Plastic film mulching is a common practice to increase crop yield in dryland, while the wide use of plastic film has resulted in ubiquitous phthalate esters (PAEs) releasing into the soil. PAEs in soil could be taken up and accumulated by dietary intake of food crops such as wheat, thus imposing health risks to residents. In the present study, samples from a long-term location-fixed field experiment were examined to clarify the accumulation of PAEs in soil and wheat, and to assess the human health risks from PAEs via dietary intake of wheat grain under plastic film mulching cultivation in dryland. Results showed that concentrations of PAEs in grains from mulching plots ranged from 4.1 to 12.6 mg kg−1, which were significantly higher than those in the control group. There was a positive correlation for the PAE concentrations between wheat grains and field soils. Concentrations of PAEs in the soil were in the range of 1.8–3.5 mg kg−1 for the mulching treatment, and 0.9–2.7 mg kg−1 for the control group. Di-n-butyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) were detected in all soil and grain samples, and DEHP was found to be the dominant PAE compound in grains. Based on DEHP concentrations in wheat grains, the values of carcinogenic risk for adults were higher than the recommended value 10−4. Results indicated that wheat grains from film mulching plots posed a considerable non-carcinogenic risk to residents, with children being the most sensitive resident group. Findings of this work call the attention to the potential pollution of grain crops growing in the plastic film mulching crop production systems.

Organic micropollutants (OMPs) are widely detected in surface waters. So far, the removal processes of these compounds in situ in river systems are not yet totally revealed. In this study, a combined monitoring and modelling approach was applied to determine the behaviour of 1-H benzotriazole, carbamazepine, diclofenac and galaxolide in a small river system. Sewage treatment plant effluents and the receiving waters of the river Swist were monitored in 9 dry weather sampling campaigns (precipitation < 1 mm on the sampling day itself and <5 mm total precipitation two days before the sampling) during different seasons over a period of 3 years. With the results gained through monitoring, mass balances have been calculated to assess fate in the river. With the DWA Water Quality Model, OMP concentrations in the river were successfully simulated with OMP characteristics gained through literature studies. No removal was determined for 1-H benzotriazole and carbamazepine, whereas diclofenac showed removal that coincided with light intensity. Moreover, modelling based on light sensitivity of diclofenac also suggested relevant degradation at natural light conditions. These two approaches suggest removal by photodegradation. The highest removal in the river was detected for galaxolide, presumably due to volatilisation, sorption and biodegradation. Furthermore, short-term concentration variability in the river was determined, showing that daily concentration patterns are influenced by dynamics of sewage treatment plant effluent volumes and removal processes in the river.

Antibiotics in water and soil are persistent, bioaccumulative and toxic to aquatic organisms and human health. To address it, as one of the new technologies, green synthesized magnetic Fe₃O₄ nanoparticles by Excoecaria cochinchinensis extract used to remove rifampicin (RIF) was investigated in this study. Results showed the adsorption efficiency of RIF reached 98.4% and the maximum adsorption capacity is 84.8 mg/g when 20 mL of RIF at a concentration of 20 M was adsorbed by 10 mg Fe₃O₄ at a temperature of 303 K. The morphology of the green Fe₃O₄ characterized by SEM demonstrated the dimensions ranging from 20 to 30 nm. The N₂ adsorption/desorption isotherms revealed that the surface area of Fe₃O₄ was 111.8 m²/g. In addition, adsorption studies indicated that the kinetics fitted the pseudo second-order and isothermal adsorption conformed to the Langmuir isotherm. Furthermore, due to their magnetic properties, the Fe₃O₄ nanoparticles were easily separated and reused and the mechanism for removing RIF occurred through adsorption rather than chemical redox reaction. Finally, the reusability of Fe₃O₄ for adsorption of RIF showed that the removal efficiency decreased to 61.5% after five cycles.

