Taking the black soil of northeastern cold land as the research object, this paper adopts the three-factor quadratic saturation D311 optimal design scheme, uses static black box-gas chromatography to analyse the irrigation season, nitrogen fertilizer and straw biochar to the impact of greenhouse gas emissions for N2O growing season in the northeast cold paddy field. This paper also studies the optimal water and fertilizer application scheme for N2O control. The results show that the effects of three factors on N2O emissions are as follows: nitrogen fertilizer > biochar > water. The irrigation and biochar have an inhibitory effect on N2O emissions, while nitrogen fertilizer has a promoting effect on N2O emissions. The performance is as follows: water + nitrogen fertilizer can promote the emission of N2O; water + biochar can inhibit the emission of N2O; nitrogen fertilizer + biochar can promote the emission of N2O. Combined with the yield, the integrated water and biochar optimization schemes, when controlling the increase of N2O growth season in paddy fields to not exceed 10% are as follows: The amount of irrigation is 4252~5531 kg/hm2; the nitrogen application rate is 103.30~117.35 kg/hm2; and the amount of biochar is 15.12~24.42 t/hm2.

The radioactive field is one of the most important areas in human health. It must be studied to see the changes in the doses of human exposure. In this study, 46 soil samples were collected from different locations of Karakh side at Baghdad Governorate. The specific activity of natural radionuclides (terrestrial gamma radiation) 238U, 232Th and 40K for soil samples were measured using gamma-ray spectroscopy with NaI(Tl) ("3×3") detector in low-background. Moreover, ten radiological hazard parameters, which include radium equivalent activity (Raeq), absorbed gamma dose rate (Dγ), external hazard index (Hext), internal hazard index (Hint), representative gamma index (Iγr), annual effective dose equivalent (AEDE) that includes the indoor and outdoor effective dose rate, and ELCR were calculated. It has also used GIS technology for mapping specific activity and radiological radiation parameters for all the samples under study. The results show that, the average value of specific activity of terrestrial gamma radiation 238U, 232Th, 40K, 238U+232Th+40K and 235U were 16.47±0.94 Bq/ kg, 9.72±0.43 Bq/kg, 367.95±11.13 Bq/kg, 394.15±11.90 Bq/kg and 0.76±0.043 Bq/kg respectively. While, the average value of radiological radiation parameters such as Raeq, Hex, Hin, Iγr , Iα, Exposure, Dr, AGED, AEDEindoor, AEDEoutdoor, AEDEtotal, and ELCR in present study were 58.7183±2.017 Bq/kg, 0.1586±0.00546, 0.2032±0.00768, 0.4523±0.0151, 0.08237±0.0046, 3.367±0.113 μR/h, 28.8309±0.968 nGy/h, 207.1078±6.86 mSv/y, 0.1415±0.00475 mSv/y, 0.03541±0.00119 mSv/y, 0.177±0.00594 mSv/y and 0.6192 ±0.0208 respectively. The results indicate that the effective dose from terrestrial gamma radiation is everywhere across the area within the acceptable level, subject to the inherent spatial averaging of the measurements.

Comprehensive harnessing of soil and water erosion can change the regional surface environment, improve ecological conditions, and promote regional social and economic development, which can also achieve good ecological, social, and economic benefits for the purpose of preventing and controlling soil erosion. Scientific evaluation of soil erosion comprehensive harnessing benefits is presented, and analysis of influencing factors is adopted, which is an important basis for further understanding of work effectiveness and optimization of governance measures. The research selects Taihang Mountain Area of Hebei Province as the research area. This paper evaluates the comprehensive treatment benefits of 16 typical small watersheds by multi-level fuzzy evaluation method, and uses the exponential, linear, logarithmic, power function and polynomial as the model. The correlation between land use type area and comprehensive treatment benefit was studied, and the corresponding improvement of management efficiency has been proposed in order to provide a reference for optimizing the comprehensive management mode of small watersheds in Taihang Mountain area and improving the efficiency of comprehensive management.

