Nitrogen (N) deposition in China may increase due to urbanization and economic growth. Current research has considered the ecological significance under the assumption of increasing N deposition. Atmospheric N deposition tending toward levelling or declining has been observed in China. Such potential recovery and responses of high N loads ecosystems under decreasing atmospheric N deposition scenarios have yet to be adequately investigated. This work reviews existing literature to consider possible responses of carbon (C) sequestration, biodiversity and species composition, soil acidification, and greenhouse emissions in ecosystems responding to recent patterns of N deposition. Potential effects of N composition and internal ratios may be further explored through state-of-the-art N addition experiments and model development.

Environmental dissolved organic matter (DOM) has been proved to increase microbial population sizes and stimulate the degradation of some pesticide molecules. Among these molecules, the present study investigated the biodegradation of the herbicide glyphosate depending on photoautotrophs DOM supply in a microbial consortium isolated from river biofilms. Degradation experiments in the laboratory were performed in dark and light conditions, as well as after antibiotic supply, in order to characterize the eventual interactions between photoautotrophs and heterotrophs activity during glyphosate degradation. Fifty percent of the initial concentration of glyphosate (0.6 mM) was transformed into aminomethyl phosphonic acid (AMPA) after 9 days in presence or absence of light. Accordingly, the photoautotrophic DOM supply was not stimulating glyphosate degradation by microbial heterotrophs. This lack of response was probably explained by the low net primary production values and weak dissolved organic carbon production recorded in light treatments. The supply of the antibiotic drastically stopped glyphosate transformation demonstrating the central role of bacteria in the biodegradation of the herbicide. Glyphosate also modified the structure of prokaryotes assemblages in the consortium by increasing the relative abundances of Alphaproteobacteria and slightly decreasing those of Gammaproteobacteria. The chemoorganotrophic bacteria Phenylobacterium sp. (Alphaproteobacteria) was related to the transformation of glyphosate in our microbial consortium. The present study highlights the complexity of microbial interactions between photoautotrophs and heterotrophs in microbial assemblages that can contribute to the degradation of pesticides present in aquatic environments.

In this study, 76 μm polyoxymethylene (POM) strips were evaluated as a passive air sampler (PAS) for monitoring the volatile emissions from dredged material placed in confined disposal facilities (CDF). Laboratory evaluations were used to assess the uptake kinetics, average equilibrium time, and estimate the POM-air partition coefficients (KPOM₋A) of 16 PCB congeners. The uptake kinetics defined the effective averaging time for air sampling and ranged from about a week for dichlorobiphenyls to 2 weeks or more for tetra- and pentachlorobiphenyls at ∼20 °C under internal mass transfer resistance control which was applicable for Log KPOM₋A < 8. The measured Log KPOM₋A for PCBs ranged from 5.65 to 9.34 and exhibited an average deviation of 0.19 log unit from the theoretical value of KPOM₋W/KAW. The PAS approach was then tested with a preliminary field application (n = 17) at a CDF allowing equilibration over 42 days. The field application focused on lower congener PCBs as a result of the estimated increase in KPOM₋A and longer uptake times expected at the low ambient temperatures during the field study (average of 3.5 °C). Total PCB air concentrations around the CDF averaged 0.32 ng/m³ and varied according to proximity to placement of the dredged materials and predominant wind directions. Average PAS concentration of low congener number PCBs (15, 18, 20/28, 31) were compared to available high volume air sampler (HVAS) measurements. The PAS concentrations were within 20% of HVAS in the dominant north and south directions and showed similar trends as east and west HVAS samplers although PAS concentrations were as much as an order of magnitude below the west HVAS.

Composting is a solid waste management alternative that avoids the emission of methane associated with its disposal in landfill and reduces or eliminates the need for chemical fertilisers if compost is applied. The main objective of this study was to analyse the environmental burdens of composting as a way to achieve a more circular valorisation of wine waste. To do so, with the purpose of identifying optimal operational conditions and determining the “hotspots” of the process, the life cycle assessment (LCA) methodology was used. The consumption of diesel fuel in machinery was determined to be the main critical point in the environmental effects of the system, followed by the transport and distribution of the compost. After the application of compost instead of mineral fertilisers, corn, tomato and strawberry crops would have a better environmental performance in most impact categories. In this sense, a maximum improvement of 65% in terrestrial ecotoxicity is achieved in strawberry cultivation. In light of the results obtained, it is demonstrated that composting is a suitable way of organic waste valorisation according to Circular Economy principles.

Rice fields significantly contribute to the global N₂O and NH₃ emissions. Nitrification inhibitors (NIs) show promise in decreasing N₂O emission, but they can increase NH₃ volatilization under traditional broadcasting. Root zone fertilization (RZF) can mitigate NH₃ volatilization, but it may pose a high risk to N₂O emission. Additionally, most chemical NIs have limited availability and potential for environmental contamination, in contrast, biological NIs, such as methyl 3-(4-hydroxyphenyl) propionate (MHPP), are easily available and eco-friendly. However, the effects of RZF combined with MHPP on N₂O and NH₃ emissions are unknown. Therefore, a field experiment was conducted in a Chinese rice field with five treatments at 210 kg urea-N ha⁻¹ (BC: 3-split surface broadcasting; BC + MHPP: BC with MHPP; RZ, root zone fertilization; RZ + MHPP, RZF with MHPP; RZ + MHPP + NBPT, RZF with MHPP and NBPT). The results showed that although RZ eliminated NH₃ volatilization, it significantly increased total N₂O emission by 761% compared with BC due to the stimulation of nitrification by mid-season aeration (MSA) and the trigger of denitrification by a large amount of NO₃⁻. Nearly 90% N₂O was emitted at MSA stage for RZF treatments, and their N₂O fluxes were exponentially related to the soil NO₃⁻-N concentrations in the 7–20 cm deep soil layer. RZ + MHPP greatly reduced the peak values of N₂O flux due to the suppression of nitrification by MHPP and then less production of NO₃⁻ for denitrification, its total N₂O emission was 79% lower compared with that of RZ. However, RZ + MHPP + NBPT further increased the total N₂O emission by 1044% compared with that of BC. Compared to BC, the RZF practice reduced total NH₃ volatilization by 88–92% regardless use of NIs. RZF had no influence on CH₄ emissions and enhanced the rice yields. In conclusion, RZF + MHPP is a promising strategy for simultaneously reducing N₂O and NH₃ emissions in rice fields.

