Llansó Roberto J, Dauer Daniel M, Vølstad Jon H
Versar Inc., Ecological Sciences and Applications, 9200 Rumsey Road, Columbia, Maryland 21045, USA.
Mar Pollut Bull. 2009;59(1-3):48-53. doi: 10.1016/j.marpolbul.2008.11.011. Epub 2008 Dec 12.
To meet the requirements of the Clean Water Act, the States of Maryland and Virginia are using benthic biological criteria for identifying impaired waters in Chesapeake Bay and reporting their overall condition. The Chesapeake Bay benthic index of biotic integrity (B-IBI) is the basis for these biological criteria. Working together with the states and the US Environmental Protection Agency, we developed a method for impairment decisions based on the B-IBI. The impaired waters decision approach combines multiple benthic habitat-dependent indices in a Bay segment (equivalent to water bodies in the European Water Framework Directive) with a statistical test of impairment. The method takes into consideration uncertainty in reference conditions, sampling variability, multiple habitats, and sample size. We applied this method to 1430 probability-based benthic samples in 85 Chesapeake Bay segments. Twenty-two segments were considered impaired for benthic community condition. The final decision for each segment considers benthic condition in combination with key stressors such as dissolved oxygen and toxic contaminants.
为满足《清洁水法》的要求，马里兰州和弗吉尼亚州正在使用底栖生物标准来确定切萨皮克湾受损水域并报告其整体状况。切萨皮克湾生物完整性底栖指数（B-IBI）是这些生物标准的基础。我们与各州及美国环境保护局合作，开发了一种基于B-IBI的受损判定方法。受损水域判定方法将海湾区域（相当于《欧洲水框架指令》中的水体）多个依赖底栖生境的指数与一项受损统计测试相结合。该方法考虑了参考条件的不确定性、采样变异性、多种生境和样本大小。我们将此方法应用于切萨皮克湾85个区域的1430个基于概率的底栖样本。22个区域被判定为底栖生物群落状况受损。每个区域的最终判定结合了底栖生物状况以及诸如溶解氧和有毒污染物等关键压力源。
