Heavy metals and Microbial assessment of Aguda-Ijesha canal, Lagos, Southwest, Nigeria

Abstract Canals are generally known to draw water from surrounding wetlands which then have negative impacts on surroundings. In tropical areas, residents in proximity to such canals tend to suffer from diseases such as malaria and typhoid due to the stagnancy of these canals. This study therefore, investigated the ecotoxicological and health threats of Aguda-Ijesha canal by microbiological and heavy metals analysis. Atomic absorption spectroscopy (AAS) and microbiological examinations were done to water samples obtained from this canal, using standard protocols and compared with the World Health Organization (WHO) permissible limits. The microbiological analysis indicated that the canal is abundant in harmful microorganisms, with bacteria, fungi/yeast, and fecal coliform accruing counts of 4.70 x 10⁷ 2.0 x 10³, and 1.10 x 10³ respectively. Isolated microorganisms included Bacillus subtilis, Micrococcus spp, Pseudomonas aeruginosa (bacteria), Fusarium spp (fungi), and Escherichia coli (fecal coliform). Heavy metal analysis revealed that the concentrations of cadmium, copper, zinc, and lead surpassed the allowable limits recommended by the World Health Organization (WHO). The specimen contained cadmium at a mean value of 0.031±0.002, while copper had a mean value of 0.414±0.002, the mean value of zinc was 2.428±0.080, and finally, lead had a mean value of 0.033±0.001. These findings pose grave public health hazards for the inhabitants, particularly those who are close to the canal. Therefore preventive and punitive measures need to be enacted, to mitigate the amount of indiscriminate waste disposal, as well as exercises like disinfection and dredging to be done intermittently Keywords: Heavy Metals, Pollution, Threat, Toxicity, Waste