The stability and dispersion of naturally occurring As have been receiving increasing attention, because As is toxic and its contamination is a widespread problem in many countries. This study investigated As fractionation and speciation in organic sediments collected from different depositional settings to elucidate the existence of stable As in humic substances. Eleven organic sediment samples were collected from marine and terrestrial alluvial regions in Hokkaido prefecture, Japan, and the chemical fraction of As and species of humic substances were identified by sequential extraction. In addition, stable As bound in organic matter was evaluated by FT-IR spectroscopy. The As fraction mainly comprised inorganic substances, especially sulfur, iron, and manganese, and terrestrial sediments (lacustrine and inland deposits) were rich in sulfides and Fe and Al (hydr)oxides. When the residual fraction was excluded, the organic fraction of As was higher in seawater sediments than in terrestrial sediments. Among humic substances, cellulose, humic acid, and hydrophilic fulvic acid were clearly associated with As accumulation, and As speciation showed that the As was of organic origin. Cellulose, an organic compound of plant origin, was abundant in As=S and As (III)=O bonds, and As accumulation was higher in sulfur-rich peat sediments, corresponding with the physiological activities of As in plants. Hydrophilic fulvic acid and humic acid in these sediments, originating from small animals and microorganisms in addition to plants, denote higher As contents and abound in As (III, V)=C and C–H, CH₃ bonds even in sulfur-rich sediments. The methylated As bonds reflect the ecological transition of organisms.

Sustainable development of food production depends on damping the environmental impacts of agricultural production. The aim of this study was to investigate the environmental performance of rice production in single crop and ratooning (main rice + ratoon crop) agro-systems through life cycle assessment (LCA) methodology in Guilan province, Northern Iran, in 2015. The flooding irrigation regime was the dominant irrigation method for single cropping system and main crop rising in ratooning agro-system. The data were gathered through a face to face interview with 215 single crop and 115 ratoon breeder paddy farmers. The environmental risks were determined in six impact categories including global warming, terrestrial eutrophication, acidification, and depletion of fossil fuels, phosphate, and potash resources. The functional unit (FU) was set as 100 kg protein. Results indicated that the CO₂, N₂O, and CH₄ emissions of the rice ratooning agro-system (661.44, 1.96, and 5.42 kg 100 kg⁻¹ protein) were less than the corresponding values in the rice single cropping agro-system (1341.63, 2.88, and 9.20 kg 100 kg⁻¹ protein, respectively). Among all the environmental impact categories, the terrestrial eutrophication had the widest negative environmental effect followed by depletion of phosphate resources in single cropping agro-system with weighted indices of 0.51 and 0.41, respectively. Moreover, the terrestrial eutrophication had the largest negative environmental effect followed by acidification in rice ratooning agro-system with weighted indices of 0.48 and 0.29, respectively. Overall, the results highlighted that the rice ratooning ago-system is more environmentally beneficial than the single cropping system, particularly in terms of depletion of fossil fuels, global warming, and depletion of phosphate and potash resources categories. This priority may be improved through adopting proper management of agronomic practices for main and ratoon rice in ratooning agro-system. Graphical abstract ᅟ

Aquatic plants play an important role in maintaining the health of water environment in nature. Studies have shown that linear alkylbenzene sulfonate (LAS), a type of omnipresent pollutant, can cause toxic damage to aquatic plants. In the present research, we studied the physiological and growth response of submerged plant Potamogeton perfoliatus L. to different concentrations of LAS (0.1, 1.0, 10.0, 20.0, and 50.0 mg l⁻¹). The results showed that LAS is toxic to P. perfoliatus, and the toxicity is dose-dependent. Only slightly reversible oxidative damages were observed in the physiological parameters of P. perfoliatus when P. perfoliatus was exposed to lower LAS doses (< 10 mg l⁻¹): soluble sugar, soluble protein, H₂O₂, and malondialdehyde (MDA) content in P. perfoliatus increased significantly at 0.1 mg l⁻¹ and then returned to normal levels at 1.0 mg l⁻¹. Antioxidant enzymes were activated before the LAS concentration reached 10 mg l⁻¹, and the activities of superoxide dismutase (SOD), catalase (CAT), and photosynthesis pigment content declined significantly when the concentration of LAS exceeded 10 mg l⁻¹. In addition, at higher concentrations (20–50 mg l⁻¹) of LAS, dry weight and fresh weight of P. perfoliatus showed significant declines. The results indicate that LAS above 10 mg l⁻¹ can cause serious physiological and growth damage to P. perfoliatus.

