Carbamazepine (CBZ) decay by electro-Fenton (EF) oxidation using a novel FeS₂/carbon felt (CF) cathode, instead of a soluble iron salt, was studied with the aim to accelerate the reaction between H₂O₂ and ferrous ions, which helps to produce more hydroxyl radicals (•OH) and eliminate iron sludge. First, fabricated FeS₂ and its derived cathode were characterized by scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. Anodes were then screened, with DSA (Ti/IrO₂–RuO₂) showing the best performance under EF oxidation regarding CBZ degradation and electrochemical characterization. Several operating parameters of this EF process, such as FeS₂ loading, current density, gap between electrodes (GBE), initial [CBZ], and electrolyte type, were also investigated. Accordingly, a nonconsecutive empirical kinetic model was established to predict changes in CBZ concentration under the given operational parameters. The contribution of different oxidation types to the EF process was calculated using kinetic analysis and quenching experiments to verify the role of the FeS₂-modified cathode. The reaction contributions of anodic oxidation (AO), H₂O₂ electrolysis (EP), and EF oxidation to CBZ removal were 12.81%, 7.41%, and 79.77%, respectively. The •OH exposure of EP and EF oxidation was calculated, confirming that •OH exposure was approximately 22.45-fold higher using FeS₂-modified CF. Finally, the 19 intermediates formed by CBZ degradation were identified by ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry. Accordingly, four CBZ degradation pathways were proposed. ECOSAR software was used to assess the ecotoxicity of intermediates toward fish, daphnia, and green algae, showing that this novel EF oxidation process showed good toxicity reduction performance. A prolonged EF retention time was proposed to be necessary to obtain clean and safe water, even if the targeted compound was removed at an earlier time.

Considering that pesticides have been used in Europe for over 70 years, a system for monitoring pesticide residues in EU soils and their effects on soil health is long overdue. In an attempt to address this problem, we tested 340 EU agricultural topsoil samples for multiple pesticide residues. These samples originated from 4 representative EU case study sites (CSS), which covered 3 countries and four of the main EU crops: vegetable and orange production in Spain (S–V and S–O, respectively), grape production in Portugal (P-G), and potato production in the Netherlands (N–P). Soil samples were collected between 2015 and 2018 after harvest or before the start of the growing season, depending on the CSS. Conventional and organic farming results were compared in S–V, S–O and N–P. Soils from conventional farms presented mostly mixtures of pesticide residues, with a maximum of 16 residues/sample. Soils from organic farms had significantly fewer residues, with a maximum of 5 residues/sample. The residues with the highest frequency of detection and the highest content in soil were herbicides: glyphosate and its main metabolite AMPA (P-G, N–P, S–O), and pendimethalin (S–V). Total residue content in soil reached values of 0.8 mg kg⁻¹ for S–V, 2 mg kg⁻¹ for S–O and N–P, and 12 mg kg⁻¹ for P-G. Organic soils presented 70–90% lower residue concentrations than the corresponding conventional soils. There is a severe knowledge gap concerning the effects of the accumulated and complex mixtures of pesticide residues found in soil on soil biota and soil health. Safety benchmarks should be defined and introduced into (soil) legislation as soon as possible. Furthermore, the process of transitioning to organic farming should take into consideration the residue mixtures at the conversion time and their residence time in soil.

Chlorpyrifos, an organophosphate (OP) insecticide, is prevalent in aquatic systems globally and is often implicated in aquatic toxicity during storm events. Chlorpyrifos induces toxicity by inhibition of acetylcholinesterase (AChE) activity, which has been related to alterations to fish swimming performance. Resistance to organophosphate insecticides, including chlorpyrifos, is prevalent in populations of the epibenthic amphipod Hyalella azteca in areas with known OP exposure. Previous studies have demonstrated an elevated bioaccumulation potential of insecticide-resistant prey items, however the potential for trophic transfer of chlorpyrifos from OP-resistant prey items and associated neurotoxic effects in fish predators has not been studied. Consequently, the present study aimed to determine the potential for trophic transfer of chlorpyrifos from OP-resistant H. azteca to a known predator, the inland silverside, Menidia beryllina at two temperatures (18 and 23 °C) to simulate temperature changes associated with global climate change (GCC). Fish were fed either ¹⁴C-chlorpyrifos-dosed H. azteca or control animals for 7 d, after which total bioaccumulation, percent parent chlorpyrifos, brain AChE activity and swimming performance (ramp-Ucᵣᵢₜ) were determined. Fish fed chlorpyrifos-dosed H. azteca bioaccumulated chlorpyrifos ranging from 29.9 to 1250 ng/g lipid, demonstrating the potential for trophic transfer. Lower bioaccumulation and greater biotransformation were observed in M. beryllina at 23 °C as compared to 18 °C, though this was not statistically significant. A significant 36.5% reduction in brain AChE activity was observed in fish fed chlorpyrifos-dosed H. azteca at 23 °C only, which may be attributed to increased biotransformation of parent chlorpyrifos to more potent AChE-inhibiting metabolites. Dietary chlorpyrifos exposure had no significant effect on swimming performance in M. beryllina, though ramp-Ucᵣᵢₜ was significantly increased by 25% at 23 as compared to 18 °C. These findings confirm the potential for trophic transfer of chlorpyrifos from OP-resistant prey to fish predators and the potential for elevated temperatures to exacerbate the neurotoxic effects of chlorpyrifos.

