People living a subsistence lifestyle in the Arctic are highly exposed to persistent organic pollutants, including polychlorinated biphenyls (PCBs). Formerly Used Defense (FUD) sites are point sources of PCB pollution; the Arctic contains thousands of FUD sites, many co-located with indigenous villages. We investigated PCB profiles and biological effects in freshwater fish (Alaska blackfish [Dallia pectoralis] and ninespine stickleback [Pungitius pungitius]) living upstream and downstream of the Northeast Cape FUD site on St. Lawrence Island in the Bering Sea. Despite extensive site remediation, fish remained contaminated with PCBs. Vitellogenin concentrations in males indicated exposure to estrogenic contaminants, and some fish were hypothyroid. Downstream fish showed altered DNA methylation in gonads and altered gene expression related to DNA replication, response to DNA damage, and cell signaling. This study demonstrates that, even after site remediation, contaminants from Cold War FUD sites in remote regions of the Arctic remain a potential health threat to local residents – in this case, Yupik people who had no influence over site selection and use by the United States military.

The Arctic is subject to long-range atmospheric deposition of globally-distilled semi-volatile organic compounds (SVOCs) that bioaccumulate and biomagnify in lipid-rich food webs. In addition, locally contaminated sites may also contribute SVOCs to the arctic environment. Specifically, Alaska has hundreds of formerly used defense (FUD) sites, many of which are co-located with Alaska Native villages in remote parts of the state. The purpose of this study was to investigate the extent of SVOC contamination on Alaska’s St. Lawrence Island through the analysis of sentinel fish, the ninespine stickleback (Pungitius pungitius), collected from Troutman Lake located within the watershed of an FUD site and adjacent to the Yupik community of Gambell. We measured the concentrations of legacy and emerging SVOCs in 303 fish samples (81 composites), including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organophosphate esters (OPEs) and their diester metabolites, and per- and poly-fluoroalkyl substances (PFAS). PBDEs and PCBs were the most abundant SVOC groups found in stickleback with ΣPBDE and ΣPCB median concentrations of 25.8 and 10.9 ng/g ww, respectively, followed by PFAS (median ΣPFAS 7.22 ng/g ww). ΣOPE and ΣOPE metabolite concentrations were lower with median concentrations of 4.97 and 1.18 ng/g ww, respectively. Chemical patterns and distributions based on correlations and comparison with SVOC concentrations in stickleback from other parts of the island suggest strong local sources of PCBs, PBDEs, and PFAS on St. Lawrence Island.

Sticklebacks (Gasterosteiformes) are increasingly used in ecological and evolutionary research and have become well established as role model species for biologists. However, ecotoxicology studies concerning behavioural effects in sticklebacks regarding stress responses, mainly induced by chemical mixtures, have hardly been addressed. For this purpose, we investigated the swimming behaviour (including mortality rate based on 96-h LC50 values) of two ecologically similar three-spined (Gasterosteus aculeatus) and nine-spined sticklebacks (Pungitius pungitius) to short-term (up to 24 h) metal mixture (MIX) exposure. We evaluated the relevance and efficacy of behavioural responses of test species in the early toxicity assessment of chemical mixtures. Fish exposed to six (Zn, Pb, Cd, Cu, Ni, and Cr) metals in the mixture were either singled out by the Water Framework Directive as priority or as relevant substances in surface water, which was prepared according to the environmental quality standards (EQSs) of these metals set for inland waters in the European Union (EU) (Directive 2013/39/EU). The performed behavioural analysis showed the main effect on the interaction between time, species, and treatment variables. Although both species exposed to MIX revealed a decreasing tendency in swimming activity, these species' responsiveness to MIX was somewhat different. Substantial changes in the activity of G. aculeatus were established after a 3-h exposure to MIX solutions, which was 1.43-fold lower, while in the case of P. pungitius, 1.96-fold higher than established 96-h LC50 values for each species. This study demonstrated species-specific differences in response sensitivity to metal-based water pollution, indicating behavioural insensitivity of P. pungitius as model species for aquatic biomonitoring and environmental risk assessments.v.

Sticklebacks (Gasterosteiformes) are increasingly used in ecological and evolutionary research and have become well established as role model species for biologists. However, ecotoxicology studies concerning behavioural effects in sticklebacks regarding stress responses, mainly induced by chemical mixtures, have hardly been addressed. For this purpose, we investigated the swimming behaviour (including mortality rate based on 96-h LC₅₀ values) of two ecologically similar three-spined (Gasterosteus aculeatus) and nine-spined sticklebacks (Pungitius pungitius) to short-term (up to 24 h) metal mixture (MIX) exposure. We evaluated the relevance and efficacy of behavioural responses of test species in the early toxicity assessment of chemical mixtures. Fish exposed to six (Zn, Pb, Cd, Cu, Ni, and Cr) metals in the mixture were either singled out by the Water Framework Directive as priority or as relevant substances in surface water, which was prepared according to the environmental quality standards (EQSs) of these metals set for inland waters in the European Union (EU) (Directive 2013/39/EU). The performed behavioural analysis showed the main effect on the interaction between time, species, and treatment variables. Although both species exposed to MIX revealed a decreasing tendency in swimming activity, these species’ responsiveness to MIX was somewhat different. Substantial changes in the activity of G. aculeatus were established after a 3-h exposure to MIX solutions, which was 1.43-fold lower, while in the case of P. pungitius, 1.96-fold higher than established 96-h LC₅₀ values for each species. This study demonstrated species-specific differences in response sensitivity to metal-based water pollution, indicating behavioural insensitivity of P. pungitius as model species for aquatic biomonitoring and environmental risk assessments.

The presence of human pharmaceuticals in the environment has garnered significant research attention because these compounds may exert therapeutic effects on exposed wildlife. Yet, for many compounds, there is still little research documenting their stability in the water column and uptake in organism tissues. Here, we measured the uptake and stability of methylphenidate (Ritalin®, a frequently prescribed central nervous system stimulant) and its primary metabolite, ritalinic acid, in (1) water only or (2) with nine-spine stickleback and water louse. Methylphenidate degraded to ritalinic acid in both studies faster at a higher temperature (20 °C versus 10 °C), with concentrations of ritalinic acid surpassing methylphenidate after 48–100 h, depending on temperature. The concentration of methylphenidate in stickleback was highest at the first sampling point (60 min), while the concentration in water louse tissues reached comparatively higher levels and peaked after ~ 6 days. Neither stickleback nor water louse took up ritalinic acid in tissues despite being present in the water column. Our findings provide valuable data for use in future risk assessment of methylphenidate and will aid in the design of studies aimed at measuring any ecotoxicological effects on, for example, the behaviour or physiology of aquatic organisms.