ABSTRACT
The presence of contaminants from industrial activities can disrupt the physicochemical characteristics of an aquatic ecosystem and cause severe imbalance to water biota. The aim of the study was to assess the physical and chemical characteristics of water and sediment in relation to benthic macroinvertebrate communities of selected water bodies around Flow station in Delta state. This study was conducted at three stations: Otumara, Saghara and Escravos River in Delta State, Nigeria; designated as Stations 1, 2 and 3 respectively. The water and sediment samples collected monthly from the study stations were analysed for their physical and chemical parameters. Sampling was done between September 2016 and August 2017 across the three study stations.
In-situ parameters were recorded for water, temperatures, total dissolved solid, conductivity and pH. Water and sediment samples were further taken to the laboratory for further analysis. The sediment samples were collected with an Eckman grab sampler and transferred into clean polyethylene bags.
The results of this study showed that majority of the physical and chemical parameters in the surface water were not significant (p>0.05) across the studied stations, except for Electrical conductivity (EC), salinity and turbidity The physical and chemical parameters (EC, Turbidity, TSS, TDS, DO) of the surface water analysed were above the Federal Ministry of Environment Nigeria (FMEnv) and World Health Organisation (WHO) standards. The mean of values obtained for the physicochemical parameters analysed for the surface water ranged from 6.9-7.78 (pH), 4.43-14.96 (salinity), 12.54-13.06mg/L (TSS), 6.02-6.48 mg/L (BOD). Mean values for sediments ranges from 5.21-5.7) (pH). The mean of values obtained for the parameters analysed for the sediments ranged from 4.20-7.09 (pH), 2030.00-21140.00 µS/cm (EC), 125.40-285.20mg/kg (Fe), 1.09-33.20mg/kg (Pb), 0.00-1.56mg/kg (Cd). The results from the assessment of the macrobenthic invertebrates revealed a total of 45 organisms Otumara (11), Saghara (12) and Escravos (12). The relative percentage composition of Benthic macroinvertebrates obtained in the stations, revealed that Gastropoda as the dominant groups; Tympanatomus radula (20.00%) station 1, (31.90%) station 2 and (15.79%) station 3, Tympanatomus fuscatus (11.21%) station 2 and (10.00%) station 3] and Neritina glabrata (10.00%) station 1. This made a total of 83.11% occurrence of the Gastropoda in the studied stations. This was followed by the Oligochaeta. The findings of this study revealed ecosystem impacts from industrial activities, thus affecting the species community structure. The treatment of effluents generated from these flow stations, other industrial and farming activities should be properly managed before being discharged into the surrounding rivers; this would further encourage environmental sustainability.
