The service life of electronic (e-) products is decreasing gradually due to the continuous improvement of manufacturing technologies and increasing prices and performance of these products, thereby accelerating the growth of e-waste. Only a small proportion of e-waste is disposed of according to standards in China. Due to a contradiction between high output and low disposal, environmental pollution and resource waste caused by e-waste intensify daily. To further analyze the e-waste recycling mode from a macroscopic level and thereby propose specific control measures, we first reviewed studies on e-waste recycling modes and control measures in foreign developed countries. Second, the e-waste recycling mode in China was analysed through political, economic, social and technological (PEST) and strengths, weaknesses, opportunities and threats (SWOT) models in combination with practical situations in China. Finally, e-waste control measures were proposed from various perspectives. Results show that the ambiguous definition of responsibilities for different e-waste disposal subjects in China has led to serious environmental pollution. This pollution, the extensive waste of natural resources, and frequent occurrence of social crises are three consequences of environmental pollution caused by e-waste in China. All four factors in the PEST model have laid the foundation to accelerate e-waste recycling in the country. Environmental pollution caused by e-waste can be relieved by perfecting relevant laws and regulations for e-waste recycling and disposal; establishing and perfecting the punitive system for e-waste recycling corporate responsibility; strengthening technological support, promotion, and education on e-waste recycling; and increasing the market supervision efforts and manufacturers’ consciousness of responsibility. Research conclusions can provide important references to analyze e-waste status, achievements, challenges, and existing problems in disposal as well as their causes. These factors can also propose countermeasures and suggestions in e-waste disposal in accordance with practical situations in China based on insights into the experiences of foreign countries with a typical level of development.

Pergularia daemia is traditionally used to treat various ailments like anthelmintic, antipyretic and expectorant and to treat infantile diarrhoea, malarial intermittent fever, asthma, mental disorder, toothache and cold. In the present study leaf extracts of P. daemia was subjected to qualitative phytochemicals, GC-MS and FT-IR analysis. The quantitative analysis of the leaves showed the presence of flavonoids, steroids, alkaloids, terpenoids, saponins, phenols, carbohydrates, amino acids, tannins and cardiac glycosides. The GC-MS study of methanol extract revealed 16 compounds. Some major compounds identified are 9-Octadecenoic Acid (E), Cis- Vaccenic Acid, N-Hexadecanoic Acid, 1- Dimethyl (Butyl), Silyl Oxy Butane along with other minor constituents. FT-IR analysis revealed the presence of 12 functional groups such as amines, alkanes, carbon dioxide and alkynes. The results suggested that P. daemia contains significant photo components and can be used as a source for many pharmacological studies and a curative for various ailments.

Toxicity effect of Chlorpyrifos 50% + Cypermethrin 5% EC to terrestrial invertebrate Eisenia fetida in two different sphagnum peat substituted soil was assessed. Artificial soil substrate for earthworm toxicity test comprises of 70% sand, 20% clay and 10% sphagnum peat. In this study, coco peat was used as an alternative substitute for sphagnum peat. The LC50 was 83.7 mg/kg for coco peat and 76.3 mg/kg for sphagnum peat soil. No significant difference was observed in mortality and biomass between the two soil substrates, but a significant difference was observed in the reproduction. Based on the observations, it is concluded that coco peat can also be used as an alternative to sphagnum peat in toxicity studies.

The long-term use of sewage to irrigate farmland will increase the content of heavy metals in the soil and cause soil pollution. Heavy metal pollution in soils will restrict the sustainable development of local agriculture and will have a negative impact on the ecological environment. In this paper, the irrigation areas using domestic sewage, mixed sewage and industrial sewage as an irrigation water source for many years have been selected as the research objects, and the content of the heavy metals lead (Pb), copper (Cu), zinc (Zn) and cadmium (Cd) in the soil with the depth of 0-20cm, 20-50cm and 50-80cm of three kinds of sewage irrigation areas are assessed using single factor pollution index method and Nemerow comprehensive index method, and the potential ecological risks of heavy metals in the soil are assessed using Hakanson ecological risk index method. The results show that the content of heavy metals Pb, Cu, Zn and Cd in different depths of the three sewage irrigation areas does not exceed the national standard limit, and the heavy metal pollution grade in the soil belongs to the safety grade, indicating that the content of heavy metals in the soil has not reached the alert level. The potential ecological risks of heavy metals in the soil show minor ecological risks judging from single indexes, while Cd shows that the ecological risks are at a strong level. Judging from the comprehensive potential ecological risk index, the potential ecological risks of the heavy metals in the study area is minor in graded, but the heavy metals in the soil of the mixed sewage irrigation area and the industrial sewage irrigation area have a moderate grade of potential ecological risks at the depth of 50-80 cm. Therefore, although the content of the heavy metals in the soil of the three kinds of sewage irrigation areas in the study area is safe, the potential ecological risk of Cd is quite high, which should be paid attention to.

