removed and land-farmed (sludge pile); and miscellaneous hydraulic fluids and solvents. There are two ponds formed out of quarry pits, the smaller of which (north pond) is bordered by the west foundry sand and slag piles and receives effluent from the sludge basin. The larger pond is located further south.

The area of and surrounding the foundry sand and slag piles contains invasive and weedy vegetation characteristic of disturbed sites. The predominant vegetation includes common mullein (Verbascum thapsus), common evening-primrose (Oenothera biennis), grape (Vitis sp.), and grasses. There are extensive areas of moss tentatively identified as Ceratodon purpureus, a common invader of disturbed and polluted sites (Crum 1983). The overstory consists of scattered individuals of boxelder (Acer negundo), tree of heaven (Ailanthus altissima), slippery elm (Ulmus rubra), quaking aspen (Populus tremuloides), staghorn sumac (Rhus typhina), hawthorn (Crataegus sp.) and willow (Salix sp.). The sludge pile is mostly unvegetated as are some portions of the foundry sand and slag piles.

A few small burrows are present that could belong to meadow voles (Microtus pennsylvanicus) or deer mice (Peromyscus maniculatus) (Burt 1972). The only tracks were of domestic cats and raccoon (Procyon lotor) . The season was inappropriate for determining avian use of the habitat.

The north (small) pond is sparsely vegetated. There were no rooted emergent aquatic plants at the time of the site visit. Duckweed (Lemna sp.) was present in a limited area near the east shore but not elsewhere. Hornwort (Ceratophyllum echinatum) and green algae (Chlorophyta) were collected near the outflow from the sludge basin. Ceratophyllum echinatum is characteristic of acid softwater ponds (Voss 1985). A bright bluish sheen was noted along the northern portion of the east shore. It was not possible to determine visually whether the phenomena was biotic (cyanobacteria) or abiotic. Samples were not taken so the identity of the coloration remains unresolved.

There were no signs of animal use of the pond; but an employee of Machine Technology, Inc., which operates in part of the former JII facility, reportedly catches and eats bluegills (Lepomis) and bass (Micropterus) from the north pond (conversation with a coworker, the fisherman was absent).

SLERA (Screening Level Risk Assessment):
Screening Level Problem Formulation (Step 1)

For this site, the Region 5 ecologist (James Chapman) performed the Ecological Risk Assessment, including calculation of Hazard Quotients (HQ), deciding on potential assessment endpoints and conceptual site models (See ERA Guidance Step 3 for more information on endpoints and site models).

This section describes the likely sources of contamination, what the contaminants are, and what plants and animals at the site are likely to be affected by those contaminants and in what manner.

Contaminants of Potential Ecological Concern (COPECs)

The sludge pile and foundry sand and slag pile soil samples that meet or exceed Netherland and Quebec soil quality guidelines are given in Table 1. Sludge basin and pond sediment samples that meet or exceed Ontario sediment quality guidelines are given in Table 2. Sample data below the soil or sediment quality guidelines are omitted. The maximum hazard quotients are also presented in each table for each area of concern.

The sludge basin is highly contaminated with PCBs, cadmium (Cd), lead (Pb), and zinc (Zn). The sludge pile has the same contaminants as well as Polycyclic Aromatic Hydrocarbons (PAHs), copper (Cu), and selenium (Se). The foundry sand and slag piles contain PAHs, PCBs, cadmium, lead, and zinc that exceed soil quality guidelines in irregularly distributed samples. The north pond sediments are contaminated with PCBs, cadmium, lead, and zinc, particularly near the outflow from the sludge basin. The south pond sediment samples do not exceed sediment quality guidelines with the exception of arsenic (As). None of the surface water samples in either pond exceed ambient water quality criteria protective of aquatic organisms.

Fate, Transport, and Ecotoxicity

Only those chemicals likely to contribute to the potential ecological risks of the site are discussed in this section. This procedure is followed because the screening level ecological risk assessment (SLERA) is based on a screening comparison of the concentrations of COPECs with benchmark guidelines by media (soil, sediment, or surface water). This numerical comparison results in a Hazard Quotient; if the HQ is greater than one, the potential for ecological risk by that COPEC is present. (See Step 2 of the Guidance for more details.)

