Glufosinate is a non-selective chiral herbicide, which has been used extensively around the world. However, limited information on the enantioselectivity of Rac- and L-glufosinate against crops. In this study, the enantioselective effects on the growth, antioxidant, and targeted enzyme activities of maize seedlings of chiral glufosinate were investigated. The results showed the enantioselective growth inhibitions were observed at both 1 and 5 mg/L concentration levels. L-Glufosinate induced more growth rate reduction in shoot height and weight compared to Rac-glufosinate. All of the antioxidant enzyme activities increased obviously in the leaves of maize seedlings treated by 1 mg/L of glufosinate. Superoxide dismutase (SOD) activity, catalase (CAT) activity, peroxidase (POD) activity, glutathione reductase (GR) activity, and malondialdehyde (MDA) content induced by L-glufosinate were 1.36, 1.16, 1.51, 1.65, and 1.65 times higher than those by Rac-glufosinate, respectively Notably, the glutamine synthetase (GS) activity was significantly reduced to 80% and 57% in the control group at 1 mg/L treated with Rac- and L-glufosinate, respectively. Our results indicated that Rac- and L-glufosinate showed the obvious enantioselectivity in the growth of maize seedlings, which has shed light on the potential enantioselective phytotoxicity of glufosinate. Data provided here will be helpful to develop the environmentally friendly herbicides.

Safe recycling of the growing amounts of municipal sewage sludge containing toxic metals had been critically challenged with the fast urbanization. In this study, we investigated soil amendment of municipal wastewater treatment (MSS) converted biochar for its recycling in agricultural soils. In a field experiment, unpyrolyzed (USS) and pyrolyzed municipal sewage sludge (PSS) was amended at 20 t ha⁻¹ on dry base to a rice paddy before rice plantation, with a control without amendment. Grain yield and emission of non-CO₂ potent greenhouse gases were examined as well as topsoil metal mobility and plant uptake determined throughout a rice-wheat rotation year. Compared to USS treatment, addition of PSS caused a significantly increased grain yield of rice by 35% but no change in grain yield of wheat following the rice season. No distinct difference was observed in grain concentration of major nutrients of N, P, and K between USS and PSS treatments. Compared to USS treatment, PSS treatment reduced CH₄ emissions by 91.6% from soil and by 78.5% from ecosystem during rice-growing season. Whereas, PSS treatment led to a reduction of ecosystem N₂O emissions by 70.8% relative to USS treatment during wheat-growing season. While both USS and PSS treatments slightly but insignificantly increased soil total content of heavy metals, PSS treatment reduced CaCl₂-extractable Cd pool by 33~40% over USS treatment. Grain contents of Cd and Pb and Cd/Zn were markedly reduced under PSS over USS, without exceeding the Chinese state guideline limit. Carbon emission intensity was considerably (by over 20%) reduced for soil and ecosystem but unchanged for wheat soil, under PSS over USS. Thus, soil amendment of pyrolyzed sewage sludge could be a measure for climate smart soil and for safe grain production in rice agriculture. It deserves further study if repeated amendment could exert sustainable impacts on soil health and food security in the paddy.

The increasing consumption of medications by humans has negative effects such as the increased disposal of these compounds in the environment. Little is known about how the disposal of a “drug mix” (DM) in aquatic ecosystems can affect their biota. Thus, we evaluated whether the exposure of Lithobates casteibeianus tadpoles to a DM composed of different medication classes (antibiotic, anti-inflammatory, antidepressant, anxiolytic, analgesic, and antacid drugs)—at environmentally relevant concentrations—may change their oral morphology, trigger behavioral disorders, and have mutagenic effects on erythrocyte cells. Based on our data, animals exposed to the DM showed changes in mandibular sheath pigmentation, dentition, and swimming activity, as well as atypical behavior in the social aggregation test [with co-specific and interspecific (Physalaemus cuvieri) individuals] and antipredatory defensive response deficit (chemical stimulus from Odonata larvae), after 15 exposure days. The mutagenic analysis revealed higher frequency of nuclear abnormalities in the erythrocytes of tadpoles exposed to the DM (e.g., multilobulated, blebbed, kidney-shaped, notched nucleus, binuclear, and micronucleated erythrocytes). Given the chemical complexity of the DM, we assumed that several organic functions may have been affected, either by the isolated, synergistic, antagonistic, or additive action of DM compounds. Finally, our study confirms the toxicological potential of DM in L. catesbeianus tadpoles, with emphasis to impacts that can affect the fitness of individuals and their natural populations. Thus, we suggest that more attention should be given to the disposal of medications in the environment and reinforce the need of improving water and sewage treatment systems.