Low temperature and high salinity can strongly inhibit metabolic activities of the microbial population, resulting in low efficiency of biological wastewater treatment. Using 70 g.L-1 NaCl pickle mustard wastewater as influent, three pilot-scale sequencing batch biofilm reactors (SBBRs), subjected to temperature downshifts and fluctuation ranging from 30 ± 4°C to 10 ± 4°C, were conducted over 200 days. Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR–DGGE) was used to reveal the microbial community structure succession in reactors. Results showed that when the temperature was 10 ± 4°C, the COD removal efficiencies of SBBRs (1, 2 and 3 kg COD m-3 d-1 organic loading rate), were 91.6% (σ = 0.87), 87.84% (σ = 0.92) and 83.34 % (σ = 0.85), respectively. Compared with the average removal efficiencies when the reactors operated at 30 ± 4°C, the efficiency reductions of 1, 2 and 3 kg COD m-3 d-1 reactors were 4.47%, 4.58% and 4.57%. As the temperature decreased, microbial population diversity did not change remarkably. However, the microbial structure changed significantly, bacteria which had strong adhesion and a wide growth temperature range were competitive. At low temperature, the predominant species were Thalassolituus oleivorans, Halotalea alkalilenta and Kangiella koreensis, which were all related to pollutant-degrading halophilic bacteria.

With the acceleration of urbanization and motorization speed boost, the development of urban green traffic has become a focus of public concern and an important way to solve urban traffic problems, which has made the low-carbon transport policy been given more attention. However, since the urban traffic is affected by multiple factors, whether the application of low-carbon transport policy could obtain corresponding or higher output is uncertain. To clarify the effects of low-carbon transport to the improvement of urban traffic ecological environment, the main indicators that measure the contribution of low-carbon transport to urban traffic ecological environment were extracted from five aspects including people, cars, roads, transportation infrastructure and traffic environment. The Guangzhou city in China was taken as an example to select index data, the regression analysis was adopted by SPSS software. Results show that the contribution rate of the low-carbon transport policy to the improvement of urban transportation ecological environment is 4.42%. The conclusions obtained from this study are of great significance to improve the low-carbon travel policy and optimize the urban traffic ecological environment

With the rapid development of the economy, people’s pursuit of the quality of life is getting higher. Thus, environmental pollution will be punished, and the high-polluting industry will face more problems in development. To explore the impact of corporate governance on environmental protection investment, 28 listed enterprises in high-polluting industry in China were selected as samples. Corporate governance was reflected from four aspects as explaining variables including shareholding structure, board composition, characteristics of the supervisory board and executive incentive. The relationship between corporate governance and high-polluting enterprises’ environmental protection investment was analysed by using the data of China’s listed enterprises in the high-polluting industry from 2015 to 2019. The results indicate that there is a positive correlation between legal person proportion and environmental protection investment of high-polluting enterprises, and a U-shaped relationship of the Herfindahl index. There is a significant positive correlation between board size and environmental protection investment of high-polluting enterprises, and the relationship is significantly negative of the size of the board of supervisors. The conclusions are helpful to improve the corporate governance of high-polluting enterprises, to enhancing environmental protection investment.

The present study aimed to develop the activated carbon from fruit waste like sapota peel and to optimize the condition of developed activated carbon for complete removal of lead ions from the desired concentration of a lead solution. The activated carbon was prepared from sapota peel by using sulphuric acid. The physicochemical characterization of the obtained activated carbon was done for various parameters along with analysis of crystal nature (XRD) and structural morphology (SEM). The optimum conditions for adsorption were studied by altering pH (2-10), agitation speed (50-250 revolution per minute), temperature (10-60°C), adsorbent dose (0.02-0.14 g) and contact time (30-240 minutes). The optimized conditions necessary for complete removal of lead ions by the prepared adsorbent were pH - 5.5, agitation speed - 200 revolutions per minute, temperature - 60°C, time - 3 hours and adsorbent dose - 0.12 g. This study can be further helpful in designing the process of wastewater treatment for the removal of toxic metals from water particularly lead by adsorption.

Evaporation from the soil is an important component of evapotranspiration, and mulching greatly affects soil evaporation. We conducted numerical simulations to study the effect of the thickness of sand mulch on soil evaporation. We tested nine treatments: mulching with sand thicknesses of 1, 3, 5, 6, 8, 10, 15 and 20 cm plus an unmulched control (CK). Accumulated evaporation was significantly lower, and the resistance to evaporation was significantly higher, for the mulched treatments than CK. The volumetric soil water content (SWC) was significantly higher for the mulched treatments than CK, but SWC varied little for thicknesses >5 cm. Heating was slower and more uniform for the mulched treatments than for CK. With the increase of the thickness of sand, the temperature transmission was slowed down. The change of soil temperature was not obvious at thicknesses >15 cm. A thickness of 5 cm was the most effective for storing water and preserving heat. Our results provide a theoretical basis and technical guidance for the effective use and management of soil water in farmland in arid regions.

The online spectrophotometric technique was adopted to monitor the degradation of simulated Acid Light Yellow 2G (ALY 2G) solution with the Fenton oxidation process, and the kinetic process was also discussed. The effects of the initial concentration of H2O2 and Fe2SO4, pH value, and initial dye concentration on the degradation process were studied. The results showed that the ALY 2G can be degraded by Fenton oxidation, and the colour removal rate of Acid Light Yellow 2G was 94.66% after 300 s when the concentration of simulated wastewater was 20 mg/L, the dosage of Fe2+ was 0.1 mmol/L, the dosage of H2O2 was 0.6 mmol/L, and the pH was 3. The degradation process was divided into two stages: the first stage, the degradation rate is very fast; in the second stage, with the extension of reaction time, the increase of decolourization rate decreases. The first stage of the reaction accords with the first-order kinetics, and the reaction rate constant Kap is 0.04824 s-1. The intrinsic reaction rate constant of ALY 2G and hydroxyl in aqueous solution in the Fenton oxidation method is 0.55 ×109 M-1s-1.