A state pollution cleanup team says it’s too soon to draw conclusions about what caused a spike in contamination this summer in three private wells south of Shoreham Yards.
The public health risk is negligible because none of the wells is used for drinking, officials said. A citizen advisory committee is asking the state to plug the wells anyway, citing the slight risk of airborne exposure to the contaminants.
“Why take the risk? If the state told these businesses to just stop using the wells, then we’d have no questions about it,” said Gayle Bonneville, chair of the Shoreham Area Advisory Committee, a Northeast residents group that monitors the railroad yard area.
The water samples were collected May 30 from wells at three Northeast businesses: Jax Cafe (the well water is used to fill an artificial stream on its patio) and manufacturers Hard Chrome and Universal Plating (the well water is used in the manufacturing processes).
A chemical used in wood treatment, pentachlorophenol, or PCP, was detected in the Jax Cafe and Hard Chrome wells in May, at the highest levels since the state started monitoring them in 1998. A well at Universal Plating had a 70 percent increase in PCP compared to testing six months earlier.
“We had some of the higher levels we’ve had in these wells,” said Jim Seaberg, a state hydrologist who conducts the monitoring. “However, they’re within the range we would expect from these wells.”
The contamination traces back to an area in Shoreham Yards where Cedar Services, a wood treating company, once leased space. It’s a grassy area just southeast of University Avenue and St. Anthony Boulevard. A truck accident in 1961 soaked the soil there with 30,000 gallons of a PCP-based wood treatment, according to the Minnesota Department of Health (MDH).
Canadian Pacific, a railroad company, now owns the Shoreham Yards property and is working with the Minnesota Pollution Control Agency (MPCA) and the Minnesota Department of Agriculture on the pollution cleanup.
In 1989, the Minnesota Pollution Control Agency discovered the PCP contamination and it was declared a state Superfund site the same year. (Superfund designation requires the property owners and those responsible for the pollution to cooperate with the state in cleaning it up. If the cooperative process breaks down, the state can unilaterally clean up the property and sue those responsible for the pollution to recover the costs.)
A cleanup is underway. The polluted groundwater extends south more than a mile and a half from the rail yard, to at least Logan Park.
The groundwater’s use is thought to be minimal. The city’s drinking water comes from an intake on the Mississippi River upstream from the yard, and the river is not known to interact with the contaminated aquifer. The few private wells existing in Northeast have limited uses. Jax Cafe only uses its well to fill the patio stream. Hard Chrome uses its for rinse water and cooling, and Universal Plating uses the water for cooling only during the summer.
“It doesn’t come in contact with humans at all, so I’m not overly concerned about it,” said Roger Fischer, vice president of Universal Plating. The company only uses the well water for processing. A representative of Jax Cafe or Hard Chrome could not be reached for comment late last week.
An MDH report last year rated the risk of exposure from the the PCP contamination very slight. The chemical is a probable carcinogen that’s also associated with damage to the liver, kidneys, blood and nervous system. It can cause sever fevers as the bodies tries to metabolize it.
The chemical is volatile, which means it can vaporize into the air from other sources. Some PCP could vaporize when contaminated water is exposed to air, but the amounts are not significant, the report says.
And the public is exposed to PCP from other sources. The report estimates that nationwide, 760,000 pounds of PCP are released into the air each year from treated wood products such as utility poles, fence posts and railroad ties.
Starting last year, a pump-and-treat system has been removing water from the ground beneath the Cedar Services site. The water is treated elsewhere and the aquifer is being naturally recharged.
Why would the contamination levels increase this year, after the cleanup is underway? State officials aren’t sure, but they do have some ideas.
Seasonal use of wells can cause pollution plumes to shift during a year, Seaberg said. Periods of high demand can capture part of a plume and tug it into different areas. The result can be fluctuation from season to season that evens out over the long run.
A large soil excavation at the site last year might also be to blame for a shift in the contaminants, Seaberg said.
“In some cases it’s like taking a tarp off a sandbox, and all of a sudden the rain can get in and flush things down,” Seaberg said.
And the measurements were still in the ballpark of what had been found at the wells during previous testing. They might be statistical outliers. More testing will help determine if that’s the case.
A second pump will be added this fall to the Cedar Services site that will increase the capacity to clean water below the site. The results of a Sept. 19 sampling are expected in early November.
“We all want to see those levels go down,” Seaberg said. “It may just be that we have to wait and take a little more time for us to see the results of our work.”