Abstract
Antarctica is one of the least anthropogenically-impacted areas of the world. Metal sources to the marine environment include localised activities of research stations and glacial meltwater containing metals of lithogenic origin. In this study, concentrations of nine metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) were examined in three species of benthic invertebrates collected from four locations near Rothera Research Station on the western Antarctic Peninsula: Laternula elliptica (mudclam, filter feeder), Nacella concinna (limpet, grazer) and Odontaster validus (seastar, predator and scavenger). In addition, metals were evaluated in sediments at the same locations. Metal concentrations in different body tissues of invertebrates were equivalent to values recorded in industrialized non-polar sites and were attributed to natural sources including sediment input resulting from glacial erosion of local granodioritic rocks. Anthropogenic activities at Rothera Research Station appeared to have some impact on metal concentrations in the sampled invertebrates, with concentrations of several metals higher in L. elliptica near the runway and aircraft activities, but this was not a trend that was detected in the other species. Sediment analysis from two sites near the station showed lower metal concentrations than the control site 5 km distant and was attributed to differences in bedrock metal content. Differences in metal concentrations between organisms were attributed to feeding mechanisms and habitat, as well as depuration routes. L. elliptica kidneys showed significantly higher concentrations of eight metals, with some an order of magnitude greater than other organs, and the internal structure of O. validus had significantly higher Ni. This study supports previous assessments of N. concinna and L. elliptica as good biomonitors of metal concentrations and suggests O. validus as an additional biomonitor for use in future Antarctic metal monitoring programs.
Highlights
By virtue of its geographic remoteness and short history of human occupation, Antarctica is one of the least anthropogenically polluted regions on Earth
Comparing sediments collected for this study in 2011 with those collected from Hangar Cove in 2006 (Grand, 2006) showed very similar concentrations of most metals except Cr, which increased from 2.9 ± 1.1 mg kg−1 to 11.6 ± 2.4 mg kg−1 and Pb, which increased from 2.4 ± 0.7 mg kg−1 to 5.0 ± 1.1 mg kg−1
O. validus and N. concinna were all confirmed as good examples of biomonitors for trace metal contamination, in support of previous studies (Ahn et al, 2002; Lohan et al, 2001) and showed limited variation in metal concentrations at each site
Summary
By virtue of its geographic remoteness and short history of human occupation, Antarctica is one of the least anthropogenically polluted regions on Earth. Heavy metals within the global environment have been increasing in concentration since the industrial revolution, and it is inevitable that metals are deposited in the Antarctic marine and terrestrial biospheres through atmospheric deposition and precipitation (Calace et al, 2017; Hur et al, 2007; Tuohy et al, 2015). Antarctica contains over 100 active scientific research stations and field camps (COMNAP, 2017) with human activities at some coastal stations having resulted in localised and occasionally severe contamination of terrestrial and marine environments (Aronson et al, 2011; Cabrita et al, 2017; Fryirs et al, 2015; Gröndahl et al, 2009; Kennicutt II et al, 1995). To determine the effects of these activities, an assessment of localised baseline metal concentrations must be established at sites of increased human activity, along with careful ongoing monitoring of metals in the surrounding environment to identify and assess anthropogenic perturbations (Ahn et al, 2002; Bargagli, 2000; Choi et al, 2003; Grotti et al, 2016; Lohan et al, 2001; Sanchez-Hernandez, 2000; Trevizani et al, 2018)
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