Genetic effects and radioactive contamination of large mammals, including wild boar (Sus scrofa), have been studied in Japan because of dispersal of radionuclides from the Fukushima Dai-ichi Nuclear Power Plant in 2011. Such studies have generally demonstrated a declining trend in measured radiocesium body burdens in wildlife. Estimating radiation exposure to wildlife is important to understand possible long-term impacts. Here, radiation exposure was evaluated in 307 wild boar inhabiting radioactively contaminated areas (50–8000 kBq m⁻²) in Fukushima Prefecture from 2016 to 2019, and genetic markers were examined to assess possible germline mutations caused by chronic radiation exposures to several generations of wild boar. Internal Cs activity concentrations in boar remained high in areas near the power plant with the highest concentration of 54 kBq kg⁻¹ measured in 2019. Total dose rates to wild boar ranged from 0.02 to 36 μGy h⁻¹, which was primarily attributed to external radiation exposure, and dose rates to the maximally exposed animals were above the generic no-effects benchmark of 10 μGy h⁻¹. Using the estimated age of each animal, lifetime radiation doses ranged from <0.1 mGy to 700 mGy. Despite chronic exposures, the genetic analyses showed no significant accumulation of mutation events. Because wild boar is an occasional human dietary item in Japan, effective dose to humans from ingesting contaminated wild boar meat was calculated. Hypothetical consumption of contaminated wild boar meat from radioactively contaminated areas in Fukushima, at the per capita pork consumption rate (12.9 kg y⁻¹), would result in an average effective annual dose of 0.9 mSv y⁻¹, which is below the annual ingestion limit of 1 mSv y⁻¹. Additionally, a consumption rate of about 1.4 kg y⁻¹ of the most contaminated meat in this study would not exceed annual ingestion limits.

The rapid expansion of organic rice cultivation areas have been accompanied by increased application of organic fertilizers. The high prevalence of soil antibiotic resistance caused by organic fertilizer application poses a severe threat to the agricultural and soil ecosystems. To date, research efforts and understanding of the effects and mechanism of action of the various organic fertilizers on antibiotic resistance in paddy soils remain poorly investigated. Tetracycline resistance genes (TRGs, including tetB, tetC, tetL, tetZ, tetM, tetO, tetT, and tetX), class 1 integron-integrase gene (intI1) and bacterial communities were characterized using quantitative-PCR and Illumina MiSeq sequencing, in paddy soils exposed to inorganic fertilizer (NPK), animal-derived organic fertilizer (AOF, composted swine and/or chicken manure), plant-derived organic fertilizer (POF, rapeseed cake and/or astragalus) and commercial organic fertilizer (COF, composted of animal manure mix with crop residues) applications. Compared with NPK, AOF applications significantly increased the relative abundance of TRGs, which was predominantly expressed in the increase of the relative abundance of tetC, tetM, tetO, tetT, and tetX, while POF and COF had no significant effect on the relative abundance of TRGs. Principal coordinate analysis revealed that AOF and POF significantly altered bacterial communities in paddy soils relative to NPK, while COF had no significant change of bacterial communities. Variation partitioning analysis indicated that soil physicochemical properties were the decisive factors for the changes of TRGs in organic paddy fields. Furthermore, redundancy analysis and the Mantel test showed that TRG profiles in AOF applied paddy soils were strongly influenced by electrical conductivity (EC). Total nitrogen (TN) and organic matter (OM) affected the distribution of TRGs in COF and POF applied paddy soils through a different mechanism. This study provides insights into the impacts of different types of organic fertilizer on the profiles of TRGs in paddy soils.

