Bacey Juanita, Spurlock Frank
California Environmental Protection Agency, Environmental Monitoring Branch, California Department of Pesticide Regulation, 1001 I Street, Sacramento, CA 95812, USA.
Environ Monit Assess. 2007 Jul;130(1-3):483-93. doi: 10.1007/s10661-006-9438-8. Epub 2006 Oct 28.
This project was designed to establish baseline aquatic biological community structure and physical habitat conditions in select wadeable streams within the California Central Valley. A secondary objective was to evaluate possible water quality differences between site types and seasons. Two agricultural and two urban streams were monitored in spring and fall for two consecutive years beginning in the fall of 2002. Bioassessment sampling was conducted according to modified US EPA methods. The study included physical habitat assessment, water and sediment chemical analysis and characterization of the benthic macroinvertebrate community at each site. Water samples were analyzed for selected organophosphate insecticides, pyrethroid insecticides and herbicides, while sediment samples were analyzed for pyrethroids only. All sites had substantial physical habitat and water quality impairments, and the absence of pollution intolerant macroinvertebrates and dominance of pollution tolerant macroinvertebrates were indications of biological impairment. Due to the limited amount of water quality and pesticide data collected, it was not possible to definitively demonstrate any cause and effect relationships between BMI community structure and water quality or pesticide concentrations. Though most physical habitat parameters were similar and EPA physical habitat scores revealed on no significant differences between urban and agricultural sites (P=0.290), a significant difference was seen in substrate embeddedness (P=0.020). Dominant taxon found at all sites were chironomids, amphipods, and oligochaetes. Benthic macroinvertebrate metrics were significantly different between both types of sites (P=0.001) and seasons (P=0.014). Chironomidae taxon and those of the functional feeding group scrapers were greater at urban sites, while those of the functional feeding group filterers were greater at agricultural sites. In addition, the metric groups Chironomidae, filterers, and predators were found in greater numbers in the spring than the fall.
本项目旨在确定加利福尼亚中央谷地部分可涉入溪流的水生生物群落结构基线和物理栖息地条件。次要目标是评估不同场地类型和季节之间可能存在的水质差异。从2002年秋季开始，连续两年在春季和秋季对两条农业溪流和两条城市溪流进行监测。生物评估采样按照美国环境保护局修改后的方法进行。该研究包括每个场地的物理栖息地评估、水和沉积物化学分析以及底栖大型无脊椎动物群落特征描述。对水样进行了选定有机磷杀虫剂、拟除虫菊酯类杀虫剂和除草剂的分析，而沉积物样本仅分析了拟除虫菊酯类。所有场地的物理栖息地和水质都有严重损害，缺乏耐污染大型无脊椎动物以及耐污染大型无脊椎动物占主导地位表明存在生物损害。由于收集的水质和农药数据有限，无法确切证明底栖大型无脊椎动物群落结构与水质或农药浓度之间的任何因果关系。尽管大多数物理栖息地参数相似，且美国环境保护局的物理栖息地评分显示城市和农业场地之间无显著差异（P = 0.290），但在基质嵌入度方面存在显著差异（P = 0.020）。在所有场地发现的优势分类群为摇蚊、端足类和寡毛类。两种场地类型（P = 0.001）和季节（P = （0.014）的底栖大型无脊椎动物指标存在显著差异。摇蚊科分类群和功能性摄食组刮食者在城市场地较多，而功能性摄食组滤食者在农业场地较多。此外，春季的摇蚊科、滤食者和捕食者指标组数量比秋季更多。
