Comparison of potential drinking water source contamination across one hundred U.S. cities
Level 4 - case-series / case-control
Cross-sectional environmental and hydrological modeling assessment across municipal water sources (graded by design analogy, not clinical CEBM).
OpenAlex W4200070576 · doi:10.1038/s41467-021-27509-9
What was done
Researchers integrated national-scale geospatial datasets with hydrologic simulations to assess potential drinking water source contamination across more than 100 large U.S. cities. They developed and calculated two metrics capturing potential exposure to point-source (e.g., treated wastewater) and nonpoint-source (e.g., agricultural, industrial, residential runoff) contamination within municipal source watersheds.
What was found
Anthropogenic exposure varied substantially across city watersheds. Approximately 5% of large U.S. cities depend on drinking water composed primarily of runoff from non-pristine lands. Additionally, approximately four-fifths (80%) of large cities relying on surface water withdrawals are exposed to upstream treated wastewater discharges in their source supplies.
Why it matters
This provides a standardized, national-scale comparative overview of upstream water source vulnerability, helping bridge gaps left by fragmented and inconsistent local water quality monitoring programs.
Limits
The abstract models potential source-water exposure based on watershed land use and hydrology rather than measuring actual finished tap water quality or specific contaminant concentrations post-treatment. Specific numerical metrics beyond the 5% non-pristine runoff and 80% wastewater exposure proportions are not detailed in the abstract.
Cited by
- contradicts There are 160,000 wastewater treatment plants serving 85% of the US population's drinking water.