基因工程的潜在影响及其对有机食品产业的冲击

基因工程的研究发展非常迅速，使其在农业和食品加工领域的应用成为不可避免，但其安全性问题在世界范围内引起了非常广泛的争议。从基因工程内涵和有机农业的要求及目标出发，讨论了基因工程的潜在影响及其对发展有机食品产业的冲击。认为有机农业运动面临的紧迫问题是尽快协调所有的行动方案来保证有机食品永远不涉及基因工程生物体。有机农业正面临基因工程的挑战，其发展的潜力是建立一个完全独立的有机食品市场。     

广东区域酸雨污染模拟研究

运用数值模拟方法，使用一年365日的风速资料、12个月的降水资料和环境监测资料以及年平均的污染源资料，对广东地区的酸雨污染进行了较细致的分析。结果认为，以日为基础的累积计算，对于提高模拟酸雨污染的能力是很有帮助的。广东省的酸雨污染主要是由自身排放的污染物造成，外来的污染是次要的，在广东边界地区发现受到外省污染的显著痕迹。     

Combined zero valent iron and hydrogen peroxide conditioning significantly enhances the dewaterability of anaerobic digestate

The importance of enhancing sludge dewaterability is increasing due to the considerable impact of excess sludge volume on disposal costs and on overall sludge management. This study presents an innovative approach to enhance dewaterability of anaerobic digestate(AD) harvested from a wastewater treatment plant. The combination of zero valent iron(ZVI, 0–4.0 g/g total solids(TS)) and hydrogen peroxide(HP, 0–90 mg/g TS) under pH 3.0 significantly enhanced the AD dewaterability. The largest enhancement of AD dewaterability was achieved at 18 mg HP/g TS and 2.0 g ZVI/g TS, with the capillary suction time reduced by up to 90%. Economic analysis suggested that the proposed HP and ZVI treatment has more economic benefits in comparison with the classical Fenton reaction process. The destruction of extracellular polymeric substances and cells as well as the decrease of particle size were supposed to contribute to the enhanced AD dewaterability by HP + ZVI conditioning.     

树木健康与病虫草害的关系分析

本文论述了树木健康与病害、虫害、草害的关系。     

新时代城市土壤环境监测点位布设应用的研究分析

新时期城市构造呈现多样性,加上城市化、工业化发展迅猛,城市的演变日新月异,如何对城市土壤环境监测点位布设的方法进行取舍是十分关键的,本文详细介绍了城市土壤环境监测点位布设的方法以及其应用的研究分析,希望能为我国城市土壤环境监测的相关研究提供参考。     

Triazines in the aquatic systems of the Eastern Chinese Rivers Liao-He and Yangtse

The results of a one-year monitoring program on the two Eastern Chinese River systems, i.e. the Liao-He and the Yangtse, with special emphasis on the presence of triazine herbicides are presented. Sediment, suspended solids and water samples from both rivers were analyzed. Additionally, recovery experiments on the SPE-in-field-enrichment procedure and the extraction methods were performed. The samples were measured by gas chromatography coupled with mass spectrometry, electron capture detection and a newly developed mu-plasma atomic emission detector. A typical result of a one-year monitoring was obtained in case of the Liao-He: During winter, at low water period, low triazine values were found. A similar situation was found in early spring. Highest concentrations of atrazine up to 1600 ng/l were found in late spring in the water samples. Maximum concentrations of atrazine, simazine, propazine, simetryn and prometryn were observed in this season as a result of the actual use of triazines. Finally, after the high water period in autumn the triazine concentrations decreased. Additionally, atrazine adsorbed on sediment (up to 2.8 ng/g) and suspended solids was determined (up to 8 ng/l) during late spring sampling. Therefore, the logarithm of the organic carbon based sorption coefficient of atrazine could be calculated. Low levels of atrazine were measured in the water of Yangtse (up to 18.3 ng/l). The concentrations from all sampling points and sampling stations of a particular sampling date were similar, which indicates a homogeneous distribution of this herbicide. Due to the high discharge rate of up to 79,000 m3/s in case of the Yangtse a considerable mass transport of up to 57.5 kg per day atrazine may take place, even at concentrations below the European drinking water limit of 100 ng/l.     

