【作者】 吴斌；

【导师】 宋金明；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 环境科学， 2014， 博士

【摘要】 海洋沉积物作为陆源物质的主要接收地，在海洋物质循环中占据极为重要的地位，海洋沉积物的环境质量与水体及生物群落息息相关，对海洋生态系统运转产生影响，所以，科学客观地表征海洋沉积物的环境质量至关重要本学位论文在揭示渤海典型河口和海湾沉积物中重金属与底栖生物群落结构耦合特征的基础上，系统开展了沉积物指标筛选评价阈值和评价方法的解析，构建了海洋沉积物环境质量新型综合评价体系获得了如下的主要结论：1．渤海沉积物中重金属含量水平与底栖生物群落具有对应关系，底栖生物群落结构受重金属的影响具有显著的区域性差异，渤海湾底栖生物群落分布显著受As影响，为As提供了群落水平上的关键生态相关性证据；莱州湾底栖生物在Zn含量较高的站位数量较多，显示在低含量水平下Zn对生物生长的促进作用；锦州湾底栖生物群落受Cu Pb Zn和Cd等重金属严重污染影响，结构和功能受到严重损害，难以在该海域生存渤海湾沉积物金属含量明显反映了沿岸人为活动的影响，南部远岸区站位底栖生物群落结构显著受到重金属影响，多样性较低，软体动物占绝对优势地位典则对应分析(Canonical correspondence analysis，简称CCA)分析结果表明Zn对近岸海域底栖生物的分布影响较大，As和Hg对南部海域的底栖生物的影响也较为显著，其中As与底栖生物群落分布显著相关(F=1.988，P=0.0260)，这为As提供了群落水平上的关键生态相关性证据莱州湾沉积物中重金属具有人为源和自然源，其中河流径流为主要输入途径，相关性分析显示Cu和As可能具有相同来源重金属(Metals-PC1)底栖生物群落结构(DIM1)无显著统计相关性，表明相较于重金属，由河流输入引起的物理栖息环境变化是影响底栖群落结构更重要的因素统计分析还显示Zn与物种总丰度具有显著相关性(rs=0.646, P<0.01)，这表明底栖生物在Zn含量较高的站位数量较多黄河口表层沉积物重金属含量水平整体较低的情况下，统计分析表明生物量大的底栖生物(软体动物)在重金属含量较高的站位数量较多锦州湾生态系统结构和功能严重退化，其沉积物中的Cu Pb Zn和Cd等长期处于高风险水平，其中尤以湾内靠近五里河排污口和葫芦岛锌厂的站位显著，对海洋生态生态系统造成了严重的影响底栖生物调查结果显示仅在零星站位发现极个别的底栖生物，表明在重金属严重污染的影响下，底栖生物仍难以在该海域生存，显示锦州湾沉积物中重金属污染严重2．基于沉积物化学-底栖生物群落结构耦合关系，以底栖生物群落结构变化与否作为沉积物环境质量好坏标准的沉积物环境质量综合评价结果显示，渤海(除锦州湾外)沉积物环境质量并未如先前人们所熟知的那么恶劣在渤海，渤海湾中部渤海中部以及莱州湾西部的沉积物环境质量普遍较好，而沉积物环境质量较差的站位仅分布于渤海湾南部黄河河口附近小清河口及莱州湾北部，其中渤海湾南部海域沉积物质量较差与高含量Hg的影响有关，莱州湾中北部沉积物质量较差与沉积物中高含量的Cu和As的影响有关，而黄河河口附近和莱州湾部分海域沉积物质量较差主要原因可能与以河流输入为主导的物理胁迫因子有关从这些海域的沉积物综合评价结果整体评判，沉积物质量较差的区域并不多，且从历史数据对分析可知，这些海域沉积物物中重金属水平均有显著下降的趋势，因此，渤海(除锦州湾外)沉积物环境质量并没有像先前人们所熟知的那么恶劣3．基于沉积物化学-底栖生物群落结构耦合关系，构建了海洋沉积物环境质量新型综合评价体系，包括筛选出5个组别共18种传统化学致污物和10种备选的新兴致污物的化学指标体系，构建了评价阈值，制定了综合评价指数(IQI)系统分析了化学评价指标的生态相关性，筛选出了5个组别共18种传统化学致污物和10种备选的新兴致污物的新型指标体系；基于柱状沉积物中重金属百年前含量，计算并确定了渤海不同区域的背景值；构建了以9个TECs8个PECs为基础，包含我国近海沉积物区域特征的一致性沉积物质量参考值；以渤海沉积物环境质量综合评价结果为依据，基于证据权重思想，构建了综合评价指数(IQI)更多还原

