Arsenic Exposure in a New Mexico Urban Community on Private Well Water *

BACKGROUND:  The presence of arsenic in private well drinking water is a public health concern in New Mexico, where it has been measured in groundwater at concentrations above the EPA maximum contaminant level (MCL) of 10 µg/L.  New Mexican private well owners, who make up 20% of the state population, are solely responsible for the maintenance and monitoring of their drinking water quality.  The objective of this project was to evaluate exposure to arsenic among private well water consumers, inform participants of their potential exposures, and deliver health education so that they could make decisions to reduce their exposures. 

METHODS:  An assessment of arsenic levels in drinking water and urine samples was conducted among participants in a New Mexico community on private wells used for drinking water. Eighty-seven well owners participated in the project, providing two water samples, a urine sample, and an exposure assessment questionnaire.  Arsenic concentrations in drinking water were speciated to determine the valence state of the inorganic arsenic.  Individual results were provided to participants with health communication regarding their water quality and urinary arsenic concentrations.  Households with arsenic concentrations in their well water above EPA standard were advised to use an alternative drinking water source and were provided with information regarding private well maintenance, potential sources of arsenic exposure and health effects, and drinking water treatment options for arsenic removal. 

RESULTS:  About thirty percent (n=25) of participants had drinking water arsenic concentrations at levels that exceeded the EPA MCL.  Of those, three participants had urinary arsenic concentrations exceeding the 95th percentile of the national exposure concentration.   Of the households with elevated arsenic levels in their drinking water, only one household was found to have both arsenic(III) and arsenic(V) in their drinking water, while all others had only arsenic (V) present.  After receiving their results, participants accessed a website dedicated to the project where they could learn about arsenic treatment options.  Google analytics showed that there were 265 page views in a 2-month period.  The majority of participants were interested in well water treatment.  Additionally, without any follow-up, 5 people called back to learn more about their results and how to reduce their exposure, which included treatment options. 

CONCLUSIONS:  Based on preliminary information, some participants appeared to change their behavior and/or sought to learn more about reducing exposures.   A comprehensive follow-up should be conducted to understand the extent of health behavior change among all participants.