The Study On Integrated Assessment Method Of Ecological Quality Status And Its Application In Coastal Waters

Due to the effection of human activities such as land reclaimation, unreasonable exploration of marine resource, aquaculture and pollutants discharge, et al., the coastal ecological environment was subjected to increasing pollution and damage, including physi-chemical change, habitat destruction and ecological diversity viriation, et al. Assessing the Ecological quality status (EcoQS) comprehensively offers positive bases for evaluating and ranking the severity of disturbance and pollution of coastal waters, and plays an important role in the course of related decision-making regarding effective remediation and management of the deteriorated ecosystem. In this study, after the EcoQS integrated assessment methods of coastal waters abroad and domestic being reviewed and discussed, the EcoQS integrated assessment method which based on'OOAO'principle proposed by WFD was modified for being used in China, and a new EcoQS integrated assessment method based on fuzzy mathematic theory was constructed. Five bays including Dongshan Bay, Tong'an Bay, Quanzhou Bay, Xinghua Bay and Luoyuan Bay in Fujian coastal water were selected as examples for application of the two methods.The research contents of this study include:(1) The EcoQS of Chinese coastal waters and the advances in EcoQS integrated assessment.The EcoQS of Chinese coastal waters and the reasons caused its deterioration were analysed first. Then the basic concept of EcoQS and the theoretical basis of its integrated assessment in coastal waters were outlined. Further the advances in EcoQS integrated assessment domestic and abroad were reviewed and the typical EcoQS integrated assessment methods were introduced. At last, the existing problems in EcoQS integrated assessment in China and the technical route of this study were proposed.(2) Analysis the quality of each element in study area.The natural general conditions, physicochemical and chemical status, ecological status and anthropogenic disturbances information of the five representative bays were analysed to provide references for the index selection in integrated assessment and the test of evaluation results in further study.(3) Study on the coastal EcoQS integrative assessment method based on'OOAO principle' and its application.Based on the monitoring items of coastal water in China and the data collected, the EcoQS evaluation index system for coastal waters in The European Water Framework Directive (WFD) was adjusted. According to historical data collected, the typespecific reference conditions of physicochemical and biological elements of Tong'an Bay and Luoyuan Bay were established. The EcoQS of study area was assessed based on'OOAO principle', i.e., the worst status of the element used in the assessment determines the final status of a water body. The results showed the assessed EcoQS grades were not high, all the satations in Dongshan Bay, Tong'an Bay and Quanzhou Bay were assigned lower than "Moderate", which meant the ecosystem was obvious polluted and affected by human disturbances and has deteriorated. Stations in Luoyuan Bay and Xinghua Bay were ranked from "Good" to "Moderate", which meant the ecosystem was on the threshold of deterioration.(4) Study on the coastal EcoQS integrative assessment method based on fuzzy mathematic thoery and its application.Based on the EcoQS integrated assessment methods for coastal waters abroad as well as the domestic related research status,11indices were selected from the biotic and physicochemical elements of water and sediment to built an integrated EcoQS assessment index system, and, with the comprehensive consideration of domestic and international evaluation standards,5levels of EcoQS classified as "high, good, moderate, poor, and bad" were determined. Then, an EcoQS integrated assessment method for coastal waters was established by using analytic hierarchy process (AHP) and fuzzy mathematics method, and was applied in study area. Results showed that more than80%stations were ranked higher than "Good" and the gradient of EcoQS was also obvious from "Bad" to "High". Seveal stations in Tong'an Bay and Quanzhou Bay were lower than "Moderate", even "Poor" or "Bad", which meant the ecosystem was markedly polluted and affected by human disturbances and has deteriorated. The EcoQS of Dongshan Bay, Xinghua Bay and Luoyuan Bay were on a good condition from "High" to "Good".(5) Results and discussion.For each methodology, an obvious EcoQS grade gradient was observed on the whole, which indicated the methodology could distinguish the degree of pollution and anthropogenic disturbances to some extent. The rationality and objectivity of evaluation results were tested by the anthropogenic disturbances information and the correlations analysis between the EcoQS grade and pollutant concentrations of study area. Validation indicated78.7%of stations were classified as rational assessment results by method based on "OOAO" principle and results for stations subjected to higher anthropogenic pressures were all rational. For FIAM, the propotion was54.3%and much higher for stations subjected to lower anthropogenic pressures. Last, on the base of the former study, the problems should be taken into account when the two methods were applied in other coastal waters, and the suggestions for the construction of EcoQS integrated assessment method in coastal water in China were proposed.