Cost-benefit of point-of-use devices for lead reduction

Public and private tapwater: Comparative analysis of contaminant exposure and potential risk, Cape Cod, Massachusetts, USA

BACKGROUND

Humans are primary drivers of environmental contamination worldwide, including in drinking-water resources. In the United States (US), federal and state agencies regulate and monitor public-supply drinking water while private-supply monitoring is rare; the current lack of directly comparable information on contaminant-mixture exposures and risks between private- and public-supplies undermines tapwater (TW) consumer decision-making.

METHODS

We compared private- and public-supply residential point-of-use TW at Cape Cod, Massachusetts, where both supplies share the same groundwater source. TW from 10 private- and 10 public-supply homes was analyzed for 487 organic, 38 inorganic, 8 microbial indicators, and 3 in vitro bioactivities. Concentrations were compared to existing protective health-based benchmarks, and aggregated Hazard Indices (HI) of regulated and unregulated TW contaminants were calculated along with ratios of in vitro exposure-activity cutoffs.

RESULTS

Seventy organic and 28 inorganic constituents were detected in TW. Median detections were comparable, but median cumulative concentrations were substantially higher in public supply due to 6 chlorine-disinfected samples characterized by disinfection byproducts and corresponding lower heterotrophic plate counts. Public-supply applicable maximum contaminant (nitrate) and treatment action (lead and copper) levels were exceeded in private-supply TW samples only. Exceedances of health-based HI screening levels of concern were common to both TW supplies.

DISCUSSION

These Cape Cod results indicate comparable cumulative human-health concerns from contaminant exposures in private- and public-supply TW in a shared source-water setting. Importantly, although this study's analytical coverage exceeds that currently feasible for water purveyors or homeowners, it nevertheless is a substantial underestimation of the full breadth of contaminant mixtures documented in the environment and potentially present in drinking water.

CONCLUSION

Regardless of the supply, increased public engagement in source-water protection and drinking-water treatment, including consumer point-of-use treatment, is warranted to reduce risks associated with long-term TW contaminant exposures, especially in vulnerable populations.

Social factors shaping the adoption of lead-filtering point-of-use systems: an observational study of an MTurk sample

Some municipalities are promoting lead-filtering point-of-use (POU) systems to minimize the risk of lead exposure through drinking water, often targeting use at racial minorities and low-income households. However, links among social inequality markers and adoption of these systems are not well understood. Survey data on adoption and use of POU systems were collected from a U.S. Mechanical Turk (MTurk) sample (N = 2,867) in March 2018. We use logistic regression to assess the association of race/ethnicity, socioeconomic status (SES), and lead-filtering POU adoption. We also examined key health behaviors related to POU systems. We found that race and SES are indirectly predictive of lead-filtering POU adoption through the propensity of some respondents to report a residence with a lead service line and levels of concern and knowledge about lead exposure. In addition, individuals with similar levels of concern about lead in water have lower odds of adopting a POU system if they have lower, rather than higher, incomes. Among POU adopters, while confidence in correct use of these devices was relatively high, the frequency of filtered water use for cooking was lower than drinking frequency. Overall, these findings inform health policies aimed at mitigating risk of lead exposure through water.