Environmental evaluation of the drinking water problems due to fluoride and other related pollutants at "Los Altos de Jalisco", Mexico
The present investigation was based on the hypothesis that one of the most serious environmental problems in Los Altos de Jalisco is the great number of drinking water sources contaminated with toxic elements. This hypothesis was stated due to the following: (1) high prevalence of dental fluorosis; (2) high temperature in tap water of numerous homes; and (3) a large number of towns are located in a region characterized by an intense hydrothermal activity. The main objectives of this research were: (1) to determine the concentration of fluoride and other possible pollutants in drinking water supplies; (2) to estimate the exposure dose to toxic elements detected in drinking water; and (3) to evaluate the potential human health risk associated with the ingestion of contaminated drinking water. ^ More than 130 public water wells were sampled and analyzed to determine fluoride and other potentially toxic elements. Fluoride, arsenic and selenium were the toxic elements that occurred in most of the sampled wells. Fluoride was determined using the ion-selective electrochemical method and the other elements were determined using inductively coupled plasma optical emission spectroscopy. The results showed that more than 46% of the sampled wells have a fluoride concentration greater than 1.5 mg/L, which is the Mexican drinking water standard. At least 34% of the wells exceeded the guideline value of 25 μg/L for arsenic, and more than 95% of the sampled wells have selenium concentrations higher than 10 μg/L, which is the World Health Organization guideline value. ^ Exposure doses to fluoride, arsenic and selenium, recommended by international organizations are 0.05 mg/kg/d, 2.14 μg/kg/d, and 0.87–1.70 μg/kg/d, respectively. Nevertheless, the mean estimated exposure doses to fluoride were 0.92, 0.23, and 0.12 mg/kg/d for babies, children and adults, respectively. For arsenic, the values were 4.4, 2.9, and 1.5 μg/kg/d, respectively. In the case of selenium, the calculated values were 6.7, 5.6, and 3.5 μg/kg/d. These values suggest that babies are the most exposed to the toxic elements. The seed data corroborate the proposed hypothesis. The data also suggest that, besides dental fluorosis, skeletal fluorosis and bone fractures could be a serious problem of public health at Los Altos de Jalisco. Skin diseases, gastrointestinal and cardiovascular problems, and neurological damages, could be caused by the high arsenic concentrations found in the sampled wells. Nevertheless, estimated exposure doses to selenium indicated that the risks to the occurrence of selenosis are minimal. Health problems could be reduced by improving the enforcement of the law, and developing a risk communication program promoting healthy nutritional practices addressed to mitigate drinking water toxicity. Epidemiological studies should be conducted to determine the prevalence of health problems caused by high levels of toxic elements present in drinking water. ^
Health Sciences, Toxicology|Environmental Sciences
Hurtado-Jimenez, Roberto, "Environmental evaluation of the drinking water problems due to fluoride and other related pollutants at "Los Altos de Jalisco", Mexico" (2005). ETD Collection for University of Texas, El Paso. AAI3168480.