[Microcosm Simulation Study and Methylmercury Forming Mechanism at Landscape Water of City]

Mercury is harmful to the environment, which has gradually become one of the research hotspots. Sediments, as a main repository of pollutants, have an important impact on water quality and the internal organisms, which deserves our research. In this paper, we focused on Hefei landscape water sediment and tried to investigate the status of inorganic mercury and methylmercury pollutions in the sediment. To study the conversion process from inorganic mercury to methylmercury and their enrichment levels and mechanism, we established the ecological chain of "sediment-water-grass-fish" through analog microcosm examination. The results were as follows: from ten water and sediment samples in Hefei landscape water sediment, we found that the contents of inorganic mercury and methylmercury ranged 11.74-13.12 µg · kg⁻¹ and 0.37-2.23 µg · kg⁻¹, respectively. The microcosm examination showed that: with increasing culture time, inorganic mercury in sediments gradually decreased. There was a phenomenon that the content of methylmercury increased at first and then decreased to reach the balance later. Both the inorganic mercury and methylmercury in water change showed an increasing trend. The enrichment contents of inorganic mercury in Egeria densa Planch, and golden mandarin fish (Siniperca scherzeri Steindachner) were low while their enrichment of methylmercury could he great. In addition, we found that both the bioaccumulation ability and the enrichment coefficient of methylmercury in the body of golden mandarin fish were the maximum during the same period.