Chemometric Assessment of Orashi River after Confluence with Oguta Lake

This study was carried out to evaluate the surficial water and sediment of Orashi River after confluence with Oguta. A total of 50 sub-samples were collected for the two media and were homogenized to form 10 composite samples (5 each). Water and sediment samples were analyzed for heavy metals concentrations and physico-chemical parameters. Data obtained was interpreted using ten chemometric models and standards of the Federal Ministry of Environment as touchstone values. Approximately 100 % of water samples were contaminated as opposed to 40 % of sediment samples. Both water and sediments showed that Cd  as the highest contaminant with contamination factors of 38 and 1.52 respectively. Water revealed pollution load index higher than sediment probably due to its dissolution ability to metals. Geo accumulation index was observed to have highest value for Cd (45) at point A while Fe (> 4) at all points and same time the highest negative value. All points exhibited very high ecological risk (RI; 1112.7–1473.9) for water while sediments at those points showed low (RI Cd>Ag>Cr>Fe>Cu>Mn>Co>Ni. In conclusion, the water was polluted but good for irrigation use. However, continuous use could lead to health problems due to bioaccumulation of metals while sediments were generally not polluted and of good qualit

Dynamism in plankton species occurrence and diversity of an impacted aquatic ecosystem, Southeastern Nigeria

Anthropogenic activities in rivers have been a major ecological problem affecting river morphology, water hydraulics, aquatic bio-systems and processes, and general water quality. This study established the diversity of planktons and physicochemical properties of dredging site of Otammiri River, Imo State. Water samples were collected from upstream, dredging site and downstream, with the aid of clean water sampling bottles and immediately transported to the laboratory for analysis. Plankton net of 55µm mesh was used to collect plankton samples and immediately transferred to plastic containers for microscopic examination, enumeration and classification. Occurrences of phytoplankton and zooplankton species were determined while Index of Diversity was computed using Margalef’s model. Multivariate redundancy analysis and biplot were used to show association among the planktons and the proportion of their occurrences at the sampling points. Phytoplankton was classified into Bacillariophyceae (Diatoms) (51.19%), Cyanophyceae (26.62%), Chlorophyceae (14.68%), Euglenophyceae (2.05%), Chrysophyceae (3.07%), and Xanthophyceace (2.39%); while zooplanktons were classified into Protozoa (47.06%), Rotifera (35.29%) and Cladocera (17.65%). Index of Diversity for phytoplankton species were: upstream (4.82), dredging site (5.19) and downstream (5.82); while for zooplankton were (1.86), (0.91) and (1.37) respectively. Physicochemical parameters showed significant variation (P<0.05) at the different sampling points. Dredging and other anthropogenic activities might be responsible for alterations in physicochemical characteristics and diversity of planktons in Otammiri River with consequences of ecological imbalance in the aquatic ecosystem