Abstract

The relationship of various benthic metrics to physical habitat metrics, pyrethroids, metals and sediment parameters was evaluated for a 10 year data set in Pleasant Grove Creek (Roseville, California) using univariate linear models, stepwise multiple regressions, and canonical correlation analysis. In general, total physical habitat scores in this residential stream were considered to be marginal to suboptimal. The most dominant benthic taxa were generally considered to be tolerant of environmental stressors and the benthic communities were rated as impaired based on a benthic index. Potentially toxic sediment concentrations of cadmium, chromium, copper, nickel and zinc were reported at various sites based on a comparison with existing threshold effect levels. The sum of pyrethroid Toxics Units (TUs) indicated that 10 of 21 sites based on a sensitive Hyalella laboratory toxicity test had TUs greater than one thus suggesting toxicity at various sites. In summary, the effects of the physical habitat, as reflected by certain habitat metrics that were indicative of stream-flow, hydrology, habitat diversity, and substrate quality overshadowed any apparent effects of pyrethroids and metals on shaping resident benthic communities when all environmental variables were considered in multivariate analyses.

摘要

使用单变量线性模型，逐步多元回归和典型相关分析，对普莱森特格罗夫克里克（加利福尼亚州罗斯维尔）的10年数据集评估了各种底栖生物指标与物理生境指标，拟除虫菊酯，金属和沉积物参数之间的关系。通常，此居住流中的总体物理栖息地得分被认为是次优的。一般认为，最主要的底栖生物分类是环境胁迫的耐受性，根据底栖生物指数将底栖生物群落定为受损。根据与现有阈值影响水平的比较，在各个地点报告了镉，铬，铜，镍和锌的潜在有毒沉积物浓度。透明质酸实验室毒性测试的TU大于1，因此表明在不同部位均具有毒性。总而言之，当所有环境变量均为在多元分析中考虑。