Is Glacial Meltwater a Secondary Source of Legacy Contaminants to Arctic Coastal Food Webs?

Abstract

Climate change-driven increases in air and sea temperatures are rapidly thawing the Arctic cryosphere with potential for remobilization and accumulation of legacy persistent organic pollutants (POPs) in adjacent coastal food webs. Here, we present concentrations of selected POPs in zooplankton (spatially and seasonally), as well as zoobenthos and sculpin (spatially) from Isfjorden, Svalbard. Herbivorous zooplankton contaminant concentrations were highest in May [e.g., ∑polychlorinated biphenyls ( 8 PCB); 4.43, 95% CI: 2.72–6.3 ng/g lipid weight], coinciding with the final stages of the spring phytoplankton bloom, and lowest in August (∑ 8 PCB; 1.6, 95% CI: 1.29–1.92 ng/g lipid weight) when zooplankton lipid content was highest, and the fjord was heavily impacted by sediment-laden terrestrial inputs. Slightly increasing concentrations of α-hexachlorocyclohexane (α-HCH) in zooplankton from June (1.18, 95% CI: 1.06–1.29 ng/g lipid weight) to August (1.57, 95% CI: 1.44–1.71 ng/g lipid weight), alongside a higher percentage of α-HCH enantiomeric fractions closer to racemic ranges, indicate that glacial meltwater is a secondary source of α-HCH to fjord zooplankton in late summer. Except for α-HCH, terrestrial inputs were generally associated with reduced POP concentrations in zooplankton, suggesting that increased glacial melt is not likely to significantly increase exposure of legacy POPs in coastal fauna.

Anthropogenic contaminants in glacial environments II: Release and downstream consequences

“…Ecosystems in glaciated environments depend on a delicate balance of nutrient availability and environmental chemistry for survival and optimal living conditions. Therefore, the re-introduction of anthropogenic contaminants into meltwater could have detrimental implications for both human and ecosystem health (Borgå et al, 2022). After being released into glaciated environments, contaminants are often diluted into safe concentrations once they enter water systems, due to the increased ratio of water to contaminants (Baccolo et al, 2020) and mixing with inorganic sediments (McGovern et al, 2022).…”

“…Therefore, the re-introduction of anthropogenic contaminants into meltwater could have detrimental implications for both human and ecosystem health (Borgå et al, 2022). After being released into glaciated environments, contaminants are often diluted into safe concentrations once they enter water systems, due to the increased ratio of water to contaminants (Baccolo et al, 2020) and mixing with inorganic sediments (McGovern et al, 2022). However, these concentrations can rise to unsafe levels via two processes: (i) bioaccumulation, which is the gradual accumulation of a substance within an organism caused when the organism absorbs the substance at a faster rate than the loss or elimination (Vorkamp and Rigét, 2014); and (ii) biomagnification, which is the progressive build-up of toxic substances by successive trophic levels (Clayden et al, 2015;Van Der Velden et al, 2013).…”

Svalbard shores under stress : Impacts of local human activities on marine invertebrates living in a warming Arctic coastal system

“…Still, concentrations in the outflowing melt water streams of glaciers were lower than in the receiving marine environment where the slightly polluted terrestrial particles were shown to act as sorbents of dissolved contaminants in the coastal water column (Johansen et al 2021). Interestingly, coastal organisms featured an overall decrease in contaminant concentrations from April, when there was no terrestrial run-off, to August, after several months of terrestrial run-off , McGovern et al 2022b). Ademollo et al (2021) however found that PCB concentrations in sea water decreased with increasing distance from a glacier.…”