Pheromone-mediated mating disruption (MD) is widely used as a control tool to manage the European grapevine moth (EGVM), Lobesia botrana. Most of the MD formulations are “passive” reservoir dispensers, which need to be used at a rather large number of units per hectare. A promising alternative is represented by automatic aerosol devices, releasing pheromone puffs at programmed time intervals. Herein, we investigated the effectiveness of MD aerosol product Isonet® L MisterX841 in reducing EGVM infestation on grape in comparison to the reference MD product Isonet® L and the grower’s standard. Experiments were carried out over 2 years in two different study sites of Aragon region (Spain). EGVM male catches were monitored using traps baited with the female sex pheromone. The effectiveness of MD formulations against the three generations of EGVM was assessed by determining the percentage of infested bunches and the number of nests per bunch. As expected, a much greater amount of male catches in the grower’s standard over Isonet® L MisterX841 and Isonet ® L was observed. No significant differences about EGVM male catches were found in vineyards where Isonet® L MisterX841 and Isonet® L were used. EGVM-infested bunches, as well as number of nests per bunch, were higher in the grower’s standard, if compared to vineyards where we tested Isonet® L MisterX841 and Isonet® L. However, the employ of the latter led to a lower EGVM bunch infestation, if compared to Isonet® L MisterX841. Overall, the MD approach proposed here is effective against EGVM. These aerosol devices require a lower number of units per hectare if compared to hand-applied dispensers, saving labor costs and contributing to reduce plastic disposal in agricultural settings.

To understand whether flavor enhancers pose potential risks to the environment, it is important to assess its effects on insects. Therefore, the objective of this study was to evaluate the toxicity of flavor enhancers on the survival and behaviors of the red imported fire ant, Solenopsis invicta. In this study, we found that the mortality of S. invicta workers that were fed glutamic acid monosodium salt hydrate, glycine, L-alanine, succinic acid, succinic acid disodium, inosinate 5′-monophosphate disodium salt hydrate, and GMP were significantly higher than the mortality rates of workers fed sucrose. Moreover, glycine and GMP exhibited the strongest toxicities and caused 100% mortality in workers after 84 h. LC₅₀ values were 0.004 g/ml and 0.02 g/ml for GMP and glycine, respectively. Additionally, at sublethal doses, both GMP and glycine solutions decreased foraging and digging behaviors. Our results suggest that flavor enhancers are toxic to insects and also likely to have a negative impact at sublethal concentrations.

Alkylphenol (AP) and bisphenol A (BPA) contamination of urban runoff has already been established. Potential sources of these contaminants in runoff are endogenous to the urban watershed and are mainly related to traffic and leaching from construction materials. This article summarizes the results of experimental work carried out on a selection of building materials, automotive materials, and consumables, which can be in contact with rain, to assess their potential emission of alkylphenols, alkylphenol ethoxylates, and bisphenol A into runoff. 36 samples of materials, new and used, across 7 major families of building materials (PVC, concrete, polycarbonate, SBS-modified bitumen, drainage materials) and automotive materials (body, tires) were subjected to leaching tests with methanol and then, for a selection of them, with water. Automotive fluids were also directly analyzed. The results demonstrate the ubiquitous presence of APs and BPA in urban materials and their extractable character with water. The compounds with the strongest emission rates were bisphenol A and nonylphenol. The most important BPA emissions into water (10 to 300 ng/g) were measured for polycarbonate, tires, some car bodies, and PVC. Nonylphenol was leached in large quantities (1 to 10 ng/g) from PVC, some concretes, SBS-modified bitumen, and body samples. The tires were the only materials having a strong emission in octylphenol (1 to 10 ng/g). The analysis of automotive fluids confirmed the presence of BPA (0.3 to 5.5 g/L) and nonylphenol (2.3 to 2.9 mg/L) in brake fluids, while APs and BPA were found at trace levels in coolants and windscreen washer. Graphical abstract ᅟ

Particulate matter (PM) has been proven to cause health risks and may result in hospital emergency room visits (ERVs), which might be complicated by extreme temperature events. However, it remains unclear how temperature modulates the effect of different-sized particles on ERVs. This study used three separate time series analyses (2009–2011) to explore such temperature modulation effect in Beijing, China. The analytical approaches included a bivariate response surface model, a non-stratification parametric model, and a stratification parametric model. Results showed that the average daily concentrations of PM₁₀ and PM₂.₅ in Beijing were 110.16 and 67.89 μg/m³, respectively, during the study period, which were higher than in most Western countries. Our findings indicated that the temperature modulation effects of PM₂.₅ were more evident than that of PM₁₀. The effects of PM on morbidity depend on temperature. The effects were estimated for the increases in total, respiratory, and cardiovascular ERVs per 10 μg/m³ increase in PM₂.₅ and PM₁₀ concentrations at high temperature level (> 28 °C). The estimated increases in the three types of ERVs for PM₂.₅ were 0.15, 0.35, and 0.34%, respectively. For PM₁₀, the increases were 0.12, 0.08, and 0.14%, respectively. In addition, the results showed that the elderly (age ≥ 65) and women are more vulnerable to PM at high temperatures. These findings may have implications for the health impact associated with both air pollution and global climate change.

