The effects of biological activated carbon treatment using Fe₂O₃ modified coconut shell-based activated carbon (Fe/CAC) were investigated on the occurrence of opportunistic pathogens (OPs) and formation of disinfection by-products (DBPs) in simulated drinking water distribution systems (DWDSs) with unmodified CAC as a reference. In the effluent of annular reactor (AR) with Fe/CAC, the OPs growth and DBPs formation were inhibited greatly. Based on the differential pulse voltammetry and dehydrogenase activity tests, it was verified that extracellular electron transfer was enhanced in the attached biofilms of Fe/CAC, hence improving the microbial metabolic activity and biological removal of organic matter especially DBPs precursors. Meanwhile, the extracellular polymeric substances (EPS) on the surface of Fe/CAC exhibited stronger viscosity, higher flocculating efficiency and better mechanical stability, avoiding bacteria or small-scale biofilms falling off into the water. Consequently, the microbial biomass and EPS substances amount decreased markedly in the effluent of Fe/CAC filter. More importantly, Fe/CAC did significantly enhance the shaping role on microbial community of downstream DWDSs, continuously excluding OPs advantage and inhibiting EPS production. The weakening of EPS in DWDSs resulted in decrease of microbial chlorine-resistance ability and EPS-derived DBPs precursors supply. Therefore, the deterioration of water quality in DWDSs was inhibited greatly, sustainably maintaining the safety of tap water. Our findings indicated that optimizing biological activated carbon treatment by interface modification is a promising method for improving water quality in DWDSs.

Cadmium (Cd) is a harmful heavy metal that can cause many health problems, while selenium (Se) is an essential nutrient for organisms that can protect them from heavy metal-induced damage. To explore the effects of Se on Cd-induced mitophagy in the liver, forty 3-month-old New Zealand white rabbits (2–2.5 kg), half male and half female, were randomly divided into four groups: the Control group, the Se (0.5 mg/kg body weight (BW)) group, the Cd (1 mg/kg BW) group and the Se+Cd group. After 30 days, the toxicity from Cd in the liver was assessed in terms of the nuclear xenobiotic receptor (NXR) response, oxidative stress and mitophagy. It was found that Cd decreased the activities of CYP450 enzymes and antioxidant enzymes and increased the contents of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) and also increased the consumption of reduced glutathione (GSH). Moreover, the mRNA levels of NXRs (CAR, PXR, AHR and Nrf2), some mitochondrial function factors (PGC-1α, Sirt1, Sirt3, Nrf1 and TFAM) and mitochondrial fusion factors (Mfn1, Mfn2 and OPA1) were downregulated, but the mRNA levels of other mitochondrial function factors (VDAC1, Cyt C and PRDX3), mitochondrial fission factors (Fis1 and MFF) and those in the PINK1/Parkin-mediated mitophagy pathway (p62, Bnip3 and LC3) were upregulated under Cd exposure. The protein expression levels of Nrf2, SOD2, PGC-1α, PINK1 and Parkin were consistent with the mRNA expression levels in the Cd group. Se alleviated the changes in the abovementioned factors induced by Cd. In conclusion, the results indicate that Cd can cause oxidative stress in rabbit livers by inhibiting NXRs and the antioxidation response leading to mitophagy, and these harmful changes caused by Cd can be alleviated by Se.

