Toxicity measurements in aqueous solution during ozonation of mono-chlorophenols

The Microtox toxicity and Oxygen Uptake Rate (OUR) inhibition tests were conducted to monitor the variation of toxicity during ozonation of 2-chlorophenol (2-CP), 3-chlorophenol (3-CP) and 4-chlorophenol (4-CP) under neutral conditions. The results revealed that the oxidized 2-CP solution exhibited new toxicity to pure bacteria and mixed microorganisms in the early stage of ozonation. The largest inhibition of OUR appeared at one mol of applied ozone dosage per mol of initial 2-CP, and the percentage of inhibition was 63.8%. In addition, ozonated 3-CP and 4-CP also significantly induced new aqueous toxicity, if these toxic intermediates were not further ozonated. Comparing the variation of toxicity and the hydroxylated/chlorinated intermediates formed, 3-chloro-catechol, 2-chloro-2, 4-hexadienedioic acid and the dimmer compounds may be related to the sources of toxicity during the ozonation of 2-CP.     

北京夏季高温高湿和降水过程对大气颗粒物谱分布的影响

2004-07-13～2004-08-23使用TDMPS-APS系统在线测量颗粒物的数浓度谱分布,并于07-16～07-18选取了高温闷热夜晚、日间高温高湿和雨后晴朗干洁3种天气条件,使用多级串联撞击式采样器(MOUDI)测量颗粒物的质量浓度谱分布,结果表明,高温高湿天气条件下颗粒物的污染、尤其细粒子污染严重,导致很低的能见度(2.5km);PM_1.8和PM₁₀的质量浓度分别为170.68μg/m³和249.35μg/m³,细粒子质量浓度占PM10的68%;粒径为50～100nm颗粒物的数浓度最高,为2×10⁴～3×10⁴个/cm³;降雨过程对粗粒子和细粒子均有去除作用,对细粒子的去除作用尤为明显;降雨后PM₁₀和PM_1.8浓度分别比降雨前降低3倍和6倍;降雨过后的晴朗干洁天气有利于新粒子(3～20nm)的生成,生成的新粒子快速长大到50～100nm;随着污染物的累积,以后几天内又变为污染天气.     

分置式膜-生物反应器凝胶层膜污染模型研究

通过紊流条件下阻力模型和凝胶极化模型对膜生物反应器的阻力进行分析,结果表明,膜面流速在3～10 m/s,运行时间在5h之内时,阻力模型可以很好地符合凝胶模型.通过分置式膜-生物反应器对染料废水超滤膜阻力进行了分析,膜的总阻力随着运行时间增加而增加,在所有阻力中,凝胶阻力占比重最大.     

Cumulative risk assessment of dietary exposure to phthalates in pregnant women in Beijing,China

Diet is an important exposure route for phthalates, such as di-iso-butyl phthalate (DiBP), dibutyl phthalate (DBP), bis(2-ethylhexyl) phthalate (DEHP), and benzyl butyl phthalate (BBP). In this study, we aimed to estimate phthalate exposure in the diet of pregnant women and assess the health risk. A total of 517 pregnant women in the first trimester were recruited, and food frequency questionnaires were collected. A simple distribution assessment method was used to estimate daily exposure, and the hazard index (HI) method was used to assess cumulative risk. The maximum daily dietary exposure to DEHP, DBP, DiBP, and BBP was 5.25, 3.17, 2.59, and 0.58 μg/kg bw/day, respectively, and did not exceed the safety limit values. Cereals and vegetables were the main sources of the estimated daily intake (EDI) of phthalates in the diet. The cumulative risk assessment, based on the European Food Safety Authority tolerable daily intake (TDI) and the US Environmental Protection Agency reference dose (RfD), did not exceed the threshold of 1. DiBP, DBP, and DEHP had higher hazard quotient (HQ) values for cumulative health risk than BBP. In conclusion, a low health risk was posed by the cumulative dietary exposure to phthalates for pregnant women in Beijing.

Graphical abstract

     

精细化工厂污水排放控制措施

中原油田天然气产销总厂精细化工一厂为了实施清洁化生产,对污水外排从控制污水产生入手,采取了改冷却水一次排放为循环利用、化学处理改善水质及提高水的循环利用率等一系列措施,投入改造资金5万余元,将污水日排放量由1200 m3降到50 m3 ,且实现达标排放,取得了较好的经济效益和环境效益。     

Successful and sustainable governance of the lower Yellow River,China: A floodplain utilization approach for balancing ecological conservation and development

Environment, Development and Sustainability - A novel model has been proposed for the methodical development and safe utilization of the lower Yellow River floodplain to provide flood control with...     

Preparation and evaluation of Pd-Sn modified Ru-Ir electrode for denitrification of high chlorine ammonia–nitrogen wastewater

Environmental Science and Pollution Research - In this paper, Pd-Sn modified Ru-Ir electrode was prepared by thermal oxidation method, and the effects of doping amount of Pd-Sn and synthesis...     

Toughness Improvement of Epoxy Composites Using a Kind of Environment-Friendly Bio-Based Polyester Polyol

Journal of Polymers and the Environment - Epoxy resin (EP) is a thermosetting resin with prominent performances and wide applications. However, the inherent brittleness limits its development in...     

遥感技术在油田开发建设项目景观生态评价中的应用

在油田开发建设项目的环境影响评价中,使用遥感技术,将卫星遥感影像数据进行分类处理,结合传统生态学中计算植被优势度值的方法,对油田开发过程中的景观生态进行了评价,取得了较好的效果。简要介绍了该技术的功能特点及应用实例。应用结果表明:遥感技术是对油田开发建设项目景观进行生态评价的重要手段,可以取得真实、可信的评价结果。     

安徽省地震谣传特征及控制对策

归纳总结安徽省自 1976年唐山大地震至 1998年 2 0余年弱震、少震的时期里地震谣传发生、发展的特征和紧急平息地震谣传的经验 ,结合实际提出了对地震谣传的长期预防对策。