Heavy metal levels in sediment and Callinectes sapidus of Okerenkoko waterfront, Delta State, Nigeria

Abstract

Effluent deposition increases sediment pollution. Information on heavy metal (HM) levels of Okerenkoko Waterfront (OWF) are limited. This study investigated the present levels of HM in OWF and their impacts on Callinectes sapidus. Spatially, OWF was stratified into three stations (1, 2 and 3) based on proximity to key industrial activities, while monthly stratification covered April to July, 2023. Sediment and C. sapidus samples were collected monthly, air-dried at room temperature and preserved in Bouin's fluid respectively. Samples were digested and concentrations of HM (Iron and Copper) mg/Kg determined using Atomic Absorption Spectrophotometer. Data obtained were analyzed using descriptive statistics and ANOVA at α _0.05 Spatially, significantly highest (11.64 ± 0.05 0.11; 3.41 ± 0.32) and least (4.99 ± 2.03; 3.26 ± 0.72) levels of iron and copper recorded in sediments occurred in 1 and 3, while it ranged from 5.02 ± 3.03 to 13.18 ± 0.11 and 7.10 ± 1.46 to 18.19 ± 0.38 for copper and iron in May and July respectively. Spatially, highest (8.49 ± 1.64) and least (4.57 ± 1.17) levels of iron in the stomach of C. sapidus occurred in 3 and 1, while it ranged from 10.13 ± 4.19 to 14.94 ± 2.33 in June and July. Copper concentration ranged from 1.12 ± 0.01 to 5.15 ± 2.09 in May and July in the
stomach of C. sapidus. Concentrations of HM recorded exceed recommended limits. Survival of C. sapidus in OWF has been threatened. Results obtained could serve as baseline reference.