[Distribution of Mercury in Plants at Water-Level-Fluctuating Zone in the Three Gorges Reservoir].

The mercury (Hg) distribution and storage in plants at water-level-fluctuating zone (WLFZ) in the Three Gorges Reservoir were investigated by analyzing the total mercury(THg) and methylmercury ( MeHg) levels in different parts of plants collected from three typical sites including Shibaozhai, Zhenxi and Hanfeng Lake in WLFZ. The results indicated that THg and MeHg concentrations in plants ranged from (1.62 ± 0.57) to (49.42 ± 3.93) μg x kg(-1) and from (15.27 ± 7.09) to (1 974.67 ± 946.10) ng x kg(-1), respectively. In addition, THg levels in different plant parts followed the trend: root > leaf > stem, and similar trend for MeHg was observed with the highest level in root. An obvious spatial distribution was also found with the THg and MeHg levels in plants in Hanfeng higher than those in the same plants in the other two sampling sites (Shibaozhai and Zhenxi), and there was a difference of THg and MeHg storage in plants in various attitudes. The corresponding THg and MeHg storages were 145.3, 166.4, 124.3 and 88.2 mg x hm(-2), and 1.9, 2.7, 3.6 and 3.2 mg x hm(-2) in 145-150, 150-160, 160-170 and 170-175 m attitudes. The accumulation ability of dominant plants in WLFZ for THg (bioaccumulation factor, BAF < 1) was weaker than that for MeHg (BAF > 1).