Household cleaning activities as noningestion exposure determinants of urinary trihalomethanes

Previous epidemiological studies linking drinking water total trihalomethanes (THM) with pregnancy disorders or bladder cancer have not accounted for specific household cleaning activities that could enhance THM exposures. We examined the relation between household cleaning activities (washing dishes/clothes, mopping, toilet cleaning, and washing windows/surfaces) and urinary THM concentrations accounting for water sources, uses, and demographics. A cross-sectional study (n = 326) was conducted during the summer in Nicosia, Cyprus, linking household addresses to the geocoded public water pipe network, individual household tap water, and urinary THM measurements. Household tap water THM concentrations ranged between 3-129 μg L(-1), while the median (Q1, Q3) creatinine-adjusted urinary THM concentration in females (669 ng g(-1) (353, 1377)) was significantly (p < 0.001) higher than that in males (399 ng g(-1), (256, 681)). Exposure assessment, based on THM exposure equivalency units, showed that hand dishwashing, mopping, and toilet cleaning significantly (p < 0.001) increased urinary THM levels. The effect of dishwashing by females ≥36 y of age remained significant, even after adjusting for potential confounders. No significant (p > 0.05) association was observed between ingestion-based THM exposure equivalency units and urinary THM. Noningestion routes of THM exposures during performance of routine household cleaning activities were shown for the first time to exert a major influence on urinary THM levels. It is warranted that future pregnancy-birth cohorts include monitoring of noningestion household THM exposures in their study design.