Previous ecological risk assessments were mainly concentration-oriented rather than source-oriented. Moreover, land use is usually related to source emissions but was rarely used to improve the source apportionment accuracy. In this study, the land-use effects of heavy metals (HMs) in surface (0–20 cm) and subsurface (20–40 cm) soils were first explored using ANOVA in a suburb of Changzhou City, China; next, based on robust absolute principal component scores-robust geographically weighted regression (RAPCS/RGWR), this study proposed RAPCS/RGWR with land-use type (RAPCS/RGWR-LUT) and compared its source apportionment accuracy with those of basic RAPCS/RGWR and commonly-used absolute principal component scores/multiple linear regression (APCS/MLR); then, the source-oriented ecological risks were apportioned based on RAPCS/RGWR-LUT and Hakanson potential ecological risk index method; finally, this study proposed robust residual kriging with land-use type (RRK) for spatially predicting the source-oriented ecological risks, and compared its spatial prediction accuracy with those of robust ordinary kriging (ROK) and traditionally-used ordinary kriging (OK). Results showed that: (i) by incorporating land-use effects, RAPCS/RGWR-LUT obtained higher source apportionment accuracy than RAPCS/RGWR and APCS/MLR; (ii) the two most important external input sources of the ecological risks were 'atmospheric deposition' (PERIₛᵤᵣfₐcₑ = 47.11 and PERIₛᵤbₛᵤᵣfₐcₑ = 35.27) and 'agronomic measure' (PERIₛᵤᵣfₐcₑ = 28.93 and PERIₛᵤbₛᵤᵣfₐcₑ = 20.37); (iii) the biggest ecological risk factor was soil Cd (ERₛᵤᵣfₐcₑ = 57.14 and ERₛᵤbₛᵤᵣfₐcₑ = 47.62), which was mainly contributed by 'atmospheric deposition' (ERₛᵤᵣfₐcₑ=33.14 and ERₛᵤbₛᵤᵣfₐcₑ=25.71); (iv) RRK obtained higher spatial prediction accuracy than ROK and OK; (v) the high-risk areas derived from 'atmospheric deposition' were mainly located in the southwest of the study area, and the high-risk areas derived from 'agronomic measure' were scattered in the agricultural land in the north and south of the study area. The above information provided effective spatial decision support for reducing the source-oriented input of the ecological risks of soil HMs in a large-scale area.

Diet, age, and growth rate influences on fish mercury concentrations were investigated for Arctic char (Salvelinus alpinus) and brook trout (Salvelinus fontinalis) in lakes of the eastern Canadian Arctic. We hypothesized that faster-growing fish have lower mercury concentrations because of growth dilution, a process whereby more efficient growth dilutes a fish’s mercury burden. Using datasets of 57 brook trout and 133 Arctic char, linear regression modelling showed fish age and diet indices were the dominant explanatory variables of muscle mercury concentrations for both species. Faster-growing fish (based on length-at-age) fed at a higher trophic position, and as a result, their mercury concentrations were not lower than slower-growing fish. Muscle RNA/DNA ratios were used as a physiological indicator of short-term growth rate (days to weeks). Slower growth of Arctic char, inferred from RNA/DNA ratios, was found in winter versus summer and in polar desert versus tundra lakes, but RNA/DNA ratio was (at best) a weak predictor of fish mercury concentration. Net effects of diet and age on mercury concentration were greater than any potential offset by biomass dilution in faster-growing fish. In these resource-poor Arctic lakes, faster growth was associated with feeding at a higher trophic position, likely due to greater caloric (and mercury) intake, rather than growth efficiency.

Nitrogen dioxide (NO₂) is one of the most important air pollutants that highly affect the formation of secondary fine particles and tropospheric ozone. In this study based on hourly NO₂ observations from June 2014 to May 2019 and a regional air quality model (WRF−CMAQ), we comprehensively analyzed the spatiotemporal variations of NO₂ concentrations throughout China and in 12 urban agglomerations (UAs) and quantitatively showed the anthropogenic and meteorological factors controlling the interannual variations (IAVs). The ground observations and tropospheric columns show that high NO₂ concentrations are predominantly concentrated in UAs such as Beijing−Tianjin−Hebei (BTH), the Shandong Peninsula (SP), the Central Plain (CP), Central Shaanxi (CS), and the Yangtze River Delta (YRD). For different UAs, the NO₂ IAVs are different. The NO₂ increased first and then decreased in 2016 or 2017 in BTH, YRD, CS, and Cheng−Yu, and decreased from 2014 to 2019 in Harbin−Changchun, CP, SP, Northern Slope of Tianshan Mountain, and Beibu−Gulf, while increased slightly in the Pearl River Delta (PRD) and Hohhot−Baotou−Erdos−Yulin (HBEY). The NO₂ IAVs were primarily dominated by emission changes. The net wintertime decreases of NO₂ in BTH, Yangtze River Middle−Reach, and PRD were mostly contributed by emission reductions from 2014 to 2018, and the significant increase in the wintertime in HBEY was also dominated by emission changes (93%). Weather conditions also have an important effect on the NO₂ IAVS. In BTH and HBEY, the increases of NO₂ in winter of 2016 are mainly attributed to the unfavorable weather conditions and for the significant decreases in the winter of 2017, the favorable weather conditions also play a very important role. This study provides a basic understanding on the current situation of NO₂ pollution and are helpful for policymakers as well as those interested in the study of tropospheric ozone changes in China and downwind areas.

