To conserve water resources and guarantee food security, a new technology termed as “wet irrigation” is developed and practiced in rice fields; thus, its impact on radiative forcing derived from nitrous oxide (N₂O) and methane (CH₄) emissions merits serious attention. Dicyandiamide (DCD), a kind of nitrification inhibitor, is proposed as a viable means to mitigate greenhouse gas (GHG) emission while enhancing crop productivity. However, little is known about the response of GHG emission and grain yield to DCD application in a rice system under wet irrigation. In these regard, effects of water regime and DCD application on CH₄ and N₂O emissions, grain yield, global warming potential (GWP), and greenhouse gas intensity (GHGI) from rice fields were studied. For this study, a field experiment, designed: Treatment II (intermittent irrigation), Treatment WI (wet irrigation), Treatment IID (II plus DCD), and Treatment WID (WI plus DCD), was conducted in Jurong, Jiangsu Province, China, from 2011 to 2012. Relative to Treatment II, Treatment WI decreased CH₄ emission significantly by 49–71 % while increasing N₂O emission by 33–72 %. By integrating CH₄ and N₂O emissions and grain yield, Treatment WI was 20–28 and 11–15 % lower than Treatment II in GWP and GHGI, respectively. The use of DCD under wet irrigation reduced N₂O emission significantly by 25–38 % (p < 0.05) and CH₄ emission by 7–8 %, relative to Treatment WI, resulting in a decline of 18–30 % in GWP. Due to the increase in N use efficiency, maximal grain yield (6–7 %) and minimal GHGI (22–34 %) was observed in Treatment WID. These findings indicate that combined application of N fertilizer and DCD is a win-win strategy in water-saving high-yield rice production with less GHG emission.

In the present study, response surface methodology (RSM) was applied to maximize As(V) removal from aqueous solutions by using modified magnetic nanoparticles with ascorbic acid (AA-MNPs). The structural features of the produced material were characterized by means of X-ray diffraction (XRD), N₂ adsorption–desorption, Fourier transform infrared (FT-IR), vibrating sample magnetometer (VSM), thermogravimetric analyses (TGA), and scanning electron microscopy (SEM). More specifically, the effects of pH, temperature, arsenic ion concentration, and sorbent dosage were investigated on the arsenic adsorption. A total of 20 sets of experiments were designed by the software to achieve maximum adsorption capacity (q ₑ) and removal efficiency (R). Analysis of variance (ANOVA) of the two-factor interaction (2FI) model suggested that the predicted values were in good agreement with experimental data. The best local maximum values for pH, arsenic concentration, and sorbent dosage were found to be 2, 5 mg L⁻¹, and 0.1 g L⁻¹, respectively, that yielding maximum q ₑ of 44.99 mg g⁻¹ and a maximum R of 42.69 %. Additionally, the obtained value for desirability was equal to 0.862. The results indicated that the Langmuir model provided the best correlation of the equilibrium data. Moreover, the obtained results revealed that the pseudo-second-order kinetic model could best describe the adsorption kinetics.

In this study, the decolorization of a dye solution via bio-Fenton process with in situ generation of H₂O₂ by enzymatic catalyzed oxidation of glucose was investigated. For this purpose, magnetite was synthesized and was used as the support for glucose oxidase immobilization. The particle size of the magnetite was estimated to be around 42 nm according to the obtained scanning electron microscope images. The magnetite crystal size was obtained approximately 26 nm by X-ray diffraction spectrum. Effective variables on immobilization were investigated. The best immobilization conditions were achieved at pH 6, temperature of 10 °C, glucose oxidase/support ratio of 1800 U/g, and time of 2.5 h. In these conditions, 450 U of glucose oxidase was immobilized per grams of magnetite. The immobilized glucose oxidase was used for the decolorization of acid yellow 12 in batch experiments. Decolorization conditions were optimized by response surface methodology. Four parameters including pH, temperature, glucose, and Fe²⁺ concentrations in five levels were investigated. The optimum conditions were obtained as follows: pH = 4.5, T = 29 °C, initial glucose concentration of 1.5 g/L, and Fe⁺² concentration of 1.4 g/L. Decolorization efficiency after 120 min at optimal conditions in the presence of 0.3 g immobilized enzyme (450 U/g) in 100 cm³ solution was observed to be equal to 62.27 %.

An estimated 4.9 million barrels of crude oil and natural gases was released into the Gulf of Mexico during the Deepwater Horizon oil spill of 2010. The Deepwater Horizon oil spill affected the aquatic species in the Gulf of Mexico, vegetation, and the human population along the coast. To reduce the effect of the spilled oil on the environment, different remediation strategies such as chemical dispersant, and mechanical booms and skimmers were utilized. Over 2.1 million gallons of dispersants was applied to minimize the impact of the spilled oil. However, environmental and human toxicity issues arose due to the perceived toxicity of the dispersant formulations applied. After the Deepwater Horizon oil spill, various studies have been conducted to find alternative and environmentally benign oil spill response strategies. The focus of this manuscript is to demonstrate an objective and an overall picture of current research work on oil spill response methods with emphasis on dispersant and oil sorbent applications. Current trends in oil spill sorbent and dispersant formulation research are presented. Furthermore, strategies to formulate environmentally benign dispersants, as well as the possible use of photoremediation, are highlighted.

