张振, 刘健, 陈彬, 徐刚, 仇建东, 王双. 浙江近岸泥质区近140年来重金属元素沉积记录及其对长江流域人类活动的响应[J]. 海洋地质与第四纪地质, 2016, 36(3): 23-33. DOI: 10.16562/j.cnki.0256-1492.2016.03.003
引用本文: 张振, 刘健, 陈彬, 徐刚, 仇建东, 王双. 浙江近岸泥质区近140年来重金属元素沉积记录及其对长江流域人类活动的响应[J]. 海洋地质与第四纪地质, 2016, 36(3): 23-33. DOI: 10.16562/j.cnki.0256-1492.2016.03.003
ZHANG Zhen, LIU Jian, CHEN Bin, XU Gang, QIU Jiandong, WANG Shuang. DEPOSITIONAL RECORDS OF HEAVY METALS FOR THE LAST 140 YEARS IN THE ZHEJIANG COASTAL MUDDY AREA OF THE YANGTZE RIVER BASIN AND THEIR RESPONSES TO HUMAN ACTIVITIES[J]. Marine Geology & Quaternary Geology, 2016, 36(3): 23-33. DOI: 10.16562/j.cnki.0256-1492.2016.03.003
Citation: ZHANG Zhen, LIU Jian, CHEN Bin, XU Gang, QIU Jiandong, WANG Shuang. DEPOSITIONAL RECORDS OF HEAVY METALS FOR THE LAST 140 YEARS IN THE ZHEJIANG COASTAL MUDDY AREA OF THE YANGTZE RIVER BASIN AND THEIR RESPONSES TO HUMAN ACTIVITIES[J]. Marine Geology & Quaternary Geology, 2016, 36(3): 23-33. DOI: 10.16562/j.cnki.0256-1492.2016.03.003

浙江近岸泥质区近140年来重金属元素沉积记录及其对长江流域人类活动的响应

DEPOSITIONAL RECORDS OF HEAVY METALS FOR THE LAST 140 YEARS IN THE ZHEJIANG COASTAL MUDDY AREA OF THE YANGTZE RIVER BASIN AND THEIR RESPONSES TO HUMAN ACTIVITIES

  • 摘要: 对取自浙江近岸泥质区的柱状样DZ-28沉积物进行了粒度分析、210Pb和137Cs同位素测年分析以及常量元素和重金属元素(As、Cd、Cr、Cu、Hg、Pb和Zn)含量分析,并用综合污染指数和潜在生态危害指数评价了近140年来研究区重金属污染程度的变迁。结果表明:柱状样沉积物的平均沉积速率为0.85 cm/a;Al、Fe、K、Mn和Mg的含量与中值粒径具有相似的变化趋势,它们在20世纪80年代后含量逐渐增加,而Si和Ca则具有相反的变化趋势,这可能是由长江流域内大坝修建等一系列水利工程建设和上游水土保持工作的广泛开展所引起的;重金属元素含量在1982年前基本保持不变;在1982-2005年间均出现较大幅度增长,表明长江流域的人类活动强度在80年代后显著增加,导致巨量的重金属污染物被释放到长江中并被输送到研究区域,从而导致沉积物中这些元素的绝对含量明显升高;2005年后,Cu、Cr和Zn的增加趋势减缓,表明该时期内我国的环保政策等措施有效地控制了重金属污染物的排放,而Pb含量的增加可能与这一时期三峡大坝蓄水有关;研究区的重金属综合污染程度和潜在生态危害程度均低,表明近140年来研究区所面临的生态风险程度很低。近140年来重金属分布及演化特征与长江流域经济发展和国家环境保护政策等人类活动密切相关。

     

    Abstract: The sediment samples of the vibrocore DZ-28 taking from the Zhejiang coastal muddy deposits are analyzed for grain-size, 210Pb and 137Cs isotopic activities, concentrations of major elements and heavy metals (Cu, Pb, Zn, Cr, Cd, As, Hg) by the authors. In addition, the comprehensive contamination degree (Cd) and potential ecological risk (RI) are adopted to evaluate heavy metals contamination in the study areas during the past~140 years. The sedimentation rate of the core DZ-28 is 0.85 cm/a, based on 210Pb dating. The contents of Al, Fe, K, Mn and Mg increase significantly since early 1980s and the grain-size shows a similar temporal distribution pattern, except the temporal variations of Si and Ca contents in an opposite trend. This may be caused by the construction of water conservation projects such as dam construction in the Yangtze River Basin and the extensive development of water and soil conservation work in the upper reaches of the river. The absolute concentration of heavy metals was nearly constant before early 1980s, and then it was substantially increased from the early 1980s to the middle 2010s, presumably due to the significant increase in heavy metals pollutants from the Yangtze River Basin. After the middle 2010s, the growth rates of absolute concentration of Cu, Cr, and Zn slow down, suggesting that the emission of heavy metals from the Yangtze River Basin has reduced likely due to the effective measures of environmental protection in China, but the Pb content remains significantly increased, possibly owing to the operation of Three George Dam (TGD). The economic risk in the study areas was minor during the last century as evidenced by the far low value of Cd and RI. Our research results demonstrate that the distribution and evolutional characters of heavy metals during the last 140 years in the study area are closely associated with the human activities in the drainage of the Yangtze River.

     

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