The effect of a reverse osmosis concentrate recirculation on the mineral and organic compounds in a landfill leachate was investigated. Investigated was the quality of a leachate from two landfills operated for different periods (a 20-year-old Cell A and a 1-year-old Cell B), where the concentrate was recirculated. Examined were general parameters (conductivity, pH), organic compounds (biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic nitrogen, BOD/COD), and inorganic compounds (nitrogen ammonia, sulfite, sulfate, cyanide, boron, chloride, ferrous, zinc, chrome, copper). The findings from the first year of investigation showed that over the initial period of recirculation, the concentration of organic compounds (BOD, COD) increased, but after 6 months their values stabilized. It indicates that the concentrate recirculation accelerated organic decomposition, especially in the new landfill Cell. The analysis of inorganic parameters showed that recirculation landfills produce a leachate with a higher concentration of N-NH₄, and Cl⁻. In case of the old landfill Cell, an increase in B and Fe was also noticeable. These compounds are cyclically washed out from a waste dump and require an additional pretreatment in order to exclude them from recirculation cycle. The increased concentration of Cu, Zn, and Fe was noticed during the initial months of recirculation and in the season of intense atmospheric precipitation in the leachate from both Cells. Higher values of electro conductivity, Cl⁻, N-NH₄⁺, B, and Fe in the leachate from the old field indicate that the attenuation capacity of this landfill is close to exhaustion.

When peat forest fires happen, it leads to burn soil and also humic acids as a dominant organic matter contained in peat soil as well as the forest. The structure and properties of humic acids vary depending on their origin and environment, therefore the transformation of humic acid is also diverse. The impacts of the peat fires on peat soil from Central Kalimantan, Indonesia were investigated through the characterization of humic acids, extracted from soil in burnt and unburnt sites. The characterization of humic acids was performed by elemental composition, functional groups, molecular weight by HPSEC, pyrolysate compounds by pyrolysis-GC/MS, fluorescence spectrum by 3DEEM spectrofluorometer, and thermogravimetry. The elemental composition of each humic substance indicated that the value of H/C and O/C of humic acids from burnt sites were lower than that from unburnt sites. The molecular weight of humic acids from burnt sites was also lower than that from unburnt sites. Pyrolysate compounds of humic acids from unburnt sites differed from those of humic acids from burnt soil. The heating experiment showed that burning process caused the significant change in the properties of humic acids such as increasing the aromaticity and decreasing the molecular weight.

An analytical methodology using automatic thermal desorption (ATD) and GC/MS was developed for the determination of 28 pesticides of different chemical classes (dichlobenil, carbofuran, trifluralin, clopyralid, carbaryl, flazasulfuron, mecoprop-P, dicamba, 2,4-MCPA, dichlorprop, 2,4-D, triclopyr, cyprodinil, bromoxynil, fluroxypyr, oxadiazon, myclobutanil, buprofezin, picloram, trinexapac-p-ethyl, ioxynil, diflufenican, tebuconazole, bifenthrin, isoxaben, alphacypermethrin, fenoxaprop and tau-fluvalinate) commonly used in nonagricultural areas in atmospheric samples. This methodology was developed to evaluate the indoor and outdoor atmospheric contamination by nonagricultural pesticides. Pesticides were sampled passive sampling tubes containing Tenax® adsorbent. Since most of these pesticides are polar (clopyralid, mecoprop-P, dicamba, 2,4-MCPA, dichlorprop, 2,4-D, triclopyr, bromoxynil, fluroxypyr, picloram, trinexapac-p-ethyl and ioxynil), a derivatisation step is required. For this purpose, a silylation step using N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (MtBSTFA) was added before thermal desorption. This agent was chosen since it delivers very specific ions on electronic impact (m/z = M-57). This method was established with special consideration for optimal thermal desorption conditions (desorption temperature, desorb flow and duration; trap heating duration and flow; outlet split), linear ranges, limits of quantification and detection which varied from 0.005 to 10 ng and from 0.001 to 2.5 ng, respectively, for an uncertainty varied from 8 to 30 %. The method was applied in situ to the analysis of passive tubes exposed during herbicide application to an industrial site in east of France.

