Toxicity of non-selective herbicide-Paraeforce® to Periwinkle snail Tympanotonus fuscatus var radula

Doris Fovwe Ogeleka; Emmanuel Temiotan Ogbomida; Precious Aghogho Odivwri; Lawrence I.N. Ezemonye; Felix Ebodaghe Okieimen

Doris Fovwe Ogeleka ¹ , Emmanuel Temiotan Ogbomida ² , Precious Aghogho Odivwri ³ , Lawrence I.N. Ezemonye ⁴ , Felix Ebodaghe Okieimen ⁵

¹ Department of Chemistry, Federal University of Petroleum Resources, Effurun, Delta State, NIGERIA
² Ecotoxicology and Environmental Forensic Unit, National Centre for Energy and Environment (Energy Commission of Nigeria), University of Benin, Benin City, Edo State, NIGERIA; Laboratory of Toxicology, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita ku, Sapporo 060-0818, JAPAN
³ Department of Chemistry, Federal University of Petroleum Resources, Effurun, Delta State, NIGERIA
⁴ Department of Animal and Environmental Biology (AEB), Faculty of Science, University of Benin, Benin City, Edo State, NIGERIA
⁵ Geo-Environmental and Climate Change Adaptation Research Centre, University of Benin, Benin City, NIGERIA

✉ Coressponding author: See PDF.

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.