Irrigation practice is one of the main factors affecting soil carbon dioxide (CO₂) emission from croplands and therefore on global warming. As a water-saving irrigation practice, the deficit irrigation has been widely used in summer maize fields and is expected to adapt to the shortage of water resources in Northwest China. In this study, we examined the impacts of deficit irrigation practices on soil CO₂ emissions through a plot experiment with different irrigation regimes in a summer maize field in Northwest China. The irrigation regimes consisted of three irrigation treatments: deficit irrigation treatments (T1: reduce the irrigation amount by 20%, T2: reduce the irrigation amount by 40%) and full irrigation (T0) treatments. The results showed that the soil CO₂ cumulative emissions with T1 and T2 were decreased by 9.8% (p < 0.05) and 14.3% (p < 0.05), respectively, compared with T0 treatment (1365.3 kg-C ha⁻¹). However, there were no significant differences between T1 and T2 treatments (p > 0.05). Soil CO₂ fluxes with different irrigation treatments showed significant correlations with soil moisture (p < 0.001) and soil temperature (p < 0.05). It was also observed that summer maize yields with T1 and T2 treatments were reduced by 4.9% (p > 0.05) and 30.9% (p < 0.05), compared with T0 (34.3 t ha⁻¹), respectively. The findings demonstrate that the deficit irrigation treatment (T1) resulted in a considerable decrease in soil CO₂ emissions without impacting the summer maize yields significantly. The results could be interpreted to develop better irrigation management practices aiming at reducing soil CO₂ emissions, saving water, and ensuring crop yield in the summer maize fields in Northwest China.

Sustainable management of dyeing industry is of paramount importance in order to minimize resource consumption and reduce related environmental impacts. Herein, an environmental study is conducted wherein life cycle assessment (LCA) is applied to a two-scenario process for Disperse blue 60 production with short and long processing chains with different (a) material types, (b) consumptions, (c) processes, and (d) functional units with yields of 300 t/a. The most important influenced substances of the two scenarios were sodium cyanide and electricity next. Results proved that the largest damage of the dye production was attributed to resources and reached 46 and 62 kPt in the two scenarios. Compared with the conventional coal-fired power generation, damaged values of electricity from nature gas (NG) could reduce from 102 to 86 kPt in scenarios 1 and from 123 to 104 kPt in scenarios 2, respectively. When the electricity switched from NG to solar power, the values of the two scenarios could further decrease by 17 and 27 kPt, respectively. Therefore, the process of scenario 1 with the short process chain was more environmentally friendly for the production of Disperse blue 60 owing to the more efficient process and lower resource consumption. Graphic abstract

Cold-pressed oils are valuable vegetable oils. Phthalates are used as plasticizers and additives in foodstuffs and personal care products. Studies have shown that phthalates have harmful effects on human health. In this study, five phthalates di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), butyl-benzylphthalate (BBP), diisononyl phthalate (DiNP), and diisodecyl phthalate (DiDP) were evaluated in 30 different cold-pressed oils marketed in Turkey. DEHP was widespread in oils and detected in 18 of the 30 samples, ranging from 0.56 to 92.12 mg/kg. DBP was the second determined phthalate and detected in six of 30 oil samples at concentrations from 0.10 to 51.63 mg/kg. The other phthalates, BBP, DiNP, and DiDP were found in 4, 5, and 2 from a total of 30 samples, respectively. BBP and DiNP ranged between 3.88–6.04 and 4.26–80.74, respectively. DiDP was found in 2 samples with 85.02 and 2.69 mg/kg.

Application of chelating and reductive agents in soils can increase the availability of potentially toxic elements facilitating their uptake by plants. This study discusses the effect of single or combined EDTA (E), sodium dithionite (SD), and olive mill wastewater (OMW) treatments on As, Pb, and Zn mobility over time in a heavily contaminated mine-affected soil. Soil samples were incubated for 1, 3, 7, 15, 30, 60, and 90 days and at each incubation time the easily mobilizable fraction obtained by (NH₄)₂SO₄ (for As) and CH₃COOH (for Pb/Zn). The results showed that the highest availability of As (mean value 41 mg kg⁻¹) was observed for the EDTA treatment followed by E+OMW (mean value 32 mg kg⁻¹) and E+SD+OMW (mean value 27 mg kg⁻¹). For Pb and Zn, significantly higher available concentrations were obtained by the EDTA and E+OMW treatments (mean values 2532 mg kg⁻¹ and 1427 mg kg⁻¹ for Pb and Zn respectively) followed by the E+SD (mean value 2259 and 1333 mg kg⁻¹ for Pb and Zn) and E+SD+OMW treatments (mean value 2388 and 1340 mg kg⁻¹ for Pb and Zn). Moreover, the incubated for 90 days soil samples subjected to two different sequential extraction protocols (SEPs): Wenzel (for As) and BCR (for Pb, Zn, Fe, and Mn). The results showed that As, Pb, and Zn mobility was mainly regulated by the amorphous Fe oxides. Our findings suggest that OMW application in soils should focus more attention since when combined with other amendments produced contradictory results.

