Comprehensive physico-chemical and heavy-metals profiling of the Epe Lagoon in south-western Nigeria

Abstract

This study focuses on surface water around the south-western part of Nigeria. This research studies the lagoon's types and amounts of chemical and heavy metal pollutants. It also checks if the lagoon water is safe to use for household purposes. This study characterised the physicochemical parameters and heavy metals in one of the major accessible lagoons. Water samples were gathered during two seasons (wet and dry) in 15 different sampling and control areas and examined using accepted standard measures and methodology. The results showed no significant difference statistically (p>0.005) at 95% confidence between the obtained results from the sampling areas. The results show a pH range of 7.12 to 8.30 and 7.22 to 8.30, total suspended solids to be 25 to 41 mg/L and 28 to 34.5 mg/L, biochemical oxygen demand to be 0.89 to 2.08 mg/L and 0.01 to 1.61 mg/L, dissolved oxygen, 7.12 to 9.0 mg/L and 3.12 to 3.19 mg/L; chemical oxygen demand, 2.8 to 3.84 mg/L and 3.60 to 4.78 mg/L; copper, 0.01 to 0.19 mg/L and 2.23 to 5.04 mg/L; and cadmium, 0.01 to 0.15below mg/L and 3.61 to 5.32 mg/L for the wet and dry seasons, respectively. Some of the obtained results do not agree with the recommended standard quality of water by the World Health Organisation, as well as the Nigerian Standard for Drinking Water Quality; however, the lagoon is safe for public health, provided proper monitoring of human activities around it is done regularly.