Feng Xinbin

The concentrations and distribution of mercury in aquatic ecosystem of Baihua Reservoir

Mercury species in water column, sediment and fish from the Hg-contaminated Baihua Reservoir were measured by trap pre-concentration and CVAFS and CVAAS detection methods. The results showed that the highest average total Hg concentration is up to 73.36 ng/L in the water column, 186.7 ng/L in pore water of surface sediment in the Baihua Reservoir. The total mercury concentrations in the sediments range from 0.87 to 33.74 mg/kg. This suggests that sediment re-suspending and Hg input from the upstream organochemical plant are the main mercury sources of water body for this reservoir. In addition, the possible reason why mercury is low in fish is that the low DOC and high pH are infavarable to methylmercury formation or absorption by fish.Mercury species in water column, sediment and fish from the Hg-contaminated Baihua Reservoir were measured by trap pre-concentration and CVAFS and CVAAS detection methods. The results showed that the highest average total Hg concentration is up to 73.36 ng/L in the water column, 186.7 ng/L in pore water of surface sediment in the Baihua Reservoir. The total mercury concentrations in the sediments range from 0.87 to 33.74 mg/kg. This suggests that sediment re-suspending and Hg input from the upstream organochemical plant are the main mercury sources of water body for this reservoir. In addition, the possible reason why mercury is low in fish is that the low DOC and high pH are infavarable to methylmercury formation or absorption by fish.

Buildup of methyl mercury in a seasonal anoxic reservoir and impact on downstream

In the present study, spatial and temporal distribution of methyl mercury in Hongfeng reservoir were investigated by distillation followed by aqueous phase ethylation, precollection on a Tenax, isothermal gas chromatog-raphy and cold vapor atomic fluorescence detection. Total methyl mercury (TMeHg) concentrations have no discernible difference (0.05 to0.33ng/L) in spring, autumn and winter. In spring, the methyl mercury in the inflows was important source of methyl mercury in reservoir. In summer, methyl mercury concentration increased significantly, and the highest value was up to0.923ng/L in the hypolimnion. The spatial distribution in summer suggested methylation in the water column and sedimentation of particle were responsible for the evaluated methyl mercury other than the release of sediment. There was a discernible negative relationship between methyl mercury and dissolved oxygen ( r = -0.81, n = 78). In spring, autumn and winter, the proportion of dissolved methyl mercury ( DMeHg) was lower than that of particulate methyl mercury, but most of methyl mercury was dissolved in hypolimnion in summer. The outflow of reservoir was rich in methyl mercury in summer, and the value was 5. 5 times higher than that in the infows. MeHg-enriched water from anoxic hypolimnia in reservoir also was discharged and potentially transported downstream where it could affect the ecosystem below the reservoir.

Distribution of Different Species of Mercury in Baihua Lake, Guizhou Province

Forty--four surface water samples were collected in Baihua Lake, Guizhou Province. The different species of mercury and water quality parameters, such as reactive mercury, dissolved mercury, particulate mercury, were tested. The spatial variability of different species of mercury in the surface water of Baihua Lake were studied based on the mathematical statistics and Geostatistics methods (Kriging). On the basis of the models of semivariance fitness, we used ArcGIS software to proceed Kriging interpolator to reveal the distribution patterns of different species of mercury in the surface water of Baihua Lake. The results indicate that mercury contamination in the surface water of Baihua Lake is due to headwaters, then mercury contents will decrease with the direction of flowing water. But in the region of eutrophication, the contents of particulate mercury and total mercury increase.

The distribution of various mercury species in soil

According to the mercury species with different solubilities, the analytical procedure involving sequential chemical extraction has been applied to partitioning the mercury species in soils into seven fractions. Soil samples collected from five localities in different areas (the high-mercury area, the man-made mercury-polluted area and the reference area) were analyzed for the seven mercury species. It is found that high mercury contents of soils can be attributed to both man-made pollution and geological processes, but the two kinds of soils show obvious differences in the distribution of their mercury species.

