Accumulation of trace metals in tissues of the Oriental river prawn Macrobrachium nipponense (Arthropoda, Crustacea, Decapoda, Palaemonidae) from polluted waters in southwestern Ukraine

We report on the bioaccumulation of trace metals (Mercury-Hg, Copper-Cu, Cadmium-Cd, Lead-Pb) in tissues of the invasive Oriental river prawn ( Macrobrachium nipponense ) sampled from three water body areas in southwestern Ukraine: (sampling site 1) Sukhyi Lyman, (2) Cuciurgan Reservoir, and (sites 3-4) two locations in the Danube delta. Results are consistent with the hypothesis that the absorption of microquantities of trace metals from water by hydrobionts primarily depends on the relative concentration of each element. The higher its respective dissolved concentration, the higher is the metals corresponding absorption by the prawn. Our study showed that trace metal contamination of the prawns did not exceed either the national (Ukraine) or the international standard levels for crustaceans. In terms of chemical contamination, all water areas appear to meet present-day Ukraine and International guidelines for Oriental river prawn aquaculture and/or its commercial harvesting. However, given the present levels and ongoing potential for additional trace metal contaminations, and accompanying or currently unassessed pollutants, as well as their likelihoods of complex chemical, biological, and ecosystem interactions, accelerated by anthropogenic unknowns as the Russia-Ukraine War drags on, extreme caution is warranted for aquaculture, commercial fishing, and recreational harvest of the Oriental river prawn as well as other seafood species in Ukraine’s waters.