Agriculture and Environmental Science Academy, Haridwar, India
Abstract
Periwinkle snails Tympanotonus fuscatus var radula, an important shellfish in the Niger Delta ecological zone are on the decline and they have not been considered in environmental risk assessment due to the lack of standardized protocols. The gastropod is an abundant species and widely distributed in the aquatic Niger Delta environments. In this study T. fuscatus var radula was exposed to ParaeForce(e), a solution of paraquat dichloride, a non-selective commonly used organochlorine herbicide due to it sensitivity to chemical compounds, as pollution indicators. The effect of lethal and sub lethal exposure of ParaeForce® was assessed using the Organization for Economic Development and Cooperation (OECD) #218 protocol to determine the toxicity and safe limit concentrations. The lethal exposure gave an average LC50 of 0.665 mg/kg with a safe limit of 0.0665 mg/kg. The sub lethal test showed that the exposed organisms reduced significantly in body mass at levels of P < 0.05 when compared to the control experiment. Mean percent growth rate relative to the control reduced from 100% to 47% while the highest growth inhibition of 53% was observed in the highest concentration. Thus, the release of the test chemical and other similar herbicides into the environment may cause alteration and loss of body mass in periwinkle molluscs due to their toxic potentials. It is important to exercise caution in the application of this herbicide especially in the aquatic environment for weed control
