Pyrene (Pyr), a widely used tetracyclic aromatic hydrocarbon, enters soil in large quantities and causes environmental pollution due to its production and mining. In order to systematically study the biotoxicity of pyrene to model organisms Eisenia fetida in soil, experiments were carried out from four dimensions: animal, tissue, cell and molecule. Experimental results proved that the mortality rate increased with increasing concentration and time of exposure to pyrene, while the mean body weight and spawning rate decreased. Meanwhile, when the pyrene concentration reached 900 mg/kg, the seminal vesicle and longitudinal muscle of the earthworm showed obvious atrophy. Experimental results at the cellular level showed that pyrene induced cell membrane damage and Ca²⁺ influx triggered mitochondrial membrane depolarization and a surge in ROS levels. Oxidative stress causes damage to proteins and lipids and DNA inside cells. When the mortality rate was 91.67 %, the Olive Tail Movement (OTM) of the comet experiment reached 15. The results of molecular level tests showed that pyrene inhibited the activity of Cu/Zn-superoxide dismutase (Cu/Zn-SOD) mainly by changing the microenvironment and secondary structure of amino acid Tyr 108. The weakened function of direct antioxidant enzymes may be the root cause of the excessive increase of reactive oxygen species (ROS) in cells. The systematic approach used in this study enriches the network of toxic pathways in toxicological studies, and basic data on the biological toxicity of pyrene can provide support for future soil contamination detection.

Thiacloprid is a neonicotinoid insecticide widely exploited in agriculture and easily mobilized towards aquatic environments by atmospheric agents. However, little information about its toxicological effects on aquatic invertebrate bioindicators is available. In this study, specimens of the mussel Mytilus galloprovincialis were exposed to thiacloprid at environmental (4.5 μg L⁻¹) and 100 times higher than environmental (450 μg L⁻¹) concentrations for 20 days. Thiacloprid affected haemolymph biochemical parameters, cell viability in the digestive gland, antioxidant biomarkers and lipid peroxidation in the digestive gland and gills at environmentally relevant concentrations (4.5 μg L⁻¹). In addition, thiacloprid exposure caused histological damage to the digestive gland and gills. Interestingly, the pesticide was detected at levels equal to 0.14 ng g⁻¹ in the soft tissues of sentinels exposed for 20 days to 450 μg L⁻¹ thiacloprid in seawaterμ. Due to its harmful potential and cumulative effects after long-term exposure of M. galloprovincialis, thiacloprid may pose a potential risk to nontarget aquatic organisms, as well as to human health. This aspect requires further in-depth investigation.

Cadmium (Cd) in the food chain poses a serious hazard to human health. Therefore, a greenhouse hydroponic experiment was conducted to examine the potential of exogenously strigolactone GR24 in lessening Cd toxicity and to investigate its physiological mechanisms in the two barley genotypes, W6nk2 (Cd-sensitive) and Zhenong8 (Cd-tolerant). Exogenous application of 1 μM GR24 (strigol analogue) reduced the suppression of growth caused by 10 μM Cd, lowered plant Cd contents, increased the contents of other nutrient elements, protected chlorophyll, sustained photosynthesis, and markedly reduced Cd-induced H₂O₂ and malondialdehyde accumulation in barley. Furthermore, exogenous GR24 markedly increased NO contents and nitric oxide synthase activity in the Cd-sensitive genotype, W6nk2, effectively alleviating the Cd-induced repression of the activities of superoxide dismutase and peroxidase, increasing reduced glutathione (GSH) and ascorbic acid (AsA) pools and activities of AsA-GSH cycle including ascorbate peroxidase, glutathione peroxidase, glutathione reductase, dehydroascorbate reductase and monodehydroascorbate reductase. The findings of the present study indicate that GR24 could be a candidate for Cd detoxification by decreasing Cd contents, balancing nutrient elements, and protecting barley plants from toxic oxidation via indirectly eliminating reactive oxygen species (ROS), consequently contributing to reducing the potential risk of Cd pollution.

Although microplastics are an emerging pollutant of global concern, little is known about the environmental behavior of microplastic in sediments. This study investigated the occurrence and seasonal variation of microplastics in the sediments of Liangfeng River, China with a fluorescence staining method, and then explored the transfer of microplastics at the water and sediment interfaces during resuspension. The results showed that smaller microplastics were detected in the sediments, which were concentrated in the size range of 50–500 μm. Microplastic abundance in the sediments in the dry season were slightly higher than those from the rainy season, and the rainy season promotes the accumulation of smaller microplastics in the sediment along the river-flow direction but not for the dry season. The shape of microplastics were predominantly fibers, followed by fragments and films. Polyethylene was the most abundant polymer, accounting for more than 50% of the total. Microplastics in the surface sediment move both to the overlying water and deeper sediment during the disturbance process. Disturbance-induced resuspension and vertical transport have significant effects on small-sized microplastics (50–500 μm). Small-sized microplastics can potentially migrate and redistribute via resuspension at different temporal and spatial scales, as some extent of resuspension is occurring in most river systems, especially in urban areas with boat traffic.