Damming effect on the distribution of mercury in Wujiang River

Seasonal changes in total mercury concentrations in surface water were observed for the Wujiang River, with higher values at the time of greater flow. The total mercury in this river was mostly associated with suspended particles, particulate mercury accounting for 84% of the total mercury flux on average during the high flow period, and 52% of the total mercury flux on average in the low flow period. Significant losses of Hg from the water were observed in the downstreams of the reservoir. In addition, the concentrations of particulate mercury in the downstreams of reservoir appeared to have been enhanced by sediment re-suspension and shoreline erosion caused by flood discharge, while the filtered portion decreased. These observations suggested that reservoirs played an important role in controlling the transport and fate of mercury in the Wujiang River.

Concentrations and distributions of mercury species in surface water and porewater of Lake Caohai, Guizhou Province

摘 要: 运用金汞齐-冷原子荧光光谱法(CVAFS)和气相色谱技术(GC), 对贵州省草海不同水文季节(枯水期和丰水期)表层水 中汞的各种赋存形态, 包括总汞(HgT)、溶解态汞(HgD)、活性汞(HgR)、颗粒态汞(HgP)、总甲基汞(MeHgT)、溶解态甲基汞 (MeHgD)和颗粒态甲基汞(MeHgP)以及沉积物间隙水剖面中的溶解态总汞和甲基汞含量进行了测定. 结果显示: 草海表层水 体总汞浓度为 1.7-9.0ng/L, 活性汞浓度为 0.06-1.4ng/L, 总甲基汞浓度为 0.11-0.67ng/L. 沉积物间隙水中溶解态汞浓度为 8.6-39.6ng/L, 溶解态甲基汞浓度为 0.11-4.9ng/L. 实验数据表明, 草海湖水以溶解态汞为主, 其占总汞的比例为枯水期 87%, 丰水期 51%, 溶解态汞与总汞呈显著相关(丰水期 P<0.01; 枯水期 P<0.05), 颗粒态汞与总汞也呈显著相关(丰水期 P<0.01; 枯 水期 P<0.05). 溶解态甲基汞与总甲基汞呈显著相关(丰水期 P<0.01; 枯水期 P<0.05), 表明溶解态甲基汞控制总甲基汞的分布. 沉积物间隙水溶解态汞与溶解态甲基汞浓度明显高于上覆水体, 表明沉积物为草海湖水中汞的一个重要来源. 关键词: 汞形态; 表层水; 间隙水; 含量分布; 草海

Distribution characteristics of mercury and methylmercury in phytoplankton at Guizhou Plateau reservoirs in winter

To understand the distribution characteristic and bioaccumulation factors(BAF) of total mercury(THg) and methylmercury(MeHg) in phytoplankton at Guizhou Plateau reservoirs,southwest of China.The phytoplankton and water samples were investigated at five reservoirs in the winter of 2012.The results showed that diatom was the dominant algae at Guizhou Plateau reservoirs in winter and phytoplankton abundance had obvious difference at the five reservoirs.The maximum phytoplankton abundance was about 29.05 × 104cells / L at Lake Baihua dam,and the minimum only 0.49 × 104cells / L at Sanbanxi Reservoir.The concentrations of THg and MeHg in phytoplankton were 29.29-277.07 ng / g(dry) and 1.12-10.93 ng / g(dry),respectively.The maximum concentrations of THg and MeHg in phytoplankton was at Lake Baihua.The BAF of THg and MeHg in phytoplankton were 1.42 × 104-9.78 × 104and 3.10 × 104-4.43 × 105,respectively.The maximum BAF in phytoplankton of THg was at Lake Baihua.The maximum BAF of MeHg in phytoplankton was at Lake Hongfeng.There was different effect on biological enrichment of mercury and methylmercury for different phytoplankton species composition.There were significant positive correlations between MeHg in phytoplankton and THg,MeHg,dissolved MeHg(DMeHg) in water.No significant correlation was found between MeHg in phytoplankton and the THg,DMeHg in water.MeHg was not only absorbed by phytoplankton.There were other factors influencing MeHg concentration in phytoplankton inevitably.There were significant negative correlations between MeHg in phytoplankton and environmental factors(SD,TN,NO-3-N).The degree of eutrophication had effects on MeHg concentration in phytoplankton.