The distribution and speciation of mercury in Wujiang river

Concentrations of reactive, dissolved, particulate and total mercury in water samples were determined at 41 locations throughout the Wujiang River Basin, China. The sampling campaign was carried out $15 \sim 30$ July 2002. During the collection of water samples for Hg analyses, other parameters were measured in situ (dissolved oxygen, pH, temperature and EC). The average concentration of the reactive mercury in surface water was 1.5 ng$\cdot$L$^{-1}$. The concentration of total mercury ranged from 10.9 to 329.6 ng$\cdot$L$^{-1}$, with a geometric mean of 44.4 ng$\cdot$L$^{-1}$, and the dissolved mercury was from 1.0 to 49.2 ng$\cdot$L$^{-1}$, with a geometric mean of 7.l ng$\cdot$L$^{-1}$. The proportion of reactive to total mercury was typically less than 5%, and the particulate to total mercury, with 90% of values higher than 50%. The pilot study indicated that Wujiang River is contaminated by mercury in a certain extent.