Although estuaries act as a sink of many pollutants, the assessment of microplastics pollution in these transition environments remain scarce or unknown. Sediments from estuarine intertidal areas possess a great ecological concern but also could act as a sink of both buoyant and non-buoyant plastic debris. In this work, we have compared microplastic abundances and their main characteristics (size, shape, colour and polymer type) on intertidal sediments from SW Atlantic Argentinean estuaries (Samborombón, Mar Chiquita, Quequén Grande and Bahía Blanca). The mean microplastics abundance in surface sediments among estuaries was ranged from 0 to 1030 ± 657 items per kg d. w. Upper intertidal areas have shown significant higher microplastic abundances in comparison with lower intertidal zones (p < 0.05). In general, higher mean abundances were observed in surface (0–10 cm) compared to deeper sediments (10–30 cm), which revealed recent deposition trends of microplastics particles. However, higher microplastic abundances were observed in deeper sediments from Bahía Blanca (p < 0.05). Large (MPs, 1–5 mm) and small microplastics (MMPs, 1–0.1 mm) were observed in sediments from all estuaries, representing from 17 to 100% of total microplastics abundance. In terms of shape, fragments and films forms were dominant in all samples while fibers and foams were moderately or poorly represented. White, black, blue and transparent particles were observed as the main colour contribution of microplastics in sediments. The most common polymers identified included polyethylene, polyethylene terephthalate/polyester, polyvinyl chloride and polypropylene. The results showed that microplastic characteristics are different among the estuarine environments, which suggests different anthropogenic sources. Besides, deeper sediments should also be included on intertidal sediment monitoring to identify potential environmental liabilities from anthropogenically impacted estuaries.

Fertilization with organic matter (farm yard manure and/or rice straw) is thought to enhance arsenic (As) mobilization into soil porewaters, with subsequent As assimilation by rice roots leading to enhanced translocation to the grain. Here, interlinked experiments (field manuring and soil batch culture) were conducted to find the effect of organic matter at a field application rate practiced in Bangladesh (5 t/ha) on As mobilization in soil for paddies impacted by As contaminated groundwater irrigation, a widespread phenomenon in Bangladesh where the experiments were conducted. Total As concentration in a paddy soil (Sonargaon) ranged from 21.9 to 8.1 mg/kg down the soil profile and strongly correlated with TOC content. Arsenic, Fe, Mn, and DOC release into soil solution, and As speciation, are intimately linked to OM amendment, soil depth and temporal variation. Organic matter amendments lead to increased mobilization of As into both soil porewaters and standing surface waters. The As speciation in the porewater was dominated by inorganic As (Asᵢ) (arsenite and arsenate), with traces amounts of methylated species (DMAⱽ and MMAⱽ) only being found with OM amendment. It was noted in field trials that OM fertilization greatly enhanced As mobility to surface waters, which may have major implications for the fate of As in paddy agronomic ecosystems.

Paraquat (PQ) is a toxic, organic herbicide for which there is no specific antidote. Although banned in some countries, it is still used as an irreplaceable weed killer in others. The lack of understanding of the precise mechanism of its toxicity has hindered the development of treatments for PQ exposure. While toxicity is thought to be related to PQ-induced oxidative stress, antioxidants are limited in their ability to ameliorate the untoward biological responses to this agent. Summarized in this review are data on the absorption, distribution, metabolism, excretion, and toxicity (ADME/T) of PQ, focusing on the essential roles of individual transporters and enzymes in these processes. Based on these findings, strategies are proposed to design and test specific and effective antidotes for the clinical management of PQ poisoning.

Coastal aquaculture area has become one of the critical zones that are more susceptible to the influence of human activity. Many aquaculture operations invariably result in the accumulation of nutrients and heavy metals in the coastal ecosystem. Our study investigated sediment bacterial community structure and function across 23 sites under the influence of nutrients and heavy metals in the coastal aquaculture area. The habitat environment of the sediment was described by analyzing physicochemical characteristics. Sediment bacterial community structure and diversity were investigated by 16S rRNA sequencing. The sequencing data presented that Proteobacteria, Bacteroidetes, Planctomycetes, Acidobacteria and Chloroflexi were predominant at phylum level. Variations in the bacterial community composition and diversity were significant (P < 0.01) among different groups (according to the distance from the bank side) which indicated that specific environmental conditions had shaped distinct bacterial community. Specifically, bacterial diversity and composition were significantly influenced by the temperature, salinity, pH, dissolved oxygen (DO), TOC, TON, nitrite, nitrate and heavy metals (P < 0.05). Results related to functional prediction demonstrated that carbon, nitrogen and sulfur metabolism were the dominant processes in the coastal aquaculture area. In the meantime, the potential pathogens such as Arcobacter was found in site S3, which indicated the possible threat to the cultured species in this area. Overall, variations in bacterial communities caused by nutrients and heavy metals can affect biogeochemical cycles, which may provide an indication for the protection of coastal aquaculture environments.

