Evaluation of Heavy metals and selected physicochemical parameters of River Rima, Sokoto State, Nigeria

Abstract

The study was conducted along the Sokoto Rima floodplain in the Wamakko area of Sokoto State, Nigeria. Water and sediment samples were collected from River Rima in Sokoto State. Sampling was conducted at three different locations along the river (Dundaye, Kwalkwalawa and Sokoto). Samples were collected twice monthly (during the first two weeks and the last two weeks) over a period of three (3) months. All samples were collected in the early hours of the day and transported to the laboratory for analysis. Four heavy metals (Zn, Pb, Cu and Cd) were analyzed. The determinations were carried   at the Agricultural and Environmental Engineering Laboratory of Usmanu Danfodiyo Univeout rsity, Sokoto. A total of nine 1-L sampling bottles were used for dissolved oxygen (DO) and biological oxygen demand (BOD) analyses. Samples for DO and BOD were fixed immediately by adding 1 mL each of manganese sulphate (MnSO₄) and alkali-iodide azide solution. The concentrations of zinc (Zn), lead (Pb), copper (Cu), and cadmium (Cd) varied across the three sampling stations; Dundaye, Kwalkwalawa, and Sokoto reflecting spatial differences in potential contamination sources. The physicochemical characteristics of River Rima across the study period (June to August) reveal both temporal variations and relative stability among certain parameters, reflecting the influence of seasonal hydrological processes. Regular monitoring and control of anthropogenic activities, particularly at Dundaye should be implemented to prevent potential accumulation of heavy metals and safeguard aquatic ecosystems and public health. Effective management of River Rima should focus on controlling organic and anthropogenic pollutant inputs particularly during the early rainy season through improved waste management and runoff regulation to enhance dissolved oxygen levels and reduce biological oxygen demand.