Effects of organophosphorus pesticides on the marine trochid monodonta turbinata

Abstract

The study deals with the toxic effects of Malathion on the mediolittoral trochid Monodonta turbinata (Born), as carried out in a laboratory. In the preliminary studies, Honodonta tubinata was exposed to Malathion at concentrations ranging from 0.0025mg/l to 5mg/l. The 96 hour LC50 value of Malathion far H.turbinata was found to be between 0.3mg/l and 1.6mg/l. The daily migrations of N. turbinata across the water/air interface were also studied. Reduction in activity and disruption of the normal circadian cycle were recorded when the test organisms were exposed to Malathion at a concentration of 0.5mg/l and O.lmg/l. The histological studies carried out on tissues of the digestive gland and foot epithelium did not reveal any abnormalities in the gross cytological architecture. The ecological significance of these results, together with the suitability of M. turbinata as an indicator species, and the appropriateness of the toxicity tests as bioassays of organophosphorus pesticides are discussed.