The solute transport model MODFLOW has become a standard tool in risk assessment and remediation design. However, particle transport models that take into account both particle agglomeration and deposition phenomena are far less developed. The main objective of the present study was to evaluate the feasibility of adapting the standard code MODFLOW/MT3D to simulate the agglomeration and transport of three different types of polymer-modified nanoscale zerovalent iron (NZVI) in one-dimensional (1-D) and two-dimensional (2-D) saturated porous media. A first-order decay of the particle population was used to account for the agglomeration of particles. An iterative technique was used to optimize the model parameters. The model provided good matches to 1-D NZVI-breakthrough data sets, with R ² values ranging from 0.96 to 0.99, and mass recovery differences between the experimental results and simulations ranged from 0.1 to 1.8 %. Similarly, simulations of NZVI transport in the heterogeneous 2-D model demonstrated that the model can be applied to more complicated heterogeneous domains. However, the fits were less good, with the R ² values in the 2-D modeling cases ranging from 0.75 to 0.95, while the mass recovery differences ranged from 0.7 to 6.5 %. Nevertheless, the predicted NZVI concentration contours during transport were in good agreement with the 2-D experimental observations. The model provides insights into NZVI transport in porous media by mathematically decoupling agglomeration, attachment, and detachment, and it illustrates the importance of each phenomenon in various situations. Graphical Abstract ᅟ

Silver nanoparticle-aided enhancement in the anti-corrosion potential and stability of plant extract as ecologically benign alternative for microbially induced corrosion treatment is demonstrated. Bioengineered silver nanoparticles (AgNPs) surface functionalized with plant extract material (proteinacious) was generated in vitro in a test tube by treating ionic AgNO₃ with the leaf extract of Azadirachta indica that acted as dual reducing as well as stabilizing agent. Purity and crystallinity of the AgNPs, along with physical and surface characterizations, were evaluated by performing transmission electron microscopy, Fourier transform infrared spectroscopy, energy dispersive x-ray spectra, single-area electron diffractions, zeta potential, and dynamic light scattering measurements. Anti-corrosion studies against mild steel (MS1010) by corrosion-inducive bacterium, Bacillus thuringiensis EN2 isolated from cooling towers, were evaluated by performing electrochemical impedance spectroscopy (EIS), weight loss analysis, and surface analysis by infrared spectroscopy. Our studies revealed that AgNPs profoundly inhibited the biofilm on MS1010 surface and reduced the corrosion rates with the CR of 0.5 mm/y and an inhibition efficiency of 77% when compared to plant extract alone with a CR of 2.2 mm/y and an inhibition efficiency of 52%. Further surface analysis by infrared spectra revealed that AgNPs formed a protective layer of self-assembled film on the surface of MS1010. Additionally, EIS and surface analysis revealed that the AgNPs have inhibited the bacterial biofilm and reduced the pit on MS1010. This is the first report disclosing the application of bioengineered AgNP formulations as potent anti-corrosive inhibitor upon forming a protective layer over mild steel in cooling water towers. Graphical Abstract ᅟ

A spent bleaching earth (SBE) from an edible oil refinery has been regenerated by thermal processing in oven, followed by washing with a cold solution of hydrochloric acid (1M). Optimal regeneration conditions have been controlled by decolorization tests of degummed and neutralized soybean oil. Optimal values of treatment (temperature 350°C, carbonization time 01 h, and HCl concentration 1M) gave a very efficient material. After bleaching oil by regenerated spent bleaching earth (RSBE), the chlorophyll-a and β-carotenes contained in crude edible oil and observed respectively at 430, 454, and 483 nm, value of λ ₘₐₓ, are very much decreased. The results obtained after decolorization of edible oil by RSBE material indicate, that, during the process, the bleaching oil did not undergo any changes in the free fatty acid content. The peroxide value (PV) was reduced from 4.2 to 1.8 meq O₂/kg, and the color has been improved (Lovibond color yellow/red: from 50/0.5 to 2.7/0.3, respectively). The RSBE material obtained was characterized by several techniques (FTIR, SEM). The results show that the heat treatment did not affect the mineral structure of RSBE, and the regenerated material recovered its porous structure.