Effects of Polymetallic Ore Occurrences on Mercury Accumulation by Aquatic Biota in River Ecosystems

The study represents the data on metal content in the body of stoneflies Perla pallida Guerin-Meneville, 1838 (Plecoptera, Perlidae) and in muscles of the fish family Cyprinidae from the small tributaries of the Belaya River (Republic of Adygea, Northwest Caucasus) with ore mineralization of various metals including mercury. It was found that mercury (Hg) concentrations in stoneflies are corresponds to from the water basins without local Hg sources. Mercury content in stoneflies depends on season and is more intensive in early ontogenesis in winter than in the warm season. Mercury concentration in 0.01–0.72 mg/kg dry weight can cause the pathomorphological changes in the structure of organs and decrease the adaptive potential in competitive population of stoneflies, in general. The Hg concentration reached 0.09–0.69 mg/kg in the studied fish species (bleak, gudgeons, and barbels) and was similar to concentrations in stonefly larvae. This can be related with low size-weight parameters of fishes in samples as wells as with similar feeding patterns of hydrobionts.

Mercury Accumulation in Terrestrial Food Chains of the Liaohe Estuary Wetlands

Mercury is a global pollutant that can accumulate in organisms and endanger human health. This paper studied the soil, plants and animals in the light beach, Suaeda wing wetland, reed wetland and rice field in the Liaohe Estuary in 2018 and 2019, and determined the stable carbon and nitrogen isotopes of animals and plants to construct the food chain. The results show that from 2018 to 2019, the accumulation of mercury in the soil of the light beach, Suaeda winged wetland and reed wetland of the Liaohe Estuary continued to increase, but the accumulation of mercury in paddy soil showed a decreasing trend; the mercury content in plant samples also showed a certain degree There is a positive correlation between the accumulation of mercury in the food chain and the construction of trophic levels in the food chain. Mercury can carry out efficient biomagnification and bioaccumulation through the food chain.

Mercury Accumulation and Elimination in Different Tissues of Zebrafish (Danio rerio) Exposed to a Mercury-Supplemented Diet

In this study, we evaluated the bioaccumulation of mercury in zebrafish (Danio rerio) exposed to mercury-contaminated food for 21 days and the depuration of mercury for a subsequent post-exposure period of 28 days. Four tissues (muscle, liver, gills, and skin) were analyzed for mercury content. Overall, data indicated that Hg accumulation in the liver is faster than in other tissues. Furthermore, the liver is the tissue with the highest accumulation rate per day (0.021 µg Hg g−1 day−1), followed by muscle, skin, and gills. Conversely, the Hg depuration rates in different tissues showed the following order: gills > skin > muscle > liver. The bioaccumulation factor values of liver and muscle increased linearly during the uptake period. The ratios between mercury concentration in liver and muscle during the experiment also increased during the uptake period and remained higher than 1 during the elimination period, suggesting that Danio rerio needed more than 4 weeks of depuration. Finally, the distribution of Hg in the water column during the accumulation period is Hg particulate > Hg dissolved, and during the depuration period it is the opposite, mercury particulate < mercury dissolved. In conclusion, this study contributes to a better understanding of the differences in Hg dynamics during the accumulation and depuration stages in a model fish, also emphasizing the alterations on Hg available in the water column.