Lead in various chemical pools in soil depth profiles on two shooting ranges of different age

We investigated the distribution of pellet-derived lead (Pb) in various chemical pools within soil depth profiles in a new and an old clay pigeon shooting range to assess its tendency for mobility. The results showed that the pellets weathered slowly: about 10% of metallic Pb had been released over 16-37 years. Nevertheless, the resulting Pb concentrations in the soil largely exceeded the upper guideline value defined as contaminated on grounds of ecological risk. The operational fractionation analysis produced a useful, although tentative, insight into the environmental fate of Pb. In the acid forest soil of the ranges studied, organic matter seemed to act as a primary sink for Pb but became a mobile carrier with increasing Pb load. Generally, the residual fraction (including oxide-bound Pb) predominated in the mineral soil layers. The estimated average migration rate was roughly 2-3 mm a year. The abnormally high Pb concentrations in the control area outside the shooting ranges suggest that environmental risks are not limited only to pellet-shot-fall areas.