Differential bioaccumulation of potentially toxic elements in benthic and pelagic food chains in Lake Baikal

Abstract

Lake Baikal is located in eastern Siberia in the center of a vast mountain region. Even though the lake is regarded as a unique and pristine ecosystem, there are existing sources of anthropogenic pollution to the lake. In this study, the concentrations of the potentially toxic trace elements As, Cd, Pb, Hg, and Se were analyzed in water, plankton, invertebrates, and fish from riverine and pelagic influenced sites in Lake Baikal. Concentrations of Cd, Hg, Pb and Se in Lake Baikal water and biota were low, while concentrations of As were similar or slightly higher compared to in other freshwater ecosystems. The bioaccumulation potential of the trace elements in both the pelagic and the benthic ecosystems differed between the Selenga Shallows (riverine influence) and the Listvenichnyĭ Bay (pelagic influence). Despite the one order of magnitude higher water concentrations of Pb in the Selenga Shallows, Pb concentrations were significantly higher in both pelagic and benthic fish from the Listvenichnyĭ Bay. A similar trend was observed for Cd, Hg, and Se. The identified enhanced bioavailability of contaminants in the pelagic influenced Listvenichnyĭ Bay may be attributed to a lower abundance of natural ligands for contaminant complexation. Hg was found to biomagnify in both benthic and pelagic Baikal food chains, while As, Cd, and Pb were biodiluted. At both locations, Hg concentrations were around seven times higher in benthic than in pelagic fish, while pelagic fish had two times higher As concentrations compared to benthic fish. The calculated Se/Hg molar ratios revealed that, even though Lake Baikal is located in a Se-deficient region, Se is still present in excess over Hg and therefore the probability of Hg induced toxicity in the endemic fish species of Lake Baikal is assumed to be low.

Seasonal and spatial variation in hydrochemical parameters of Lake Onego (Russia): insights from 2016 field monitoring

“…Further research is needed to understand whether or not this mechanism operates in the Shuya River-PB-Lake Onego system. Lake Onego THg concentrations exhibited the same range as those measured from other large lakes such as Listvenichenyi Bay of Lake Baikal (Ciesielski et al 2016), Lake Geneva (Switzerland; Guédron et al 2016), Lake Michigan (USA; Mason and Sullivan 1997), and Lake Victoria (Africa; Campbell et al 2003). THg concentrations observed from all sampling sites and at all depths fell significantly below average annual limits of 0.05 mg L −1 specified by environmental quality standards for inland surface waters (EU 2008).…”

Past and present mercury accumulation in the Lake Baikal seal: Temporal trends, effects of life history, and toxicological implications

“…The lack of a relationship between total Hg and MeHg concentrations and age for blood is likely attributable to blood Hg concentrations reflecting Hg content in the seal's recent diet, which would be expected to be relatively constant and independent of age, given that seals do not appear to undergo substantial dietary shifts during their adult lives (as observed in the present study, by Yoshii et al [1999], and by Ozersky et al [2017]). Furthermore, the prey that dominates the seals' diet (2 species of Comephorus [pelagic sculpins] and, to a lesser degree, pelagic amphipods) has Hg concentrations that do not differ substantially (Ciesielski et al 2016). Given the potential for remobilization and loss of Hg during reproduction and lactation, we expected that adult female seals may have reduced Hg compared to male seals, which lack these Hg excretion FIGURE 1: Stable carbon (a) and nitrogen (b) isotope values and total Hg concentrations (c) for select soft tissues (blue ¼ blood; red ¼ muscle; orange ¼ liver) for seals collected in 2013.…”

Changes of cellular stress response relatedhsp70andabcb1transcript and Hsp70 protein levels in Siberian freshwater amphipods upon exposure to cadmium chloride in the lethal concentration range

“…Baikal's water is generally highly pristine; however, the risk of water contamination by heavy metals is increasing. In particularly the Selenga river, the largest tributary of Lake Baikal comprising almost half of the riverine inflow into the lake, is the main source of such contaminants (Ciesielski et al, 2016;Kulikova et al, 2017).…”