The smart water quality monitoring, regarded as the future water quality monitoring technology, catalyzes progress in the capabilities of data collection, communication, data analysis, and early warning. In this article, we survey the literature till 2014 on the enabling technologies for the Smart Water Quality Monitoring System. We explore three major subsystems, namely the data collection subsystem, the data transmission subsystem, and the data management subsystem from the view of data acquiring, data transmission, and data analysis. Specifically, for the data collection subsystem, we explore selection of water quality parameters, existing technology of online water quality monitoring, identification of the locations of sampling stations, and determination of the sampling frequencies. For the data transmission system, we explore data transmission network architecture and data communication management. For the data management subsystem, we explore water quality analysis and prediction, water quality evaluation, and water quality data storage. We also propose possible challenges and future directions for each subsystem.

Controversy surrounds the green credentials of hydroelectricity because of the potentially large emission of greenhouse gases (GHG) from associated reservoirs. However, limited and patchy data particularly for China is constraining the current global assessment of GHG releases from hydroelectric reservoirs. This study provides the first evaluation of the CO₂and CH₄emissions from China’s hydroelectric reservoirs by considering the reservoir water surface and drawdown areas, and downstream sources (including spillways and turbines, as well as river downstream). The total emission of 29.6 Tg CO₂/year and 0.47 Tg CH₄/year from hydroelectric reservoirs in China, expressed as CO₂equivalents (eq), corresponds to 45.6 Tg CO₂eq/year, which is 2-fold higher than the current GHG emission (ca. 23 Tg CO₂eq/year) from global temperate hydropower reservoirs. China’s average emission of 70 g CO₂eq/kWh from hydropower amounts to 7 % of the emissions from coal-fired plant alternatives. China’s hydroelectric reservoirs thus currently mitigate GHG emission when compared to the main alternative source of electricity with potentially far great reductions in GHG emissions and benefits possible through relatively minor changes to reservoir management and design. On average, the sum of drawdown and downstream emission including river reaches below dams and turbines, which is overlooked by most studies, represents the equivalent of 42 % of the CO₂and 92 % of CH₄that emit from hydroelectric reservoirs in China. Main drivers on GHG emission rates are summarized and highlight that water depth and stratification control CH₄flux, and CO₂flux shows significant negative relationships with pH, DO, and Chl-a. Based on our finding, a substantial revision of the global carbon emissions from hydroelectric reservoirs is warranted.

In recent years, all-male cultures of Nile tilapia (Oreochromis niloticus) have been the most preferred mode of production in aquaculture industry. All-male individuals achieve higher somatic growth rate and shut high energy losses associated with gonadal development and reproduction. The economic advantages of culturing all-male tilapia have led to the development of procedures for producing unisex cultures, using 17α-methyltestosterone (MT). Despite widespread use of the MT in tilapia farming, the implications of hormone treatment in relation to human health and the environment have raised a number of concerns in the scientific community. In this review, the hormonal application processes, economic and ecological significance of MT, food safety and residual MT, comparative uses of steroids in aquaculture, animal husbandry, and medicine have been briefly reviewed for regulatory guidelines, and finally, future research perspectives have been addressed. The review can be used as policy-making guidelines in aquaculture framework development as can be emphasized in African continent, among others. The most important conclusion to draw is that the quantity of MT used in conventional practice is large compared to the actual dose required for sex reversal, fish produced are safe for human consumptions, and the environmental hazards should be further emphasized.

