[Greenbuilding] Toxic Materials in Roof Runoff

[Erin Rasmussen]

I was at a stormwater conference.  I could have shared the studies that also
look at Copper and Zinc from cars, but it's the green building list.... so I
assumed you would prefer the one about roofs.   

Copper and Zinc from roofs comes up quite a bit in stormwater run-off, and
the allowed limits here in the US have dropped quite a bit especially for
industrial permit holders.  In this context, understanding the contribution
to run-off from the roof material becomes more important,  especially for
businesses that have to cope with levels of Zinc flowing off their roofs at
levels that exceed the maximum levels.  Washington State Dept of Ecology has
several studies looking at sources of metal toxins, and also ambient
airborne toxics.  

Part of the problem may be that fairly obvious point that metal dust from
cars doesn't stay on cars or roads, it can also become airborne and join a
variety of other airborne contaminants that stormwater managers, business
owners and others have to cope with. So the problem for city managers
becomes one of trying to determine the most effective methods of control. (I
just saw some really good statistical analysis of this from the city of
Tacoma, if anyone cares). 

And you know, it's not just the folks in the US that worry about metals and
other pollutants in water.... 

 - Erin