Fish embryos, as an endogenous system, strictly regulate an energy metabolism that is particularly sensitive to environmental pressure. This study used orange-spotted grouper embryos and stable isotope ⁶⁷Zn to test the hypothesis that waterborne Zn exposure had a significant effect on energy metabolism in embryos. The fish embryos were exposed to a gradient level of waterborne ⁶⁷Zn, and then sampled to quantify ⁶⁷Zn bioaccumulation and mRNA expressions of key genes involved glucose metabolism. The results indicated that the bioaccumulated ⁶⁷Zn generally increased with increasing waterborne ⁶⁷Zn concentrations, while it tended to be saturated at waterborne ⁶⁷Zn > 0.7 mg L⁻¹. As we hypothesized, the expression of PK and PFK gene involved glycolysis pathway was significantly up-regulated under waterborne ⁶⁷Zn exposure >4 mg L⁻¹. Waterborne ⁶⁷Zn exposure >2 mg L⁻¹ significantly suppressed PCK and G6PC gene expression involved gluconeogenesis pathway, and also inhibited the AKT2, GSK-3beta and GLUT4 genes involved Akt signaling pathway. Our findings first characterized developmental stage-dependent Zn uptake and genotoxicity in fish embryos. We suggest fish embryos, as a small-scale modeling biosystem, have a large potential and wide applicability for determining cytotoxicity/genotoxicity of waterborne metal in aquatic ecosystem.

In Europe, emerging organic compounds (EOCs) in groundwater is a growing research area. Prioritisation for monitoring EOCs in Europe was formalised in 2019 through the development of the first voluntary groundwater watch list (GWWL). Despite this, groundwater occurrence data in the peer reviewed literature for Europe has not been reviewed to date. Questions surrounding the effect, toxicity, movement in the subsurface and unsaturated zone make the process of regulating EOC use difficult. The aim in Europe is to develop a unified strategy for the classification, and prioritisation of EOCs to be monitored in groundwater. This paper compiles evidence from the recent published studies from across Europe, since 2012, when the last major literature global review of EOCs in groundwater took place. A total of 39 studies were identified for review based on specific selection criteria (geography, publication date, sample size>10, inclusion of EOCs data). Data on specific compounds, and associated meta-data, are compiled and reviewed. The two most frequently detected EOCs, carbamazepine and caffeine, occurred in groundwater at concentrations of up to 2.3 and 14.8 μg/L, respectively.The most frequently reported category of compounds were ‘Pharmaceuticals’; a highly studied group with 135 compounds identified within 31 of the 39 studies. In Europe, the majority of reviewed studies (23) were at a regional scale, looking specifically at EOCs in a specific city or aquifer. The use of analytical methods is not uniform across Europe, and this inevitably influences the current assessment of EOCs in groundwater. A correlation between the number of compounds analysed for, and the number detected in groundwater highlights the need for further studies, especially larger-scale studies throughout Europe. For the development of EU and national regulation, further work is required to understand the occurrence and impacts of EOCs in groundwater throughout Europe and elsewhere.

Antifouling paint particles (APPs) and associated metals have been identified in sediments around boatyards and marinas globally, but the effects of APPs on benthic organisms are largely unknown. Sub-lethal endpoints were measured following laboratory exposures of the harbour ragworm (Hediste diversicolor) and the common cockle (Cerastoderma edule) to environmentally relevant concentrations of biocidal (‘modern’ and ‘historic’) and biocide-free (‘silicone’) APPs added to clean estuarine sediment. Further, the 5-day median lethal concentrations (LC₅₀) and effects concentrations (EC₅₀) for modern biocidal APPs were calculated. For ragworms, significant decreases in weight (15.7%; p < 0.01) and feeding rate (10.2%; p < 0.05) were observed in the modern biocidal treatment; burrowing behaviour was also reduced by 29% in this treatment, but was not significant. For cockles, the modern biocidal treatment led to 100% mortality of all replicates before endpoints were measured. In cockles, there was elevated levels of metallothionein-like protein (MTLP) in response to both modern and historic biocidal treatments. Ragworms had a higher tolerance to modern APPs (5-day LC₅₀:19.9 APP g L⁻¹; EC₅₀: 14.6 g L⁻¹) compared to cockles (5-day LC₅₀: 2.3 g L⁻¹ and EC₅₀: 1.4 g L⁻¹). The results of this study indicate that modern biocidal APPs, containing high Cu concentrations, have the potential to adversely affect the health of benthic organisms at environmentally relevant concentrations. The findings highlight the need for stricter regulations on the disposal of APP waste originating from boatyards, marinas and abandoned boats.

