Activity of the microbial decomposer community in metal-contaminated roadside soils

1. Rates of resource decomposition were measured in SW London roadside soils of high and low-metal concentrations to determine whether metal contamination from traffic had affected the activity of the soil microbial community. 2. Cellulose-strip degradation studies demonstrated that total soil metal concentrations per se were not associated with any negative effect on the rate of decomposition of a simple and uncontaminated resource. 3. Basal respiration per gram of metal-contaminated kerbside soil was higher than that of less contaminated soil at a distance from the road. 4. Litter-bag studies and soil respiration measurements based on high and low metal-contaminated roadside soil and litter additions revealed that metal contamination of roadside plant litter was associated with significant reductions in decomposition rates. 5. Rate of litter decomposition, however, was not affected by increases in soil metal concentrations with proximity to the road.