ACCUMULATION OF METALS IN ZOOPLANKTON FROM KARST PLATEAU RESERVOIRS WITH DIFFERENT EUTROPHIC STATUS IN GUIZHOU PROVINCE, P. R. CHINA

Metal concentrations in large zooplankton from three karst reservoirs with different eutrophic status (Hongfeng Lake reservoir, Baihua Lake reservoir, and Aha reservoir) in Guizhou Province, China, were investigated. Samples of zooplankton were collected in 2014 and 2015. It was found that accumulation of metals in zooplankton was significantly correlated with Chl-a (chlorophyll a), which can be attributed to the characteristic distribution of species of phytoplankton. A low concentration of metals in water means a higher bioaccumulation factor (BAF) and a stronger transfer to zooplankton via the trophic chain, and hence a higher ecological risk. Zooplankton in the eutrophic Aha reservoir had lower concentrations of Fe (mean 1264.25 mg/kg) than in Hongfeng (mean 2566.07 mg/kg) and Baihua (2246.87 mg/kg) in 2014-2015, because of high TP (Total Phosphorus) concentration, which has an affinity with suspended particles matter. A high level of Cd (mean 0.62 mg/kg) was found in Hongfeng. This study shows that zooplankton in the eutrophic Aha reservoir had higher concentrations of metals (Mn, mean 590.47 mg/kg; Pb, mean 7.6 mg/kg; Cr, mean 26.31 mg/kg; Ni, mean 8.54 mg/kg; Zn, mean 225.73 mg/kg; and Cu, mean 238.33 mg/kg) than in the mesotrophic Hongfeng and Baihua reservoirs. Thus, the eutrophic status was significantly, positively correlated with high concentrations of metals in the zooplankton, as also observed in other reservoir studies.