title: Arsenic bio-accessibility and bioaccumulation in aged pesticide contaminated soils: A multiline investigation to understand environmental risk.
abstract: Bio-accessibility and bioavailability of arsenic (As) in historically As-contaminated soils (cattle tick pesticide), and pristine soils were assessed using 3 different approaches. These approaches included human bio-accessibility using an extraction test replicating gastric conditions (in vitro physiologically-based extraction test); an operationally defined bioaccessibility extraction test - 1.0M HCl extraction; and a live organism bioaccumulation test using earthworms. A sequential extraction procedure revealed the soil As-pool that controls bio-accessibility and bioaccumulation of As. Findings show that As is strongly bound to historically contaminated soil with a lower degree of As bio-accessibility (<15%) and bioaccumulation (<9%) compared with freshly contaminated soil. Key to these lower degrees of bio-accessibility and bioaccumulation is the greater fraction of As associated with crystalline Fe/Al oxy-hydroxide and residual phases. The high bio-accessibility and bioaccumulation of freshly sorbed As in pristine soils were from the exchangeable and specifically sorbed As fractions. Arsenic bioaccumulation in earthworms correlates strongly with both the human bio-accessible, and the operationally defined bioavailable fractions. Hence, results suggest that indirect As bioavailability measures, such as accumulation by earthworm, can be used as complementary lines of evidence to reinforce site-wide trends in the bio-accessibility using in vitro physiologically-based extractions and/or operationally defined extraction test. Such detailed knowledge is useful for successful reclamation and management of the As contaminated soils.
authors.affiliation: School of Environment Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia; Marine Ecology Research Centre, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia.
authors.forename: M S
authors.initials: MS
authors.lastname: Rahman
authors.affiliation: School of Environment Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia; Marine Ecology Research Centre, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: Reichelt-Brushet
authors.affiliation: School of Environment Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia; Marine Ecology Research Centre, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia. Electronic address: malcolm.clark@scu.edu.au.
authors.forename: M W
authors.initials: MW
authors.lastname: Clark
authors.affiliation: Southern Cross Plant Science, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Farzana
authors.affiliation: School of Environment Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia; Marine Ecology Research Centre, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia.
authors.forename: L H
authors.initials: LH
authors.lastname: Yee
mesh_terms: D000818:Animals; D001151:Arsenic / Q000032:analysis*; D001682:Biological Availability; D004787:Environmental Pollution; D006801:Humans; D009835:Oligochaeta; D010575:Pesticides / Q000032:analysis*; D012987:Soil; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D010575:Pesticides; D012987:Soil; D012989:Soil Pollutants; D001151:Arsenic
keywords: Contaminated soils; Earthworms; Holistic approach; Physiologically based; Risk assessment; Sequential extractions