Environmental and Occupational Health Sciences, School of Public Health and Information Sciences, University of Louisville, 485 E. Gray Street, Louisville, Kentucky 40202, USA.
Integr Environ Assess Manag. 2012 Oct;8(4):709-22. doi: 10.1002/ieam.1302. Epub 2012 Apr 25.
A complex interplay of factors determines the degree of bioaccumulation of Hg in fish in any particular basin. Although certain watershed characteristics have been associated with higher or lower bioaccumulation rates, the relationships between these characteristics are poorly understood. To add to this understanding, a dynamic model was built to examine these relationships in stream systems. The model follows Hg from the water column, through microbial conversion and subsequent concentration, through the food web to piscivorous fish. The model was calibrated to 7 basins in Kentucky and further evaluated by comparing output to 7 sites in, or proximal to, the Ohio River Valley, an underrepresented region in the bioaccumulation literature. Water quality and basin characteristics were inputs into the model, with tissue concentrations of Hg of generic trophic level 3, 3.5, and 4 fish the output. Regulatory and monitoring data were used to calibrate and evaluate the model. Mean average prediction error for Kentucky sites was 26%, whereas mean error for evaluation sites was 51%. Variability within natural systems can be substantial and was quantified for fish tissue by analysis of the US Geological Survey National Fish Database. This analysis pointed to the need for more systematic sampling of fish tissue. Analysis of model output indicated that parameters that had the greatest impact on bioaccumulation influenced the system at several points. These parameters included forested and wetlands coverage and nutrient levels. Factors that were less sensitive modified the system at only 1 point and included the unfiltered total Hg input and the portion of the basin that is developed.
各种因素的复杂相互作用决定了汞在任何特定流域鱼类中的生物积累程度。尽管某些流域特征与更高或更低的生物积累率有关，但这些特征之间的关系尚不清楚。为了增加对此的了解，构建了一个动态模型来检查溪流系统中的这些关系。该模型从水柱中跟踪 Hg，通过微生物转化和随后的浓缩，通过食物网到食鱼性鱼类。该模型经过校准，可应用于肯塔基州的 7 个流域，并通过将输出结果与俄亥俄河谷（生物积累文献中代表性不足的地区）内或附近的 7 个地点进行比较，进一步进行评估。水质和流域特征是模型的输入，Hg 的组织浓度为通用营养级 3、3.5 和 4 的鱼类是输出。监管和监测数据用于校准和评估模型。肯塔基州站点的平均平均预测误差为 26%，而评估站点的平均误差为 51%。自然系统内的变异性可能很大，并通过对美国地质调查局国家鱼类数据库的分析对鱼类组织进行了量化。该分析指出需要更系统地采集鱼类组织样本。模型输出分析表明，对生物积累影响最大的参数在几个点上影响系统。这些参数包括森林和湿地覆盖以及营养水平。敏感度较低的因素仅在 1 个点上修改系统，包括未经过滤的总 Hg 输入和流域的开发部分。