Schwertmannite is an important sink for cadmium (Cd) in acid mine drainage (AMD) environments and is unstable when environmental conditions change. However, the release and redistribution of Cd during schwertmannite transformation with respect to pre-bound Cd are poorly understood. In this work, the transformation of cadmium-associated schwertmannite and subsequent Cd repartitioning behaviors were investigated. The way of schwertmannite associated with Cd was predominant by absorption, and the diffuse layer model (DLM) showed that Cd²⁺ existed as monodentate complexes ≡Fe₍₁₎OCd⁺ and ≡Fe₍₂₎OCd⁺ on schwertmannite surfaces. Kinetics of SO₄²⁻ release and mineralogical characterization both showed that the mineral transformation rates decreased and more lepidocrocite aggregated with increasing adsorbed Cd levels. The shrinking core model revealed that Fe(II)-induced process would affect mineral dissolution by changing surface reaction-controlled step to internal diffusion-controlled step, and significantly promote the dissolution rate of Cd-adsorbed schwertmannite. Adsorbed Cd blocked the surface sites for later Fe(II) adsorption and the Fe(II)-Fe(III) electron transfer, then resulted in the decelerated transformation and the accumulation of intermediate phase lepidocrocite. The maximum release of aqueous Cd occurred after 1 mM Fe²⁺ addition, then over 69% of initial added Cd₍ₐq₎ re-bound to solid-phase accompanying with mineral transformation, and finally, Cd was mainly associated with the secondary minerals by complexation with surficial OH groups. These findings are useful for developing the strategies for treating Cd contamination in AMD affected areas.

Soil contamination with heavy metals is a global issue confronting the environmental pollution and human/animal health. Much work has been done on physiological and antioxidant responses of wheat in hydroponic experiments and health risks from individual heavy metal contamination to human, but limited information is available on their combined application in soil. Therefore, this pot study delineates the uptake of lead and cadmium, as well as physiological responses of wheat and associated health risks under different levels of alone and combined Cd and Pb treatments. Metal uptake increased with their increasing applied levels. The highest Cd (4.24, 1.38, and 0.92 mg kg⁻¹) and Pb (763.33, 39.63, and 16.35 mg kg⁻¹) concentrations in root, shoot, and grain, respectively, were observed at highest applied levels (0.4 mM Cd and 10 mM Pb). Furthermore, all the treatments increased lipid peroxidation and activities of superoxide dismutase, catalase, ascorbate peroxidase, and peroxidase, while decreased total chlorophyll contents and membrane stability index. Under combined application of Cd and Pb, the toxicity and detoxification responses of wheat increased compared to alone treatments. Multivariate analysis further confirmed the toxicity and accumulation pattern of metals under alone and combined treatments. Target hazard quotient values of Cd and Pb were < 1 under alone and combined treatments. The health hazard index values of Pb (97.07 and 87.89%) were higher than those of Cd (2.93 and 12.10%) in combined application for human and buffalo, respectively. This study highlights that the multi-metal contamination (Cd and Pb) is detrimental for wheat growth and human/animal health.

Cotton crops generate millions of tons of lignocellulosic waste in Brazil that could be used in energy generation; however, the main destination of this raw material is soil incorporation. The aim of this work was to perform an energetic characterization and evaluation of briquettes produced from different agricultural waste of naturally colored cotton for power generation. The cultivars Brasil Sementes (BRS) Jade and Topazio were studied, with white cotton (BRS 286) as standard for comparison purposes. Two different parts of each species, stalk and cotton shell, were analyzed by bulk density, proximate analysis, higher heating value, cellulose, hemicellulose, protein, fat and lignin content, thermogravimetric analysis, and briquette mechanical strength. The results of the energetic characterization indicated a higher energetic potential of the colored species when compared with the white cotton, especially because of the volatile matter content, fixed carbon, and higher heating value. The briquette mechanical strength was higher in the samples formulated by a mixture of stalk and shell. Finally, it was concluded that the waste from colored cotton cultivars, Jade and Topazio, is capable to generate briquettes with good mechanical and physico-chemical characteristics, especially those formed by the mixture of stalk and shell.

The addition of biochar has been reported as a strategy for improving soil fertility, crop productivity, and carbon sequestration. However, information regarding the effects of biochar on the carbon cycle in paddy fields under water-saving irrigation remains limited. Thus, a field experiment was conducted to investigate the effects of biochar addition on the net ecosystem exchange (NEE) of CO₂ and soil organic carbon (SOC) content of paddy fields under water-saving irrigation in the Taihu Lake region of China. Four treatments were applied: controlled irrigation (CI) without biochar addition as the control (CA), CI with biochar addition at a rate of 20 t·ha⁻¹ (CB), CI with biochar addition at a rate of 40 t·ha⁻¹ (CC), and flooding irrigation (FI) with biochar addition at a rate of 40 t·ha⁻¹ (FC). Biochar addition increased rice yield and irrigation water use efficiency (IWUE) by 24.0–36.3 and 33.4–42.5%, respectively, compared with the control. In addition, biochar addition increased the NEE of CI paddy fields. The average NEE of paddy fields under CB and CC was 2.41 and 30.6% higher than that under CA, respectively. Thus, the increasing effect of biochar addition at a rate of 40 t·ha⁻¹ was considerably better than those of the other treatments. Apart from biochar addition, irrigation mode was also identified as an influencing factor. CI management increased the NEE of paddy fields by 17.6% compared with FI management. Compared with CA, CB increased total net CO₂ absorption by 10.0%, whereas CC decreased total net CO₂ absorption by 13.8%. Biochar addition also increased SOC, dissolved organic carbon, and microbial biomass carbon contents. Therefore, the joint regulation of biochar addition and water-saving irrigation is a good technique for maintaining rice yield, increasing IWUE, and promoting soil fertility. Furthermore, when amended at the rate of 20 t·ha⁻¹, biochar addition will be a good strategy for sequestering carbon in paddy fields.

