Nontarget Analysis of Drinking Water from Danish Waterworks: Profiling of Organic Micropollutants and Health Risk Screening

Quantitative nontarget
analysis (qNTA) was used for a
comprehensive
screening of organic micropollutants (OMs) in groundwater-based drinking
water, and their hazard and risk profiles were evaluated. Chemical
structures were allocated for 278 features representing diverse chemical
classes across the investigated 18 Danish waterworks, among which
one is nonoperational. The micropollutant concentrations ranged from
0.03 to 1500 ng/L, with detection frequencies between 5 and 100%.
In all of the waterworks in operation, the concentrations of pesticides
and their metabolites were below 100 ng/L, the EU parametric value
for drinking water. A quantitative risk screening of 87 OMs showed
that they individually pose no immediate health risk for consumers,
except some OMs whose risk screening was derived based on the threshold
of toxicological concern. The remaining 191 micropollutants were qualitatively
screened by the US-EPA’s Cheminformatics Hazard Module and
revealed that 39 substances were categorized with “high”
combined hazard score ratings. Additional work is needed to confirm
compounds identified under probable structures (confidence levels
of 2 and 3). The current study provided a snapshot of the prevalence
of OMs in drinking water for human consumption, flagging those that
can pose a potential hazard to humans and warrant follow-up investigations.