Riparian zones suffer from increased human disturbances and the plant communities change unpredictably in response to altered conditions. It is important to understand the effects of human activities on plant communities for rational tourism development and ecological protection programs. We sampled 14 and 27 sites in nearly natural and human-influenced landscapes along the Lijiang River in southwest China, respectively, to detect human impacts on the ecosystem. We set three survey lines, based on a submersion gradient, at each site to determine whether herbaceous species richness increased with distance from the river, and we examined the effects of disturbance on herbaceous distribution. The landscapes shared 101 common species, and unique species in the human-influenced landscape were partly synanthropic. The species richness and diversity indices of the nearly natural landscape were significantly higher than those of the human-influenced landscape (P < 0.01). Species richness increased with distance from the river in the nearly natural landscape, and a significant difference was detected among the variances of survey lines (P < 0.05) in the human-influenced landscape. In the nearly natural landscape, species richness increased with fewer hydrological effects, and a stable community was maintained. However, human disturbances led to community variability and fragmented riparian habitats, resulting in species extinction and ecological degradation. We suggest that appropriate dam and reservoir regulations, prohibition of soil destructions, and a long-term research program for ecosystem protection may help in improving the monitoring of human influences and sustainable management in riparian zones of tourist rivers.

Landfill leachate is a complex mixture of organic and inorganic compounds and their concentration level highly depends on the type of waste dumped, age of the landfill, etc. Last few decades, the researchers are exploring the feasibility of treating landfill leachate using physicochemical, biological, advanced processes and combination of these methods. The current study focused on the comparison of two commonly adopted technologies for landfill leachate treatment, chemical coagulation/flocculation and electrocoagulation process. The leachate samples were collected from two different places and examined for the following parameters: pH, turbidity, chemical oxygen demand, chlorides, alkalinity, hardness, solids and nutrients. The current study focused on studying the effect of different inorganic coagulants (alum and ferric chloride), coagulant dosages, different electrode material (titanium coated with platinum/stainless steel and aluminium/stainless steel), electrolysis time and current intensity on the removal of pollutants from leachate and reuse for non-potable applications. The raw leachates collected from the two sites were found to be significantly different in their characteristics due to the age of landfill and physiognomies of wastes dumped. The batch treatment studies showed that both the treatment systems are nearly displaying a similar kind of removal efficiency (more than 74%). Amongst that, the coagulation/flocculation process showed a better removal efficiency and cost effectiveness compared to electrocoagulation process. Additionally, the treated water was found to be not meeting the Indian Standard for inland disposal. Therefore, an additional post treatment like reed bed process or sand filtration will be a viable option for non-potable applications.

Reservoirs are the major source of water supply in many localities for meeting the water demand of the people, and hence it is important to monitor the metal concentration of the water stored in such reservoirs for the benefit of the people in terms of drinking water and irrigation. The main objective of this study is to monitor the metal concentrations of Arsenic (As), Boron (B), Cadmium (Cd), Chromium (Cr), Copper (Cu), Iron (Fe), Nickel (Ni), Lead (Pb), Selenium (Se), and Zinc (Zn) in the water of the Amaravathi and Thirumoorthy reservoirs located in the Tiruppur district of the state of Tamil Nadu, India. Results indicate that the water collected from the Thirumoorthy reservoir is free from metal contamination while that from the Amaravathi reservoir has a marginal contamination of Fe concentration. Thus, the water stored in these reservoirs is suitable for drinking and irrigation purpose.

Microbial transformation is an environment-friendly approach to produce diosgenin from natural plant tubers. However, improving the bioconversion efficiency of this process remains a challenge. Saponin hydrolase plays a major role during the transformation. a-rhamnase, b-glycosidase and C3 b-glycosidase have been identified as three key enzymes in the stepwise conversion of saponins to diosgenin. The three enzymes have not been molecularly characterized. Here, a-rhamnase, b-glycosidase and C3 b-glycosidase were purified from Trichoderma reesei, Trichoderma viride and Aspergillus fumigatus, respectively. SDS-polyacrylamide gel electrophoresis showed that the molecular masses of the three enzymes were approximately 60, 36 and 56 kDa, respectively. a-rhamnase could efficiently hydrolyse the terminal rhamnoside on the C3 site in saponins. b-glycosidase could cleave the terminal b-glycoside at the C3 position, while C3 b-glycosidase demonstrated significant affinity to the b-glycoside at the C3 position. The amino acid sequences of the three saponin hydrolases were determined. Reverse transcription-PCR was used to clone the three plasmids with lengths of approximately 1035, 1416 and 1752 bp from the strains and expressed in Escherichia coli. The recombinant saponin hydrolases from the recombinant strains also demonstrated the hydrolysing of rhamnoside and glycosides of saponins similar to those of the wild-type hydrolases from T. reesei, T. viride, and A. fumigatus. The findings could facilitate the construction of recombinant cells by gene fusion to produce diosgenin from plant tubers.

