Presence of pesticides, mercury and trihalomethanes in water supply in Ibagué, Colombia: threats to human health

Chemical contamination of the water supply system caused by anthropic activities can cause adverse health effects. This study determined the presence of toxic metals, organic substances, pesticides and trihalomethanes in the water supply systems of the urban area of Ibague City. The economic and sanitary activities located in the 25 surface streams of the 32 water supply systems of the municipality were characterized. A total of 25 water samples were taken from the surface streams, and 35 samples in the water network of each drinking water service provider for the identification of pesticides (carbamates, organochlorines, organophosphorus), mercury, arsenic, cyanide, lead, cadmium, antimony, cobalt, selenium, silver, nickel and hydrocarbons. The presence of trihalomethanes was sampled after the treatment process given. A total of 775 economic and sanitary activities were detected in the surface streams of the water supply systems, highlighting the human settlements, agricultural and tourist activities impact on the water sources. Organochlorine pesticides (0.009-0.109 mg/L), mercury (0.001-0.004 mg/L) were identified in the water supply system in concentrations higher than those permitted by local regulation. Concentrations of trihalomethanes (0.064-1.260 mg/L) were detected in 68.7% of the water supply systems with treatment. The presence of chemical contaminants occurs mainly in communities with water supply systems of low complexity with high anthropic affectation. It is necessary to strengthen the assessment of hazards and risk by health surveillance, as well as intersectoral intervention for the protection of water sources and the improvement of water treatment technologies.