It's funny how sometimes seemingly unrelated, random things cross your desk and it makes you pause at the irony of it. Today was one of those days.

The first was a government issued request for bids to manage a publicly-owned parking lot in Milwaukee.  While not unusual, the bid called for the use of coal tar sealants on the parking lot. Unfortunately governments, schools, big box stores and churches still specify spreading this nasty stuff (a la a 1965 spec) on their on property, but again it happens all the time.

Interestingly, this afternoon an email passed my desk about a new study by the USGS that looked at the concentrations of pollutants coming from urban runoff in....Milwaukee, Wisconsin and nearby Madison.


Geometric mean concentrations of total PAHs
They looked at the concentrations of polycyclic aromatic hydrocarbons (PAH) at 4 different locations: stormwater bed sediment (the sediment that settles out in a storm sewer between rains), stormwater, street dirt, and streambed.  Not too surprising was the fact that the highest mean levels were what settles out in a stormsewer pipe, but all four locations were at or exceeding the probable effects concentration for PAHs of 23,000 ng/g or 23 ppm.  They also found that the most abundant source of the PAHs were coal tar based pavement sealcoat.

So the report shows that coal tar sealants are the main source of environmentally-affected contamination, not in some far away city, but in your own town; yet the County still specifies it.  Isn't this kind of embarrassing?

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Jamie Brown said... April 18, 2013 at 9:08 AM

In my home town of South Bend IN I approached an engineering firm with these same concerns. This firm writes the specs. for schools and other government projects. If there is seal coating to be preformed it always specifies coal tar based. Some times it goes as far as to ask for a specific name brand. Once this has been brought to someone attention and nothing is done, your left wondering why has nothing been done?

 
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