title: Assessment of metal toxicity and bioavailability in metallophyte leaf litters and metalliferous soils using Eisenia fetida in a microcosm study.
abstract: The leaf litters of tree species, Acacia pycnantha (Ap) and Eucalyptus camaldulensis (Ec), predominantly growing at an abandoned copper (Cu) mine and mine soils including controls, were assessed for determining the metal toxicity and bioavailability using earthworm species Eisenia fetida, in a microcosm. Significant reduction in body weight as well as mortality were observed when the worms were introduced into mine soil or its combination with mine Ap litter. Virtually, there were no juveniles when the worms were fed on substratum that contained mine soil or mine leaf litter. The extent of bioaccumulation was dependent on water-soluble fraction of a metal in soil. The accumulation of cadmium, lead and copper in worm tissue was significantly more in treatments that received mine soil with or without mine leaf litter. However, the tissue concentration of zinc did not differ much in earthworms irrespective of its exposure to control or contaminated samples. Mine leaf litter from Ec, a known Cu hyperaccumulator, was more hospitable to earthworm survival and juvenile than that of Ap litter. Validation of the data on bioaccumulation of metals indicated that the mine leaf litter significantly contributed to metal bioavailability. However, it was primarily the metal concentration in mine soil that was responsible for earthworm toxicity and bioavailability. Our data also indicate that detrivores like earthworm is greatly responsible for heavy metal transfer from mines into the ecosystem.
authors.affiliation: Future Industries Institute, Division of Information Technology Engineering and the Environment, University of South Australia, SA 5095 Australia. Electronic address: ramkrishna.nirola@mymail.unisa.edu.au.
authors.forename: Ramkrishna
authors.initials: R
authors.lastname: Nirola
authors.affiliation: Global Centre for Environmental Research (GCER), University of Newcastle, ATC Building, Callaghan, Newcastle, NSW 2308, Australia.
authors.forename: Mallavarapu
authors.initials: M
authors.lastname: Megharaj
authors.affiliation: Formerly Professor of Microbiology & Dean, Faculty of Life Sciences, Sri Krishnadevaraya University, Anantapur 515055, India.
authors.forename: Kadiyala
authors.initials: K
authors.lastname: Venkateswarlu
authors.affiliation: School of Natural and Built Environments, Division of Information Technology Engineering and the Environment, University of South Australia, SA 5095, Australia.
authors.forename: Rupak
authors.initials: R
authors.lastname: Aryal
authors.affiliation: Future Industries Institute, Division of Information Technology Engineering and the Environment, University of South Australia, SA 5095 Australia.
authors.forename: Ray
authors.initials: R
authors.lastname: Correll
authors.affiliation: Global Centre for Environmental Research (GCER), University of Newcastle, ATC Building, Callaghan, Newcastle, NSW 2308, Australia.
authors.forename: Ravi
authors.initials: R
authors.lastname: Naidu
mesh_terms: D000045:Acacia / Q000737:chemistry; D000818:Animals; D001682:Biological Availability; D002104:Cadmium / Q000493:pharmacokinetics / Q000633:toxicity; D003300:Copper / Q000493:pharmacokinetics / Q000633:toxicity; D004784:Environmental Monitoring; D005052:Eucalyptus / Q000737:chemistry; D007854:Lead / Q000493:pharmacokinetics / Q000633:toxicity; D009835:Oligochaeta / Q000187:drug effects* / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry; D015203:Reproducibility of Results; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000493:pharmacokinetics / Q000633:toxicity*; D014197:Trees / Q000737:chemistry; D015032:Zinc / Q000493:pharmacokinetics / Q000633:toxicity
chemical_list: D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium; D007854:Lead; D003300:Copper; D015032:Zinc
keywords: Bioavailability; Earthworm; Food chain; Leaf litter; Metals; Phytoaccumulation