Atopic asthma is characterized by the presence of sensitization to common aeroallergens, which tends to have a worse prognosis than non-atopic asthma. The objectives were to determine the prevalence of aeroallergens sensitization in the Lebanese pediatric asthmatic population and determine the relationship between allergens sensitization (indoor and outdoor) and age, area of residence and altitude. A sample, consisting of 919 asthmatic children (aged 1 to 18 years, from 2010 until 2017), underwent skin prick testing (SPT) with 21 common allergens: 5 grasses (cocksfoot, sweet vernal-grass, rye-grass, meadow grass, timothy), Parietaria, olive, Dermatophagoides pteronyssinus and Dermatophagoides farina (DP-DF), dog and cat dander, Alternaria longipens, Aspergillus fumigatus and nidulans, Cupressaceae, pine, German cockroach, and 4 cereals (oat, wheat, barley, maize). Seven hundred fifty-two patients had positive SPT. The distribution of sensitization was as follows: DP-DF 59%; 5 grasses 34%; 4 cereals 33.9%; cat 29.9%; Alternaria 27.9%; Parietaria 23%; dog 21.9%; olive 20.5%; Aspergillus mix 18.6%; Cupressaceae 18.2%; pine 17%; cockroach 15.3%. House dust mites sensitization was frequent at lower altitude (< 900 m) (56.3%) and in the whole country (a median prevalence of 53.05%) except for the Beqaa region (negative HDM in 82.4%). Non-atopic asthma was more frequent in early childhood (40.5% at 1–4 years vs 11.2% at 11–18 years). The sensitization rate increased with age, starting at 5 years. Higher age (aOR = 1.24) and altitude less than 900 m compared with ≥ 900 m (aOR = 2.03) were significantly associated with the presence of aeroallergens in children. House dust mites and grasses are the most common allergens in Lebanese asthmatic children. Non-atopic asthma is more frequent at early age. Lebanese children with asthma showed a polysensitized pattern starting at 5 years.

This work studies the degradation of seven representative antibiotics (ciprofloxacin, norfloxacin, levofloxacin, oxacillin, cloxacillin, cefalexin, and cefadroxil) by solar photo-Fenton process. The removal of antibiotics by the individual components (i.e., light, H₂O₂, or Fe (II)) and the complete photochemical system (light/H₂O₂/Fe (II)) was initially evaluated. Then, the effect of citric acid addition to the photo-Fenton system was assessed. In the third place, the primary transformation products for two illustrative cases (ciprofloxacin and oxacillin treated by photo-Fenton) were determined. Also, photo-Fenton in the presence of citric acid was applied to remove antibiotics from a simulated hospital wastewater. It was found that the solar light component induced degradation of ciprofloxacin, norfloxacin, and levofloxacin, but the rest of the considered antibiotics were not reduced by photolysis. In turn, the photo-Fenton system showed a degrading action on all the tested antibiotics. The addition of citric acid to the system significantly increased the removal of antibiotics. Initial degradation products indicated that hydroxyl radical attacked moieties of antibiotics responsible for their antimicrobial activity. Finally, the treatment of hospital wastewater evidenced the high potentiality of photo-Fenton process for degrading antibiotics in aqueous matrices containing elevated concentrations of citric acid.

Compound pollution refers to two or more kinds of pollutants with different properties, a pollutant from different sources, or the simultaneous existence of two or more different types of pollutants in the same environment. In this study, we aimed to investigate the individual and combined toxicity of the insecticide imidacloprid (IMI), the herbicide acetochlor (ACT), and the fungicide tebuconazole (TBZ) to zebrafish. The acute toxicity test results showed that the 96-h LC₅₀ values of IMI, ACT, and TBZ were 276.84 (259.62–294.35) mg active ingredient (a.i.) L⁻¹, 1.52 (1.34–1.74) mg a.i. L⁻¹, and 8.16 (7.7–8.6) mg a.i. L⁻¹, respectively. The combinations of IMI, ACT, and TBZ with toxicity ratios of 1:2:2, 1:4:4, 2:4:1, and 4:1:4 displayed synergistic toxic effects on zebrafish, while the toxicity ratios of 1:1:1, 1:1:2, 2:1:2, 2:2:1, and 4:2:1 of IMI, ACT, and TBZ, respectively, exhibited antagonistic toxic effects on zebrafish. The following experiments were performed with a toxicity ratio of 1:4:4 (IMI:ACT:TBZ). The activities of four enzyme biomarkers related to oxidative stress in the liver, catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), and malondialdehyde (MDA) content were evaluated in each exposure group on days 7, 14, 21, and 28. Compared with those of the control group, the activities of CAT, SOD, and GST and the MDA content were significantly altered at different time points in the individual and combined exposure groups. Additionally, the activities of CAT, SOD, and GST and the MDA content were significantly altered in the combined group compared with those of the individual group after 14 days or 21 days of exposure. Therefore, it was confirmed that combined toxicity studies are indispensable in risk assessment. Graphical abstract .

