The impact of land use and land cover change on the stream water quality in Limbe I municipality, Cameroon

Abstract

Inland aquatic ecosystems cover 0.1%–3.0% of Earth's surface. They provide different ecosystem services to the area, such as drinking water, transportation, and hydropower generation. However, increasing land use changes threaten their ecological integrity. This study aims to assess land use and land cover change and their impact on stream water quality in Limbe I municipality. The study was conducted in the rainy season, with sampling points chosen based on anthropogenic impacts. Hanna multi-probe model number HI9829 was used for in-situ measurements. The research detects and presents changes in the vegetation cover between three LULC maps (1990, 2010, and 2021). The result suggested that over the last 31 years, vegetation cover decreased by 8.1, 4.8, and 10.6 hectares, respectively. The settlement expanded by 23.5 hectares in the years 1990–2021. In situ measurements, temperature ranged from 23 to 25.8°C; pH, 8–9.4; DO, 1.0–5.9 mg/L; turbidity, 12.4–449.5 NTU; phosphorus, 1–3.4 mg/L. Iron ranges from 0.39 to 0.49 mg/L; cadmium from 0.025 to 0.03 mg/L; and lead from 0.07 to 0.15 mg/L. The heavy metal levels exceed the World Health Organization's acceptable limits for recreational water. The study indicated that the water quality was poor for swimming and aesthetic uses. Total bacteria count ranges from 8500 to 41,000 cfu/mL; total coliforms, 720–6400 cfu/mL; Escherichia coli, 65–300 cfu/mL; and salmonella, 1–46 cfu/mL. The water's bacteriological load indicates high fecal contamination and exceeds the World Health Organization's drinking water limit. LUCC has affected the physico-chemical and bacteriological quality of the stream water. Hence, the stream needs continuous monitoring of the physico-chemical and biological indicators to safeguard the aquatic ecosystem's environment and public health.