Mercury Status of the Primorsky Minnow, Phoxinus oxyrhynchus (Mori, 1930) and the Manchurian Lake Minnow, Rhynchocypris mantschurica (Berg, 1907)

The total mercury (THg) content was evaluated in muscles (mg.kg-1 wet weight) of the Primorsky minnow, Phoxinus oxyrhynchus (Mori, 1930) and the Manchurian Lake minnow, Rhynchocypris mantschurica (Berg, 1907) from the unique ecoregion of Ussuri broadleaf and mixed forests in the Russian Far East in 2023. The results showed that the THg concentration in the muscles of the Primorsky minnow from the Kievka River basin ranged from 0.052 to 0.350 mg.kg-1; with a mean of 0.106 ± 0.015, and a median of 0.078 mg.kg-1. The THg concentration in the muscles of the Manchurian Lake minnow from the Melgunovka River basin were lower than those for R. mantschurica with a range of 0.025–0.097 mg.kg-1; and a mean of 0.047 ± 0.004, and median of 0.046 mg.kg-1. The THg concentrations in minnows of the same size group (<115mm in body length i.e. immature) from the Kievka River and Melgunovka River basins differed significantly (P= 0.001) and were about 2 times higher in the Kievka than the Melgunovka. The THg levels in the minnows (0.047–0.106 mg.kg-1) and the frequency of consumption by people (once per week) indicate a low risk to human health. These data are close to the range of Hg concentrations in freshwater fish (0.038–0.02 mg.kg-1 WW) in the Songhua and Liaohe River basins in China bordering the study region.