The annual production of sludges is significant all over the world, and large amounts of sludges have been improperly disposed by random dumping. The contaminants in these sludges may leak into the surrounding soils, surface and groundwater, or be blown into the atmosphere, thereby causing adverse effects to human health. In this study, the (anti-)androgenic activities in organic extracts of sludges produced from both industrial and domestic wastewater treatment plants (WWTPs) were examined using reporter gene assay based on MDA-kb2 cell lines and the potential (anti-)androgenic risks were assessed using hazard index (HI) based on bioassays. Twelve of the 18 samples exhibited androgen receptor (AR) antagonistic activities, with AR antagonistic equivalents ranging from 1.2 × 10² μg flutamide/g sludge to 1.8 × 10⁴ μg flutamide/g sludge; however, no AR agonistic activity was detected in any of the tested samples. These 12 sludges were all from chemical WWTPs; no sludges from domestic WWTPs displayed AR antagonistic activity. Aside from wastewater source, treatment scale and technology could also influence AR antagonistic potencies. The HI values of all the 12 sludges exceeded 1.0, and the highest HI value was above 3.0 × 10³ for children; this indicates that these sludges might cause adverse effects to human health and that children are at a greater risk than adults. The anti-androgenic potencies and risks of the subdivided fractions were also determined, and medium-polar and polar fractions were found to have relatively high detection rates and contribution rates to the AR antagonistic potencies and risks of the raw sample extracts.

Increasing concerns over bisphenol A (BPA) as an endocrine disrupting chemical (EDC) and its adverse effects on both humans and animals have led to the substitution by structural analogs, such as bisphenol F (BPF), in many application areas. Information regarding to the carry-over of this emerging chemical in farm animals is essential for legislation and risk assessment purposes. In this study, a large-scale number of animal experiments were designed to investigate the transfer of BPF from feed to eggs. One control and three experimental groups of laying hens (72 hens per group) were fed with basal diets and BPF-contaminated feed at concentration levels of 0.1, 0.5 and 2.5 mg kg⁻¹, respectively, for two weeks. The hens were then fed with BPF-free diets for a further four weeks. Eggs were collected daily, and separated into egg yolk and white for BPF analysis. The effects of different levels of BPF exposure on laying performance followed a non-monotonic dose-response curve, since low level BPF (0.1 mg kg⁻¹) exposure did increase the laying rate, mean egg weight and daily feed intake, while high level BPF (2.5 mg kg⁻¹) exposure showed a decreasing trend. BPF residues were detected in both egg yolks and whole eggs after two days of administration, and plateau phase was achieved within 9–18 days. There are clear linear dose-response relationships between the plateau BPF concentrations in feed and eggs. The residue of BPF was found mainly in egg yolks with conjugated form and depleted slowly (still detected 21 days after feeding the BPF-free diet of the high level group). Mean carry-over rate of 0.59% BPF from feed to eggs was obtained. Compared with the carry-over rates of PCBs and dioxins, BPF showed a relatively minor trend of bioaccumulation in eggs. To the best of our knowledge, this is the first report on the deposition, depletion, and bioaccumulation study of bisphenols in farm animals. The quantity of data can therefore be helpful in the frame of risk assessment, especially for a comprehensive estimation of consumer exposure to the residues of bisphenols.

