HEAVY METAL ACCUMULATION RATES IN DEYEUXIA ANGUSTIFOLIA AND CAREXLASIOCARPA WETLANDS OF SANJIANG PLAIN, NORTHEAST CHINA

摘要

Wetlands are typically sedimentary environments and function as either a "source" or "sink" for heavy metals in regional or global biogeochemistry circulations. Copper, manganese and mercury accretion rates were estimated by dating soil profiles from Deyeuxia angustifolia and Carex lasiocarpa wetlands of the Sanjiang Plain using Cesium-137. Results indicated that soils from the D. angustifolia wetland were possessed relatively higher Cu and Mn content and lower Hg content than those in the C. lasiocarpa wetland soils. Annual soil accretion rates in the D. angustifolia wetland and C. lasiocarpa wetland were 2.55 mm yr~(-1) and 4.26 mm yr~(-1), respectively, indicating high soil accretion rates in the C. lasiocarpa wetland. Based on soil bulk density, metal contents and accretion rates, Cu, Mn and Hg accumulation rates were 46.40±13.56 mg yr~(-1) m~(-2), 464.05±96.65 mg yr~(-1) m~(-2) and 0.09±0.02 mg yr~(-1) m~(-2) in the D. angustifolia wetland and 49.66±11.18 mg yr~(-1) m~(-2), 498.25±86.26 mg yr~(-1) m~(-2), and 0.15±0.03 mg yr~(-1) m~(-2) in C. lasiocarpa wetland. Thus, the heavy metal accumulation rates were higher in the C. lasiocarpa wetland than the D. angustifolia wetland, possibly as a result of differing hy-drologic conditions and biological uptake between these two wetland types.