Horizontal gene transfer (HGT) plays an important role in the dissemination of antibiotic resistance genes. In sewer systems, human-associated and environmental bacteria are mixed together and exposed to many substances known to increase HGT, including various antibacterial compounds. In wastewaters, those substances are most often detected below concentrations known to induce HGT individually. Still, it is possible that such wastewaters induce HGT, for example via mixture effects. Here, a panel of antibiotics, biocides and other pharmaceuticals was measured in filter-sterilized municipal and hospital wastewater samples from Gothenburg, Sweden. The effects on HGT of the chemical mixtures in these samples were investigated by exposing a complex bacterial donor community together with a GFP-tagged E. coli recipient strain. Recipients that captured sulfonamide resistance-conferring mobile genetic elements (MGEs) from the bacterial community were enumerated and characterized by replicon typing, antibiotic susceptibility testing and long read sequencing. While exposure to municipal wastewater did not result in any detectable change in HGT rates, exposure to hospital wastewater was associated with an increase in the proportion of recipients that acquired sulfonamide resistance but also a drastic decrease in the total number of recipients. Although, concentrations were generally higher in hospital than municipal wastewater, none of the measured substances could individually explain the observed effects of hospital wastewater. The great majority of the MGEs captured were IncN plasmids, and resistance to several antibiotics was co-transferred in most cases. Taken together, the data show no evidence that chemicals present in the studied municipal wastewater induce HGT. Still, the increased relative abundance of transconjugants after exposure to hospital wastewater could have implications for the risks of both emergence and transmission of resistant bacteria.

Low doses of neuroactive chemicals end up in the environment and disrupt behaviour of non-target organisms. Although a whole range of studies have documented pollutant-induced changes in behaviour, natural daily variability in behaviour is rarely taken into account. This is surprising because biological rhythms may affect the outcome of experiments, are adaptive and are expected to be sensitive to neurochemical exposure. Here, we exploit daily behavioural variation in the fish model Nothobranchius furzeri to examine if behavioural effects of chronic exposure (74 days) to an environmentally relevant level (28 ng/L) of the neurochemical fluoxetine depend on the time of day. Fluoxetine exposure induced an increase in anxiety-related behaviour that was slightly more pronounced in the evening compared to the morning. Moreover, open-field locomotor activity was disrupted and daily patterns in activity lifted upon exposure to the compound. These results imply that short-term behavioural variability should be considered both to standardise ecological risk assessment of neuroactive chemicals as well as to better understand the environmental impact of such compounds in aquatic ecosystems.

Traditional composting has already shown a certain effect in eliminating antibiotic residues, antibiotic-resistant bacteria (ARBs), and antibiotic resistance genes (ARGs). It is worth noting that the rebounding of ARGs and the succession of the bacterial community during conventional aerobic composting are still serious threats. Considering the probable risk, improved and adaptable technologies are urgently needed to control antibiotic resistance efficiently. This study monitored how thermophilic aerobic composting affected the ARGs, as well as the bacterial diversity during the composting of cow manure spiked with sulfamethoxazole (SMX) at different concentrations. Results showed that the degradation of SMX was enhanced during thermophilic aerobic composting (control > SMX25 > SMX50 > SMX100) and was no longer detected after 20 days of composting. High temperature or heat significantly stimulated the rebounding of certain genes. After 35 days, the abundance of detected genes (sul2, sulA, dfrA7, and dfrA1) significantly decreased (p < 0.05) in control and antibiotic-spiked treatments, except for sul1. The addition of three concentrations of SMX elicited a sharp effect on bacterial diversity, and microbial structure in SMX25 led to significant differences with others (p < 0.05). The network analysis revealed more rigorous interactions among ARGs and abundant genera, suggesting that the host of ARGs potentially increased at low concentrations of SMX. Especially, genera g_norank_f__Beggiatoaceae, Ruminiclostridium, Caldicoprobacter, g_norank_o_MBA03, Hydrogenispora, and Ruminiclostridium_1 were major potential hosts for sul1. In conclusion, the rebounding of ARGs could be intermitted partially, and more efficient control of antibiotic resistance could be achieved in the thermophilic composting compared to conventional methods.