The benchmark values are sufficiently conservative so that chemicals detected at concentrations below the guidelines are not expected to exhibit significant ecological effects, even if fully bioavailable. Since fate, transport and toxicity variables do not modify the outcome of the screening (these effects are embedded in the derivation of the particular guidelines), discussions of these processes for the chemicals screened out are unlikely to contribute meaningful information to the SLERA.

See TOXICITY PROFILES for more information on the toxic effects of the various COCs found at this site.

SLERA: Risk Calculations/Exposure Estimates (Step 2)

This section includes calculations of Hazard Quotients and calculated estimations of risk by COPECs to potential receptors in different media (soil, sediment, surface water). This step involves the comparison of the concentrations of COPECs with benchmark guidelines by media (sediment, soil, surface water). If the maximum concentration of a chemical found at the site exceeds the screening benchmark guideline, then there is the potential for risk and further study is needed to clarify that risk. (See SLERA Step 2 for more information on the screening process, including calculating Hazard Quotients.)

Ecotoxicological Benchmark Values and Hazard Quotient Calculations

The Screening Level Ecological Risk Assessment (SLERA) is based on a screening comparison of the concentrations of COPECs with benchmark guidelines by media.

Because the site is highly degraded, there is little habitat suitable for wildlife. Hence, no exposure pathways or conceptual site models are presented here. See the remainder of this section for additional details on potential wildlife exposure.

The following is a summary of the results of risk calculations. Risk calculations are the results of comparing maximum contaminant concentrations to effects levels that are determined from literature sources. (See Step 2 of the Guidance for more details.)

• The concentrations of PCBs, cadmium, lead, and zinc in the sludge pile and basin are 1 to 2 orders of magnitude greater than the soil or sediment quality guidelines that indicate potential ecological effects.
• The absence of vegetation on the sludge pile is probably due to zinc. Seeds germinate successfully in the presence of high soil zinc levels, but seedlings are stunted and suffer heavy mortality at soil concentrations of 2000 ppm because of root growth inhibition (Jordan 1975).
• Four of 6 samples taken from the sludge pile substantially exceed this level. Several PAHs also exceed soil quality guidelines in the sludge pile.
• There are scattered "hot spots" in the foundry waste piles. Although the soil quality guidelines for PAHs, PCBs, cadmium, lead, and zinc are exceeded in the northwest pile, nearly all occur in 1 of 6 samples (SS15). Only the lead soil quality guideline is also exceeded by 2 other northwest pile samples. Similarly, of 5 samples taken in the southwest pile, one (S4) exceeds heavy metal and PCB soil quality guidelines, and one (SS18) meets PAH guidelines. Both Southeast pile samples meet or exceed PAH guidelines, but neither meet those for PCBs or heavy metals. The presence of vegetation on the foundry waste piles is consistent with the low proportion of soil samples showing high zinc levels (2 out of 13).
• The contamination of the north pond sediments is substantially higher near the inflow from the sludge basin (S2) than elsewhere in the pond (SD5/SD6). The difference is particularly marked for PCBs, lead and zinc. The concentrations of Arochlor-1254 and -1260 near the inflow are an order of magnitude greater than sediment quality guidelines, and those of Arochlor-1248 and total PCBs are double the guidelines. In the rest of the pond, Arochlor-1260 just meets the guideline in one of the samples, but the other congeners and the total PCBs are below the benchmarks. Lead and zinc are 1 to 2 orders of magnitude greater than sediment quality guidelines, and cadmium is approximately 5 times greater than the guideline.

Potential Terrestrial Effects

• The terrestrial habitat at Johnson Iron Industries is of low quality. The plants are common weedy species of disturbed sites. There are no species of special concern. The potential terrestrial receptors include granivores (rodents and birds feeding on grass and weed seeds), rodentivores (cats, snakes, and perhaps raptors), frugivores (birds and raccoons feeding on grapes), and birds or mammals feeding on earthworms and other soil invertebrates.
• The poor vegetative cover of the sludge basin and piles deters use of these areas by vertebrates; for example, reductions in amphibian, avian and mammalian populations near a zinc smelter were associated with lack of plant cover (Storm, et al. 1993). The contaminants exceed the levels that adversely affect sensitive soil invertebrate populations (470 to 1600 mg Zn kg-1 soil for earthworms and woodlice, respectively), but are not high enough to completely eliminate all soil invertebrates (Eisler 1993). This means that a complete terrestrial exposure pathway for biomagnification of PCBs may be present for the organisms that feed on soil invertebrates, and their associated predators. The primary concern is reproductive impairment (Eisler 1986).
• Wildlife make greater use of the foundry sand and slag pile habitat; however, the irregular distribution of contaminants complicates assessment of potential effects. Biomagnification of PCBs via soil invertebrates is again a potential concern. There is insufficient information to evaluate this pathway (presence of soil invertebrate populations and contaminant levels).
  
