Typical azole biocides in biosolid-amended soils and plants following biosolid applications

Biosolid application on agricultural land may contaminate soils with various household chemicals and personal care products. This study investigated the occurrence and dissipation of typical azole biocides climbazole, clotrimazole, and miconazole in biosolid-amended soils as well as the uptake of these biocides by plants. The field trial includes two treatment groups: old groups with biosolid application at rates of 5, 10, 20, and 40 t/ha every year within 5 years, and new groups with only one biosolid application. The results showed that climbazole, clotrimazole, and miconazole were detected in biosolid-amended soils, but not detected in control soils. These biocides were not found in the crop plants collected from the trial plots. The dissipation half-lives for climbazole, clotrimazole, and miconazole under the field conditions were 175-179, 244, and 130-248 days, respectively. High biosolid application rates and repeated biosolid applications could lead to higher persistence of the biocides in the agricultural soils. An exposure model could effectively predict the residual concentrations of climbazole and miconazole in the biosolid-amended soils of the old treatments with different biosolid application rates. Thus, the field trial demonstrated high persistence of these three biocides in the soil environments.