Environmental Science and Pollution Research - This paper investigates the impact of several comprehensive risks such as credit risk, capital risk, liquidity risk, and insolvency risks on Pakistani... 相似文献
A variety of methods based on air quality models, including tracer methods, the brute-force method (BFM), decoupled direct method (DDM), high-order decoupled direct method (HDDM), response surface models (RSMs) and so on forth, have been widely used to study the transport of air pollutants. These methods have good applicability for the transport of air pollutants with simple formation mechanisms. However, differences in research conclusions on secondary pollutants with obvious nonlinear characteristics have been reported. For example, the tracer method is suitable for the study of simplified scenarios, while HDDM and RSMs are more suitable for the study for nonlinear pollutants. Multiple observation techniques, including conventional air pollutant observation, lidar observation, air sounding balloons, vehicle-mounted and ship-borne technology, aerial surveys, and remote sensing observations, have been utilized to investigate air pollutant transport characteristics with time resolution as high as 1 sec. In addition, based on a multi-regional input-output model combined with emission inventories, the transfer of air pollutant emissions can be evaluated and applied to study the air pollutant transport characteristics. Observational technologies have advantages in temporal resolution and accuracy, while modeling technologies are more flexible in spatial resolution and research plan setting. In order to accurately quantify the transport characteristics of pollutants, it is necessary to develop a research method for interactive verification of observation and simulation. Quantitative evaluation of the transport of air pollutants from different angles can provide a scientific basis for regional joint prevention and control. 相似文献
To identify the critical factors impacting the number concentration of particles with the aerodynamic diameters less than 2.5 μm(PNC_(2.5)), the continuous measurement of PNC_(2.5),chemical components in PM_(2.5), gaseous pollutants and meteorological conditions were conducted at an urban site in Tianjin in June 2015. Results indicated that the average PNC_(2.5) was 2839 ± 2430 d N/dlog Dp 1/cm~3 during the campaign. Compared to other meteorological parameters, the relative humidity(RH) had the strongest relationship with PNC_(2.5), with a Pearson's correlation coefficient of 0.53, and RH larger than 30% influenced strongly PNC_(2.5).The important influence of secondary reactions on PNC_(2.5) was inferred due to higher correlation coefficients between PNC_(2.5) and SO_4~(2-), NO_3~-, NH_4~+(r = 0.78–0.89; p 0.01) and between PNC_(2.5) and ratios that represent the conversion of nitrogen and sulfur oxides to particulate matter(r = 0.42–0.49; p 0.01). Under specific RH conditions, there were even stronger correlations between PNC_(2.5) and NO_3~-, SO_4~(2-), NH_4~+, while those between PNC_(2.5) and EC, OC were relatively weak, especially when RH exceeded 50%. Principal component analysis(PCA) and Pearson's correlation analysis indicated that secondary sources, vehicle emission and coal combustion might be major contributors to PNC_(2.5). Backward trajectory and potential source contribution function(PSCF) analysis suggested that the transport of air masses originated from these regions around Tianjin(Liaoning, Hebei, Shandong and Jiangsu) influenced critically PNC_(2.5). The north of Jiangsu, the west of Shandong, and the east of Hebei were distinguished as major potential source-areas of PNC_(2.5) by PSCF model. 相似文献
Environmental Science and Pollution Research - Composting has become the most important way to recycle medicinal herbal residues (MHRs). The traditional composting method, adding a microbial agent... 相似文献
Environmental Science and Pollution Research - In this study, we investigated the removal of metolachlor (MET) by biochar (BC) prepared from walnut shells (W-BC) compared with BCs made from cow... 相似文献
The phosphorus chemical industry is an important source of heavy metals in farmland. Vegetables grown on contaminated soil potentially impose adverse effects on human health. In this study, the pollution status and health risks of heavy metals in vegetables around a phosphorus chemical plant in Kaiyang County, Guizhou Province, southwestern China, were assessed, and the low-accumulation vegetables were screened by bioaccumulation factor (BAF) and cluster analysis. Results showed the average concentrations of Hg, As, Cd, Pb, Cr, Mn, Co, and Zn in vegetables were 0.015, 0.728 0.382, 0.227, 0.850, 27.227, 0.525, and 6.438 mg/kg, respectively. The single-factor pollution index showed that Cd was moderately polluted, and Cr, Hg, As, and Pb were slightly polluted. The Nemerow pollution index showed that the overall heavy metal pollution was classified as moderately polluted. The accumulation of heavy metals in different vegetables varied greatly, and chard, crown daisy, chayote, pumpkin, eggplant, white radish, sweet potato, carrot, and potato were selected as the low-accumulator vegetables. The consumption of all vegetables except chayote poses both carcinogenic and noncarcinogenic risks; among them, the consumption of sweet potato leaves has the highest health risks. The local population needs to adjust plantation structure and change dietary habits, and government should strengthen the management of phosphorus chemical plant pollution.
Monosodium glutamate (MSG) effluent was sampled from three MSG mills and 21 metal elements were measured with a inductively coupled plasma (ICP) Spectrometer. The total metal concentration of each MSG wastewater sample was 19192, 3190 and 3161 mg/L respectively. Compared with the water quality standard issued by the Chinese Government and the World Health Organization (WHO), some values were found to exceed the standards. The 24hr‐LC50, 48hr‐LC50, 72hr‐LC50 and 96hr‐LC50 to the fish Ctenopharyngodon idellus were 6.9%, 3.2%, 2.5% and 1.4% MSG wastewater individually. The specific growth rate for photosynthetic bacteria (PSB) Rhodopseudomonas sphaeroides was inhibited by the metals in MSG wastewater. Therefor the MSG wastewater should not be discharged into drinking, irrigation and fishery water systems, moreover it cannot be treated by general biological processes efficiently. How to develop an effective biotechnique for the utilization of organic pollutants in MSG effluent will also be discussed in this paper. 相似文献
China’s paper production reached 79.8 ×106 t in 2008 and ranked number one in the world. Because of its high consumption of water, energy and materials and its serious pollution, the present processes are not likely to be sustainable. An alternative, the closed Water Loop-Papermaking Integration (WLPI) method, is put forward in this paper. The WLPI method can be realized in a recycled paper mill by adding technologies and using recycled water. Many industrial case studies have shown that a large quantity of water, energy and materials can be saved, and the quantity of waste sludge and wastewater discharge was minimized by using the WLPI method. The design of the water reuse system, control of calcium hardness, water recycling and minimal waste sludge are discussed. Anaerobic technology plays an important role in the WLPI method to lower cost, energy use and waste. In the brown paper and coated white board production, zero-effluent discharge can be realized. Fresh water consumption is only 1–2 m3·t-1. For the paper mills with deinking and bleaching processes, about 10 m3·t-1 of fresh water and a similar amount of effluent discharge are needed. Power saving using anaerobic technology is 70% when recycled water is used in comparison with the conventional activated sludge process. Waste sludge can be decreased to about 5% of the initial process due to reuse of the waste sludge and the lower bio-sludge production of the anaerobic process. 相似文献
Acute toxicities (15min‐EC50) of 21 substituted benzaldehydes to Photobacterium phosphoreum were determined. A quantitative structure‐activity relationship (QSAR) was developed using molecular connectivity indices and quantum chemical parameters, which show that the toxicity is influenced mainly by the difference of the simple and valence‐corrected fourth path molecular connectivity, polarizability, dipole moment, and the most negative net atomic charge on an atom. This study further shows that benzaldehydes are reactive chemicals, which exhibit bioreactive toxicity. 相似文献