DDT levels in Elmira's Canagagigue Creek much higher than previously thought
Report presented to Woolwich council Tuesday night
Levels of the pesticide DDT in the Canagagigue Creek in Elmira south of the Chemtura chemical plant are much higher than previously thought, according to testing done this summer on behalf of a volunteer citizen committee.
The Chemtura Public Advisory Committee (CPAC) retained an environmental engineering firm to do tests on the creek downstream from the Chemtura site. CPAC members believe Chemtura's existing treatment system and pump aren't enough to control contaminant leakage from the site into the creek.
"We didn't know quite what to expect. We did know there had been high levels in the past," said Graham Chevreau, a member of the Chemtura Public Advisory Committee and a chartered chemist. One spot tested just south of the Chemtura site found DDT levels were 2900 times higher than Ontario Ministry of the Environment maximum allowable concentration standards.
"It was a surprise to us that it was that high.It wasn't a surprise to us that we were seeing contamination off site," said Chevreau. "A site of this seriousness needs to have a comprehensive sampling and analysis of the off site impact."
Agent Orange and DDT
Uniroyal Chemical, which became Crompton Chemical in 2001 and then Chemtura in 2006, manufactured DDT at the site from 1945 to 1948. The company used two gravel pits, GP-1 and GP-2, to collect and dispose of seepage and storm water contaminated with DDT, according to CPAC.
In the 1960s, Uniroyal became one of seven companies to manufacture Agent Orange for the U.S. military.It was a toxic herbicide used to defoliate jungles during the Vietnam War. Waste from Agent Orange production, containing dioxins, was dumped into the gravel pits according to the committee.
"In two of the samples, and those are the ones that are very close to the south end of the site, the gravel pits, those are the ones where we saw the elevated levels and one that [had a] particularly elevated level, the one that was 20,800 parts per billion," said Chevreau.
The chemical NDMA leaked into Elmira's groundwater and contaminated it in 1989, forcing the township to close wells and construct a pipeline from Waterloo to bring clean water into town.
Push for resolution
CPAC is pushing for Woolwich Township to pass a resolution to ask the province to do a comprehensive study and cleanup of the site, and to take remedial actions to stop further contamination.
"Chemtura is keenly aware of the presence of contaminants in the Canagagigue Creek to the south of our
property," wrote company representative Jeff Merriman in an email to Woolwich township council. The email and other documents from the company will be presented at the council meeting Tuesday night.
However, according to Merriman, Chemtura doesn't believe the gravel pits are a source of contamination for the creek.
"In the mid 1990's, we determined conclusively that these contaminants are not transported by groundwater due to their hydrophobic properties, but rather by erosion of on-Site contaminated soils with deposition as sediment further downstream in the Creek environment. CPAC seems to have completely missed this point.," wrote Merriman.
Latest round of tests
It's not the first time testing has revealed higher than allowable levels of DDT and dioxins south of the site. Testing by a consultant for Chemtura in 2011 revealed high levels of dioxins and DDT around the gravel pit area, levels higher than "human health risk-based cleanup criteria" according to CPAC.
Downstream creek tests by the Ministry of the Environment in 2012 and 2013 reveal concentrations of DDT between 700 and 1700 times higher than maximum allowable concentrations.