Basin-scale exposure risk of psychiatric pharmaceuticals and illicit drugs in tap water in Eastern China

Abstract

A total of twenty-three psychiatric pharmaceuticals and illicit drugs were analyzed in tap water covering seven basins in Eastern China. The residual concentrations of these substances were detected up to 22.4 ng L^-1. Among the substances, benzodiazepines were more often detected with higher median concentrations than those of illicit drugs. Generally, the higher residual levels of psychoactive substances were detected in the upstream of the basins compared with the downstream. For example, the concentrations of diazepam, temazepam, and oxazepam in the downstream were much higher than those in the upstream in OJ. Among the basins, YH was the most polluted region. Exposure assessment indicated the median exposure doses of diazepam and temazepam were from 85 to 99 and 3.5–4.1 pg kg^-1 bw d^-1 in the basins, respectively. Benchmark quotient for the nine detected substances was calculated in each basin with the range from 0.0001 to 0.0389, indicating low risk in the tap water for human health under current concentrations.