TORCH LAKE AREA BROWNFIELDS
HOUGHTON COUNTY, MICHIGAN
The sampling results discussed in this consultation were taken from the available investigations ofthe property, and are not adjusted for limitations or bias in the sampling programs. The Tablespresented in this consultation include maximum and median concentrations in the samplescollected. Health discussions are based on the maximum concentrations reported and long-term,frequent exposure scenarios, reasonably conservative assumptions.
In August 1997, the MDEQ collected a total of 50 surface soil samples from 11 locations in theTorch Lake area (Table 2). These were all analyzed for metals, and a selected 9 samples weresplit for analysis for semi-volatile organic chemicals. The arsenic concentration in one sample, from the Quincy Smelter area (area F in Figure 1), and the lead concentration in another sample,from the Tamarack/Mason Dredge area (area C), exceeded the MDEQ Generic Clean-Up Criteriafor Industrial, Commercial or Residential Use2 (Table 3) (5, 6). Many other samples containedarsenic, benzo(a)pyrene, beryllium, or copper concentrations above the MDEQ Residential UseCriteria (Table 3) (6). The sample with the benzo(a)pyrene concentration above the ResidentialCriteria was collected from the Tamarack/Mason Dredge area (area C), those with berylliumabove the Residential Criteria were collected from the Hubbell Slag area (area B) (4).
A child subject to pica behavior3 might ingest enough arsenic from the soil on the Hubbell Slag(B), Tamarack/Mason Dredge (C), or Quincy Smelter (F) areas to exceed the doses at whichpeople experienced impairments of the circulatory system, gastrointestinal distress, changes in theliver, neurological effects, and changes in the skin on long-term exposure. Any child mightincidentally ingest enough arsenic from the same areas to exceed the ATSDR Minimum Risk Levels (MRLs) for non-cancer adverse health effects, though they would not be likely to exceedthe levels at which adverse health effects have been observed. Exposure to arsenic has beendirectly linked to skin cancer in humans, and there is weaker evidence linking exposure to thechemical with increased incidence of cancers of the liver, lung, and bladder. The U.S. EPA hasclassified arsenic as a human carcinogen (U.S. EPA Class A). People who spend their lifetimenear soils containing the arsenic concentration found in the areas mentioned above mightincidentally ingest enough arsenic to incur some increased risk of contracting skin cancer. Thereis not enough information available to evaluate the increased risk of contracting other types ofcancer from exposure to arsenic (7). The Hubbell Slag and Quincy Smelter areas are under consideration for future residential development (Table 1). Recreational use of any of these areas is not likely to lead to exposures of human health concern.
The lead concentrations found in soil from the various areas were within the range commonlyfound in urban areas. Lead is a cumulative poison, causing damage to the nervous system,kidneys, and blood. A child might incidentally ingest enough lead from the soil in the Tamarack/Mason Dredge area (C) to exceed the amounts that were observed to cause minor adverse healtheffects in experimental studies on human volunteer subjects.4 A child subject to pica behaviormight ingest enough lead from the soil in the Lake Linden Campground (A), Hubbell Slag (B),Tamarack/Mason Dredge (C), Quincy Smelter (F), or Calumet Lake (G) areas to attain that dose. There is no evidence directly linking exposure to lead to cancer in humans, though somelaboratory animals who ingested lead in their food or water developed cancer of the kidneys. TheU.S. EPA has classified lead as a probable human carcinogen (U.S. EPA Class B2). It is notpossible to evaluate the cancer risk from exposure to lead based on the available information (8). The Hubbell Slag and Quincy Smelter areas are under consideration for future residentialdevelopment (Table 1). Recreational use of the properties is not likely to result in exposures ofhuman health concern.
Benzo(a)pyrene is one of a class of chemicals known as polycyclic aromatic hydrocarbons(PAHs)5. PAHs are ubiquitous products of incomplete combustion. The concentrations of PAHsfound in the soils of the study areas are within the range of concentrations typically found in urbanareas. Benzo(a)pyrene and several other PAHs have been linked to cancer in workers who wereexposed to them on the job and in laboratory animals who had the chemicals applied to the skin. The U.S. EPA has classified benzo(a)pyrene as a probable human carcinogen (U.S. EPA ClassB2). People who spend their lifetime exposed to soil containing the benzo(a)pyrene found in theTamarack/Mason Dredge area might incur a low increased risk of contracting cancer. PAHs insoils tend to bond to organic materials in the soil and are not readily absorbed through the skin(11). The Tamarack/Mason Dredge area is not currently under consideration for residentialdevelopment (Table 1), and recreational use of the property is not likely to result in significantlyincreased risk of contracting cancer.
No one is likely to ingest enough beryllium from the soils within the study areas to experience anynon-cancer adverse health effects. Some laboratory animals who inhaled or ate berylliumcompounds developed lung cancer more often than did animals who were not exposed to themetal. The U.S. EPA has classified beryllium compounds as probable human carcinogens (U.S.EPA Class B2). A person who spends his lifetime around soils containing the berylliumconcentrations found in the study areas would not be likely to ingest enough of the metal to incurany apparent increased risk of contracting cancer (12).
The health effects from exposure to copper depends upon the chemical form the element is in. There is no information available on the form of the copper found in the study areas. From thehistory of the areas, copper is probably present in the soil primarily in its metallic, elemental state,with a thin patina of copper carbonate covering the copper particles. There is little evidencelinking exposure to metallic copper with adverse health effects (13).
Parts of the Lake Linden Campground (A), Tamarack/Mason Dredge (C), Mason Sands (D),Calumet Lake (G), Point Mills (I), and North Entry (J) areas are fenced, according to mapsprovided by the MDEQ. However, the other areas, including the Hubbell Slag (B) and QuincySmelter (F) areas, are not fenced, and the MDEQ reports signs of access to all of the areas they have investigated (4).