Leave the source, block the pathway
By MARY ELLEN MacINTYRE Staff Reporter
Sydney - The project to address contaminants at the Sydney tar ponds and coke ovens site is called a cleanup but is it really?
Stabilization and solidification — mixing contaminated sediments or earth with cement powder and slag or gravel and then encapsulating the area with concrete — has been used at a number of so-called Superfund sites in the United States.
It is a technology that has been in use to some degree since the late 1950s. It doesn’t rid the area of the pollution but, if the engineering is right, it appears to contain it.
Some say the $400-million solution announced last Sunday by the provincial and federal governments is the same plan that was proposed over a decade ago.
The CEO of the Sydney Tar Ponds Agency begs to differ.
"Well, it’s the same philosophical approach — we would leave the source but cut off the pathway," said Frank Potter.
The source he refers to is the contamination. The pathway is the ability for the contamination to come into contact with human or animal life.
Although the philosophy is the same as it was in 1996, Mr. Potter says the scope and technology are much more sophisticated and effective.
"In New Bedford, Mass., they are solidifying and stabilizing near the edge of the water, just like in this area," he said.
"They’re binding the contaminants, which makes it impermeable so nothing leaches out."
The Sydney site is twice as large as the New Bedford site but Mr. Potter said that shouldn’t make a difference.
As for freezing and thawing of the concrete cap and the effects of salt water, Mr. Potter said experts agree they shouldn’t be a factor.
"This is a recognized approach to dealing with the problem — it’s not something new," he said.
It comes down to a good understanding of a risk-benefit analysis.
"The risks and costs are more significant if you take the contaminants out."
Alternative technologies were abandoned for a variety of reasons.