Efficacy of arsenic exposure reduction via drinking water treatment systems

Arsenic, a known human carcinogen, exceeds the maximum contaminant level in New Jersey private wells at a higher percentage than any other contaminant with a primary drinking water standard. New Jersey’s drinking water standard for arsenic at 5 µg/L is currently the most protective in the world. Water treatment systems can remove arsenic from drinking water, either from the entire home (point-of-entry) or just at a single tap (point-of-use) for drinking and cooking. The goal of this research was to compare human exposure to arsenic between point-of-entry and point-of-use water treatment, by biomonitoring, to determine which level of treatment most effectively reduced arsenic exposure and dose from water at home to acceptable risk levels. The study recruited 53 subjects in 22 households obtaining arsenic water treatment, and five control subjects with little or no measurable arsenic in their water supply. The mean arsenic concentration in untreated water was 44 µg/L. Biomonitoring started before initiation of water treatment and continued for up to three years with samples analyzed at the Environmental and Occupational Health Sciences Institute. The study determined that: 1) dietary arsenic can be a major confounder in arsenic biomonitoring studies; 2) arsenic speciation techniques are extremely valuable for arsenic biomonitoring studies; 3) sampling protocols and reference values for arsenic in urine and blood should be recommended; 4) arsenic water treatment systems are effective in reducing arsenic exposure from well water; 5) there is a measurable arsenic body burden after chronic exposure to arsenic in drinking water; 6) there is a two-compartment clearance of arsenic from urine, after cessation of ingesting the arsenic contaminated water; and 7) after nine months of water treatment, the adjusted mean inorganic-related arsenic concentrations in urine were significantly lower in the point-of-entry treatment group with a mean ± standard error of 2.7 ± 0.6 µg/g creatinine than in the point-of-use treatment group at 6.1 ± 0.7 µg/g creatinine. In conclusion, point-of-entry treatment of arsenic-contaminated well water should be recommended in preference to point-of-use.Ph.D.Includes abstractVitaIncludes bibliographical referencesby Steven E. Spay