Currently, there is a lack of information about the influence of foliar-applied nanoplastics on crop growth and nutritional quality. To fill the knowledge gap, soil-grown lettuces (Lactuca sativa L.) were foliar-exposed to polystyrene nanoplastics (PSNPs) at 0, 0.1 and 1 mg/L for one month. Foliar exposure to PSNPs significantly decreased the dry weight, height, and leaf area of lettuce by 14.3%–27.3%, 24.2%–27.3%, and 12.7%–19.2%, respectively, compared with the control. Similarly, plant pigment content (chlorophyll a, b and carotenoid) was considerably reduced (9.1%, 8.7%, 12.5%) at 1 mg/L PSNPs. However, the significant increase in electrolyte leakage rate (18.6%–25.5%) and the decrease in total antioxidant capacity (12.4%–26%) were the key indicators of oxidative stress in lettuce leaves, demonstrating the phytotoxicity of PSNPs by foliar exposure. In addition, the remarkable reduction in micronutrients and essential amino acids demonstrated a decrease in nutritional quality of lettuce caused by PSNPs. Besides, SEM and TEM analysis indicated the possible absorption of PSNPs through leaves stoma and the translocation downwards to plant roots. This study provides new information about the interaction of airborne NPs with plants. It also warns against atmospheric NPs pollution that the adverse effects of airborne NPs on crop production and food quality should be assessed as a matter of urgency.

The synergistic photoelectrochemical (PEC) technology is a robust process for the conversion of CO₂ into fuels. However, designing a highly efficient UV–visible driven photoelectrocatalyst is still challenging. Herein, a plasmonic Ag NPs modified TiO₂/RGO photoelectrocatalyst (Ag–TiO₂/RGO) has been designed for the PEC CO₂ reduction into selective production of CH₃OH. HR-TEM analysis revealed that Ag and TiO₂ NPs with average sizes of 4 and 7 nm, respectively, were densely grown on the few-micron-sized 2D RGO nanosheets. The physicochemical analysis was used to determine the optical and textural properties of the Ag–TiO₂/RGO nanohybrids. Under VU-Vis light illumination, Ag–TiO₂/RGO photocathode possessed a current density of 23.5 mA cm⁻² and a lower electrode resistance value of 125 Ω in CO₂-saturated 1.0 M KOH-aqueous electrolyte solution. Catalytic studies showed that the Ag–TiO₂/RGO photocathode possessed a remarkable PEC CO₂ reduction activity and selective production of CH₃OH with a yield of 85 μmol L⁻¹ cm⁻², the quantum efficiency of 20% and Faradic efficiency of 60.5% at onset potential of −0.7 V. A plausible PEC CO₂ reduction mechanism over Ag–TiO₂/RGO photocathode is schematically demonstrated. The present work gives a new avenue to develop high-performance and stable photoelectrocatalyst for PEC CO₂ reduction towards sustainable liquid fuels production.

Biogas slurry (BS) and bio-waste hydrothermal carbonization aqueous phase (HP) are nutrient-rich wastewater. To prevent environment contamination, transforming BS and HP into synthetic fertilizers in the agricultural field can potentially realize resource utilization. We hypothesized that acidic HP could neutralize alkaline BS, adjusting floodwater pH from 6.88 to 8.00 and mitigating ammonia (NH₃) volatilization from the paddy soil. In this soil column study, the mixture of BS and HP was applied to paddy soil to substitute 50%, 75%, and 100% to urea. With a low (L) or high (H) ratio of HP, treatments were labeled as BCL50, BCL75, BCL100, BCH50, BCH75, and BCH100. Results showed that microbial byproduct- and fulvic acid-like substance were the main components in BS and HP using 3D-EEM analysis, respectively. Co-application of BS and HP mitigated the NH₃ volatilization by 4.2%–65.5% compared with CKU. BCL100 and BCH100 treatments significantly (P < 0.05) mitigated NH₃ volatilization by 65.5% and 56.8%, which also significantly (P < 0.05) mitigated the yield-scale NH₃ volatilization by 49.6% and 42.3%, compared with CKU. The low NH₄⁺-N concentration and pH value in floodwater were the main reason explained the NH₃ mitigation. Therefore, this study demonstrated that BS and HP co-application can substitute the urea as a valuable N fertilizer in a rational rate and meanwhile mitigate the NH₃ volatilization. This study will provide new ideas for the utilization of BS and HP resources in the context of ammonia mitigation.

