Health risk assessment of drinking water: Case study of city of Latacunga and the canton of Pedro Vicente Maldonado (Ecuador)

Abstract

Introduction. The quality of drinking water in the city of Latacunga and the canton of Pedro Vicente Maldonado was investigated. The health risk assessment related to the use of the studied water after its treatment was carried out. Materials and methods. Drinking water quality was assessed according to the Ecuadorian and Russian hygiene standards. Methodological recommendations in the study were used to calculate risks for indicators and chemicals characterized by the olfactory-reflex effect of exposure to drinking water, as well as guidelines to assess the risk to public health when exposed to chemicals of a non-carcinogenic and carcinogenic nature. Carcinogenic risk study was conducted by taking into consideration the potentially carcinogenic substances such as trihalomethanes and volatile organic compounds. The chemical safety of drinking water and the effectiveness of water treatment measures were carried out based on an comprehensive assessment of the quality of drinking water. Results. When analyzing drinking water in the city of Latacunga, exceedance of the Ecuadorian and Russian hygienic standards was revealed in terms of such indicators as phosphates (up to 1.3 TLV), bromoform (up to 1.6 TLV) and dibromochloromethane (up to 4 TLV). According to the criteria for assessing the risk of reflex factors when using drinking water in the city of Latacunga and in the canton of Pedro Vicente Maldonado, the risk of immediate action is at the acceptable level of risk. In accordance with the criteria for assessing the magnitude of the non-carcinogenic risk of chronic exposure to water in the city of Latacunga, assessed by the effect of non-specific action, it can be considered as a matter of concern, and the water of the canton of Pedro Vicente Maldonado can be considered as acceptable. The individual carcinogenic risk in both cities is at an unacceptable carcinogenic risk level. Assessment of the integral indicator of the hazard of drinking water revealed the lack of chemicals safety of drinking water treatment both in the city of Latacunga and in the canton of Pedro Vicente Maldonado and poor efficiency of water treatment. Limitations. This study does not show the effect of seasonal changes in the course of the integral assessment of drinking water as per chemical safety parameters. Conclusion. The results obtained underline the need for special attention to the substances formed during disinfection, since high hazard indices are due to the content of trihalomethanes, especially bromodichloromethane and dibromochloromethane.