The biochemical activity of soil contaminated with fungicides

Excess fungicides can pose a serious threat to the soil environment. Fungicides can lower the microbiological and biochemical activity of soil and lead to yield declines. Soils contaminated with fungicides have to be remediated to maintain the optimal function of soil ecosystems. This study evaluates the effect of neutralizing substances on soil enzymatic activity and the yield of Triticum aestivum L. in soil contaminated with fungicides. Sandy loam (Eutric Cambisols) with pH_KCl 7.0 was contaminated with an aqueous solution of Amistar 250 SC and Falcon 460 EC in the following doses: 0 (soil without fungicide – treated as a control), RD (dose recommended by the manufacturer) and 300?×?RD (dose 300-fold higher than the recommended dose). Soil was supplemented with bentonite and basalt meal at a dose of 10?g kg^?1 DM of soil (dry mass of soil). The fungicide dose recommended by the manufacturer did not induce changes in soil enzymatic activity or the yield of T. aestivum L. Our findings indicate that the tested fungicides can be safely applied to protect crops against fungal pathogens. However, when applied at the dose of 300?×?RD, the tested fungicides strongly inhibited soil enzymatic activity and disrupted the growth and development of spring wheat. Soil supplementation with bentonite and basalt meal improved the yield of T. aestivum L., and bentonite was more effective in reducing fungicide stress. The analyzed substances were not highly effective in restoring biochemical homeostasis in soil.     

Distribution of perfluorinated alkyl substances in marine shellfish along the Chinese Bohai Sea coast

Perfluorinated alkyl substances (PFASs) are emerging persistent organic pollutants, which pose a threat to human health primarily by dietary exposure, especially through seafood. Bohai Sea (a semi-closed sea located north of China) is an important shellfish aquaculture area that is possibly highly-polluted with PFASs. In this study, we first evaluated contamination by PFASs in a total of 230 samples of marine shellfish from the Bohai Sea. Samples included five important shellfish species, collected from important aquaculture spots distributed around the Bohai Sea. Samples were analyzed by an ultra-fast liquid chromatography-tandem mass spectrometry method, which could simultaneously detect 23 PFASs in shellfish. Our research verified that PFASs have become a threat to the safety of shellfish products in this area. Furthermore, contamination by PFASs in shellfish changed depending on the components of PFASs, the species of shellfish, and the sampling sites. Many of the 23 target compounds contributed to the high detection ratio (>50%) as follows: perfluorooctanoic acid (PFOA)?>?perfluorononanoic acid?>?perfluorodecanesulfonic acid?>?perfluorooctanesulfonic acid (PFOS). Compared with other dominant components, PFOA not only had the highest detection percentage in shellfish samples (98.3%), but its detection level contributed to 87.2% of total PFASs concentrations, indicating that PFOA is the major threat to the safety of shellfish products. The highest level of PFAS was found in clams (62.5?ng?g^?1 wet weight of PFOA). The concentration of total PFAS in different shellfish species showed the following trend: clams?>?mussels?>?scallops?>?whelks?>?oysters. The maximum concentration of total PFAS or PFOA was found in Shouguang. The total concentration of PFOS and its precursor were highest in Cangzhou, possibly due to local industrial activities. The results presented in this paper provide new data on the contamination of marine shellfish along the Bohai Sea coasts in China, and constitute a reference for future monitoring of contamination by emerging contaminants in Bohai coast.     

Emergency evacuation model assuming leakage of toxic substances in a chemical plant

Preparedness of emergency evacuation for the leakage of toxic substances in chemical plants is very important in order to reduce damage. In order to implement an emergency evacuation properly, it is necessary to comprehensively and concretely determine the conditions of the leakage and atmospheric conditions and predict the consequences of the dispersed gases. Repeated training for emergencies is also essential. In order to realize effective evacuation, a prediction model of the evacuation area that anyone can use to obtain the same results both accurately and promptly is developed in the present study. The prediction model is designed such that the wind speed and atmospheric conditions are automatically set, and the leakage rate is the only input parameter, so that anyone can use the model easily. In addition, the model can also predict the atmospheric parameters for up to 3 h and can calculate the evacuation distance so that smooth evacuation can be achieved for changing atmospheric conditions. Finally, the evacuation area is defined by statistically analysed wind fluctuations, and a series of emergency evacuation measures is implemented.     