Sediment serves as a sink for metals, thus it is critical to assess its contamination and associated risk. A typical riparian wetland close to a Zn-smelting operation in karst areas in southwest China was investigated. Sediment and reed plant (Phragmites australis) samples from wet and dry seasons were analyzed for total As, Cu, and Zn concentrations. Metal pollution in the sediment was assessed based on geoaccumulation index (Igₑₒ). Further, metals in the sediment were fractionated into exchangeable, water and acid-soluble, reducible, oxidizable, and residual fractions based on the BCR sequential extraction. The results showed that the As, Cu, and Zn concentrations in the sediment were significantly higher than the background values (740–4081, 96–228, and 869–3331 vs. 10, 22, and 70 mg kg⁻¹). With the Igₑₒ being 10–17, the data indicate that the sediment was highly-polluted. While total As, Cu and Zn in the sediment increased from dry to wet season, their available concentrations decreased except Cu. With 62–94% of As, Cu, and Zn being in the residual fraction, metal availability in the sediment was low based on fractionation data. The data are consistent with low metal uptake by reed as their concentration ratios in plant roots to the sediment were 0.01–0.32. The results suggest that the riparian sediment was highly-polluted with As, Cu and Zn, but showing low metal availability and limited plant uptake.

Microplastics, an emerging pollutant in the environment, have attracted extensive attention in recent years for their possible negative impact on organisms. However, direct and indirect effects of polystyrene (PS) microplastics on vegetables are still not completely known. In this study, we used red lettuce (Lactuca sativa L. Red Sails) in a hydroponic system to investigate the effects of nano- and micro-sized PS and dibutyl phthalate (DBP) on the photosynthesis and red lettuce quality. The results clearly indicated that PS reduced the bioavailability of DBP while causing a decrease in the photosynthetic parameters as well as the total chorophyll content compared to DBP alone by affecting the crystalline structure of the water-soluble chlorophyll protein. Compared with DBP monotherapy, the presence of PS significantly increased hydrogen peroxide and malondialdehyde content in the lettuce treated with DBP, indicating serious oxidative damage. Furthermore, the soluble protein and sugar content in lettuce leaves decreased with higher PS concentration and smaller PS size. It may be due to PS inhibited lettuce root and ribulose-1,5-bisphosphate carboxylase/oxygenase activities. In contrast, nitrite content increased significantly with the induction of the glutathione-ascorbic acid cycle, indicating that the presence of PS reduced the quality of DBP-treated-red lettuce. Additionally, the nano-sized PS greatly inhibited lettuce growth and quality more than the micro-sized PS. This study described the interactions between microplastics and phthalates using molecular simulation and experimental validation to highlight the potential risks of microplastics on vegetable crop production.

Plastics are globally distributed in oceans and can pose a threat to the environment and organisms. In this study, plastic pollution in surface water and sediments of the Bohai Sea was assessed based on plastic abundance, distribution and characteristics (shape, polymer, size and color). Water and sediment samples were collected across the sea using a plankton net (330 μm) and a grab sampler, respectively. The following conclusions were reached. 1) In surface water, large plastics were less abundant (0.14 items/m³) and showed less diverse characteristics than microplastics (0.79 items/m³) but did not significantly differ in spatial distribution. 2) Microplastics in water were more abundant (1.95 items/m³) with more diverse characteristics in Liaodong Bay than in other regions of the sea (0.26–0.59 items/m³). Plastic waste from highly concentrated agricultural, industrial and fishery activities could make large contributions to microplastics in Liaodong Bay. Additionally, low hydrodynamics and long distance to Bohai Strait are unfavorable for diffusion of particles, facilitating the retention of microplastics and increasing the abundance in this bay. 3) Microplastics in sediments were smaller in terms of dominant sizes (<0.5 mm) with less diverse characteristics than particles in water (0.5–1.5 mm). Specifically, fragments, foams and lines dominated among the microplastics in water, whereas fibers and fragments were dominant particles in sediments; alkyd resin, polyethylene, polystyrene and polypropylene (PP) predominated among the particles in water, but rayon, cellulose and PP were dominant particles in sediments. 4) Neither abundance nor size of microplastics in the two media was proportionally correlated and showed low similarity indexes of polymer (0.16), shape (0.29) or color (0.38). This could be related to mismatch in spatiotemporal distributions and variations in the characteristics, fate and behavior of microplastics in the two media. The findings provide knowledge for tracing the sources of plastics in the Bohai Sea.