Study of water quality using benthic biological indicators in rural and urban streams

Abstract Methods other than physical-chemical and geochemical analyses can be used to assess water quality in surface drainage. This study used intolerant, tolerant and resistant benthic species as bioindicators of changes in water quality of two streams, taking in account particle size of sediments and volatile solids. Eight points were sampled in the stream Bandeirinha and four points in the stream Josefa Gomes in January and September 2013 in the municipality of Formosa-GO. The two streams were chosen in order to study two different environments. The study used the diversity indexes of Shannon (H), Equitability (E) and Bray-Curtis Similarity and the grouping analysis method UPGMA (Unweighted Pair Group Method with Arithmetic Mean). The results of particle size and volatile solids study of Bandeirinha stream located in rural areas showed bioindicator species intolerant of changes in water quality. The stream Josefa Gomes, completely inserted in an urban environment, showed alteration identified by tolerant and resistant species. The results demonstrate differences in water quality in the rural and urban environments and the relationship of bioindicators with sediments. The study aids the interpretation of changes in the water quality of the two drainages areas. Analysis of water quality based upon benthic biological indicators associated with physical-chemical and geochemical analyses of water and sediments provide a better interpretation of the results.

摘要：除理化分析与地球化学分析外，其他方法亦可用于地表排水的水质评价。本研究以不耐污、耐污及抗污底栖生物（benthic species）作为两条溪流水质变化的生物指示物，同时考量沉积物粒径与挥发性固体含量。2013年1月与9月，在戈亚斯州福尔摩沙市（Formosa-GO）的班德林哈溪（Bandeirinha）与若泽戈麦斯溪（Josefa Gomes）分别布设8个与4个采样点。选取这两条溪流旨在对比研究两种不同的生境环境。本研究采用香农多样性指数（Shannon (H)）、均匀度指数（Equitability (E)）与Bray-Curtis相似性指数，并使用非加权组平均法（Unweighted Pair Group Method with Arithmetic Mean, 简称UPGMA）开展聚类分析。对地处农村区域的班德林哈溪开展沉积物粒径与挥发性固体分析的结果显示，其对应的生物指示物种为不耐污类群，提示其水质未出现显著改变；而完全处于城市生境中的若泽戈麦斯溪，则通过耐污与抗污类群的生物指示结果，体现出水质已发生改变。研究结果证实了农村与城市生境的水质差异，以及生物指示物与沉积物之间的关联关系。本研究有助于解读这两处地表排水区域的水质变化情况。将底栖生物指标与水体、沉积物的理化及地球化学分析相结合的水质评价方法，可对研究结果提供更具说服力的解读。