Mercury distribution and accumulation in typical wetland ecosystems of Sanjiang Plain, Northeast China

Total mercury in soil, water, plant, insects, fishes and bird feathers were determined to study mercury distribution and accumulation in typical wetland ecosystems in the Sanjiang Plain, Northeast China. Results show that total mercury concentrations in soils of Deyeuxia angustifolia wetland and Carex lascarpa wetland are 0.046 mg/kg and 0.063 mg/kg, respectively. Total mercury concentration in water bodies is 0.053 μg/L on average. Of four plants studied, total mercury in moss is the highest with the mean of 0.132 mg/kg. Of 10 terrestrial insect species studied, total mercury in centipede (Scolopendra spp.) is the highest with the mean of 0.515 mg/kg while total mercury in grasshopper (Oxya spp.) bodies is the lowest. Total mercury concentrations in the herbivorous, omnivorous and predatory insects are 10.18 ng/g, 16.47 ng/g and 213.35 ng/g on average, respectively. Total mercury concentrations of the adult feather (549.88 ± 63.04 ng/g), nestling feather (55.15 ± 23.53 ng/g), and eggshell (22.05 ± 5.96 ng/g) of the Grey heron (Ardea cinerea) are higher than those of the Great egret (Egretta alba) (adult feather: 446.57 ± 90.89 ng/g; nestling feather: 32.99 ± 17.15 ng/g; eggshell: 21.02 ± 3.17 ng/g) in the wetlands of the Sanjiang Plain. The bioconcentration factors decrease in the order of piscivorous fish muscle > omnivorous fish muscle > herbivorous fish > insect.