【作者】 王长友；

【导师】 王修林；

【作者基本信息】 中国海洋大学 ， 海洋化学， 2008， 博士

【摘要】 本论文针对东海重金属污染状况总体上把握不清等问题,汇总并分析了20世纪80年代初以来东海重金属排海通量及海水中浓度时空变化规律;建立了以浮游植物为实验生物的重金属非检测毒性浓度的现场测定方法,进而以浮游植物生长抑制率为指标参数完善了重金属环境生态效应评价方法,并对东海水生生态系统重金属环境生态效应进行了评价;应用箱式模型方法,结合海域平均浓度空间网格离散化计算方法,首次估算了东海重金属极小海洋环境容量。主要结果如下:1、20世纪80年代初以来东海Cu、Pb、Zn、Cd重金属污染物主要来源于以河流为主的陆源排放,排海总量整体上都呈现先增加、后保持、再降低的不对称倒“U”形变化趋势。(1)对于东海Cu、Pb、Zn、Cd等重金属主要来源,河流排放占东海重金属污染物排海总量的比例处于绝对优势,平均高达88.0%左右,而排污口次之,平均可达7.5%左右,大气沉降最小,平均只有4.5%左右。东海重金属污染物主要来源于以河流为主的陆源排放。对于Cu、Zn和Cd的排放通量,长江流域最高、钱塘江流域次之,闽江流域较小;对于Pb的排放通量,长江流域最高,闽江流域次之,钱塘江流域较小。(2)20世纪80年代初期东海Cu、Pb、Zn、Cd排海总量较低,分别仅有1.68×103、1.69×103、4.26×103、0.073×103 t/a左右,80年代中后期开始逐渐增加,90年代都达到最大值,分别为13.58×103、5.34×103、295.73×103、0.41×103 t/a左右,进入21世纪以后开始降低,目前分别减少到的3.47×103、1.84×103、5.66×103、0.081×103 t/a左右,仍高于20世纪80年代初期的水平。2、20世纪80年代初以来东海海水中Cu、Pb、Zn、Cd重金属浓度平面分布整体上没有呈现出明显的由沿岸向外海递减的分布特征;域均浓度季节变化不明显;年均浓度基本上都呈现不对称倒“U”形变化趋势。(1)20世纪80年代初以来东海海水中Cu、Pb、Zn、Cd浓度差别不大,整体上没有呈现出明显的由沿岸向外海递减的分布特征。高值区主要出现在长江口、杭州湾沿岸、舟山渔场水域。(2)东海海水中Cu、Pb、Zn、Cd域均浓度各季节差别不大,季节变化不明显。(3)20世纪80年代初到80年代中期,东海海水Cu、Pb、Zn、Cd年均浓度都低于国家一类海水水质标准, 20世纪80年代末至90年代末,年均浓度较高,若干年份Cu和Pb年均浓度超过国家二类海水水质标准,Zn、Cd年均浓度超过国家一类海水水质标准,21世纪初年均浓度又逐渐降低,目前均低于国家一类海水水质标准。3、20世纪80年代初期至80年代中期,东海海水中重金属年均浓度对水生生态系统不存在抑制作用,20世纪80年代中后期至90年代末期存在明显抑制作用,21世纪初期基本不存在抑制作用。(1)东海海水中Cu、Pb、Zn、Cd重金属对东海典型浮游植物的非检测毒性浓度分别为4.1、45.2、131.7、138.9μg/L;对东海水生生态系统的非检测毒性浓度分别为4、0.8、20、0.2μg/L。(2)20世纪80年代初期至80年代中期,重金属Cu年均浓度一般低于东海典型浮游植物非检测毒性浓度,对典型浮游植物一般不存在抑制作用,而20世纪80年代中后期至20世纪90年代末抑制作用时有发生,最高年均浓度下估计抑制率可达80%以上,局部水域最高浓度条件下可达90%以上;21世纪初期不存在抑制作用,但局部水域最高浓度抑制率也可达30%。重金属Pb、Zn、Cd的非检测毒性浓度远远高于20世纪80年代初期以来相应的历史最高年均浓度甚至局部水域最高浓度,对东海典型浮游植物种群生长一般不存在抑制作用。(3)对于东海水生生态系统,20世纪80年代初期至80年代中期,重金属Cu、Pb、Zn、Cd年均浓度及局部水域最高浓度低于其非检测毒性浓度,一般不存在抑制作用;而20世纪80年代中后期至90年代末Cu、Pb、Zn、Cd年均浓度高于其相应的东海水生生态系统非检测毒性浓度的情况时有发生,存在明显的抑制作用,最高年均浓度下估计抑制率分别可达85%、10%、30%、20%以上,局部水域最高浓度条件下分别可达95%、30%、60%、50%以上;21世纪初期,Cu、Pb、Zn、Cd年均浓度一般低于其非检测毒性浓度,一般不存在抑制作用,Pb、Zn、Cd局部水域最高浓度下也不存在抑制作用,但Cu局部水域最高浓度抑制率可达30%以上。4、东海Cu、Pb、Zn、Cd重金属污染物极小海洋环境容量分别约为1.70×104、0.47×104、11.31×104、0.071×104 t/a。在当前排海总量条件下,东海Cu、Pb、Zn、Cd重金属极小剩余环境容量分别约为-0.004×104、0.02×104、4.5×104、0.003×104t/a,表明东海最高浓度水团中Pb、Zn、Cd年均浓度仍然满足东海水生生态系统非检测毒性浓度的要求,但大约需要削减相当于当前排海总量8%左右的Cu,才能分别满足该要求。更多还原

【Abstract】 In this paper, aiming at the blurry grasp about contaminated status of heavy metals as a whole in the East China Sea, the heavy metals fluxes into sea and their concentrations since1980 are collected, their temporal and spatial changing trend are analyzed, the in situ mensuration for heavy metal NDEC with phytoplankton as experimenting object is established, and applied to perfect assessment method for environmentally ecological effect with phytoplankton growth inhibition rate as target parameter. Then environmentally ecological effect of heavy metal in the East China Sea is assessed. Based on box model and combination with calculating method of spatial gridding average concentration, minimum environmental capacity in the East China Sea is estimated. Main achievements are described as follows:1. Since the begining of 1980s, contamination Cu, Pb, Zn and Cd into East China Sea largely come from land source especially discharge by river, the changing trend of total fluxes basically took on the pattern of asymmetric inverse‘U’, which increased firstly, then kept up and decreased finally.