title: Recycled water sources influence the bioavailability of copper to earthworms.
abstract: Re-use of wastewaters can overcome shortfalls in irrigation demand and mitigate environmental pollution. However, in an untreated or partially treated state, these water sources can introduce inorganic contaminants, including heavy metals, to soils that are irrigated. In this study, earthworms (Eisenia fetida) have been used to determine copper (Cu) bioavailability in two contrasting soils irrigated with farm dairy, piggery and winery effluents. Soils spiked with varying levels of Cu (0-1,000 mg/kg) were subsequently irrigated with recycled waters and Milli-Q (MQ) water and Cu bioavailability to earthworms determined by mortality and avoidance tests. Earthworms clearly avoided high Cu soils and the effect was more pronounced in the absence than presence of recycled water irrigation. At the highest Cu concentration (1,000 mg/kg), worm mortality was 100% when irrigated with MQ-water; however, when irrigated with recycled waters, mortality decreased by 30%. Accumulation of Cu in earthworms was significantly less in the presence of recycled water and was dependent on CaCl2-extractable free Cu(2+) concentration in the soil. Here, it is evident that organic carbon in recycled waters was effective in decreasing the toxic effects of Cu on earthworms, indicating that the metal-organic complexes decreased Cu bioavailability to earthworms.
authors.affiliation: Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, Adelaide, SA 5095, Australia; Chemical Safety Division, Department of Agro-Food Safety, National Academy of Agricultural Science, Suwon-si, Gyeonggi-do 441-707, Republic of Korea. Electronic address: a.kunhikrishnan@hanmail.net.
authors.forename: Anitha
authors.initials: A
authors.lastname: Kunhikrishnan
authors.forename: Nanthi S
authors.initials: NS
authors.lastname: Bolan
authors.forename: Ravi
authors.initials: R
authors.lastname: Naidu
authors.forename: Won-Il
authors.initials: WI
authors.lastname: Kim
mesh_terms: D000383:Agriculture / Q000379:methods; D000818:Animals; D001682:Biological Availability; D003300:Copper / Q000378:metabolism* / Q000633:toxicity; D009835:Oligochaeta / Q000187:drug effects / Q000378:metabolism*; D059027:Recycling; D012989:Soil Pollutants / Q000378:metabolism* / Q000633:toxicity; D062065:Wastewater
chemical_list: D003300:Copper; D012989:Soil Pollutants; D062065:Wastewater
keywords: Bioavailability; Complexation; Copper; Dissolved organic carbon; Recycled water