烟花爆竹禁燃对春节期间东北地区空气质量影响评估

利用2015—2017年春节期间东北地区主要大气污染物(PM_(10)、PM_(2.5)、SO_2、NO_2、CO和O3)质量浓度监测资料及相应气象因子(温度、湿度、风速和气压)观测资料,分析了春节期间烟花爆竹禁燃对东北地区空气质量的影响。结果表明:随着东北地区主要城市禁燃力度的增强,空气质量逐年提升,PM_(2.5)和SO_2浓度逐年大幅度下降。禁燃可明显降低城区PM_(2.5)浓度,而由于春节期间污染源整体减少,城区和城郊监测点PM_(2.5)浓度值差异减小。烟花爆竹对PM_(10)和PM_(2.5)浓度影响高于对气体污染物SO_2、NO_2和CO的影响。此外,气象条件对东北地区春节期间禁燃改善空气质量的效果也有明显影响。因此,结合春节期间的气象条件,在东北地区实施禁燃政策动态调整非常必要。     

一株双酚A降解菌的筛选、鉴定及其生长、降解条件

从沈阳北部污水处理厂曝气池活性污泥中驯化、分离及筛选得到一株以双酚A为唯一碳源的高效降解菌株D-17,通过菌体形态、生理生化反应特性及16S r DNA基因测序分析对其进行了鉴定,并研究了该菌株的生长及双酚A降解条件。菌种鉴定结果表明,该菌为乙酸钙不动杆菌(Acinetobacter calcoaceticus)。实验结果表明:该菌株的生长及降解双酚A的最适条件为溶液pH 7.0,接种量10%,摇床转速150 r/min,降解温度30℃,降解时间5d;当双酚A初始质量浓度为60 mg/L时,双酚A降解率达52.62%;投加蛋白胨后,双酚A降解率提高至57.15%。     

Antibiotic resistance,virulence factors and biofilm formation ability in Escherichia coli strains isolated from chicken meat and wildlife in the Czech Republic

Attachment of pathogenic bacteria to food contact surfaces and the subsequent biofilm formation represent a serious threat for the food industry, since these bacteria are more resistant to antimicrobials or possess more virulence factors. The main aim of this study was to investigate the correlation between antibiotic resistance against 13 antibiotics, distribution of 10 virulence factors and biofilm formation in 105 Escherichia coli strains according to their origin. The high prevalence of antibiotic resistance that we have found in wildlife isolates could be acquired by horizontal transfer of resistance genes from human or domestic or farm animals. Consequently, these commensal bacteria might serve as indicator of antimicrobial usage for human and veterinary purposes in the Czech Republic. Further, 46 out of 66 resistant isolates (70%) were able to form biofilm and we found out statistically significant correlation between prevalence of antibiotic resistance and biofilm formation ability. The highest prevalence of antibiotic resistance was observed in weak biofilm producers. Biofilm formation was not statistically associated with any virulence determinant. However, we confirmed the correlation between prevalence of virulence factors and host origin. Chicken isolates possessed more virulence factors (66%), than isolates from wildlife (37%). We can conclude that the potential spread of antibiotic resistance pattern via the food chain is of high concern for public health. Even more, alarming is that E. coli isolates remain pathogenic potential with ability to form biofilm and these bacteria may persist during food processing and consequently lead to greater risks of food contamination.     

某沿海城市典型行业NMHCs排放特征及对二次污染物生成潜势研究

采用SUMMA罐采样、GC-FID技术分析了威海市渔具、造船和橡胶等6种典型行业代表企业废气中59种非甲烷碳氢化合物(NMHCs)组分及占比,并计算了各行业NMHCs的臭氧(O3)和二次有机气溶胶(SOA)生成潜势,提出了NMHCs治理建议.结果表明,涉及溶剂使用的渔具、造船、汽车制造业喷涂工序的NMHCs组分以芳香烃...     

汽车工业区大气挥发性有机物(VOCs)变化特征及来源解析

挥发性有机物(volatile organic compounds,VOCs)作为臭氧和细颗粒物的重要前体物已日益受到关注.鲜有针对汽车工业区大气VOCs 长期观测的报道.2019-01-01～2019-12-31 期间在上海某汽车工业园区边界,采用在线气相色谱仪对79 种VOCs 组分定量检测,分析大气VOCs 组成...     

