Interaction of dequat and paraquat with clay minerals and carbon in aqueous solutions.

Abstract

In recent years, the demand for aquatic weed-free surface waters is on the increase. This is occasioned by greater and greater demands by the public for recreational and potable waters. One approach is to control aquatic weed growth in surface waters through the application of chemical herbicides. Several compounds and formulations are available of which diquat (l,l’-ethylene-2,2’-bipyridylium dibromide) and paraquat (1,1’-dimethyl-4,4’-bipyridylium dimethyl sulfate) are effective. These compounds are divalent cations and are quite soluble in water to the extent of 70 percent and greater. Furthermore, these compounds resist biological degradation in aquatic environments (Hemmett 1968). Hence they may persist after an initial application for considerable periods of time and affect water quality for human consumption. The question of organic pesticide effects on water quality has been reviewed recently by Faust and Suffet (1966).