THE EFFECT OF STEADY STATE DEPOSITION OF LEAD WHEEL WEIGHTS ON LEAD DISTRIBUTION IN THE ENVIRONMENT

Lead is a dense (11.34g/cm³), easy to work, soft, durable metal that has long been the preferred metal to balance wheels on cars and light trucks. A good number of events can cause the lead wheel weights to be released onto roads and berms. These events include sudden stops, bumps, hitting curbs and potholes, and auto accidents. While on the road, lead wheel weights are broken, flattened, and ground into smaller and smaller particles. These particles are mixed into roadside soil, washed into drainage ditches and streams, and ground into lead dust. Eh-pH diagrams of lead indicate that under both low and high pH conditions, that lead is soluble in surface and groundwater.

Our research deals with the fate of lead wheel weights in the environment and the most efficient methods to remove lead wheel weights from the environment. Based on methods developed by Root (2000) we have been experimenting on the most efficient method for manual removal of lead wheel weights from roadways, sidewalks, berms and yards near busy urban streets. Training and motivation of volunteers are required to remove lead wheel weights trapped between the curb and the road. Several large finds of lead wheel weights were collected by students after they became aware of the authors efforts to remove lead from roads. For example, one student in one hour found 100 lead wheel weights (2,845 g) along one mile of sidewalk in Whitesburg, Georgia. Four months later when much of the road was repaved only nine (194 g) wheel weights were found. Two years later when Whitesburg was revisited 35 lead wheel weights (939g) were collected and one iron wheel weight was found. Each time we have collected from an area there was always a range of degrees of breakdown of the weights – from weights that were untouched to those that were broken into small thin flakes. After our collection of wheel weights from a road, when we return after weeks or months there are abundant new deposits of wheel weights in various stages of breakage.