Nutrient dynamics and the eutrophication of shallow lakes Kasumigaura (Japan), Donghu (PR China), and Okeechobee (USA)

We compared the nutrient dynamics of three lakes that have been heavily influenced by point and non-point source pollution and other human activities. The lakes, located in Japan (Lake Kasumigaura), People's Republic of China (Lake Donghu), and the USA (Lake Okeechobee), all are relatively large (> 30 km2), very shallow (< 4 m mean depth), and eutrophic. In all three lakes we found strong interactions among the sediments, water column, and human activities. Important processes affecting nutrient dynamics included nitrogen fixation, light limitation due to resuspended sediments, and intense grazing on algae by cultured fish. As a result of these complex interactions, simple empirical models developed to predict in-lake responses of total phosphorus and algal biomass to external nutrient loads must be used with caution. While published models may provide 'good' results, in terms of model output matching actual data, this may not be due to accurate representation of lake processes in the models. The variable nutrient dynamics that we observed among the three study lakes appears to be typical for shallow lake systems. This indicates that a greater reliance on lake-specific research may be required for effective management, and a lesser role of inter-lake generalization than is possible for deeper, dimictic lake systems. Furthermore, accurate predictions of management impacts in shallow eutrophic lakes may require the use of relatively complex deterministic modeling tools.     

A modified cyanobacteria prediction model based on cellular automata model using N and P concentration reverse data: a case study in Taihu Lake

The problem of algal bloom caused by eutrophication has attracted global attention. Many scholars have studied the problem associated with algae bloom, but few have carried out dynamic monitoring, instead focusing on the formation mechanism of cyanobacteria. For our study of the Taihu Lake in China, we used Moderate-Resolution Imaging Spectroradiometer (MODIS) and Landsat remote sensing image data from 2017 to establish a prediction model. First, we used MODIS data to retrieve the concentration of N, P, and chlorophyll a in water. Then, we applied the analytic hierarchy process (AHP) model to the inversion results to construct the diffusion potential index. Finally, we used C# to compile the cellular automata (CA) model. We found that the distribution of cyanobacteria predicted by our method was consistent with the algal bloom situation of Taihu Lake in 2017. The results showed that the method effectively predicts the dynamic transfer of cyanobacteria from outbreak to diffusion in a short period of time, which can help decision-makers monitor lake health.

     

Association between ambient temperature and childhood respiratory hospital visits in Beijing,China: a time-series study (2013–2017)

Environmental Science and Pollution Research - Little is known on the potential impact of temperature on respiratory morbidity, especially for children whose respiratory system can be more...     

Photoinductive activity of humic acid fractions with the presence of Fe(III): the role of aromaticity and oxygen groups involved in fractions

Relationship between the photoinductive activity and the properties of humic acids (HA) fractions were investigated with and without Fe(III). Three fractions were separated based on the molecular weight (M(w)) and were obtained following the order of M(w): F(A)>F(B)>F(C). Compared to F(A) and F(B), photodegradation of atrazine under simulated sunlight was much faster in solution containing F(C), whose structure was dominated by greater aromaticity, more oxygen groups and fluorophores. The interaction of HA fractions and Fe(III) was studied using fluorescence spectrometry and F(C) had the largest quenching constant. The capacity of electron transfer, estimated from the amount of photoformed Fe(II), was also highest for F(C). Thus, the Fe(III)-F(C) complex was efficient in phototransformation of atrazine in nearly neutral aqueous solutions. These results suggest that the aromaticity and oxygen groups content of HA exert great influence on the binding ability of metals and on the fate of pollutants in natural waters.