[Mercury in the peat bog ecosystem in Xiaoxing'an mountain in China]

The mercury content in Tangwang River forested catchment of Xiaoxingan Mountain in Northeast of China was studied. The average total mercury (THg) in peat profile ranged from 65.8 ng/g to 186.6 ng/g with the highest in the depth of 5-10 m. THg in the peat surface was higher than the background in Heilongjiang province, and higher than the Florida Evergrade in America and Birkeness in Sweden. MeHg ranged from 0.16 ng/g to 1.86 ng/g with the highest in the depth of 10-15 cm. MeHg was 0.2-1.2% of THg. They all decreased with the depth. There was no strong significant correlation between the THg and MeHg (p = 0.05, r = 0.28). THg in upland mor layer of soil (0-20 cm) was comparable to the peat surface (0-20 cm), but in deeper layer THg in peat was much higher than the forested mineral soil. THg in the peat bog increased, but MeHg decreased after it was drained 30 years ago. THg in plant was different, THg in the moss (119 ng/g, n = 12) was much larger than the herbage, the arbor and the shrub. The peat bog was contaminated by mercury coming from the atmosphere to some degree.