Assessing the Risk of Metals and Their Mixtures in the Antarctic Nearshore Marine Environment with Diffusive Gradients in Thin-Films

Robust environmental assessments and contaminant monitoring in Antarctic near-shore marine environments need new techniques to overcome challenges presented by a highly dynamic environment. This study outlines an approach for contaminant monitoring and risk assessment in Antarctic marine conditions using diffusive gradients in thin-films (DGT) coupled to regionally specific ecotoxicology data and environmental quality standards. This is demonstrated in a field study where DGT samplers were deployed in the near-shore marine environment of East Antarctica around the operational Casey station and the abandoned Wilkes station to measure the time-averaged biologically available fraction of metal contaminants. The incorporation of DGT-labile concentrations to reference toxicity mixture models for three Antarctic organisms predicted low toxic effects (<5% effect to the growth or development of each organism). The comparison of metal concentrations to the Australian and New Zealand default water quality guideline values (WQGVs) showed no marine site exceeding the WQGVs for 95% species protection. However, all sites exceeded the 99% WQGVs due to copper concentrations that are likely of geogenic origin (i.e., not from anthropogenic sources). This study provides evidence supporting the use of the DGT technique to monitor contaminants and assess their environmental risk in the near-shore marine environment of Antarctica.