Critical metal concentrations for forest soil invertebrates

Based on a review of the literature on metal effects on forest soil invertebrates 100 to 200 mg Pb, < 100 mg Cu, < 500 mg Zn and 10 to 50 mg Cd kg^?1 soil or litter are suggested as maximum allowable metal concentrations that will cause no adverse effects. These critical levels, emphasizing effects on abundance, diversity and life history parameters, are considered conservative and tentative, since few of the surveys they rely on were designed for critical level assessment; especially with respect to long-term consequences on decomposition and nutrient regeneration. The variation between animal species and individuals in susceptibility to metals due to differences in uptake, storage and tolerance are addressed.