International Joint Commission, 100 Ouellette Ave., N9A 6T3, Windsor, Ontario, Canada.
Environ Monit Assess. 1989 Nov;13(2-3):343-57. doi: 10.1007/BF00394239.
Areas of Concern such as the Niagara and Detroit Rivers contain a myriad of point and non-point sources. These are difficult and expensive to monitor and often present unique analytical problems and so are subject to analytical error. The Niagara River Toxics Committee (NRTC) and the Upper Great Lakes Connecting Channels Study Modeling Committee designed programs to indirectly monitor these sources by upstream/downstream sampling at the head and mouth of the rivers. These two studies are compared and the data analysis problems that were encountered are discussed. Upstream/downstream samples were paired to obtain differential loadings wherever possible, but when some results were reported as below the detection limit, a maximum likelihood estimate was used. The resulting differential loading, adjusted for non-point sources, is the total point source load to the river minus any losses due to volatilization, settling or degradation.
关注领域，如尼亚加拉河和底特律河，包含了无数的点源和非点源。这些污染源很难监测，成本也很高，而且往往存在独特的分析问题，因此容易出现分析误差。尼亚加拉河毒物委员会（NRTC）和上大湖连接航道研究模型委员会设计了方案，通过在河流源头和河口进行上下游采样，间接监测这些污染源。本文比较了这两项研究，并讨论了所遇到的数据分析问题。上下游样品进行了配对，尽可能获得差异负荷，但当一些结果报告为低于检测限时，使用了最大似然估计。经非点源调整后的差异负荷，是河流中总点源负荷减去由于挥发、沉降或降解造成的任何损失。