Geochemical cycling of iron (Fe) mediated by sediment microbes drives the remobilization of phosphorus (P). Understanding the underlying mechanism is essential for the evaluation of P retention by wetlands. The diffusive gradients in thin film (DGT) and 16S rDNA sequencing techniques were combined to explore seasonal variations in the remobilization mechanism of sediment P in a free water surface wetland in southwest China. A significantly positive correlation between labile P and Fe concentrations was found from the sediment profiles, indicating coupled remobilization of Fe and P in the sediment. Fe-reducing bacterial genera, particularly Sphingomonas and Geothermobacter, were responsible for the reductive dissolution of Fe oxides and subsequent P release in sediment. The efflux of sediment P was higher in the rainy season (95 ± 87 ng cm⁻² d⁻¹) than in the dry season (39 ± 29 ng cm⁻² d⁻¹). Based on the significantly positive relationship between the efflux and total concentration of sediment P, we propose a promising regression equation for quantifying the release risk of sediment P. The Luoshijiang Wetland exhibited a higher release potential as indicated by a greater regression slope (0.558) compared to the other water bodies (0.055), which was mainly attributed to the lower labile Fe:P molar ratio in the sediment. Based on estimations of the diffusive flux of P at the sediment-water interface, sediment contributed more than 172 and 413 g of P per day to the water column in the dry and rainy seasons, respectively, accounting for 14.0% and 1.9% of the P mass in the surface water of the wetland.

Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) are two common contaminant groups of concern in aquaculture products. While biochar amendment can be one of the solutions to immobilize these contaminant in pond sediment, its in situ effectiveness in mitigating the bioavailability, tissue residue, and dietary risk of these contaminants is yet to be tested. In this study, we added wheat straw biochar in sediments of three aquaculture ponds with polyculture of fish and shrimps and employed passive sampling techniques (i.e., diffusive gradient in thin film for HMs and polydimethylsiloxane for PAHs) to assess the diffusion flux and bioavailability throughout the culturing cycle. Reduction in HM concentrations in organisms by biochar after 28 weeks ranged from 17% to 65% for benthic organisms and from 6.0% to 47% for fish. ΣTHQs values of HMs dropped from 2.5 to 2.1 and 1.2 to 0.91 for the two organisms with the initial ΣTHQs value above 1.0. The decrease rates of both the concentrations and ΣTHQs values followed the order of Cu > Cr > Pb > Cd, which was closely correlated with the speciation of HMs in the sediments. ΣPAHs values dropped significantly at the growth stage (20ᵗʰ week) and the mature stage (28ᵗʰ week), and, on average, by 34% across all the organisms. Carcinogenic PAHs in aquaculture products decreased dramatically at the seedling stage (12ᵗʰ week), while there was no significant change observed for the Incremental Lifetime Cancer Risk values. By comparing the freely-dissolved concentrations in pore water of sediments and the overlying water, consistently enhanced diffusion fluxes of HMs and PAHs from water to sediment over the whole culturing cycle were obtained. Our results demonstrated the in situ applicability of biochar amendment to remediating chemical pollution in aquaculture environment and safeguarding quality of aquatic products.

The sight into photoconversion of toluene, a ubiquitous typical pollutant, attentively by the involvement of PM2.5 in the real air environment is crucial for controlling haze pollution. Compared with the large-size PM2.5 on normal day (PM2.5-ND), the PM2.5 on haze day (PM2.5-HD) formed of small particle agglomerates featured greater oxidation capability, evidenced by the valence distribution of sulfur species. Notably, PM2.5-HD had abundant O₂⁻• and •OH and participated in the photochemical reaction of toluene, giving it a greater toluene conversion with a first-order kinetic rate constant of 0.4 d⁻¹ on haze day than on normal day (0.2 d⁻¹). During the toluene photoconversion, isotopic labelling traced small molecules including benzene and newfound pentane, ethylbenzene, 1,3,8-p-menthatriene and 4-methyl-1-pentanone benzene that could be formed by methyl breakage, ring opening, fragmentation reforming and addition reaction of toluene. Given ADMET properties, 1,3,8-p-menthatriene was assigned high priority since it had poor metabolism, low excretion and severe toxicity, while benzene and 4-methyl-1-pentanone benzene should also be noticeable. FT-ICR MS results indicated that toluene could create multiple macromolecular products that are more sensitive to SOA generation in haze air matrix with broader carbon number and O/C, more oxygenated substitution with CHO/CHON occupying by 81.4%, lower DBEₐᵥₑᵣₐgₑ at 4.66 and higher OSC‾ at −1.60 than normal air matrix. Accordingly, a photochemical reaction mechanism for toluene in real air atmosphere was proposed. The stronger oxidation property of PM2.5 not only facilitated toluene to generate small molecules but also boosted the conversion of intermediates to oxygenated macromolecular products, contributing to the formation of SOA.

