Changes in microbial properties associated with long-term arsenic and DDT contaminated soils at disused cattle dip sites

This work examined the effect of long-term arsenic (As) and DDT contamination on soil microbial properties at 11 cattle dip sites in northern New South Wales, Australia. Total As in the surface (0–10 cm) soils from these sites ranged from 34 to 2941 mg As kg−1 soil and hexane-extractable DDT concentrations ranged between 2.9 and 7673 mg DDT kg−1 soil. The concentrations of water and oxalate-extractable As were positively correlated with total As. Oxalate-extractable As was more strongly correlated (r2=0.87) with total As than water-extractable As (r2=0.34). A weak positive relationship was observed between the level of nutrient (organic carbon and nitrogen) and microbial biomass C (r2=0.61 and 0.45, respectively). There was a highly significant difference between the microbial properties of polluted and unpolluted sites (