Preozonation of bromide-bearing source water in south China

The effectiveness of preozonation was evaluated on treating a bromide-bearing dam source water in south China through batch-scale experiments. Preozonation at ozone doses of 0.5-1.0 mg/L （at ozone consumption base） enhanced total organic carbon （TOC） removal through coagulation, and resulted in an almost linear reduction of ultraviolet absorbance at 254 nm （LW2s4）. The removals of TOC （after coagulation） and UV254 at the ozone dose of 1.0 mg/L were 36% and 70%, respectively. Preozonation at an ozone dose between 0.5 and 1.0 mg/L resulted in the removal of disinfection byproducts formation potential （DBFP） including trihalomethane formation potential （THMFP） and haloacetic acid formation potential （HAAFP） for about 50%. The removals of THMFP and HAAFP decreased with the further increase of ozone dose. Ozonation of bromide-bearing water （bromide concentration, 34 μg/L） produced a bromate concentration under the detection limit（2μg/L） at ozone doses 〈1.5 mg/L. However, bromate 〉10μg/L could be produced when the bromide concentration was increased to 96 μg/L.     

地下停车库火灾风险性的评价研究

本文分析了地下停车库的火灾特点。并从停车库的火灾规模、发生轰燃的烟气条件、释放辐射热的大小、相邻汽车被引燃的临界条件和自动喷水系统的动作时间等几方面对停车库潜在的火灾危险性进行了探讨。以某地下一层停车库为例,对其火灾风险性进行了具体评价。     

Evaluating Ecological Condition Using Soil Biogeochemical Parameters and Near Infrared Reflectance Spectra

Rapid, repeatable assessment of ecological condition is critical for quantitative ecosystem monitoring. Soils provide a sensitive, integrative indicator for which sampling and analysis techniques are well defined. We evaluated soil properties as indicators of ecological condition (subjectively classified into minimally/moderately/severely degraded based on vegetative, hydrologic and edaphic cues) at 526 sites within Ft. Benning military installation (Georgia, USA). For each sample, we measured 17 biogeochemical parameters, and collected high-resolution diffuse reflectance spectra using visible/near infrared reflectance spectroscopy (VNIRS). VNIR spectra have been related to numerous soil attributes — we examine them here for diagnosing integrated response (i.e., ecological condition). We used ordinal logistic regression (OLR) and classification trees (CT) to discriminate between condition categories using both sets of predictors (biogeochemistry and spectra). Sixteen biogeochemical parameters were significantly different across condition categories; however, multivariate models greatly improved discrimination ([calibration, validation] accuracy of [69%, 66%] and [96%, 73%] for OLT and CT models, respectively). Important predictors included total C, total P, and Mehlich K/Ca/Mg. VNIR spectra further improved discrimination ([calibration, validation] accuracy of [74%, 70%] and [96%, 75%] for OLR and CT models, respectively). While spectra were comparably effective at discriminating minimally degraded sites, they were significantly more effective at discriminating severely degraded sites. Error rates across confounding factors suggest that watershed of origin and landscape position were the only important confounders, likely due to imbalanced sampling. We conclude that multivariate diagnosis improves accuracy, and that VNIR spectroscopy, which yields substantial cost and logistical improvements over conventional analyses, provides an effective tool for rapid condition diagnosis.     

微生物絮凝剂高产菌株的筛选及培养条件的研究

采用随机分离的方法,从旱地、水田和池塘的污泥中分选出12种产絮凝剂的菌株。其中随机标号为I2、F11和G菌株的絮凝效果比较好,进一步根据不同培养时间、碳源、氮源和助凝离子,对此3株菌进行了培养条件及絮凝条件的研究。又依据絮凝反应时凝聚团产生的快慢和大小,确定菌株I2、F11有最好的絮凝效果。实验过程中还发现了筛选产絮凝剂菌株的新方法。     

正交优化制备污泥水解蛋白质的实验研究

以武汉市污水处理厂剩余活性污泥为原料,在不同加水量、温度和催化条件下水解制备水解蛋白质,并通过正交试验优化了剩余污泥水解的反应条件。结果表明,当时间固定在6h时,以固液比(此为鲜泥与加水量的质量之比)为1∶2,温度1200℃,盐酸催化(pH为1.5)为水解反应的最佳条件。本研究为污泥水解蛋白液的制备及污泥处理的减量化、无害化和资源化提供了理论支持和数值依据。