Occurrence and dissipation of benzotriazoles and benzotriazole ultraviolet stabilizers in biosolid-amended soils.

Benzotriazoles (BTs) and benzotriazole ultraviolet (UV) stabilizers (BUVSs) are commonly used industrial and household chemicals, but little is known about their dissipation behavior in the soil environment associated with biosolid application. The authors investigated the occurrence and dissipation of 4 BTs (BT, 5-methyl-1H-benzotriazole [5-TT], 5-chloro-1H-benzotriazole [CBT], and 5,6-dimethyl-1H-benzotriazole [XT]) and 5 BUVSs (UV-326, UV-327, UV-328, UV-329, and UV-P) in biosolid-amended soil of 3 trial sites (Zhejiang, Hunan, and Shandong) in China following 2 treatments (treatment 1: a single application of biosolid; treatment 2: repeated application of biosolid). The results showed that except for CBT and XT, the other 7 compounds could be detected in most of the biosolid and biosolid-amended soils at levels of a few to tens of nanograms per gram and that the concentrations of the 7 compounds for treatment 2 were obviously higher than those for treatment 1. In the 1-yr monitoring of the Shandong site, 2 BTs (BT and 5-TT) and 5 BUVSs (UV-326, UV-327, UV-328, UV-329, and UV-P) were significantly dissipated in the biosolid-amended soils. The field half-lives of BT and 5-TT ranged from 217 d to 345 d, while those for the BUVSs ranged between 75 d and 218 d. The field half-lives of target compounds in soil were found to be comparable to the modeling results. The results suggest the persistence of BTs and BUVSs in soil environments with quite slow dissipation rates.