Parental phenols exposure and spontaneous abortion in Chinese population residing in the middle and lower reaches of the Yangtze River

Widespread use of phenols has led to ubiquitous exposure to phenols. In experimental animals, phenols increased resorptions, reduced live litter size and fetal body weights. However, there are limited epidemiological evidences of the relationships between exposure to phenols and pregnancy outcomes. We evaluated the associations between parental urinary levels of various phenols and spontaneous abortion in a Chinese population residing in the middle and lower reaches of the Yangtze River. A case-control study was conducted that included 70 case couples with medically unexplained spontaneous abortion and 180 control couples who did not have a history of spontaneous abortion and had at least one living child. Both parental urinary phenols were measured by ultra-high performance liquid chromatography-tandem mass spectrometry including bisphenol A (BPA), benzophenone-3 (BP-3), 2,3,4-trichlorophenol (2,3,4-TCP), pentachlorophenol (PCP), 4-n-octylphenol (4-n-OP) and 4-n-nonylphenol (4-n-NP). Compared with the low exposure group, there was an increased risk of spontaneous abortion with high paternal urinary PCP concentration [odds ratio (OR) = 2.09, 95% Confidence Interval (CI), 1.05–4.14], and maternal exposure to 4-n-OP and alkylphenol(s) also significantly increased the risk of spontaneous abortion (OR = 2.21, 95% CI, 1.02–4.80; OR = 2.81, 95% CI, 1.39–5.65, respectively). Our study firstly provides the evidence that paternal PCP exposure, maternal 4-n-OP and alkylphenol(s) exposure are associated with spontaneous abortion in humans.     

烟气同时脱硫脱硝化学反应的可能性分析

根据烟气气体组分情况，将可能发生的化学反应方程式进行筛选，确定独立反应个数。通过热力学计算得到了标准状态下热力学函数值，进而求得了不同温度下的热力学性质。通过标准生成自由焓、标准吉布斯自由能变、标准熵变的计算，分析了烟气同时脱硫、脱硝中发生化学反应的可能性，为烟气同时脱硫、脱硝动力学理论的研究打下了基础。     

曝气生物流化床处理高氨氮粪便污水

应用好氧曝气生物流化床反应器处理动车集便器粪便污水,研究反应器同步硝化反硝化脱氮及去除COD效能,以及DO对处理效能的影响,通过镜检观察反应器内微生物特性,探究反应器同步硝化反硝化脱氮机理。结果表明,反应器维持DO在2.5 mg/L左右时,对粪便污水中氨氮、TN和COD的去除率分别达99.8%、84.1%和95.5%,在好氧曝气生物流化床反应器中,实现同步硝化反硝化脱氮并去除有机物。分析认为,反硝化脱氮主要发生在生物膜内的厌氧微环境,反硝化反应主要由厌氧反硝化菌完成,曝气生物流化床反应器同步硝化反硝化脱氮机理主要从微环境理论解释。     

A Monte Carlo study of radon detection in cylindrical diffusion chambers

The functioning of radon diffusion chambers was studied using the Monte Carlo code RAMMX developed here. The alpha particles from radon are assumed randomly produced in the volume of the cylinder, and those from the progeny are assumed to originate randomly at the cylindrical surface. The energy spectrum, the distribution of incident angles, and the distribution of path lengths of the alpha particles on the detector were obtained. These quantities vary depending on input parameters such as initial alpha particle energy, radius and depth of the diffusion chamber, detector size and atmospheric pressure. The calculated energy spectrum for both ²²²Rn and ²²⁰Rn was compared with experiment, permitting the identification of each peak and its origin, and a better understanding of radon monitoring. Three aspects not considered in previous calculations are progeny alphas coming from surfaces of the monitor, taking into account the atmospheric pressure, and including the isotope ²²⁰Rn.     

干法烟气同时脱硫脱硝技术的应用及进展

综述了目前国内外干法烟气同时脱硫、脱硝技术．详细介绍了各种技术的机理、研究现状及最新进展，并分析了这些技术的优点和缺点，最后对其发展前景作了展望。     

2008年我国环境保护投资总体特征分析

立足于环保投资数据库,从投资构成、空间分布和行业分布3个方面对我国环保投资进行综合分析。2008年,全国环保投资增幅持续保持较快增长,环保投资弹性系数为1.9,环保投资增速大大超过经济增速,"三同时"项目成为拉动环保投资的主要驱动力。引入了环保投资平衡度的概念,在此基础上对各地区环保投资的合理性进行了初步分析。重点行业环保投资方面,工业治污设施运行费用远远大于同期固定资产投资,一定程度上说明了应对治污运行费用来源给予充分重视,采取措施确保稳定可靠的资金渠道。     

碱式硫酸铝溶液中SO42-的测定

建立了以铬黑T为指示剂，乙二胺四乙酸二钠反滴定过量BaCl₂的碱式硫酸铝溶液中SO₄^2-的测定方法。实验确定的操作条件为：待测试样稀释后ρ（SO_4^2-）为0.025 ~0.100 g/L，BaCl₂过量率为25%~100%，并且在加入BaCl₂前将试样煮沸，三乙醇胺加入量为0.10 L/L。该法回收率在98.90%~100.72%，相对标准偏差小于1%。测定方法准确，可靠，且操作简便、快速。     

原子吸收法直接测量土壤中的汞含量

实验采用DMA-80自动测汞仪直接测定土壤中的汞含量，详细介绍了土壤样品中汞分析条件的选择，方法在0．4—400ng范围内，线性良好，其检出限为0．2ug／kg。     

颗粒化序列间歇式活性污泥反应器工艺处理化粪池污水

在序列间歇式活性污泥反应器(SBR)中成功培养出适应化粪池污水水质的好氧颗粒污泥.并将其应用于化粪池污水的处理.在好氧颗粒污泥培养的第15天左右,SBR中开始出现细小的颗粒,然后微生物在其上繁殖生长使颗粒逐渐增大而成熟;在第24天时,SBR中絮状活性污泥已基本实现了颗粒化.培养出的好氧颗粒污泥对化粪池污水有稳定的处理效果,在进水完全为化粪池污水时,COD、NH_4~+-N、TN的平均去除率分别为77%、61%、47%.但是,由于化粪池污水COD较低,因此无法维持较高的生物量,在后期的稳定运行过程中MLSS始终维持在2 500 mg/L左右.好氧颗粒污泥的同步硝化反硝化作用是其稳定脱氮的保证.     

CONFLICTING PERSPECTWES ABOUT DETECTION LIMITS AND ABOUT THE CENSORING OF ENVIRONMENTAL DATA1

ABSTRACT: Current conventions for reporting analytical results from environmental samples brings the objectives of laboratory scientists into conflict with those of environmental scientists. The objective of chemical analyses is to provide estimates of the true composition of samples. Reported results must reflect the analytical uncertainty. Current conventions require left-censoring of those results below the Limit of Detection. The objective of statistical interpretation of environmental data is to provide estimates of the characteristics of ecosystems. Such statistical analyses are often confounded by left-censoring of analytical results. We review the different points of view and propose a compromise which recognizes these conflicting perspectives.