  The PAHs and inorganics (cadmium, lead, and zinc) are subject to bioaccumulation in plants, but do not biomagnify. Potential effects include cancer and mutations (benzo(a)pyrene, cadmium, and, to a lesser extent, indeno(1,2,3-cd)pyrene) and adverse effects on soil invertebrate populations (Eisler 1985a, 1987).
  
  Terrestrial avian and mammalian receptors are unlikely to be adversely affected by the heavy metals present in the foundry sand and slag piles, because of the lack of biomagnification, irregular distribution of contaminants, and relatively low sensitivity (Eisler 1985a, 1988, 1993).

Potential Aquatic Effects

Scientific-Management Decision Point (SMDP)

The sludge basin and sludge pile are highly contaminated with PCBs, metals, and, in the latter, PAHs. Zinc (Zn) exceeds levels that are toxic to plants (phytotoxicity) and is probably responsible for the lack of vegetation of these waste areas. Both areas are considered to present significant potential ecological risks in two general categories: 1) direct ecotoxic effects (zinc phytotoxicity, PCB biomagnification and reproductive impairment, and PAH and cadmium cancer-causing and mutation-causing effects), and 2) sources of pond contaminates (the sludge basin is the primary contributor, but erosion from the mostly bare sludge pile may also be important).

It was recommended that actions be taken to prevent runoff/erosion and direct access by wildlife. A question was raised whether liming, fertilization and tillage would stimulate vegetative growth on the sludge pile. This is unlikely since it would not address the probable cause for the lack of vegetation: zinc phytotoxicity. Although combined liming and tillage treatments have been shown to reduce zinc, lead, and cadmium levels in earthworms in moderately contaminated sewage sludge-treated soils, even in the most successful treatment the worm contaminant levels remained greatly elevated in comparison with worms from soils without sludge applications (Benninger-Truax and Taylor 1993). The treatment would probably have little or no effect on the heavily contaminated sludge pile, and is not recommended.

Mulching has been shown to be a successful means of revegetating areas lacking in vegetation that surround smelter operations (U.S. EPA 1987); however, the zinc-contaminated zone is only a few inches thick since it was formed by air deposition. The roots of young plants are capable of growing through a narrowly contaminated zone so long as they have an initially healthy start in an uncontaminated medium. This approach will not be applicable to the sludge pile since the contaminated zone is much deeper (to at least 20"). In situ revegetation is probably infeasible because the entire plow layer is contaminated, and, therefore, in situ revegetation cannot be recommended.

The pond is also highly contaminated with PCBs, zinc, lead, and cadmium. The predominant ecological risks are associated with PCB biomagnification and zinc toxicity. While the potential risks of PCBs are primarily localized near the inflow from the sludge basin, the levels of zinc throughout the pond greatly exceed sediment concentrations that have been associated in other sites with waterfowl deaths. It was recommended that actions be taken to prevent bioaccumulation of sediment zinc and PCBs by benthic invertebrates and aquatic macrophytes.

No potential ecological risks were identified in the south (large) pond. The potential ecological risks of the foundry sand and slag piles are highly variable: low for much of the area of the piles, but high for irregularly distributed "hot spots". Capping would resolve any ecological concerns regarding the hot spots.

Risk Management SMDP/Current Status (Step 8)

• January, 1995 - Screening Level Ecological Risk Assessment completed.
• July 31, 1995 - Removal action completed
• June 2, 1998 - Engineering Evaluation/Cost analysis completed
• March 15, 1999 - Agreement on Consent signed

Links to more information on this site

• CERCLIS Hazardous Waste Sites Information: Johnson Iron

Contacts for this site

• James Chapman, Ecologist (chapman.james@epa.gov)

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