Moss is usually as an initial colonizer in alpine glacier retreated regions. We hypothesized that moss can significantly facilitate the toxic metals accumulation in alpine ecosystems based on its strong ability of absorption and the role in soil development. Hence, we investigated the trace element pool sizes and enrichment factors, especially for mercury (Hg) by using the Hg isotopic compositions to determine the source contributions in a moss-dominated ecosystem over glacial erratic in Eastern Tibetan Plateau. Results show that Hg, lead (Pb) and cadmium (Cd) are highly enriched in organic soils. Specifically, Cd concentration is 5–20 times higher than the safety limit of the acid soil (pH ≤ 5.5) in China. Atmospheric depositions dominantly contribute to the Pb and Cd sources in organic soils, and followed by the moraine particles influences. The lowering pH in organic soils increasing with glacial retreated time results in the desorption of Cd in organic soils. Atmospheric Hg⁰ uptake by moss predominantly contributes to the Hg sources in organic soils. The average Pb accumulation rate over last 125-year is about 5.6 ± 1.0 mg m⁻² yr⁻¹, and for Cd is 0.4 ± 0.1 mg m⁻² yr⁻¹, and for Hg⁰ is 27.6 ± 3.2 μg m⁻² yr⁻¹. These elevated accumulation rates are caused by the high moss biomass and elevated atmospheric Hg, Pb and Cd pollution levels in China and neighbouring regions. Our study indicates that the moss not only as the bioindicator, but also plays an important role in the hazardous metal biogeochemical cycling in alpine regions.

Denitrification is considered as the dominant nitrogen (N) removing pathway, however, anaerobic oxidation of ammonium (anammox) also plays a significant part in N loss in agricultural ecosystems. Large N inputs into agricultural soils may stimulate the growth of anammox bacteria, resulting in high activity and diversity of anammox bacteria and subsequent more N loss. In some specific niches, like oxic-anoxic interface, three processes, nitrification, anammox and denitrification couple with each other, and significant anammox reaction could be observed. Soil parameters like pH, dissolved oxygen, salinity, oxidation-reduction potential (ORP), and substrate concentrations impact the anammox process. Here we summarize the current knowledge on anammox activity and contribution to N loss, abundance and diversity of anammox bacteria, factors affecting anammox, and the relationship between anammox and other N loss pathways in agricultural soils. We propose that more investigations are required for (1) the role of anammox to N loss with different agricultural management strategies; (2) microscale research on the coupling of nitrification-anammox-denitrification, that might be a very complex process but ideal model for further studies responsible for N cycling in terrestrial ecosystems; and (3) new methods to estimate differential contributions of anammox, codenitrification and denitrification in total N loss in agricultural ecosystems. New research will provide much needed information to quantify the contribution of anammox in N loss from soils at landscape, ecosystem and global scales.

The impact of commonly-used livestock antibiotics on soil nitrogen transformations under varying redox conditions is largely unknown. Soil column incubations were conducted using three livestock antibiotics (monensin, lincomycin and sulfamethazine) to better understand the fate of the antibiotics, their effect on nitrogen transformation, and their impact on soil microbial communities under aerobic, anoxic, and denitrifying conditions. While monensin was not recovered in the effluent, lincomycin and sulfamethazine concentrations decreased slightly during transport through the columns. Sorption, and to a limited extent degradation, are likely to be the primary processes leading to antibiotic attenuation during leaching. Antibiotics also affected microbial respiration and clearly impacted nitrogen transformation. The occurrence of the three antibiotics as a mixture, as well as the occurrence of lincomycin alone affected, by inhibiting any nitrite reduction, the denitrification process. Discontinuing antibiotics additions restored microbial denitrification. Metagenomic analysis indicated that Proteobacteria, Bacteroidetes, Actinobacteria, and Chloroflexi were the predominant phyla observed throughout the study. Results suggested that episodic occurrence of antibiotics led to a temporal change in microbial community composition in the upper portion of the columns while only transient changes occurred in the lower portion. Thus, the occurrence of high concentrations of veterinary antibiotic residues could impact nitrogen cycling in soils receiving wastewater runoff or manure applications with potential longer-term microbial community changes possible at higher antibiotic concentrations.