【Abstract】 Marine sediments are main sinks for terrigenous materials, which play a critical rolein the marine biogeochemical cycles of matters. The environmental quality ofsediment is closely correlated with the water column and the benthic invertebratesinfaunal in particular. Thus a scientifically robust quality assessment framework isvital for marine sediments, since the latter ones are essential component of marineecosystem. Based on systematic study of coupling relationships between toxicmetals and benthic community structure in typical estuarine and marine sediments inBohai Sea, a novel integrated sediment quality assessment framework wasestablished including chemical measurement endpoints, chemical screening values,and an integrated sediment quality index. The main conclusions are as follows:1. The benthic community structures were closely correlated with the toxicmetal in the sediment of Bohai Sea. There were enormous regional variations onthe influences of metals on benthic community structures. Our results indicatedthat As in sediments of Bohai Bay was significantly correlated with the benthiccommunity alteration, providing key evidences in community levels in terms ofecological relevance. In case of Laizhou Bay, a trend of increasing species withincreasing proximity to stations with high concentration of Zn, which wassuggested by positive and significant correlations them. In respect of JinzhouBay, sediments were heavily contaminated by Cu, Pb, Zn and Cd, where onlyfew individuals on very occasional locations were found, indicating hardship forsurvival of benthos. Variations of toxic metals in sediment from Bohai Bay revealed the significantanthropogenic stressors from the coast. The benthic community structures wereapparently influenced by the toxic metals in the southern portion of Bohai Bay, withthe overwhelming predominance of Mollusca species and low diversity subsequently.Canonical correspondence analysis (CCA) results showed the benthic distribution inthe near shore stations was significantly influenced by Zn. For benthic community inthe southern portion of the Bay, CCA also suggested As and Hg were the mostinfluential stressors. Further, As was significantly correlated to the difference ofbenthic community structure at stations in the surveyed area implied by Monte Carlopermutation test (F=1.988, P=0.0260), which provides key evidences of ecologicalrelevance in the community level.For Laizhou Bay, trace metals in this area originate from both the natural andanthropogenic processes, with the riverine inputs predominated. There were alsopossible common sources of Cu and As indicated by significant positive correlations.The major axes of heavy metals (Metals-PC1) and benthic community structure(DIM1) were weak and insignificant correlated, indicating that metals may not be theprimary explanatory factors for benthic alterations. There were significantcorrelations (rs=0.646, P<0.01) between benthic abundance and Zn, which indicateda trend of increasing species with increasing proximity to stations with highconcentration of Zn. In respect of Huanghe River Estuary, the overall metalcontamination level was relatively low. The presence of larger size species (Mollusca)with increasing proximity to stations with higher metal contamination level wasinferred from Pearson correlation analysis between benthic data and chemical data.The Jinzhou Bay ecosystem has been severely degraded. Sediments in the surveyedregion were heavily contaminated by Cu, Pb, Zn and Cd, which poses highecological risks. Our results showed that the higher concentrations of metals werefound in the sediments located near the Wulihe River and Huludao Zinc Smelter,which indicated massive influences of the source locations. Benthic investigationrevealed that there were very few individuals on very occasional locations, which further indicated that the Jinzhou Bay ecosystem were seriously impaired.2. Integrated sediment quality assessment was performed in light of thecoupling relationships between benthic community structure alterations andtheir possible explanatory factors, usually toxic metals. The resulting pictures ofsediment quality in the Bohai Sea (excluding Jinzhou Bay) however showed thatlevels of metal contamination were minor-than-expected.In the study areas, unimpaired sediments were mainly rested far from the rivermouth, including the central portion of Bohai Bay and Bohai Sea, the western part ofLaizhou Bay. Impaired sediments however mainly distributed near the HuangheRiver mouth, Xiaoqinghe River mouth and northern portion of Laizhou Bay.Sediment degradation in southern portion of Bohai Bay was mainly resulted from Hg,while Cu and As may be the caused for sediment impairment in central north ofLaizhou Bay. For sediments in the Huanghe River Estuary and parts of Laizhou Bay,sediment impairment was mainly explained by river dominated stressors such asphysical habitat alteration rather than toxic metals. The overall results of integratedsediment quality assessment showed that the majority of sediment locations were notthe impaired ones. Additionally, Decades records of heavy metals in variouspublication results also suggested a mitigation trend of metals. Therefore, theenvironment quality of sediments in Bohai Sea (except Jinzhou Bay) wasminor-than-expected.3. In light of the coupling relationships between toxic metals and benthiccommunity alterations, a novel marine sediment quality assessment frameworkincluding18measurement endpoints in5categories and10backupmeasurements of emerging contaminants, chemical screening values, and anintegrated quality index was established.A selection of18traditional chemical endpoints distributed in5chemical groups and10backup measurements of emerging contaminants on the basis of the ecologicalsignificances. The geochemical background values for metals were calculated and summarized from the concentrations of metals in deep layers of core sediments formBohai Bay, Laizhou Bay and Jinzhou Bay, respectively. Further, the toxicitythreshold for metals were also derived from9single TECs and8single PECs(including TEL-PEL in China) by the method of consensus-based sediment qualityguidelines. Based on the integrated assessment results of Bohai Sea, an integratedquality index (IQI) was condensed form benthic community structure, predictedtoxicity and sediment contamination through a weight of evidence method.更多还原