(1) For the main source of Cu, Pb, Zn and Cd into East China Sea, the flux discharged by rivers is overwhelmingly dominant, being up to 88.0% on average; the sewage takes second place, being 7.5% approximately; sedimentation from atmosphere is smallest, being 5.5% on average. The heavy metals into East China Sea mostly come from the land-based discharge, especially from rivers. The flux of Cu, Zn and Cd from Changjiang drainage area are the highest, that from Qiantangjiang the second and that from Minjiang the lowest. The flux of Pb from Changjiang drainage area are the highest, that from Minjiang the second and that from Qiantangjiang the lowest.(2) The total flux of Cu, Pb, Zn and Cd into East China Sea were about 1.68×103, 1.69×103, 4.26×103, 0.073×103 t/a respectively at the end of 1970s, however, the values began to increase from the middle end of 1980s; in the 1990s, they increased to the max of 13.58×103, 5.34×103, 295.73×103, 0.41×103 t/a respectively, and presently decreased to 3.47×103, 1.84×103, 5.66×103, 0.081×103 t/a respectively, which still higher than those at the beginning of 1980s.2. Since 1980, the horizontal concentration distribution of Cu, Pb, Zn and Cd in the East China Sea don’t basically take on the obvious pattern of decrease from inshore to offshore area, the seasonal changing of spatial average concentrations of them in this sea area isn’t large basically, the chronical changing trend of annual average concentrations of them in this sea area basically take on the pattern of asymmetric inverse‘U’.(1) Since 1980, the concentration changes of Cu, Pb, Zn and Cd are not big in the East China Sea, and their horizontal concentration distributions do not basically take on the clear pattern of decrease from inshore to offshore area. The relatively high concentrations often locate in the Changjiang River estuary, inshore part of Hangzhou Bay and Zhoushan fishery.(2) The difference of spatial average concentration of Cu, Pb, Zn and Cd in the East China Sea is not big seasonally, the seasonal changing is not clear.(3) From the beginning to the middle of 1980s, the annual average concentrations of Cu, Pb, Zn and Cd in the East China Sea are lower than the grade-one sea water quality standard of China. From the end of 1980s to the end of 1990s, the annual average concentrations of them are the highest, with the Cu and Pb levels higher than the grade-two sea water quality standard of China and Zn and Cd concentrations higher than the grade-one sea water quality standard of China. In the beginning of 21st century, , the annual average concentrations of