Based on a monthly field survey in 2011 of the Pearl River Estuary, the dynamics of polycyclic aromatic hydrocarbons (PAHs) in surface sediments (depth < 5 cm) were explored. The seasonal variations in PAH level and composition were investigated in this study, as well as their environmental behaviors, the role of particles, and source apportionment. The concentration of the sum of 16 priority PAHs (defined as ∑₁₆PAHs) ranged from 0.32 to 1.10 μg/g, while that of the sum of 62 PAHs (defined as ∑ₜPAHs) varied from 0.83 to 2.75 μg/g. The levels of both the ∑₁₆PAHs and ∑ₜPAHs peaked in February, although the minimum levels appeared in different months—December and August, respectively. The seasonal difference in the ∑ₜPAHs was significant (flood season, 7.69 μg/g; dry season, 10.51 μg/g). The 5-ring PAH compound (e.g., perylene) was the most abundant and was responsible for 35% of the total, which implied a terrestrial input source via the Pearl River. Sediment particles were predominantly composed of clayed sand, and sediment PAHs showed a greater tendency to be adsorbed onto the large-sized particles rather than the fine fractions. Total organic carbon (TOC) could considerably facilitate the sediment PAHs. Principal component analysis revealed that vehicle emission sources, petroleum sources, and combustion sources were the major anthropogenic contamination sources. The diagnostic ratios of various individual PAHs were also explored. These findings are particularly useful for understanding the geochemistry of organic pollutants in the complex estuarine environment.

Rampant use of tetracycline in animal feed is a threat to food security, the environment, and human health because of the risk of drug residues. Therefore, it is necessary to establish a sensitive, efficient, and reliable method for qualitative and quantitative detection of tetracycline. In this paper, we synthesized fluorescent carbon dots (FCDs) by thermal cracking of crab shell waste, and obtained a fluorescence quantum yield of 30%. Characterization of the FCDs by transmission electron microscopy, Fourier-transform infrared spectroscopy, ultraviolet visible absorption spectroscopy, and photoluminescence spectroscopy showed that they were fluorescent and evenly distributed with an average size of approximately 10 nm. We designed a sensitive probe for detecting tetracycline using the fluorescence intensity change of the FCDs. This method is sensitive, inexpensive, and environmentally friendly. The concentration of tetracycline was examined by comparing the fluorescence intensities of the FCDs before and after tetracycline addition. The limit of detection for tetracycline was 0.005 mg/L (signal-to-noise ratio = 3), which is promising for method development.

The study’s objective was to evaluate the nitrate level safety for Macrobrachium amazonicum juvenile in the laboratory, a potential native species for culture in Brazil. The experiment consisted of six treatments with six replicates in a completely randomized block design: 0, 250, 500, 1,000, 1,500, and 2,000 mg L⁻¹. Physical and chemical water quality parameters were recorded every 12 h, while the shrimp mortalities in the 24-h interval. Except for nitrate, all physical and chemical water quality parameters remained within the ideal range rearing to this species. No deaths were observed during the first 6 h of exposure range 0-500 mg L⁻¹ concentrations. At 250 mg L⁻¹ N-NO₃⁻, the mortality (10%) started from 48 h. At 500 mg L⁻¹ N-NO₃⁻, shrimp mortalities occurred after 24 h, reaching 60% after 72 h. In the treatments with 1000 and 1500 mg L⁻¹ N-NO₃⁻ concentrations, dead shrimps can be observed after 24 h, with a mortality rate of 78% and 90% of the population in 96 h, respectively. All shrimps exposed at 2000 mg L⁻¹ died in 96 h. The LC50 values obtained decreased with increasing exposure time. Based on LC50 (96 h), the N-NO₃⁻ level safety to M. amazonicum is 48.5 mg L⁻¹.