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A new study suggests that a holistic approach is needed in assessing the potential environmental and health effects of toxic effluent from industry. Studies of industrial effluent toxicity usually focus on a single contaminant, such as an environmental or marine pollutant, a potential carcinogen, or a toxic heavy metal. However, toxicity tests of effluent using bacteria generally underestimate the total toxicity.
http://www.sciencedaily.com/releases/2007/11/071110081909.htm