While terrestrial organisms such as livestock are consumed regularly, studies of internal distribution and bioaccumulation of persistent organic pollutants (POPs) have been focused more on aquatic organisms. In this study, we have assessed the internal distribution and fate of legacy (PCDD/Fs and PCBs) and emerging POPs (HBCDs and PFASs), and TBBPA in 42 tissues of a Bos Taurus. PCDD/Fs, DL-PCBs, and HBCDs were found 3, 4, and 4-fold higher in the lipid-rich organs (subcutaneous fat, visceral fat, large intestine) compared to the remaining organs and muscles, owing to their hydrophobic properties. The TBBPA concentration in the excrement was 36-fold higher compared to the average tissues, suggesting a short internal half-life of TBBPA. Among PFASs, PFUnDA displayed 98% contribution from all ionic PFASs in the tissues due to its strong binding affinity, high exposure via feed and water, and increasing emergence of PFUnDA and its precursors in the Southeast Asian countries. While our study suggests that, at the moment, there is no significant health risks to the general Korean population, the future changes in environmental exposure as well as the internal dynamics and fate of various POPs species should be kept in mind when consuming various parts of livestock.

The sorption behaviour of three perfluoroalkyl substances (PFASs), namely perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonic acid (PFHxS), was determined on 28 tropical soils. Tropical soils are often highly weathered, richer in sesquioxides than temperate soils and may contain variable charge minerals. There are little data on sorption of PFASs in tropical soils. The highest Kd values were found for PFOS with mean values ranging from 0 to 31.6 L/kg. The Kd values for PFOA and PFHxS ranged from 0 to 4.9 L/kg and from 0 to 5.6 L/kg, respectively. While these values are in the range of literature sorption data, the average Kd values for PFOS and PFOA from the literature were 3.7 times and 3.6 times higher, respectively, than those measured in this study. Stepwise regression analysis did explain some of the variance, but with different explanatory variables for the different PFASs. The main soil properties explaining sorption for PFOS and PFOA were oxalate-extractable Al and pH, and for PFHxS was pH.

Dissolved phosphate (Pᵢ) can be released during resuspended sediments exposed to sunlight. However, the significance of this phenomenon in the process of eutrophication is not clear. In this study, the behavior of photo-induced Pᵢ release during sediment resuspension in shallow lakes with the different trophic states was investigated. The amount of photo-induced Pᵢ release in the sediment resuspension from Lake Liangzi, Lake Dong, Lake Tangxun and Lake Longyang in China was 0.013, 0.019, 0.032, and 0.048 mg/L, respectively, and increased as the trophic states of the lakes increased. The results of phosphorus speciation analysis showed that the phosphate monoester in the particulate phosphorus is the organic phosphorus species participated in the photochemical reaction. The steady-state concentration of hydroxyl radical (OH) in the sediment resuspension also increased along with the trophic states of lakes increased and dissolved organic matter (DOM), nitrate, and Fe³⁺ presented in sediment resuspension were the main photosensitizers for OH production. All these results indicate that the increase of trophic states of lakes leads to the accumulation of organic phosphorus and OH, resulting in more dissolved phosphate photo-released, which accelerate the eutrophication process in a form of positive feedback.

Diesel exhaust (DE) had been associated with cardiopulmonary toxicity and developmental toxicity. However, neonatal very early-in-life exposure had not been extensively studied previously. To investigate the potential effects of neonatal very early-in-life exposure to DE, a brand-new chicken embryo in ovo exposure model had been established, with which the cardiopulmonary effects of DE exposure via air cell infusion at embryonic day 18/19 (ED18/19) were assessed in hatchling chicks post-hatch 0-, 1-, or 2-weeks. Heart rates were assessed with electrocardiography. Cardiac and pulmonary morphologies were investigated with histopathological methods. Cardiopulmonary effects were explored with immunohistochemistry for alpha smooth muscle actin (alpha-SMA). In further investigations, the expression levels of phosphorylated AhR, serum levels of TGF-β1, phosphorylated SMAD2/3 and phosphorylated p38MAPK were assessed in the lung tissues. Significantly elevated heart rates, increased right ventricular wall thickness and cardiac collagen deposition were observed in the hearts of exposed hatchling chicks. Significantly increased collagen deposition as well as increased vascular alpha-SMA layer thickness/decreased cavity area were observed in exposed animal lungs. These effects persisted up to two weeks post-hatch. Mechanistic studies revealed elevated phosphorylated AhR expression levels in 0-week and 1-week chicken lungs, while phosphorylated SMAD2/3 levels significantly increased in 0-week chicken lungs but decreased in 2-week chicken lungs following DE exposure. Phosphorylation of p38MAPK did not remarkably increase until 2-week post-hatch. In summary, the novel chicken neonatal very early-in-life exposure model effectively exposed the chicken embryos during the neonatal initial breathing, resulting in cardiopulmonary toxicity, which is associated with AHR, TGF-β1 and MAPK signaling.