Lead in the Environment-Studying the Strong Decline in Germany

In Germany, samples of sewage-sludge ash and samples of common grass near a major roadway were collected over the period 1972 92 and in 1973 and 1992, respectively, and analyzed for concentrations of lead. In the grass samples, Pb concentrations decreased with increasing distance from the roadway, but the decreases were not as dramatic in 1973 as in 1992. The lowest Pb concentrations were found in 1973 and 1992 at a distance of 300 and 50 m, respectively, from the roadway. In the ash samples, the greatest decrease in Pb levels occurred between 1972 and 1974, when the Pb content was halved. Over the period 1972 92, the Pb content in the sludge ash diminished by a factor of 0.12.