Analysis of Cumulative Cancer Risk Associated with Disinfection Byproducts in United States Drinking Water
Level 5 - mechanism / opinion, no new human data
Quantitative risk modeling and secondary data analysis (non-clinical study graded by design analogy)
OpenAlex W3013625816 · doi:10.3390/ijerph17062149
What was done
Conducted a comparative cumulative cancer risk assessment for drinking water disinfection byproducts, specifically trihalomethanes and both regulated and unregulated haloacetic acids. The authors evaluated occurrence data from the U.S. EPA fourth Unregulated Contaminant Monitoring Rule (UCMR4) dataset and compared toxicological risk modeling (using standard default parameters and age sensitivity factors) against epidemiological risk estimates for community water systems.
What was found
Toxicological assessment showed haloacetic acids, particularly brominated forms, posed higher carcinogenicity than trihalomethanes. The toxicologically modeled cumulative lifetime cancer risk from trihalomethanes and haloacetic acids was 7.0 × 10⁻⁵ (3.5 × 10⁻⁵–1.3 × 10⁻⁴) using standard parameters, and 2.9 × 10⁻⁴ (1.7 × 10⁻⁴–6.2 × 10⁻⁴) when including age sensitivity factors. Epidemiological data yielded an estimated lifetime cancer risk of 3.0 × 10⁻³ (2.1 × 10⁻⁴–5.7 × 10⁻³), corresponding to approximately 3 cases per 1,000 individuals.
Why it matters
This study provides comparative risk estimates indicating that toxicological modeling may underestimate total cancer burden compared to epidemiological observations, highlighting the importance of monitoring unregulated brominated haloacetic acids in public water supplies.
Limits
The study is an exposure and risk modeling exercise dependent on default intake parameters and assumed toxicity factors rather than directly measured individual exposures or clinical outcomes. Specific sample sizes, individual water system characteristics, and potential unmeasured confounding from underlying epidemiological datasets are not reported in the abstract.
Cited by
- context The Environmental Working Group reported that over 122 million Americans drink tap water containing high levels of chemicals known to cause cancer.
- context The Environmental Working Group has reported that over 122 million Americans drink tap water containing high levels of chemicals known to cause cancer.
- supports The Environmental Working Group demonstrated that over 122 million Americans drink tap water containing elevated levels of carcinogenic chemicals.
- context According to the Environmental Working Group, more than 122 million Americans drink tap water containing high levels of chemicals known to cause cancer.