Arsenic in drinking water in the Los Altos de Jalisco region of Mexico.
OBJECTIVE
To establish the degree of contamination by arsenic in drinking water in the Los Altos de Jalisco (LAJ) region of west-central Mexico, and to estimate the levels of exposure that residents of the area face.


METHODS
Total arsenic concentration (the sum of all arsenic forms, organic and inorganic) was determined for 129 public water wells in 17 municipal capitals (cabeceras municipales) of the LAJ region, using inductively coupled plasma-optical emission spectroscopy. For most of the wells, water samples were taken in both November 2002 and October 2003. The levels of exposure to arsenic were estimated for babies (10 kg), children (20 kg), and adults (70 kg).


RESULTS
Mean concentrations of arsenic higher than the Mexican national guideline value of 25 micro g/L were found in 44 (34%) of the 129 wells. The mean concentration of total arsenic for the 129 wells ranged from 14.7 micro g/L to 101.9 micro g/L. The highest concentrations were found in well water samples collected in the cities of Mexticacán (262.9 micro g/L), Teocaltiche (157.7 micro g/L), and San Juan de los Lagos (113.8 micro g/L). Considering the global mean concentration for all the wells in each of the 17 cities, the mean concentration of arsenic exceeded the Mexican guideline value in 7 of the cities. However, the global mean concentration in all 17 cities was higher than the World Health Organization guideline value of 10 micro g/L for arsenic. The range of the estimated exposure doses to arsenic in drinking water was 1.1-7.6 micro g/kg/d for babies, 0.7-5.1 micro g/kg/d for children, and 0.4-2.7 micro g/kg/d for adults.


CONCLUSIONS
At the exposure doses estimated in the LAJ region, the potential health effects from chronic arsenic ingestion include skin diseases, gastrointestinal effects, neurological damage, cardiovascular problems, and hematological effects. While all the residents may not be affected, an important fraction of the total population of the LAJ region is under potential health risk due to the ingestion of high levels of arsenic. Epidemiological studies to determine the arsenic levels in the blood, hair, and nails of humans should be conducted in the LAJ region to help assess the relationship between the prevalence of health problems and the chronic ingestion of arsenic.
Hurtado-Jiménez
Roberto
R
El Colegio de la Frontera Norte, AC, Ciudad Juárez, Chihuahua, México. rhurtado@colef.mx
Gardea-Torresdey
Jorge L
JL
D001151:Arsenic / Q000032:analysis*; D008800:Mexico; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
D014874:Water Pollutants, Chemical; D001151:Arsenic