Abstract: Aimed to approach the possible ecological risk of fish mercury from Hongjiadu Reservoir, a newly built reservoir located in Wujiang River Basin of Guizhou Province, a total of 124 fishes belonging to 8 species were collected, with their total mercury (THg) and total methylmercury (TMeHg) concentrations measured. The THg was measured with cold vapor atomic fluorescence spectrometry (CVAFS), and the TMeHg was analyzed by digesting the samples with 20% KOH, GC separation, and CVAFS detection. The results showed that carnivorous species had higher THg and TMeHg concentrations than omnivorous species. The average concentrations of THg and TMeHg in the fishes were 0.063±0.046 mg·kg^-1 and 0.028±0.019 mg·kg^-1, respectively. There were no significant linear relationships between the THg and MeHg concentrations and fish body length or weight. The Hg concentrations in fish body were related to the feeding habits and habitat preference of the fishes. The Hg concentrations in Hongjiadu Reservoir were lower than those in the newly built reservoirs in North America and Europe. Our results suggested that the TMeHg and THg concentrations in the fishes in Hongjiadu Reservoir did not have a dramatic increase, but with the evolvement of the newly built reservoir, the MeHg concentrations in the fishes could be increased gradually due to the increase of organic matter concentration in the reservoir.

Key words: Conservation tillage, No-tillage, Soil erosion, China