Soil/sediment organic matter (SOM) releasing with inherent dissolved organic matter (DOM) formed in solution was confirmed both in rhizosphere sediment (S) and uncultivated sediment (P) water systems, and correlations between SOM characteristics subject to sediment’s humification degree and its releasing effects on phenanthrene sorption were emphasized. The sequential SOM releasing evidenced by fluorescence and ¹H-NMR profiles coupled with aqueous DOM solubilization was found to make sorption kinetics atypical and sorption capacity reduced, by comparing sorption results among sediments of different pretreatments. More importantly, the tested S was proved less humified with inherent DOM rich in microbial sources than P, and DOM affinity to phenanthrene was thus weakened (K dₒc values of 2.02–3.63 × 10⁴ L kg⁻¹), while the inhibitive effects of SOM releasing on sorption were strengthened, ascribing to the enlarged alterations of sediment characters, and particularly the amplified solubilization effects resulted from the larger proportion of soluble SOM and lower critical micelle concentration (5.66 mg L⁻¹) of DOM. Moreover, relative contribution of DOM solubilization to the releasing effects enhanced from 0.67 for P to 0.78 for S relative to alterations of sediment characters. Consequently, mobility and exposure risk of polycyclic aromatic hydrocarbons would be enhanced in a plant-soil/sediment-water system.

The environmental stress is a major area of scientific concern because it constraints plant as well as crop productivity. This situation has been further worsened by anthropogenic activities. Therefore, there is a much scientific saddle on researchers to enhance crop productivity under environmental stress in order to cope with the increasing food demands. The abiotic stresses such as salinity, drought, cold, and heat negatively influence the survival, biomass production and yield of staple food crops. According to an estimate of FAO, over 6 % of the world’s land is affected by salinity. Thus, salinity stress appears to be a major constraint to plant and crop productivity. Here, we review our understanding of salinity impact on various aspects of plant metabolism and its tolerance strategies in plants.

Various biochar (BC) types have been investigated as soil amendment; however, information on their effects on trace element (TE) biogeochemistry in the soil-water-plant system is still scarce. In the present study, we determined aqua-regia (AR) and water-extractable TEs of four BC types (woodchips (WC), wheat straw (WS), vineyard pruning (VP), pyrolyzed at 525 °C, of which VP was also pyrolyzed at 400 °C) and studied their effects on TE concentrations in leachates and mustard (Sinapis alba L.) tissue in a greenhouse pot experiment. We used an acidic, sandy agricultural soil and a BC application rate of 3 % (w/w). Our results show that contents and extractability of TEs in the BCs and effectuated changes of TE biogeochemistry in the soil-water-plant system strongly varied among the different BC types. High AR-digestable Cu was found in VP and high B contents in WC. WS had the highest impact on TEs in leachates showing increased concentrations of As, Cd, Mo, and Se, whereas WC application resulted in enhanced leaching of B. All BC types increased Mo and decreased Cu concentrations in the plant tissue; however, they showed diverging effects on Cu in the leachates with decreased concentrations for WC and WS, but increased concentrations for both VPs. Our results demonstrate that BCs may release TEs into the soil-water-plant system. A BC-induced liming effect in acidic soils may lead to decreased plant uptake of cationic TEs, including Pb and Cd, but may enhance the mobility of anionic TEs like Mo and As. We also found that BCs with high salt contents (e.g., straw-based BCs) may lead to increased mobility of both anionic and cationic TEs in the short term.

Sulfonylurea herbicides (SUs) were detected in natural waters and could be potentially exposed to human beings via portable use. Thus, the removal of five representative SUs in simulated water treatment processes including coagulation, activated carbon adsorption, and chlorination disinfection was systematically investigated. Results showed that coagulation had little effect on the removal of the herbicides with the average removal less than 10 %. Powder-activated carbon adsorption was apparently more effective with removal rates of 50 ~ 70 %. SUs were also partially removed in chlorination process. A complete removal was achieved when the three treatments were performed in series. However, it was found that parts of the SUs were transformed into certain stable products with triazine/pyrimidine structures which might be of potential health risks in chlorination process. Thus, current drinking water treatment processes are not likely to provide sufficient protection for human population from exposure to SUs.