Triclosan in the urine of Chinese youth: concentration, temporal variability, sources of exposure and predictive ability.

Triclosan (TCS) is an antimicrobial agent commonly used in personal care products. The assessment of TCS exposure in humans frequently relies on analyzing urinary TCS levels. Consequently, it is crucial to have a comprehensive understanding of the variability of TCS levels in urine. However, studies of temporal variations in urinary TCS levels at different time intervals among youth are lacking. This study collected urine samples from 109 participants over a period of one year to assess the temporal variability of TCS over different time intervals. The detection rate of TCS in urine was 75%. The intraclass correlation coefficient (ICC) indicated good reproducibility of TCS in spot urine among youth at a day, a week, and a month (ICC = 0.541-0.857), but the poor reproducibility within one year (ICC = 0.209). The number of spot urine samples needed to provide dependable exposure estimates (ICC > 0.8) at different time periods over the course of a year ranges from 1 to 16 tubes (m = 1-16). The sensitivity and specificity of TCS as a predictor of the mean annual top 33% concentration of TCS ranged from 0.667 to 1.000 and from 0.519 to 1.000, respectively. In addition, Spearman correlation analysis revealed that TCS levels were significantly associated with the use of various personal care products (antibacterial ointment, mouthwash or body deodorant, hand sanitizer) (p < 0.05). In light of these findings, it is recommended that urine samples be collected in 1 to 16 tubes at least 3 months apart to accurately assess the level of exposure at the appropriate time of the year, facilitating the prospective assessment of TCS exposure in different epidemiological studies.