Spatial distribution and ecological risk assessment of sediment heavy metals from salt marsh of Yangtze River estuary
ZHANG Nuo1,2,3, LIU Qigen1,2,3, CHEN Liping1,2,3, ZHAN Yuan1,2,3, HU Zhongjun1,2,3*
1.National Demonstration Center for Experimental Fisheries Science Education,Shanghai Ocean University, Shanghai 201306, China；2 Shanghai Engineering Research Center of Aquaculture，Shanghai 201306, China；3.Centre for Research on Environmental Ecology and Fish Nutrition (CREEFN), Ministry of Agriculture and Rural Affairs, Shanghai 201306, China
Abstract: The contents of heavy metals Cu, Cr, Zn, Mn, As, Pb, and Cd and carbon and nitrogen were determined in the sediment samples collected from different habitats including bare tidal flat and salt marshs with Scirpus, Spartinaalterniflora and/or Phragmitesaustralis in tidal flat of five sites including Luchao Port (LCG), Eastern Nanhui (NHDT), Dongwangsha (DWS) and Tuanjiesha (TJS) of Eastern Chongming Wetland and Paotaiwan Wetland Forest Park (PTW)in Yangtze River estuary in August and September, 2018 in order to evaluate the potential ecological risk (PER) of heavy metals and organic pollution of sediments from salt marsh of the Yangtze River estuary, and to reveal their large-scale distribution characteristics and change pattern along different habitats. There were significant differences in the concentrations of the seven heavy metals, total organic carbon (TOC), total nitrogen (TN), and grain size (GS) of sediments among the five sampling sites (P<0.05). An increasing tendency of the concentrations of the most heavy metals was observed along habitats from the sea to the land in LCG and NHDT and Pb in TJS, and the reverse were found for Cu, Cr, Mn, Pb, Cd in PTW and Cu, Cr, Cd in TJS. The trends from rise to decline were observed for Zn and As in PTW and for Zn, Mn and As in TJS. However, the significant differences in concentrations of a few heavy metals and nutrients such as Zn (P<0.05) and TN (P<0.01) were only found between habitats in LCG, Cu (P<0.05), TN (P<0.01) and TOC (P<0.01) in NHDT, Cr, Mn (P<0.01), As (P<0.05) and Cd (P<0.05) in PTW, and Zn, Cd , TN and TOC (P<0.01) in TJS. There were significantly positive correlations between heavy metals in the seven heavy metals, all of which were significantly and positively correlated with TOC (P<0.01). The significantly negative relationships between GS and the five heavy metals other than As and Cd were detected (P<0.05). The cadmium was shown to be the most polluted heavy metal with mean concentration of (1.11±0.04) mg/kg and high PER (192.30) in the salt marsh sediments of Yangtze River estuary. The high PER to very high PER, PER index ranging from 175.41 to 297.48, in the five sites were also confronted with relatively serious organic pollution (organic index fluctuating from 0.17 to 0.43), and with seriously pollution of organic nitrogen (organic nitrogen index fluctuating from 0.16 to 0.26). The findings indicated that the differences in concentrations of heavy metals among the five sites and the complex of their change patterns along different habitats from the sea to land was attributed to the strength of the hydrodynamically controlled sedimentary differentiation, whose complex might be involved in the absorption and accumulation of heavy metal by salt marshes, which needs further research.
张诺, 刘其根, 陈丽平, 展源, 胡忠军, . 长江口盐沼湿地沉积物重金属空间分布特征及其潜在生态风险评价[J]. 大连海洋大学学报, 2021, 36(1): 135-146.
ZHANG Nuo, LIU Qigen, CHEN Liping, ZHAN Yuan, HU Zhongjun, . Spatial distribution and ecological risk assessment of sediment heavy metals from salt marsh of Yangtze River estuary. Journal of Dalian Ocean University, 2021, 36(1): 135-146.
2021, Vol. 36 