Bisphenol A (BPA) is one of the recalcitrant contaminants that are detected in drinking water sources, as the conventional water treatment plant is incapable of removing it completely. This study was conducted to explore the performance of ultrafiltration (UF) membrane system for the BPA removal in which BPA was spiked in water sample collected from a treatment plant. The effects of process conditions that may influence the removal and flux performance of the membrane including operating pressure, feed pH and BPA concentration, and backwash cleaning were investigated. The results showed that an applied pressure of 1 bar was the optimum pressure for achieving good balance of BPA removal (95 %) and water flux (109 L m⁻² h⁻¹) compared to operating pressure of 0.5 and 1.5 bar. The variation of feed pH showed significant impact on BPA elimination with the highest rejection (90 %) achieved at pH 7 while the lowest removal (20 %) at pH 10. BPA concentration had no significant impact on BPA removal as high removal rate (>95 %) was observed regardless of feed concentration (between 10 and 100 μg L⁻¹). The normalized flux showed decreasing trend with filtration cycle due to increased membrane resistance of BPA adsorption onto the membrane. The membrane cleaning via backwash was able to recover 90 % BPA removal even after three consecutive cycles of filtration. This indicated the promising performance of UF membrane system for industrial water treatment.

Stormwater filtration system has proven to be effective for the removal of dissolved and particulate pollutants from roadways and car parking areas. However, the long-term treatment performance of filtration systems strongly depends on the hydraulic conductivity and sorption capacity of the filter media. This paper sought to provide information regarding the hydraulic performance, characteristics and metal concentration profiles in sediments accumulated at the surface of filtration systems (SDPL) and core filter media (FMC). The lifespan of the filter media was used to estimate the lifespan of the filter media. The results showed that saturated hydraulic conductivity of the filtration systems have significantly reduced over the operational time, yet acceptable (Kf = 5.9 × 10⁻⁵ to 1.4 × 10⁻⁴ m/s). The accumulated sediments (SDPL) were predominantly composed of fine particles with 70 % < 63 μm but the heavy metals were rather uniformly distributed in the different size fractions. The concentrations of heavy metals, particularly Cu, Pb and Zn were significantly higher in the SDPL and decreased with depth of the filter bed. However, Cr and Ni increased with depth of filter media demonstrating their removal was mainly by adsorption. Concentrations of Ba, Mn, Ti and V were comparable to Zn levels indicating comparable concentrations in roadway runoff. Simultaneous adsorption of multiple heavy metals in a column experiment demonstrated that the filter media could remain operational for over 34 years. However, there is a significant concern about their lifespan, particularly due to significant reduction in the hydraulic performance and the possibility of clogging of the systems over time. Therefore, to minimize hydraulic failure, the accumulated sediment be scraped off every 7 years.

Copper-based algaecides are used to control algae that compromise uses of lakes and reservoirs. However, there are concerns regarding potential adverse effects to benthic macroinvertebrates following long-term, repeated applications. Multiple lines-of-evidence are useful for evaluating potential ecological risks. These lines-of-evidence are encompassed in the sediment quality triad (SQT) and include sediment copper concentrations, in situ benthic invertebrate abundance, and sediment toxicity testing. The objective of this study was to measure potential ecological risks associated with long-term applications of copper algaecides in coves in Lay Lake, Alabama. Sediments from three coves treated for 7, 10, and 20 years were compared to sediments from three untreated coves in terms of copper concentrations, in situ benthic macroinvertebrate total abundance, and survival of Hyalella azteca and Chironomus dilutus in laboratory sediment toxicity tests. Sediment copper concentrations were not different between treated and untreated coves, with the exception of one treated cove (PC-1S) that contained elevated sediment copper concentrations compared to all other coves. However, the copper was not bioavailable to organisms based on in situ macroinvertebrate abundance and laboratory toxicity tests. In situ benthic invertebrate abundance was not different between treated and untreated coves. In all sediments tested, there were no measurable adverse effects to H. azteca and there were no significant differences in survival of C. dilutus between treated and untreated coves. Based on the weight-of-evidence approach utilized in this study, long-term copper use in three Lay Lake coves has not resulted in adverse effects to benthic invertebrates compared to untreated coves.

The study was developed at the Municipality of São Gabriel do Oeste, State of Mato Grosso do Sul, Brazil, where were performed analyses of water samples, including physical and chemical aspects, obtained through Hanna multi-parameter probe into four different parts of the study area. Landsat satellite 8 (L8) and unmanned aerial vehicle (UAV) was also used to generate vegetation indices, using the visible spectral range for both types of images and normalized difference vegetation index (NDVI) just for L8. Later, these ratios were correlated to chlorophyll a that has a key role in photosynthesis. Regarding the physical and chemical parameters, the collection point 2 was the most differed to the others; this may have happened to be a dam with little flow in an eutrophication process. Through the water absorbance curve in the visible wavelengths, it is possible to estimate comparatively water body that has larger amounts of dissolved materials in the water. There was a high correlation between vegetation indices generated from aerial photographs and L8 image, with chlorophyll a extracted from water in the laboratory. In this sense, they are likely to use to forecast future scenarios. It is suggested the use of aerial photographs of UAVs for monitoring the environmental quality of small water bodies, considering its high spatial and temporal resolution.

A new procedure for the determination of chromium species in polluted environmental samples by flame atomic absorption spectrometry was developed in this work. A new material containing 1,5-diphenylcarbazone included in a polymeric matrix was prepared and employed as a solid-phase extraction material for selective separation of Cr(III) ions under dynamic conditions. Chromium(III) ions were retained on this sorbent with high efficiency and repeatability (95 %, RSD = 1 %) from solutions with pH 9.0. The quantitative recovery of analyte was obtained with 0.1 mol L⁻¹ EDTA. The concentration of Cr(VI) ions was calculated from the difference between the concentration of total chromium and Cr(III) ions. The prepared sorbent exhibits good chemical and mechanical stability, sorption capacity and selectivity towards Cr(III) ions in the presence of Cu(II), Ni(II), Mn(II) and Ca(II) ions. The accuracy of the separation method was proved by analysis of reference material of wastewater RES 10.2. The developed procedure was applied for chromium speciation analysis in municipal sewage samples.