title: Influence of arsenic co-contamination on DDT breakdown and microbial activity.
abstract: The impacts of arsenic co-contamination on the natural breakdown of 1,1,l1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) in soil are investigated in a study of 12 former cattle dip sites located in northeastern NSW, Australia. This study examines the relationship between the intrinsic breakdown of DDT to 1,1 -dichloro-2,2-bis(4-chlorophenyl)ethane (DDD) and 1,l-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE), and the impacts of arsenic co-contamination on this breakdown. Between-site analysis demonstrated that arsenic at 2000 mg/kg gave a 50% reduction in the concentration of DDD compared to background arsenic of 5 mg/kg.Within-site analysis also showed the ratio of DDT:DDD increased in soils as arsenic concentrations increased. This within-site trend was also apparent with the DDT:DDE ratio, suggesting inhibition of DDT breakdown by arsenic co-contamination. Microbial activity was inhibited as residues of total DDTs and arsenic increased. Hence arsenic co-contamination and high concentrations of DDT in soil may result in an increased persistence of DDT in the environment studied.
authors.affiliation: Environmental Centre of Excellence, NSW Agriculture, Bruxner Highway, Wollongbar NSW 2477, Australia. lukas.van.zwieten@agric.nsw.gov.au
authors.forename: Lukas
authors.initials: L
authors.lastname: Van Zwieten
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Ayres
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Morris
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D001151:Arsenic / Q000737:chemistry*; D001673:Biodegradation, Environmental; D002417:Cattle; D003634:DDT / Q000737:chemistry*; D003633:Dichlorodiphenyl Dichloroethylene / Q000737:chemistry / Q000378:metabolism; D003632:Dichlorodiphenyldichloroethane / Q000737:chemistry / Q000378:metabolism; D007306:Insecticides / Q000737:chemistry*; D008828:Microbiological Techniques; D009517:New South Wales; D012988:Soil Microbiology; D012989:Soil Pollutants; D013983:Tick Control
chemical_list: D007306:Insecticides; D012989:Soil Pollutants; D003633:Dichlorodiphenyl Dichloroethylene; D003634:DDT; D001151:Arsenic; D003632:Dichlorodiphenyldichloroethane