Abstract
Two controlled release formulations (CRF) of copper sulphate as a molluscicide loaded onto natural clay are described. A binding agent such as cement is preferable to heat treatment. The accumulative release of copper ions in water for 6-8 weeks revealed that these CRF follow a zero order release system of theoretical life of 270-350 days. The released dose is 0.3 to 0.15 mu g/ml daily which is above the lethal dose for the host schistosomiasis snails.