Industrial development and urbanization progress have been rapidly increasing in China, consequently accelerating infrastructure constructions, such as real estates and public facilities. Building construction dust has become one of the main sources of atmospheric particulate matter (PM) pollution in China. In this study, a typical building in Zhengzhou City was taken as an example, wherein the total suspended particle (TSP) and PM10 and PM2.5 indicators in the foundation excavation phase of the building construction were comprehensively monitored. The emission levels of both indicators were analyzed, and the periodic change laws of dust concentration and the correlations among TSP, PM10, and PM2.5 were quantitatively measured. Results indicate that the PM10 and PM2.5 concentrations at the monitoring points in the downwind direction of prevailing wind were higher than those in the upwind direction. TSP, PM10, and PM2.5 concentrations reached the maximum values at 10:00-12:00 in the morning of most days, and the TSP concentration was maintained at 250-500 μg/m3. Moreover, the coefficient of determination between TSP and PM10/PM2.5 was 0.8164/0.8376, signifying favorable correlations. The proposed management and control measures include perfecting the construction dust pollution control and management system, establishing the responsibility management mechanism of construction dust, realizing the comprehensive refined control of construction dust, promoting the innovation of building construction dust control technology, and improving the environmental consciousness for building construction dust control. These findings can serve as references for construction dust source pollutant emission control and as scientific decision-making bases for environmental researchers and managers in this field.

The hospital environment requires indoor air quality conducive to the recovery of patients with poor health. Low indoor air quality is associated with an increased incidence of respiratory tract diseases and the development of cancer. This study investigated the mutagenicity of air particulate matter soluble in bulk, aqueous, and organic partitions collected from naturally and mechanically ventilated wards in the hospital environment through the Ames test and the mutagenicity testing with the D7 strain of Saccharomyces cerevisae. Bulk, aqueous, and organic fractions of air particulate matter at maximum (100% concentration), 10% concentration, and 1% were found to be mutagenic with both the Ames test (p < 0.05) and mutagenicity testing with D7 strain of S. cerevisae (p < 0.05). The Ames test suggested slight dominance of the aqueous phase-soluble mutagens in naturally ventilated wards (p < 0.05), and a more balanced mix of aqueous and organic phase mutagens in mechanically ventilated wards. Mutagenicity testing with the D7 strain of S. cerevisae showed no significant differences between the naturally and mechanically ventilated wards (p > 0.05), but showed the relative dominance of the organic phase-soluble mutagens over the other fractions (p < 0.05). Few other studies have compared naturally and mechanically ventilated wards through the lens of potential effect on the mutagenic activity of air particulate matter, but more understanding in this area is important in moving towards the development and implementation of policies to optimize ventilation systems for the health and safety of hospital staff and patients. Albeit coming from the study of concentrated air particulate matter samples, the mere presence of these mutagens in the air of the hospital highlights the importance of monitoring their quality and quantity such that they do not become concentrated enough to induce mutation-related etiologies of disease such as cancer.

Fine blue-coke and direct liquefaction residue of coal are byproducts in the process of coal chemical production. They were taken as raw materials for the preparation of activated coke by the activation of carbon dioxide. The conditions (activation temperature, activation time and carbon dioxide flow rate) for activated coke preparation were optimized by response surface methodology (RSM). Results showed that activation temperature and activation time had a significant effect on the activated coke iodine adsorption value. The synergistic effect of activation time and carbon dioxide flow had a great influence on iodine adsorption value of activated coke. RSM optimization experiment obtained the optimum activation conditions were activation temperature of 850°C, activation time of 90min and carbon dioxide flow rate of 60 mL/min. Under these conditions, the obtained activated coke iodine adsorption value can reach 401 mg/g, which could meet the needs of industrial desulphurization.