Derivation of Water Quality Criteria for Carbamazepine and Ecological Risk Assessment in the Nansi Lake Basin

Emerging Contaminants in the Effluent of Wastewater Should Be Regulated: Which and to What Extent?

Effluent discharged from urban wastewater treatment plants (WWTPs) is a major source of emerging contaminants (ECs) requiring effective regulation. To this end, we collected discharge datasets of pharmaceuticals (PHACs) and endocrine-disrupting chemicals (EDCs), representing two primary categories of ECs, from Chinese WWTP effluent from 2012 to 2022 to establish an exposure database. Moreover, high-risk ECs' long-term water quality criteria (LWQC) were derived using the species sensitivity distribution (SSD) method. A total of 140 ECs (124 PHACs and 16 EDCs) were identified, with concentrations ranging from N.D. (not detected) to 706 μg/L. Most data were concentrated in coastal regions and Gansu, with high ecological risk observed in Gansu, Hebei, Shandong, Guangdong, and Hong Kong. Using the assessment factor (AF) method, 18 high-risk ECs requiring regulation were identified. However, only three of them, namely carbamazepine, ibuprofen, and bisphenol-A, met the derivation requirements of the SSD method. The LWQC for these three ECs were determined as 96.4, 1010, and 288 ng/L, respectively. Exposure data for carbamazepine and bisphenol-A surpassed their derived LWQC, indicating a need for heightened attention to these contaminants. This study elucidates the occurrence and risks of ECs in Chinese WWTPs and provides theoretical and data foundations for EC management in urban sewage facilities.

Ecological risk of phenol on typical biota of the northern Chinese river from an integrated probability perspective: the Hun River as an example

Phenol, known for its bioaccumulative nature and severe toxicity to riverine organisms, poses complex challenges for ecological risk assessment. To tackle this issue, we developed a three-stage incremental assessment method, providing an integrated perspective on phenol toxicity risk for aquatic organisms. The findings indicated that phenol concentrations were generally higher in the aquatic environments of northern rivers, such as the Hun River, Taizi River, and Liao River, compared to those in southern China. The evaluation results at individual points showed that the ecological risk of phenol to aquatic organisms ranked from high to low during rainy, dry, and normal seasons, showing seasonal variation characteristics. Regarding spatial variation along the river, the ecological risk of phenol gradually increased from upper reaches, peaked in the middle reaches, and then decreased in the lower reaches. Considering the different species types, fish face a higher risk of toxic effects of phenol than invertebrates when exposed to phenol over a long period of time, probably due to the bioaccumulative nature of phenol. To address ecological risk control at the watershed scale, there is an urgent need to revise China's current river water quality standards. It is essential to increase the emphasis on ecological risk control for aquatic organisms. Developing more targeted and refined ecological risk control strategies for river phenols is crucial to maintain a healthier and more vibrant river ecosystem.

Impact of Voltage Application on Degradation of Biorefractory Pharmaceuticals in an Anaerobic-Aerobic Coupled Upflow Bioelectrochemical Reactor

Diclofenac, ibuprofen, and carbamazepine are frequently detected in the environment, where they pose a threat to organisms and ecosystems. We developed anaerobic-aerobic coupled upflow bioelectrochemical reactors (AO-UBERs) with different voltages, hydraulic retention times (HRTs), and types of electrode conversion, and evaluated the ability of the AO-UBERs to remove the three pharmaceuticals. This study showed that when a voltage of 0.6 V was applied, the removal rate of ibuprofen was slightly higher in the system with aerobic cathodic and anaerobic anodic chambers (60.2 ± 11.0%) with HRT of 48 h than in the control systems, and the removal efficiency reached stability faster. Diclofenac removal was 100% in the 1.2 V system with aerobic anodic and anaerobic cathodic chambers, which was greater than in the control system (65.5 ± 2.0%). The contribution of the aerobic cathodic-anodic chambers to the removal of ibuprofen and diclofenac was higher than that of the anaerobic cathodic-anodic chambers. Electrical stimulation barely facilitated the attenuation of carbamazepine. Furthermore, biodegradation-related species (Methyloversatilis, SM1A02, Sporomusa, and Terrimicrobium) were enriched in the AO-UBERs, enhancing pharmaceutical removal. The current study sheds fresh light on the interactions of bacterial populations with the removal of pharmaceuticals in a coupled system.