Cu, Pb, Zn and Cd decrease gradually, and are lower than the grade-one sea water quality standard of China at present.3. From the begining to the middle of 1980s, the annual concentration of heavy metal in the East China Sea do not inhibit the water ecosystem, but inhibition exist obviously from the middle end of 1980s to the end of1990s. At the beginning of 21st century, inhibition don’t exist basically. (1) Heavy metal NDECs to typical phytoplankton in the East China Sea are 4.1, 45.2, 131.7, 138.9μg/L respectively, and those to water ecosystem are 4, 0.8, 20, 0.2μg/L respectively.(2) From the begining to the middle of 1980s, annual average concentrations of Cu is usually lower than its NDEC to typical phytoplankton, the inhibition don’t exist. However, in 1990s, inhibition happenes every now and then, the biomass inhabitation rates is estimated to be up to 80% with maximum annual average concentrations and up to 90% with maximum concentrations in partial sea area. At the beginning of 21st century, inhibition don’t exist basically with annual average concentrations but up to 30% with maximum concentrations in partial sea area. NDECs of Cu, Pb, Zn and Cd to typical phytoplankton are higher than maximum annual average concentrations and maximum concentrations in partial sea area since 1980, inhibition don’t exist basically.(3) From the begining to the middle of 1980s, annual average concentrations of Cu, Pb, Zn and Cd are usually lower than their NDECs to seawater ecosystem, the biomass inhibition don’t exist, it is the same with the maximum concentrations in partial sea area. From the middle end of 1980s to the end of 1990s, it happenes every now and then that annual average concentrations of Cu, Pb, Zn and Cd are higher than their NDECs to seawater ecosystem, the biomass inhabitation exist obviously, and the biomass inhabitation rates are estimated to be 85%, 10%, 30%, 20% respectively with maximum annual average concentrations and up to 95%, 30%, 60%, 50% respectively with maximum concentrations in partial sea area. At the beginning of 21st century, annual average concentrations of Cu, Pb, Zn and Cd are usually lower than their NDECs to seawater ecosystem, inhibition don’t exist basically. With maximum concentrations in partial sea area, the biomass inhabitation rate of Pb, Zn and Cd are 0, but that of Cu is up to 30%.4. Minimum oceanic environmental capacities of Cu, Pb, Zn and Cd in the East China Sea are computed to be approximately 1.70×104, 0.47×104, 11.31×104, 0.071×104 t/a, and minimum surplus environmental capacities of them are about -0.004×104, 0.02×104, 4.5×104, 0.003×104 t/a with present gross discharge fluxes, indicating that maximum concentrations of Pb, Zn and Cd in the East China Sea can still comply with their no detected toxic concentrations to seawater ecological system, but 8% of present gross discharge fluxes of Cu must be reduced for satisfying this criterion.更多还原