TY - JOUR
T1 - Bioavailability and toxicity of zinc from contaminated freshwater sediments: Linking exposure-dose-response relationships of the freshwater bivalve Hyridella australis to zinc-spiked sediments
AU - Marasinghe Wadige, Chamani
AU - TAYLOR, Anne
AU - MAHER, Bill
PY - 2014
Y1 - 2014
N2 - To evaluate the use of the freshwater bivalve Hyridella australis as a potential biomonitor for zinc con-tamination in freshwater sediments, the bioavailability and toxicity of zinc contaminated sediments (low44 ± 5, medium 526 ± 41, high 961 ± 38 g/g dry mass) were investigated in laboratory microcosms for28 days by examining H. australis exposure-dose–response relationships. Zinc concentrations in sedi-ments and surface waters were measured as zinc exposure. Zinc in whole organism soft body tissuesand five individual tissues were measured as organism zinc dose. Sub-cellular localisation of zinc in hep-atopancreas tissues was investigated to further understand the zinc handling strategies and tolerance ofH. australis. Total antioxidant capacity, lipid peroxidation and lysosomal membrane stability were measured in hepatopancreas tissues as zinc induced biomarker responses. Accumulated zinc concentrations in whole body tissues of H. australis reflected the zinc exposure and exhibited exposure dependent zincaccumulation at day 28. Gills accumulated significantly higher zinc concentrations than other tissues,however, no significant differences in zinc accumulation between treatments were detected for any of the individual tissues analysed. Analysis of individual tissue zinc concentrations, therefore, may not offer any advantages for monitoring bioavailable zinc in freshwater environments with this organism. Relationships between tissue zinc and calcium concentration suggest accumulation of zinc by H. australis may have occurred as an analogue of calcium which is a major constituent in shell and granules of unionid bivalves. A high percentage of accumulated zinc in the hepatopancreas tissues was detoxified and stored in metallothionein like proteins and metal rich granules. Of the zinc accumulated in the biologicallyactive metal pool, 59–70% was stored in the lysosome + microsome fraction. At the concentrations tested,increasing zinc exposure resulted in decreasing total antioxidant capacity and measurable increases in the sublethal effects, lipid peroxidation and lysosomal membrane destabilisation, were observed. Based on exposure-dose analysis, H. australis partially regulates zinc uptake and weakly exhibits bioavailability of zinc in freshwater environments, however, exposure-response analysis shows zinc induced toxicological effects, suggesting the potential of this organism as a biomonitor for zinc in heavily contaminated freshwater environments.
AB - To evaluate the use of the freshwater bivalve Hyridella australis as a potential biomonitor for zinc con-tamination in freshwater sediments, the bioavailability and toxicity of zinc contaminated sediments (low44 ± 5, medium 526 ± 41, high 961 ± 38 g/g dry mass) were investigated in laboratory microcosms for28 days by examining H. australis exposure-dose–response relationships. Zinc concentrations in sedi-ments and surface waters were measured as zinc exposure. Zinc in whole organism soft body tissuesand five individual tissues were measured as organism zinc dose. Sub-cellular localisation of zinc in hep-atopancreas tissues was investigated to further understand the zinc handling strategies and tolerance ofH. australis. Total antioxidant capacity, lipid peroxidation and lysosomal membrane stability were measured in hepatopancreas tissues as zinc induced biomarker responses. Accumulated zinc concentrations in whole body tissues of H. australis reflected the zinc exposure and exhibited exposure dependent zincaccumulation at day 28. Gills accumulated significantly higher zinc concentrations than other tissues,however, no significant differences in zinc accumulation between treatments were detected for any of the individual tissues analysed. Analysis of individual tissue zinc concentrations, therefore, may not offer any advantages for monitoring bioavailable zinc in freshwater environments with this organism. Relationships between tissue zinc and calcium concentration suggest accumulation of zinc by H. australis may have occurred as an analogue of calcium which is a major constituent in shell and granules of unionid bivalves. A high percentage of accumulated zinc in the hepatopancreas tissues was detoxified and stored in metallothionein like proteins and metal rich granules. Of the zinc accumulated in the biologicallyactive metal pool, 59–70% was stored in the lysosome + microsome fraction. At the concentrations tested,increasing zinc exposure resulted in decreasing total antioxidant capacity and measurable increases in the sublethal effects, lipid peroxidation and lysosomal membrane destabilisation, were observed. Based on exposure-dose analysis, H. australis partially regulates zinc uptake and weakly exhibits bioavailability of zinc in freshwater environments, however, exposure-response analysis shows zinc induced toxicological effects, suggesting the potential of this organism as a biomonitor for zinc in heavily contaminated freshwater environments.
KW - Biologically active zinc
KW - Biologically detoxified zinc
KW - Biomarkers
KW - Freshwater bivalve
KW - Oxidative stress
KW - Sub-cellular partitioning
U2 - 10.1016/j.aquatox.2014.08.012
DO - 10.1016/j.aquatox.2014.08.012
M3 - Article
C2 - 25238458
VL - 156
SP - 179
EP - 190
JO - Acquayic Toxicology
JF - Acquayic Toxicology
SN - 0166-445X
ER -