Black carbon (BC), by the combustion of fossil fuels and biomass, has profound effects on climate change and glacier retreat in industrial eras. In the present study, we report refractory BC (rBC) in an ice core spanning 1850–2014, retrieved from the Hariqin Glacier of the Tanggula Mountains in the central Tibetan Plateau, measured using a single particle soot photometer (SP2). The rBC concentration shows a three-fold increase since the 1950s. The mean rBC concentration was 0.71 ± 0.52 ng mL⁻¹ during 1850s–1940s and 2.11 ± 1.60 ng mL⁻¹ during 1950s–2010s. The substantial increase in rBC since the 1950s is consistent with rBC ice core records from the Tibetan Plateau and Eastern Europe. According to the predominant atmospheric circulation patterns over the glacier and timing of changes in regional emissions, the post-1950 amplification of rBC concentration in the central Tibetan Plateau most likely reflects increases in emissions in Eastern Europe, former USSR, the Middle East, and South Asia. Despite the low-level background rBC concentrations in the ice cores from the Tibetan Plateau, the present study highlights a remarkable increase in anthropogenic BC emissions in recent decades and the consequent influence on glaciers in the Tibetan Plateau.

Developing a biotechnical system with rapid degradation of pesticide is critical for reducing environmental, food security and health risks. Here, we investigated a novel epigenetic mechanism responsible for the degradation of the pesticide atrazine (ATZ) in rice crops mediated by the key component CORONATINE INSENSITIVE 1a (OsCOI1a) in the jasmonate-signaling pathway. OsCOI1a protein was localized to the nucleus and strongly induced by ATZ exposure. Overexpression of OsCOI1a (OE) significantly conferred resistance to ATZ toxicity, leading to the improved growth and reduced ATZ accumulation (particularly in grains) in rice crops. HPLC/Q-TOF-MS/MS analysis revealed increased ATZ-degraded products in the OE plants, suggesting the occurrence of vigorous ATZ catabolism. Bisulfite-sequencing and chromatin immunoprecipitation assays showed that ATZ exposure drastically reduced DNA methylation at CpG context and histone H3K9me2 marks in the upstream of OsCOI1a. The causal relationships between the DNA demethylation (hypomethylatioin), OsCOI1a expression and subsequent detoxification and degradation of ATZ in rice and environment were well established by several lines of biological, genetic and chemical evidence. Our work uncovered a novel regulatory mechanism implicated in the defense linked to the epigenetic modification and jasmonate signaling pathway. It also provided a modus operandi that can be used for metabolic engineering of rice to minimize amounts of ATZ in the crop and environment.

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.

Cadmium (Cd) and excess molybdenum (Mo) are harmful to animals, but the combined nephrotoxic mechanism of Cd and Mo in duck remains poorly elucidated. To assess joint effects of Cd and Mo on pyroptosis via ROS/PTEN/PI3K/AKT axis in duck renal tubular epithelial cells, cells were cultured with 3CdSO₄·8H₂O (4.0 μM), (NH₄)₆Mo₇O₂₄·4H₂O (500.0 μM), MCC950 (10.0 μM), BHA (100.0 μM) and combination of Cd and Mo or Cd, Mo and MCC950 or Cd, Mo and BHA for 12 h, and the joint cytotoxicity was explored. The results manifested that toxicity of non-equitoxic binary mixtures of Mo and Cd exhibited synergic interaction. Mo or/and Cd elevated ROS level, PTEN mRNA and protein levels, and decreased PI3K, AKT and p-AKT expression levels. Simultaneously, Mo or/and Cd upregulated ASC, NLRP3, NEK7, Caspase-1, GSDMA, GSDME, IL-18 and IL-1β mRNA levels and Caspase-1 p20, NLRP3, ASC, GSDMD protein levels, increased the percentage of pyroptotic cells, LDH, NO, IL-18 and IL-1β releases as well as relative conductivity. Moreover, NLRP3 inhibitor MCC950 and ROS scavenger BHA could ameliorate the above changed factors induced by Mo and Cd co-exposure. Collectively, our results reveal that combination of Mo and Cd synergistically cause oxidative stress and trigger pyroptosis via ROS/PTEN/PI3K/AKT axis in duck tubular epithelial cells.