The soil environment serves as an assembling area for microplastics, and is an important secondary source of microplastics in other environmental media. Recently, soil microplastics have been extensively studied; however, high variability is observed among the research results owing to different soil properties, and the complexity of soil microplastic composition. The present study amassed the findings of 2886 experimental groups, across 38 studies from 2016 to 2022, and used meta-analysis to quantitatively analyze the differences in the effects of microplastic exposure on soil physicochemical properties and biota. The results showed that among the existing soil microplastic research, agricultural soils maintained a higher environmental exposure distribution than other environments. Microplastic fibers and fragments were the predominant shapes, indicating that the extensive use of agricultural films are the primary influencing factor of soil microplastic pollution at present. The results of the meta-analysis found that microplastic exposure had a significant negative effect on soil bulk density (lnRR = −0.04) and aggregate stability (lnRR = −0.085), indicating that microplastics may damage the integrity of soil structure or damage the soil surface. The significant changes in plant root biomass and soil phosphatase further signified the potential impact of microplastics on soil nutrient and geochemical element cycling. We further constructed species sensitivity distribution curves, revealing that invertebrates had a higher species sensitivity to microplastics, as they can pass through the gut wall of soil nematodes, causing oxidative stress and affecting gene expression. In general, soil is an interconnected complex, and microplastic exposure can directly or indirectly interact with environmental chemical processes in the soil environment, potentially harming the soil ecosystem; however, current research remains insufficient with respect to breadth and depth in terms of the comprehensive “source-sink” mechanism of soil microplastics, the hazard of exposure, and the overall toxic effects.

Imazalil (IMZ) is an imidazole fungicide commonly used by fruit-packaging plants (FPPs) to control fungal infections during storage. Its application leads to the production of pesticide-contaminated wastewaters, which, according to the European Commission, need to be treated on site. Considering the lack of efficient treatment methods, biodepuration systems inoculated with tailored-made inocula specialized on the removal of such persistent fungicides appear as an appropriate solution. However, nothing is known about the biodegradation of IMZ. We aimed to isolate and characterize microorganisms able to degrade the recalcitrant fungicide IMZ and eventually to test their removal efficiency under near practical bioengineering conditions. Enrichment cultures from a soil receiving regular discharges of effluents from a FPP, led to the isolation of a Cladosporium herbarum strain, which showed no pathogenicity on fruits, a trait essential for its biotechnological exploitation in FPPs. The fungus was able to degrade up to 100 mg L⁻¹ of IMZ. However, its degrading capacity and growth was reduced at increasing IMZ concentrations in a dose-dependent manner, suggesting the involvement of a detoxification rather than an energy-gain mechanism in the dissipation of IMZ. The isolate could tolerate and gradually degrade the fungicides fludioxonil (FLD) and thiabendazole (TBZ), also used in FPPs and expected to coincide alongside IMZ in FPP effluents. The capacity of the isolate to remove IMZ in a practical context was evaluated in a benchtop immobilized-cell bioreactor fed with artificial IMZ-contaminated wastewater (200 mg L⁻¹). The fungal strain established in the reactor, completely dominated the fungal community and effectively removed >96% of IMZ. The bioreactor also supported a diverse bacterial community composed of Sphingomonadales, Burkholderiales and Pseudomonadales. Our study reports the isolation of the first IMZ-degrading microorganism with high efficiency to remove IMZ from agro-industrial effluents under bioengineering conditions.