MSWI BA treated with Advanced Dry Recovery: a field scale study on materials’ leaching properties

In many European countries, the environmental properties of waste-derived aggregates are mostly assessed based on laboratory leaching tests such as the standardised percolation tests CEN/TS/14405, ISO/TS 21268-3, or DIN 19528. These tests are conducted under specified conditions, which are similar yet somewhat different from realistic field conditions. Therefore, this study aimed to investigate the leaching properties of ADR (Advanced Dry Recovery) recovered MSWI BA in the field in order to understand more about its environmental impacts in actual civil engineering structures. Two field scale studies (a lysimeter and a larger interim storage field study) were constructed and the leachate quality was investigated. These results were then complemented with the results of previously conducted laboratory leaching tests using a liquid to solid ratio (L kg^?1) comparison. The results demonstrated that the leaching behaviours of many potentially harmful substances, such as chloride, copper and antimony, was similar despite the study scale. In addition, this study illustrated the importance of investigating the leaching properties of waste-derived aggregates on a larger scale, even though the uncertainties in such studies may not be easily controlled.     

好氧颗粒污泥胞外聚合物的产生及其分布

考察了不同操作条件和基质条件对好氧颗粒污泥中胞外聚合物(EPS)产生的影响及其在污泥和体系上清液中的分布.结果表明:随体系操作条件和基质条件的变化,好氧颗粒污泥内部和上清液中的EPS含量呈规律性变化.相对而言,好氧颗粒污泥中EPS含量的变化幅度较小,过多的EPS则释放到上清液中.大量EPS的释放只发生在颗粒污泥解体时,而酸性条件和不适当的C/N比不利于好氧颗粒污泥的形成及形态保持.体系溶解氧为4.5 mg·l-1,pH为中性,污泥负荷小于等于0.37kgCOD·kg-1MLSS·d-1,碳氮比为20∶ 1时,好氧颗粒污泥中EPS的含量约占污泥总质量的9%-12%,与厌氧颗粒污泥(0.6%-20%)相近,但远低于絮状活性污泥(80%),此时,EPS在上清液中的含量最低或接近最低,为14-26 mg·l-1.     

城市污水活性污泥处理系统中有机物分子量的分布及其变化

利用凝胶过滤色谱法对某城市污水处理系统(缺氧/好氧,A/O活性污泥法)中有机物的分子量在水相和胞外聚合物(EPS)中的分布及其变化进行研究.结果表明:污水处理过程中分子量的分布沿程变窄,对分布在各段分子量之间的有机物都有大幅度的去除;缺氧池和好氧池的EPS中都有14%的物质分子量大于1000万,而水相中各类物质的分子量均小于200万,说明该类大分子的EPS并非因吸附而成.     

胞外聚合物物理法提取过程的优化

对物理法提取活性污泥中的胞外聚合物(EPS)进行了优化.分别考察了超声时间、振摇时间、离心速度和时间以及加热时间对EPS的松散附着(LB)和紧密粘附(TB)提取的影响,得出污泥EPS物理法提取的优化方案.     

大型危险化工企业气体危险源监测与预警系统建设

阐述了当前我国大型危险化工企业危险源监测及预警系统建设的现状与不足,以泰州梅兰集团为例,提出了大型危险化工企业危险源监测及预警系统的建设目标及原则,应急预警处置系统的主要内容、标准与要求。     

好氧活性污泥胞外聚合物的影响因素研究

研究了4种活性污泥处理工艺和两种污泥培养基质对好氧活性污泥胞外聚合物(EPS)的影响,包括对EPS总量和组分的影响。EPS的提取总量以TOC来表示,并以DNA的浓度来衡量提取过程中细胞裂解的程度。结果发现,处理工艺不同,导致EPS的含量和组成不相同,主要体现在蛋白质和多糖含量比的不同;淀粉基质培养的污泥的EPS总量平均值比葡萄糖基质培养的污泥的EPS总量平均值略高一些,它们都比实际污水处理厂污泥的EPS含量高。     

翻堆对好氧堆肥腐殖质电子转移能力的影响

开展了连续通风和翻堆两种典型的通风方式进行污泥好氧堆肥,通过分析堆肥腐殖质中富里酸(FA)和胡敏酸(HA)的光谱特征以及本底/化学还原容量(NRC/CRC)的时态变化,研究其对污泥好氧堆肥过程中富里酸(FA)和胡敏酸(HA)的形成和电子转移能力(ETCs)的影响.结果表明:与翻堆处理相比,连续通风处理促进了堆肥FA和HA中类蛋白质组分的减少和类腐殖质组分的增加,强化了高温期和腐熟期FA的电子转移能力(CRC分别增加了176.55和123.24μmol e^-/gC),但降低了HA和升温期FA的电子转移能力(CRC分别降低了246.47和116.13μmol e-/gC).相关性分析表明,影响污泥堆肥腐殖质电子转移能力的主要因素为pH值、SUVA₂₅₄、SUVA₂₉₀和类蛋白质组分,翻堆处理促进了类腐殖质组分对腐殖质电子转移能力的影响.