A considerable quantity of microplastic debris exists in the environment and the toxicity of these materials has a notable impact on aquatic ecosystems. In this paper, 50–500 µm polystyrene microplastics (exposure concentrations were 200 µg/L, 800 µg/L, and 3200 µg/L concentrations) were selected to study the effects of polystyrene microplastics (PS-MPs) on cell morphology, detoxification enzyme activity, and mRNA expression in the liver tissues of crucian carp juveniles. The results demonstrated that: (1) Different concentrations of PS-MPs cause varying degrees of pathological and oxidative damage to liver tissue cells of crucian carp. The higher the concentration of microplastics, the lower the antioxidant enzyme (CAT, GST, SOD) activity and the greater the tissue cell damage. These results demonstrate a typical dose–effect relationship. (2) Principal component analysis and Spearman’s correlation analysis demonstrated that four components, namely glutathione S-transferase (GST) and its related genes (GSTpi, GSTα), along with catalase (CAT), contributed the most to the observed outcome. These four components demonstrated a relatively high level of responsiveness to PS-MP exposure and can be employed as ecotoxicological indicators of microplastics. (3) This experiment evaluated five genes in three treatments, which found that PS-MPs had different effects on gene expression in the liver and the tested genes were involved in different response pathways associated with virulence. In this study, the toxicity of PS-MPs to crucian carp was determined at the cellular, protein, and mRNA expression levels, and combined with principal component analysis and correlation analysis to identify response sensitivity indicators that provide a scientific basis for ecological risk assessment and the safe use of microplastics.

The concentrations of 17 antibiotics in the surface water and groundwater of a typical river in the Huixian Wetland were measured, and the ecological and health risks of these antibiotics to surface water and groundwater were assessed. The three types of antibiotics measured included quinolones, tetracyclines, and sulphonamides. The results showed that the mean values of the three antibiotics in surface water were sulfonamides > quinolones > tetracyclines and in groundwater were sulfonamides > tetracyclines > quinolones, and the antibiotic residues were associated with aquaculture and livestock breeding in the wetland, which indicated that antibiotics had a very high rate of use in the Huixian Wetland. The results of the ecological risk evaluation showed that the potential risk of five antibiotics, namely ofloxacin, sulfadiazine, sulfamethoxazole, enrofloxacin, and doxycycline, was high. The results of the health risk evaluation indicated that most of the residual antibiotics were of a medium and low risk to humans.

The membrane biofilm reactor (MBfR) is a novel wastewater treatment technology, garnering attention due to its high gas utilization rate and effective pollutant removal capability. This paper outlines the working mechanism, advantages, and disadvantages of MBfR, and the denitrification pathways, assessing the efficacy of MBfR in removing oxidized pollutants (sulfate (SO₄⁻), perchlorate (ClO₄⁻)), heavy metal ions (chromates (Cr(VI)), selenates (Se(VI))), and organic pollutants (tetracycline (TC), p-chloronitrobenzene (p-CNB)), and delves into the role of related microorganisms. Specifically, through the addition of nitrates (NO₃⁻), this paper analyzes its impact on the removal efficiency of other pollutants and explores the changes in microbial communities. The results of the study show that NO³⁻ inhibits the removal of other pollutants (oxidizing pollutants, heavy metal ions and organic pollutants), etc., in the simultaneous removal of multiple pollutants by MBfR.

This study analyzed three years of data (2021–2024) from three wastewater treatment plants (WWTPs), namely D, X, and T, in the main urban area of Handan, a typical city in the southern Hebei region, and investigated the influent characteristics and impact of temperature on these wastewater treatment facilities. With 90% assurance, the overall influent conditions of the three WWTPs in this region were normal. However, Plant T operated more effectively with slightly lower BOD₅/COD_Cr (B/C), organic carbon/total phosphorus (C/TP), and organic carbon/total nitrogen (C/TN) ratios in the influent. Plant D consistently met the Level A standard, Plant X essentially reached the Level A standard, while Plant T attained the Level 2 standard prior to its upgrade. Following the upgrade, Plant T also steadily met the Level A standard. The effluent from all plants was relatively stable, primarily influenced by the influent characteristics and slightly influenced by temperature, but without having a noticeable impact on the effluent quality.