DNA methylation (DNAm) plays a significant role in deleterious health effects inflicted by fine particulate matter (PM₂.₅) on the human body. Recent studies have reported that DNAm of imprinted control regions (ICRs) in imprinted genes may be a sensitive biomarker of environmental exposure. Less is known about specific biomarkers of imprinted genes after PM₂.₅ exposure. The relationship between PM₂.₅ and its chemical constituents and DNAm of ICRs in imprinted genes after short-term exposure was investigated to determine specific human biomarkers of its adverse health effects. A panel study was carried out in healthy young people in Guangzhou, China. Mixed-effects models were used to evaluate the influence of PM₂.₅ and its constituent exposure on DNAm while controlling for potential confounders. There was no significant correlation between DNAm and personal PM₂.₅ exposure mass. DNAm changes in eight ICRs (L3MBTL1, NNAT, PEG10, GNAS Ex1A, MCTS2, SNURF/SNRPN, IGF2R, and RB1) and a non-imprinted gene (CYP1B1) were significantly associated with PM₂.₅ constituents. Compared to non-imprinted genes, imprinted gene methylation was more susceptible to interference with PM₂.₅ constituent exposure. Among those genes, L3MBTL1 was the most sensitive to personal PM₂.₅ constituent exposure. Moreover, transition metals derived from traffic sources (Cd, Fe, Mn, and Ni) significantly influenced DNAm of the imprinted genes, suggesting the importance of more targeted measures to reduce toxic constituents. Bioinformatics analysis indicated that imprinted genes (RB1) may be correlated with pathways and diseases (non-small cell lung cancer, glioma, and bladder cancer). The present study suggests that screening the imprinted gene for DNAm can be used as a sensitive biomarker of PM₂.₅ exposure. The results will provide data for prevention of PM₂.₅ exposure and a novel perspective on potential mechanisms on an epigenetic level.

The concentrations of PBDEs, NBFRs, DP, PCBs, and OCPs were analyzed in water samples of the Yellow River Basin (YRB) and in soil and maize samples collected from basin irrigation areas to understand the status of POPs and associated health risks. The results showed: (1) the congeners of eight PBDEs and seven NBFRs were detected in 10 tributaries, with average concentrations of 1575 and 4288 pg. L⁻¹. Thirty-three congeners of PCBs were detected, and the average concentration of PCB was 232 pg. L⁻¹. Five HCHs were the primary congeners among twenty-three congeners of OCPs in the ten tributaries, accounting for 79% of the total. The average concentration of OCPs was 8287 pg. L⁻¹. (2) Similar congeners of HFRs, PCBs, and OCPs were found in the trunk water. The ranking based on the HFR concentration was upstream > downstream > midstream, and that of the PCB and OCP concentration was downstream > upstream > midstream. (3) PCBs and OCPs in the trunk water of the YRB and in the soil and maize irrigated with river water pose potential carcinogenic and non-carcinogenic risks. The results indicate considerable organic pollution in the YRB, suggesting that national emission standards for POPs should be implemented soon.

In this work, ZnO–CdWO₄ nanoparticles have been synthesized by the ecofriendly green method with lemon leaf extract to favorably anchor functional groups on their surface. The prepared ZnO–CdWO₄ nanoparticles are used as adsorbent to treat Congo red (CR) dye after characterization through FT-IR, UV–Vis, TEM, SEM-EDX, and HRTEM techniques. The equilibrium partition coefficient and adsorption capacity values for CR by ZnO–CdWO₄ are estimated as 21.4 mg g⁻¹ μM⁻¹ and 5 mg g⁻¹, respectively (at an initial dye concentration of 10 mg L⁻¹). The adsorption process is found as exothermic and spontaneous, as determined by the ΔG°, ΔS°, and ΔH° values. The Boyd plot has been used as a confirmatory tool to fit the adsorption kinetics data along with intraparticle diffusion and pseudo-second-order models. Based on this research, ZnO–CdWO₄ nanoparticles are validated as an effective adsorbent for CR dye in aqueous solutions.