Calcium peroxide (CaO₂) has been proven to oxidize various organic pollutants when they exist as a single class of compounds. However, there is a lack of research on the potential of unactivated CaO₂ to treat mixed chlorinated organic pollutants in soils. This study examined the potential of CaO₂ in treating soils co-contaminated with p-dichlorobenzene (p-DCB) and p-chloromethane cresol (PCMC). The effects of CaO₂ dosage and treatment duration on the rate of degradation were investigated. Furthermore, the collateral effects of the treatment on treated soil characteristics were studied. The result showed that unactivated CaO₂ could oxidize mixed chlorinated organic compounds in wet soils. More than 69% of the pollutants in the wet soil were mineralized following 21 days of treatment with 3% (w/w) CaO₂. The hydroxyl radicals played a significant role in the degradation process among the other decomposition products of hydrogen peroxide. Following the oxidation process, the treated soil pH was increased due to the formation of calcium hydroxide. Soil organic matter, cation exchange capacity, soil organic carbon, total nitrogen, and certain soil enzyme activities of the treated soil were decreased. However, the collateral effects of the system on electrical conductivity, available phosphorus, and particle size distribution of the treated soil were not significant. Likewise, since no significant release of heavy metals was seen in the treated soil matrix, the likelihood of metal ions as co-pollutants after treatment was low. Therefore, CaO₂ can be a better alternative for treating industrial sites co-contaminated with chlorinated organic compounds.

Chloropicrin (CP) controls soil-borne plant diseases caused by pathogenic microbes, increases crop yield, but has a long-term inhibitory effect on beneficial soil microorganisms. Therefore, we evaluated the effects of biofumigation material fresh chicken manure (FCM) on soil microorganisms, and the duration of those effects in this experiment. Our results showed that in the laboratory, FCM significantly increased substrate-induced respiration (SIR) of soil microorganisms by 2.2–3.2 times at 80 d compared to the control, however, CP significantly inhibited the SIR of soil microorganisms. FCM and CP increased NH4+-N concentration within 40 days which then returned to the control level. FCM increased NO3--N by 2.82–5.78 times by 80 days, compared with the control, while the concentration of NO3--N in the CP treatment was not significantly different from the control at the 80 day. Although in the laboratory FCM inhibited the relative abundance of 16 S rRNA and the nitrogen cycle functional genes AOA amoA, AOB amoA, nirK and nosZ over a 40-day period, the taxonomic diversity of soil bacteria and fungi in the FCM treatment were restored to unfumigated level within 90 days in the field. However, CP treatment has a strong inhibitory effect on soil microorganisms after 90 days. Importantly, the relative abundance of some beneficial microorganisms that control soil-borne pathogenic microbes or degrade pollutants increased significantly in FCM, including Bacillus, Pseudomonas and Streptomyces bacterial genera and Chaetomium and Mycothermus fungal genera. Noteworthy, like CP, FCM still had a strong inhibitory effect on Fusarium at 90 d. Our results indicated that FCM not only increased the content of inorganic nitrogen and improved the respiration rate of soil microorganisms, but it also shortened the recovery time of beneficial soil microorganisms and increased taxonomic diversity. Our previous reports showed that FCM and CP treatments had the same effect in disease control and crop growth. Combined with the results of this experiment, we believe that FCM has the potential to replace CP, which would eliminate CP's detrimental environmental impact, improve farmer safety and promote sustainable crop production.

Given extensive use of pesticides in agriculture, there is concern for unintended consequences to non-target species. The non-target freshwater amphipod, Hyalella azteca has been found to show resistance to the organophosphate (OP) pesticide, chlorpyrifos, resulting from an amino acid substitution in acetylcholinesterase (AChE), suggesting a selective pressure of unintended pesticide exposure. Since resistant organisms can survive in contaminated habitats, there is potential for them to accumulate higher concentrations of insecticides, increasing the risk for trophic transfer. In the present study, we estimated the uptake and elimination of chlorpyrifos in non-resistant US Lab, and resistant Ulatis Creek (ULC Resistant), H. azteca populations by conducting 24-h uptake and 48-h elimination toxicokinetic experiments with ¹⁴C-chlorpyrifos. Our results indicated that non-resistant H. azteca had a larger uptake clearance coefficient (1467 mL g⁻¹ h⁻¹) than resistant animals (557 mL g⁻¹ h⁻¹). The half-life derived from the toxicokinetic models also estimated that steady state conditions were reached at 13.5 and 32.5 h for US Lab and ULC, respectively. Bioaccumulation was compared between non-resistant and resistant H. azteca by exposing animals to six different environmentally relevant concentrations for 28 h. Detection of chlorpyrifos in animal tissues indicated that resistant animals exposed to high concentrations of chlorpyrifos were capable of accumulating the insecticide up to 10-fold higher compared to non-resistant animals. Metabolite analysis from the 28-h concentration experiments showed that between 20 and 50 % parent compound was detected in H. azteca. These results imply that bioaccumulation potential can be more significant in chlorpyrifos resistant H. azteca and may be an essential factor in assessing the full impacts of toxicants on critical food webs, especially in the face of increasing pesticide and chemical runoff.