With more municipal coal tar sealant bans than any other state in the US, another Minnesota community is moving toward passage of a ban. The real cost of disposing dredged sediment from retention ponds has led the City of Inver Grove Heights to begin the process to pass a ban.
According to an article in the Minneapolis Star Tribune, Inver Grove Heights found that 25% of their tested stormwater ponds (3 out of 12) showed the presence of polycyclic aromatic hydrocarbons (PAH's). The sediment from two of the ponds would have to go to a landfill at a cost of $180,000 to $200,000. The problem is that Inver Grove Heights has 578 stormwater ponds.
"Every city is in the same situation -- it's a huge problem," said White Bear Lake public works director Mark Burch. White Bear Lake was the first Minnesota community to pass a coal tar sealant ban.
It is reasonable to expect these high levels are caused by coal tar sealant pollution. "Data we have collected over the last year indicate that there is a good percentage of these pollutants tied to coal-tar sealants," said Don Berger of the Minnesota Pollution Control Agency. It is estimated that there are over 20,000 stormwater ponds in the Twin Cities area under MS4 permitting, but there are many more private ponds at private facilities and under homeowner association control.
So it seems that industry's solution to the problem of coal tar sealant pollution, stormwater ponds, doesn't really work. It just delays and moves the cost burden to someone else. Time to try something else: complete elimination of this product.