Duarte et al. 2022 — Cancer mortality and arsenic in drinking water, central Argentina
A retrospective ecological study across 62 departments in five provinces of central Argentina examined whether arsenic concentrations in public drinking water correlated with cancer mortality in both sexes over two consecutive decades (1997–2006 and 2007–2016). Arsenic was measured using Standard Method 3120 Method B (ICP-OES equivalent), with an LOQ of 0.001 mg/L. Departments were classified as elevated-arsenic (>0.01 mg/L, i.e., above the WHO/Argentine permissible limit) or below-threshold. The study found statistically significant positive correlations between elevated arsenic exposure and total cancer mortality in both men (Spearman ρ = 0.713, p = 0.001) and women (ρ = 0.676, p = 0.003) for the first period, with similar but somewhat attenuated patterns in the second decade. Nitrates in drinking water did not show the same pattern independently.
Key numbers
- Study period: 1997–2006 and 2007–2016, covering 62 administrative departments.
- Arsenic threshold used: >0.01 mg/L (Argentine regulatory limit, aligned with WHO guideline).
- Departments with elevated As: approximately 40% of the study area.
- Correlation with total cancer mortality (men, 1997–2006): Spearman ρ = 0.713, p = 0.001.
- Correlation with total cancer mortality (women, 1997–2006): Spearman ρ = 0.676, p = 0.003.
- Second decade (2007–2016) correlations also positive but weaker, possibly reflecting mortality lag or partial mitigation.
- Analytical method: SM 3120 Method B, LOQ = 0.001 mg/L; as-measured in public supply water.
- Nitrate correlations: not significant for either sex.
Methods (brief)
Retrospective ecological design linking departmental arsenic monitoring data from public water supply systems to age-standardized cancer mortality data from official vital statistics. Arsenic analyzed by SM 3120 Method B (ICP). No individual-level biomonitoring; geographic unit is the department (county-equivalent). Spearman rank correlation used throughout; multivariate regression also performed. Limitation: ecological design cannot exclude confounding by unmeasured co-exposures; arsenic values represent long-term public supply data, which may not capture private-well exposure in rural areas.
Implications
Certification: Confirms that even at concentrations near or modestly exceeding the 10 µg/L threshold, chronic dietary and water-borne arsenic exposure is associated with elevated cancer mortality at the population level; relevant context for HMT&C water-use and supply-chain standards. Courses: Case study illustrating ecological epidemiology linking drinking water arsenic to cancer endpoints; illustrates the regional scale of endemic arsenic exposure in the Southern Cone. App: Not directly applicable (drinking water, not food matrix).