Assessment of Seasonal Variations in Physicochemical Characteristics of Crude oil Polluted Erhioke River, Kokori, Delta State, Nigeria

Abstract

                                                                           Abstract
Erhioke River in Kokori, Delta State, serves as a vital water source for domestic and agricultural use but may be impacted by seasonal pollution from surrounding anthropogenic activities. This study aimed to assess and compare the physicochemical properties of the river during the rainy and dry seasons, using WHO standards as a benchmark for water safety. Water samples were collected across both seasons and analyzed for key parameters including pH, temperature, conductivity, biological oxygen demand (BOD), chemical oxygen demand (COD), sulphate, ammonia, total hardness, total suspended solids (TSS), and total dissolved solids (TDS) using standard analytical methods. The results showed that while pH and conductivity remained within WHO acceptable limits, temperature exceeded the 25°C guideline in both seasons. More critically, BOD (30.99 ± 0.51 mg/L in rainy season; 18.79 ± 0.31 mg/L in dry season), COD (982.00 ± 8.00 mg/L; 560.00 ± 7.00 mg/L), ammonia (2.95 ± 0.45 mg/L; 5.35 ± 0.15 mg/L), and TSS (123.50 ± 3.50 mg/L; 66.50 ± 0.50 mg/L) were significantly above permissible limits, indicating substantial organic and nutrient pollution. Sulphate levels also exceeded the WHO limit during the dry season.

Keywords: Erhioke, River, water, seasonal, variation, physicochemical, parameters.