This article contains a brief overview of the European and Spanish environmental law framework for the prevention of soil contamination, for the management of contaminated soils and for consumers health protection in relation to agricultural crops. Some important aspects of the legislative framework for the prevention and management of soil contamination include recognising the possible risk to both human health and ecosystems that certain agricultural and industrial activities pose given the use of organic and inorganic chemical substances of a hazardous nature and pathogenic microorganisms. It is worth highlighting the milestone that many national constitutions include about the right to the environment. This right entails the obligation to protect it and to, therefore, protect soil from any degradation, including contamination. Legislation that protects soil from contamination and, consequently human health and ecosystems, is related mainly to agricultural activities (use of sewage sludge on farmlands, use of wastewater for irrigation, use of organic fertilisers and pesticides), and to industrial and commercial soil-contaminating activities. Consumer protection may be achieved through a legal system of environmental liability, specific measures to prevent contaminants entering soil, managing contaminated soils and a food traceability system. It is crucial to make the penalties for soil contamination offenses, and for violators of protective prohibitions, effective, proportionate and dissuasive. Global standards and guidelines on soil contamination could provide national legislative systems with substantive and procedural legal mechanisms to help prevent and manage soil contamination.

The measurement of aerosols (PM₁.₀ and PM₂.₅) was conducted during 2016 and 2017 in Beijing, Tangshan and Shijiazhuang, investigating the spatial and temporal variations of aerosols and major chemical components. The WRF-Chem model was applied to simulate the impacts of aerosol direct and semi-direct feedbacks on meteorological factors and identify the source of PM₂.₅. The results showed that the average annual concentrations were 63.3–88.7 μg/m³ for PM₁.₀ and 81.3–112 μg/m³ for PM₂.₅ at the three study cities, and the average seasonal concentration ratios of PM₁.₀/PM₂.₅ ranged from 64.3% to 86.0%. PM₁.₀ and PM₂.₅ showed a good correlation that the squared correlation coefficients were all higher than 0.9, indicating both mainly came from the same emission sources. Water-soluble inorganic ions and carbonaceous components were major chemical species in PM₁.₀ and PM₂.₅, accounting for 48.9%–54.1% and 25.6%–27.8% in PM₁.₀, 48.1%–52.3% and 22.7%–24.7% in PM₂.₅. Those chemical species showed spatially similar characteristics but pronounced seasonal differences, with higher concentrations in autumn and winter, lower in spring and summer. Aerosol feedbacks had different effects on various meteorological factors. Three study cities monthly-mean incoming solar radiation decreased by 40.6 W/m², 82.2 W/m², 38.4 W/m², and 49.9 W/m²; planetary boundary layer height reduced by 54.0 m, 109 m, 32.2 m and 85.2 m; temperature at 2 m decreased by 0.5 °C, 0.8 °C, 0.5 °C and 1.3 °C; relative humidity increased by 1.5%, 2.6%, 1.3% and 4.7% in April, July, October and January, respectively, while wind speed changes were relatively smaller than above factors. Additionally, the major sources of PM₂.₅ in January were identified as transportation in Beijing, while industrial and domestic sources in Tangshan and Shijiazhuang. The obtained results will provide more in-depth and comprehensive understanding of aerosol pollution and management strategies.

Application of controlled release urea (CRU) is recommended to reduce the undesirable environmental effects resulting from urea application. However, the overall effects of CRU on maize productivity and reactive nitrogen (N) losses remain unclear. Our global meta-analysis based on 866 observations of 120 studies indicated that application of CRU instead of urea (same N rate) increased maize yield by 5.3% and nitrogen use efficiency (NUE) by 24.1%, and significantly decreased nitrous oxide (N₂O) emission, N leaching and ammonia (NH₃) volatilization by 23.8%, 27.1% and 39.4%, respectively. The increase of NUE and reduction of N₂O emission by CRU application were greater with medium and high N rates (150 ≤ N < 200 and N ≥ 200 kg N ha⁻¹) than with low N rates. The reduction in N₂O emission and N leaching with CRU application were enhanced when soil organic carbon (SOC) content was <15.0 g kg⁻¹, and soil texture was medium or coarse. The reduction in N₂O emission and NH₃ volatilization with CRU were greater in soils with pH ≥ 6.0. We concluded that use of CRU should be encouraged for maize production, especially on light-textured soils with low organic matter content.