Health Risks Associated with Contaminants in the Lake Bosomtwe, Ghana.

Abstract

This study assessed the physicochemical, microbial, and heavy metal contamination of water from Lake Bosomtwe and the associated health risks using a cross-sectional design. A total of 100 respondents from surrounding communities participated in a survey on water use and waste management practices, and 50 water samples were collected from multiple locations in the lake using cluster sampling. Physicochemical parameters were analyzed using standard procedures: pH was measured with a Mettler Toledo SevenCompact pH meter, turbidity with a Hach 2100Q turbidimeter, total dissolved solids (TDS) and electrical conductivity (EC) using Hanna HI 8734 and HI 9033 meters, and fluoride, sulphate, nitrate, and free chlorine were determined using a Hach DR 6000 spectrophotometer following SPADNS, turbidimetric, cadmium reduction, and DPD titrimetric methods. Microbial quality for Escherichia coli, Total Coliforms, Faecal Coliforms, Salmonella, and Enterococcus was assessed using membrane filtration and selective culture media (APHA, 2017). Heavy metals, including arsenic and mercury, were quantified using atomic absorption spectroscopy (PerkinElmer AAnalyst 800) with graphite furnace digestion and calibration standards. The results showed that physicochemical parameters were within acceptable limits: pH (8.6–8.8), turbidity (0.90–4.50 NTU), TDS (85–420 ppm), fluoride (0.45–0.80 mg/L), sulphate (3.8–60 mg/L), EC (290–1600 µS/cm; mean ~1350 µS/cm), nitrate (22–70 mg/L), and free chlorine (0.00–0.04 mg/L). Microbial loads of E. coli (~280,000 CFU/g), Total Coliforms, and Faecal Coliforms exceeded WHO guidelines, which recommend 0 CFU/100 mL for drinking water and ≤1,000 CFU/100 mL for recreational water. Salmonella was not detected, while Enterococcus was present in high concentrations. Arsenic concentration was elevated at 85 µg/L and mercury at 0.0006 µg/L. Hazard quotients (HQ_ing and HQ_derm) and the hazard index (HI = 0.42–0.56) indicated that non-carcinogenic risks were generally within acceptable limits, though chronic exposure could pose health concerns. Regarding waste management, 63% of respondents lacked proper disposal infrastructure, with open dumping (34%) and burning (28%) being common. However, 78% were willing to participate in recycling if facilities were provided, and 81% of law-aware respondents engaged in clean-up efforts. Perception of plastic waste as a serious issue was significantly associated with willingness to recycle (Chi-square = 95.00, p < 0.001). The study concludes that Lake Bosomtwe’s water quality is compromised, posing health risks from microbial and heavy metal contamination. Mitigation strategies are recommended to safeguard this important ecological and recreational resource.