Biological and toxicological aspects of smelter waste reclamation using biosolids

摘要

The goal of the studies was to assess effectiveness of biosolids treatment of Zn/Pb smelter wastes to reduce metals dispersion in the environment and ecosystem functioning as measured by biochemical indicators to reduce metals. A field experiment was conducted on a barren smelter waste deposit in Piekary Slaskie, Poland with two separate fields- established on Welz and Doerschel wastes. The Welz field was treated by application of municipal biosolids at the rate 300 dry tons per hectare (dry matter basis) combined with the incorporation of lime in an oxide and carbonate form. Treatment of more toxic Doerschel waste involved use of a 30cm by- product lime cap which was lined over the top of the waste surface. This capping operation was followed by incorporation of biosolids at a rate of 300t·ha<'-1>. Both sites were sampled in a grid in subsequent years. The treatments used allowed the establishment of plant cover over more than 80%-90% percent of each tested area. Assessment of metal solubility in subsequent years showed substantial decreases of Zn, Cd and Pb solubility as measured by water extraction. The spatial structure of enzyme activities was highly correlated to the distribution of organic matter. Feeding trial with young cattle indicated that crop contamination with Pb, Cd and Zn by natural uptake of these elements had significantly different effects on their transfer to animal tissues than from feedstuff amended with metal salts. Forage crops grown on Zn, Cd and Pb contaminated sites reclaimed using lime and biosolids do not pose identified risk for wildlife.