A series of activated carbons (ACs) were prepared by modifying a commercial AC by physical activation using CO₂ during different activation times. The ACs were designated as F, F12, F24, and F40 corresponding to the activation times of 0, 12, 24, and 40 h, respectively. The surface area, total pore volume, micropore volume, and mean micropore width were determined for all the ACs. The textural properties of the modified ACs increased substantially with the activation time, and the capacity of the ACs for adsorbing diclofenac (DCF) was almost linearly dependent upon the surface area of the ACS. The maximum adsorption capacities of F, F12, F24, and F40 carbons towards diclofenac (DCF) from aqueous solution were 271, 522, 821, and 1033 mg/g, respectively. Hence, the adsorption capacities of ACs were considerably enhanced with the activation time, and F12, F24, and F40 carbons presented the highest adsorption capacities towards DCF reported in the technical literature. The F40 adsorption capacity was at least twice those of other carbon materials. The adsorption capacities decreased by raising the pH from 7 to 11 due to electrostatic repulsion between the ACs surface and anionic DCF in solution. The removal of DCF from a wastewater treatment plant (WWTP) effluent was effectively carried out by adsorption on F40. Hence, the capacity of ACs for adsorbing DCF can be optimized by tailoring the porous structure of ACs.

The objective of the paper was to use transport model of selected pesticides (carbendazim, acetamiprid and imidacloprid) in determination of linear sorption coefficients in alluvial aquifer. For constructing transport model, results of a field experiment at the location of Kovin-Dubovac drainage system in Serbia were used in order to set hydraulic parameters (hydraulic conductivity, aquifer layer thickness of the observed area, effective porosity etc.). The field experiment consisted of a tracer test during which concentrations of non-reactive tracer (Cl⁻) and selected pesticides (carbendazim, acetamiprid and imidacloprid) were monitored. For better characterization of hydraulic parameters, a pumping test was conducted at the observed well and results were used in designing transport model. Simulation model was constructed with Lizza groundwater flow software and W.O.D.A. (Well Outline and Design Aid) solver. Obtained linear sorption coefficients in the sand and gravel water-bearing layer were 0.14 mL g⁻¹ for carbendazim and 0.11 mL g⁻¹ for acetamiprid and imidacloprid. Results from this study are a unique insight into mobility of observed pesticides in the alluvial groundwater in natural conditions and can be used in contamination assessment for drinking water wells.

The genetic basis and biochemical aspects of heavy metal endurance abilities have been precisely studied in planktonic bacteria; however, in nature, bacteria mostly grows as surface-attached communities called biofilms. A hallmark trait of biofilm is increased resistance to heavy metals compared with the resistance of planktonic bacteria. A proposed mechanism that contributes to this increased resistance is the enhanced expression of metal-resistant genes. bmtA gene coding for metallothionein protein is one such metal-resistant gene found in many bacterial spp. In the present study, lead (Pb) remediation potential of a biofilm-forming marine bacterium Pseudomonas aeruginosa N6P6 was explored. Biofilm-forming marine bacterium P. aeruginosa N6P6 possess bmtA gene and shows resistance towards many heavy metals, i.e., Pb, Cd, Hg, Cr, and Zn. The expression of metallothionein encoding gene bmtA is significantly high in 48-h-old biofilm culture (11. 4 fold) followed by 24-h-old biofilm culture of P. aeruginosa N6P6 (4.7 fold) (P < 0.05). However, in the case of planktonically grown culture of P. aeruginosa N6P6, the highest expression of bmtA gene was observed in 24-h-old culture. The expression of bmtA also increased significantly with increase in Pb concentration up to 800 ppm. CSLM analysis indicated significant reduction in the raw integrated density of biofilm-associated lipids and polysaccharides (PS) of P. aeruginosa N6P6 biofilm grown in Pb (sub-lethal concentration)-amended medium (P < 0.05), whereas no significant reduction was observed in the raw integrated density of EPS-associated protein. The role of bmtA gene as Pb(II)-resistant determinant was characterized by overexpressing the bmtA gene derived from P. aeruginosa N6P6 in Escherichia coli BL21(DE3). ESI-MS and SDS-PAGE analyses validated the presence of 11.5-kDa MT protein isolated from Pb(II)-induced recombinant E. coli BL21(DE3) harboring bmtA gene.