BAY CITY AIRPORT
BAY CITY, BAY COUNTY, MICHIGAN
The Bay City government has proposed to develop a boat launching ramp on the BCA property(1). The individuals with the most exposure to the environmental media on the property would beattendants working there, if any. People using the boat launch would most likely spend shortperiods of time on the property and visit it only occasionally. To determine whether furthertoxicological evaluation is necessary, the concentrations of chemicals found on the property willbe compared with the MDEQ Generic Clean-up Criteria for Industrial or Commercial Use (3).
During the BFRA, MDEQ staff collected 25 samples of surface soil from the BCA property, in asampling gridwork drawn across the entire parcel area. None of the samples contained anychemical at a concentration above the MDEQ Generic Clean-up Criteria for Industrial orCommercial Use (Table 1) (2, 3).
MDEQ staff also collected 13 samples of subsurface soil from the BCA property, from locationson a similar gridwork across the entire parcel. Again, none of the samples contained any chemicalat a concentration above the MDEQ Generic Industrial/Commercial Criteria (Table 2) (2, 3).
In 1988, the Michigan Department of Natural Resources (MDNR)1 Surface Water QualityDivision collected sediment samples from the Saginaw River, from the city of Saginaw (south andupstream of Bay City) to the mouth (north of Bay City), and from Saginaw Bay, and analyzed thesamples for polychlorinated biphenyls (PCBs). A sample collected from the main channel of theriver near the BCA property contained 0.050 parts per million (ppm) PCBs (5).
During the BFRA, MDEQ staff collected 12 samples of sediment from water bodies adjacent tothe BCA property, four each from the Saginaw River just offshore, the creek on the north side ofthe property, and the canal on the east side. None of these samples contained any chemicals atconcentrations above the MDEQ Generic Industrial/Commercial Criteria or any PCBs above thedetection limit (Table 3) (2, 3).
The Saginaw River has had a history of PCB contamination in the sediment, surface water, andbiota, because of industrial activities in the River's basin (5, 6, 7). The MDCH has issued anadvisory that people should not consume any carp or catfish taken from the Saginaw orTittabawassee Rivers, and that they should limit their consumption of fish of any species takenfrom either river, due to contamination with PCBs and dioxins (8). The PCB concentrations inSaginaw River sediment near the BCA property would not be considered to pose a health threatfrom direct contact even if the sediments were on shore, where contact might be much morefrequent.2 A person using the river for recreation is not likely to drink enough water from theSaginaw River to incur any significant increased cancer risk from the PCBs in the water. NoPCBs were found in any medium on the BCA property sampled during the BFRA (2).
During the BFRA, MDEQ staff collected unfiltered groundwater samples from 5 temporarymonitoring wells on the BCA property, four located along the Saginaw River bank on the westside of the property and one in the center of the property. At least one of these samples containedantimony, beryllium, chromium, cobalt, lead, manganese, methylene chloride, nickel, or vanadiumat a concentration above the MDEQ/U.S. EPA health-based drinking water standards (Table 4)(2, 4). The highest concentrations of the above-named metals were found in the sample from thecenter of the property. All five samples contained 5 parts per billion (ppb) methylene chloride,equal to the MDEQ/U.S. EPA drinking water standard. The chemical is a common laboratorycontaminant. None of the chemicals is present in the water at a concentration that would pose ahealth hazard by direct contact or by inhalation after volatilization to indoor air during householduse of the water (9). There is no known current use of the groundwater at the property. Theavailable information does not identify the direction of the groundwater flow at the property. However, because the property borders on the Saginaw River, it is most likely that thegroundwater flows directly into the river. There are no wells between the property and the river.
The BCA property itself poses no physical hazards. Drums and abandoned storage tanks havebeen seen in the wooded area north of the property, which is privately owned. There is no fencebetween the BCA property and the wooded area. Vehicle access to the BCA property is via atwo-track path across the wooded area north to 41st Street, at which point there's a gated fence. However, there is a foot path into the wooded area from the east, which crosses the canal on amakeshift bridge.