A preliminary study on mercury contamination to the environment from artisanal zinc smelting using indigenous methods in Hezhang county, Guizhou, China—Part 1: mercury emission from zinc smelting and its influences on the surface waters

Zinc smelting is one of the important anthropogenic atmospheric mercury emission sources, but research on mercury emission from this source category is limited. Using a mass balance method, we estimated the average mercury emission factors from artisanal zinc smelting using indigenous method in Hezhang, Guizhou, China to be 155 and 79 g Hg t−1 of Zn produced from sulfide ore and oxide ore, respectively. These emission factors are much higher than the literature value used to estimate mercury emission from zinc smelting in developing countries, which is 25 g Hg t−1 of Zn produced. Annual mercury emission rates from artisanal zinc smelting in this area were calculated from 1989 to 2001. Up to 2003, a few metric tons of mercury was annually emitted to the ambient air from zinc smelting in such a small area (<150 km2), posing a threat to the local environment. It highlighted that artisainal zinc smelting in Hezahng was an important global atmospheric mercury emission source. The local surface waters were seriously contaminated with mercury due to zinc smelting. Apart from the deposition of mercury species was that emitted from zinc smelting, smelting residues are also the sources of mercury contamination to surface water systems.