[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2012/03/EW-04-04-12-Lead.mp3|titles=EW 04-04-12 Lead]
One of the biggest success stories of the environmental movement was getting the lead out of gasoline. Tetra-ethyl lead was first put into gasoline in the 1920s to improve engine performance and eliminate “knock.” Of course, it was necessary to get the lead out of the engine, so potassium bromide was added to the gas as well, and the lead was emitted as a lead bromide aerosol. Most of this fell beside the road.
When toxicologists began to notice elevated lead levels in blood samples from urban children, they were worried. Lead poisoning has a long history, and the levels found in urban youth were high enough to impair normal brain development. Was the increased lead exposure coming from the aerosols of leaded gasoline or from old buildings that contained leaded paints?
When leaded gasoline and paints were outlawed, the blood-lead levels of urban children declined. And it was determined that at least some of the lead was from gasoline. Without leaded gas, the lead content of rain falling downwind of urban areas also declined. Our environment is a better place without this potent neurotoxin.
“The most important thing for folks to understand is that lead is still a problem.”
In recent studies, Kirsten Schwarz, a post doctoral research associate at the University of California-Davis, has shown that the past use of lead is still present in the residential soils of Baltimore…
“We often see spikes of lead near sources, for example buildings and roads. Our research in Baltimore has shown that lead in soil is correlated with three variables: building age, distance to buildings, and distance to roads.”
Yes, the story of lead shows the success of environmental regulation, but it also shows how the residual effects of past practices take a long time to clean up.
Full interview with Kirsten Schwarz, a post doctoral research associate at the University of California-Davis…[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2012/04/Schwarz_edited_web.mp3|titles=Schwarz_edited_web]
Photo, taken on June 27, 2011 using a Canon PowerShot SD400, courtesy of ClintJCL via Flickr.