基于大型底栖动物群落生物指数的清河水环境模糊综合评价

为评价不同水期清河流域水环境状态,采用模糊综合评价法以大型底栖动物Shannon-Wiener多样性指数、Margalef丰富度指数、Simpson多样性指数、Pielou均匀度指数、FBI(Family Biotic Index)指数和敏感性指数6个生物指数为评价因子进行水体等级隶属度计算,综合比较得到枯水期和丰水期各点位的水体状态等级。清河流域大型底栖动物群落结构组成及生物指数在枯水期和丰水期之间发生变化,整体表现为丰水期生物物种丰度、多样性、丰富度及敏感性指数大于枯水期,清河及主要支流上游生物多样性及敏感性类群比例较大,下游、乡镇及城区附近的生物类群多样性降低,耐污值高的生物比例增加。模糊综合评价结果表明,枯水期和丰水期水体呈清洁、轻度污染、中度污染的样点比例分别为12.5%、12.5%、75%和18.75%、43.75%、37.5%,清河流域干流及支流上游点位多为清洁和轻度污染,下游点位多呈中度污染状态。

Fuzzy comprehensive evaluation based on macroinvertebrate biological indices for water quality monitoring in the Qing River basin

Macroinvertebrates, the main aquatic organisms in riverine environments, can reflect changes in river water quality. This study used a fuzzy comprehensive evaluation method based on macroinvertebrate indices to evaluate the quality of the water in the Qing River basin during different water periods. Macroinvertebrate species abundance, density, and related indices were first calculated and analyzed. Then the Shannon-Wiener diversity index, Margalef richness index, Simpson diversity index, Pielou evenness index, family biotic index (FBI), and sensitivity index for macroinvertebrates were used as evaluation factors to establish fuzzy and weight matrices and the water grades were calculated. By comparing these grades, the water level of each point in the dry and wet seasons was obtained. The macroinvertebrate community structure and biological indices in Qing River basin changed between dry and wet seasons at different sites. Overall, the abundance, diversity, richness, and sensitivity indices were higher in the wet season than in the dry season. The upper reaches of Qing River and its main tributaries were more biodiverse and sensitive to change than the lower reaches. Biodiversity decreased downstream, near townships and urban areas, and the proportion of benthic macroinvertebrates with a high tolerance for pollution increased. The results of the fuzzy comprehensive evaluation showed that the proportion of clean, slightly polluted, and moderately polluted samples from the dry and wet seasons was 12.5%, 12.5%, 75% and 18.75%, 43.75%, 37.5%, respectively. The number of moderately polluted sites decreased and the number of clean and slightly polluted sites increased, during the wet season. Most of the upper reaches of the main stream and its tributaries were clean or slightly polluted while the lower reaches were mostly moderately polluted.