THE NUMBER OF COMPONENTS IN A MIXTURE DETERMINES WHETHER SYNERGISTIC AND ANTAGONISTIC OR ADDITIVE TOXICITY PREDOMINATE - THE FUNNEL HYPOTHESIS

A new hypothesis, the funnel hypothesis, was derived to explain the va riation in toxicity of equitoxic multicomponent mixtures of nonspecifi c toxicants (narcotics). The variation is explained in terms of the vo lumes associated with solute-solute and solute-solvent interactions. T he hypothesis predicts that as the number of components in a mixture i ncreases, the range of deviation from toxic additivity decreases. It a lso predicts that the toxicity of mixtures measured using biological e ndpoints that require high toxicant concentrations will deviate more f rom toxic additivity than endpoints that require low concentrations. A quatic toxicity data for equitoxic mixtures of narcotic toxicants to a range of aquatic organisms compiled from the literature support the p redictions of the funnel hypothesis. (C) 1995 Academic Press, Inc.