The persistent, bioaccumulative, toxic, and resistance (PBTR) risk assessment framework of antibiotics in the drinking water sources.

Antibiotics are emerging pollutants largely considered to have a lower risk based on persistent, bioaccumulative, toxic (PBT) risk assessments. However, an increasing number of studies have illustrated that antibiotics are responsible for the global increase in antimicrobial resistance (AMR), which suggests that the risk of antibiotics has been largely underestimated by using PBT risk assessment. Here, we designed an integrated innovation risk assessment framework of persistent, bioaccumulative, toxic, and resistance (PBTR) that accounts for antibiotic resistance to better represent the antibiotic environmental risk. This novel antibiotic risk assessment framework was further verified via application to 39 target antibiotics in the 23 drinking water sources of the lower Yangtze River (LYR), China, during the normal and flood seasons. In contrast with the PBT assessment, single toxicity assessment and single resistance assessment, in the PBTR assessment, 7 of 39 target antibiotics with bacterial insensitivity were observed to represent a more prominent risk, as were the sites sampled during the flood season with low concentrations but high pollution loads, which confirmed that the sensitivity of PBTR risk assessment was instructive. The PBTR risk assessment for the screened priority antibiotics contributes not only representative data but also an innovative approach for identifying resistance risks. Using the positive matrix factorization (PMF) model, the sources of priority antibiotics can be predicted and thus supported the corresponding policy. Overall, this study first constructed a PBTR risk assessment framework, then applied it to facilitate the accurate management of antibiotic pollution at the basin level.

Comparative analysis of the sorption behaviors and mechanisms of amide herbicides on biodegradable and nondegradable microplastics derived from agricultural plastic products.

Coexisting of microplastics (MPs) and residual herbicides has received substantial attention due to concerns about the pollutant vector effect. Here, the widely used amide herbicides were examined for their sorption behaviors on the priority biodegradable and nondegradable MPs identified in intensive agriculture. The fitting results indicated that the interactions between napropamide (Nap)/acetochlor (Ace) and the MPs, i.e., poly (butyleneadipate-co-terephthalate) microplastic (PBATM), polyethylene microplastic (PEM), and polypropylene microplastic (PPM), may be dominated by hydrophobic absorptive partitioning on the heterogeneous surfaces. Additionally, chemisorption cannot be ignored for the sorption of Nap/Ace on the biodegradable MPs. The sorption capacities of Nap/Ace on the MPs followed the order of PBATM > PEM > PPM. The differences in sorption capacity which varied by the MP colors were not significant. The hydrophobicity of the herbicides and the MPs, the rubber regions, surface O-functional groups, benzene ring structures and large specific surface area of the biodegradable MPs played key roles in the better performance in sorbing amide herbicides. Moreover, MPs, especially biodegradable MPs, might lead to a higher vector effect for residual amide herbicides than some other common environmental media. This study may provide baseline insights into the great potential of biodegradable MPs to serve as carriers of residual amide herbicides in intensive agrosystems.