Indoor airborne microplastics fibers (MPFs) are emerging contaminants of growing concern. Nowadays, air conditioners (ACs) are widely used in indoor environments. However, little is known about their impact on the distribution of indoor MPFs. In this study, we first disclosed the prevalence of MPF contamination in filters for indoor split ACs used in living rooms, dormitories, and offices. The average density of microfibers was 1.47–21.4 × 10² items/cm², and a total 27.7–35.0% of fibers were MPFs. Of these fibers, the majority were polyester (45.3%), rayon (27.8%), and cellophane (20.1%). We further tracked the long-term accumulation of MPFs on AC filters in three types of rooms, and demonstrated that dormitories showed relatively heavy accumulation especially after running for 35–42 days. Furthermore, we found that simulative AC filters which had been lined with PET MPFs could effectively release those MPFs into indoor air, propelling them away from the ACs at varying distances. Statistical analysis showed that the estimated daily intake of MPFs (5–5000 μm length) from AC filters would increase gradually with their usage, with the intake volume reaching up to 11.2 ± 2.2–44.0 ± 8.9 items/kg-BW/day by the 70th day, although this number varied among people of different ages. Altogether, these findings suggest that AC filters can act as both a sink and a source of microplastics fibers. Therefore, AC filters should be evaluated not only for their substantial impact on the distribution of indoor airborne MPFs, but also for their role in the prevalence of the related health risks.

Human exposure to organic contaminants is widespread. Many of these contaminants show adverse health effects on human population. Human biomonitoring (HBM) follows the levels and the distribution of biomarkers of exposure (BoE), but it is usually done in a targeted manner. Suspect and non-targeted screening (SS/NTS) tend to find BoE in an agnostic way, without preselection of compounds, and include finding evidence of exposure to predicted, unpredicted known and unknown chemicals. This study describes the application of high-resolution mass spectrometry (HRMS)-based SS/NTS workflow for revealing organic contaminants in urine of a cohort of 200 children from Slovenia, aged 6–9 years. The children originated from two regions, urban and rural, and the latter were sampled in two time periods, summer and winter. We tentatively identified 74 BoE at the confidence levels of 2 and 3. These BoE belong to several classes of pharmaceuticals, personal care products, plasticizers and plastic related products, volatile organic compounds, nicotine, caffeine and pesticides. The risk of three pesticides, atrazine, amitraz and diazinon is of particular concern since their use was limited in the EU. Among BoE we tentatively identified compounds that have not yet been monitored in HBM schemes and demonstrate limited exposure data, such as bisphenol G, polyethylene glycols and their ethers. Furthermore, 7 compounds with unknown use and sources of exposure were tentatively identified, either indicating the entry of new chemicals into the market, or their metabolites and transformation products. Interestingly, several BoE showed location and time dependency. Globally, this study presents high-throughput approach to SS/NTS for HBM. The results shed a light on the exposure of Slovenian children and raise questions on potential adverse health effects of such mixtures on this vulnerable population.

Methyl Chloride (CH₃Cl) is the largest source of stratospheric chlorine, which has a significant impact on the depletion of the stratospheric ozone layer. Detailed information on anthropogenic CH₃Cl emissions in China is still lacking. This study establishes a comprehensive bottom-up inventory of anthropogenic CH₃Cl emissions in China during 2000–2020. Results show that China's anthropogenic CH₃Cl emissions have increased significantly, from 34.1 ± 11.6 Gg/yr (gigagrams per year) in 2000 to 128.5 ± 26.5 Gg/yr in 2018 with a slight decrease to 124.9 ± 26.0 Gg/yr in 2020. The main sources of anthropogenic emissions of CH₃Cl in China are chemical production (37.1%), solvent use (35.4%), and coal combustion (13.6%) in 2020. China's contribution to global anthropogenic emissions of CH₃Cl reached almost 50%. Moreover, the ratios of CH₃Cl CFC-11-eq emissions relative to emissions of ozone-depleting substances (ODSs) controlled under the Montreal Protocol in China have increased from 0.8% in 2000 to 11.6% in 2020 and are estimated to continue increasing in the future. In summary, China's anthropogenic CH₃Cl emissions have shown an increasing trend in the past two decades, made a huge contribution to the total global anthropogenic emissions, and presented a potential increasing impact on the depletion of the ozone layer and global warming.