St. Clair ShoresMarch 29, 2013
More sampling expected by EPA
By Kristyne E. Demske
C & G Staff Writer
Officials from the Environmental Protection Agency are back — giving residents an update on the 10 Mile Drain Superfund Site and kicking off another month-and-a-half of field work to investigate how far the contamination may have spread.
Officials from the federal agency were at the St. Clair Shores Public Library for two open house sessions March 25, as well as a public meeting that evening in City Council chambers.
In April, the EPA will be taking up to a dozen soil samples each from yards along Bon Brae Street and the Lange and Revere canal where they have received signed access agreements. The agency will also take up to 50 two-inch cores 20 feet deep from commercial properties near Bon Brae and Harper, and four-foot sediment samples from the Rio Vista and Lakecrest canals.
EPA Remedial Project Manager Colleen Moynihan said they saw in historical aerial photos that, in the 1950s, there was an above-ground “Martin Drain” north of Bon Brae Street with an outfall at Rio Vista canal. The sampling of that canal is “to sort of rule them out to see if there’s contamination there or not,” she said. That canal was eliminated sometime before the 1960s.
The site-wide remedial investigation aims to discover the nature and extent of the contamination of polychlorinated biphenyls (PCBs) found in the 10 Mile Drain storm sewer system in 2001, she said.
“Ultimately, we want to design an ultimate cleanup plan. We designed a field-sampling plan to determine, is there contamination or not in the residents’ backyards?”
The agency will also be investigating the entire 10 Mile Drain system, which contains 250 manholes, to make sure that the contamination isn’t actually outside of the bounds of Bon Brae to 10 Mile Road and Harper Avenue to Jefferson.
Consistently, the investigation has found contamination levels higher near Bon Brae and Harper Avenue that decrease as the pipes move toward Jefferson Avenue. Moynihan said this tells them that the absorbent snares in the 17 weirs placed 2010 on Harper at Bon Brae — and east down Bon Brae toward Lake St. Clair — are catching PCBs before they hit the Lange and Revere streets canal and the lake.
“There is contamination within the system,” she said. “It is entering the system, but we’re trying to grab it out of there as soon as we see it.”
The EPA Mobile Lab will be in the city during the 4-6 weeks of field work beginning in April to help process tests and get results more quickly. Moynihan said they have about 40 yards to sample in the area.
“If there is contamination (in the yards), we’ll extend the sampling,” she said. About half of the property owners contacted have already given the EPA permission to sample in their yard.
After the results are processed and reviewed by the Michigan Department of Environmental Quality and St. Clair Shores officials, it will be about six months before the EPA is back with some more possible answers.
Moynihan said they will be looking at potential cleanup options of the four vaulted manhole locations along the drain where the highest concentration of PCB contamination has been found in the past. A final cleanup of the Lange/Revere canal will likely include dredging, but that won’t happen until the PCB source contamination is stopped.
In the backfill materials of four manhole vaults — at the western intersection of Bon Brae and Harper, at the eastern intersection of Bon Brae and Harper, near the intersection of Bon Brae and E Street, and a little farther east along Bon Brae — the EPA has found PCB concentrations greater than 10,000 parts per million. The greatest concentrations of PCBs are in the sandy backfill material surrounding the manholes.
“The oil is entering through the concrete pipe at these four locations,” said Moynihan.
In prior investigations, the EPA has ruled out the water and sanitary sewer trenches as a “source conduit” for PCB contamination.
Michigan Department of Community Health Toxicologist Christina Bush said nothing has changed regarding the fish advisories for the area yet. It is still not recommended to eat any fish caught in the Lange or Revere canals or carp or catfish caught in any part of Lake St. Clair.
Fish samples were collected five miles north of Lange and Revere and four miles south, close to shore, to see if lake fish are being affected by the contamination. Those results are expected to be included in a new fish advisory to be released by the state later in the spring, she said.
For now, residents can check what is recommended at www.michigan.gov/eatsafefish.
“Fish is a great and healthy choice, but if the contamination is too great, that might mitigate the healthy benefits,” she said. “We are not concerned about touching the fish or touching the water. That is not a typical way for PCBs to get into the body.”
But, she said, the state hopes residents will pay attention to signs posted behind Mike’s Marine, West Marine and where Lange crosses the canal, because there is some evidence that fishing has occurred near where the signs direct anglers not to eat fish caught in those waters.
For continued updates and more information, visit www.epa.gov/region5/cleanup/tenmiledrain.