Use of QSARs to promote more cost-effective use of chemical monitoring resources. 2. Screening chemicals for hydrolysis half-lives, Henry's Law constants, ultimate biodegradation potential, modes of toxic action and bioavailability

To promote more cost-effective use of chemical monitoring resources, quantitative structure activity relationships (QSARs). are proposed as methods to identify chemicals that could be found in, and cause adverse effects to, organisms in water, sedi-: ment and soil from the Great Lakes basin. QSARs were used to evaluate the hydrolysis half-lives, Henry's Law constants, ultimate biodegradation potential in water, modes of toxic action and bioavailability of 47 industrial chemicals and pesticides, 20 direct food additives, 13 indirect food additives, and 7 pharmaceuticals that were previously predicted to partition to sediment and to have bioconcentration or aquatic toxicity potential or potential to not biodegrade readily in sediment (Walker et al. 2004). Using these QSARs Will promote more cost-effective use of chemical monitoring resources by allowing researchers to focus their analytical techniques on measuring chemicals that are not likely to hydrolyze, volatilize or biodegrade rapidly to carbon dioxide, but are likely to have specific modes of toxic action and be bioavailable.