The composition, occurrence, distribution, and possible toxicity of chemical mixtures in the environment are research concerns of the U.S. Geological Survey and others. The presence of specific chemical mixtures may serve as indicators of natural phenomen
Scott, Jonathon C. jcscott@usgs.gov,Skach, Kenneth A. kaskach@usgs.gov,Toccalino, Patricia L.. Software for analysis of chemical mixtures--composition, occurrence, distribution, and possible toxicity. 2013-01-01.