餐厨垃圾中油类的测定方法初探

建立用四氯乙烯提取餐厨垃圾中的油类物质、用红外分光测油仪测定餐厨垃圾中油类的测定方法,呈现良好的线性关系,相关系数为r=0.999 7.该方法操作简单快捷,具有可行性、实用性及准确性.本研究分别从样品类型、前处理、取样量、萃取时间和萃取剂体积等方面进行了探究,实验论证确定了样品中油类的测定参数:称取2.00 g以上预处...     

北京市春季生活垃圾组成在物流系统中的变化分析

在北京市生活垃圾的物流流程的2个流向中,按照流向选取8个功能区、1个垃圾楼、1个转运站、1个处理处置场(堆肥厂、填埋场)的垃圾作为垃圾物流流程分析的取样点,测定垃圾的组分,以分析垃圾的组成、水分和密度在物流系统中的变化.     

垃圾填埋场设计计算中垃圾密度的取值

针对我国城市垃圾卫生填埋设计与建设中的问题，结合垃圾理化特性，提出垃圾填埋场 不同工序的工艺设计应选用不同的垃圾密度值，即填埋库容量计算应以沉降为设计参数；而填埋单元作业有关设计应以压实密度为设计参数，这样才能保证增圾填蛙场有关技术经济指标的科学性与准确性。真实可靠的垃圾密度值取决于科学合理的取样测算方法，即沉降密度取样测算应考虑取样时间，位置等多因素对密度值的影响；而压实密度取样测量试验在在与生     

温州杨府山垃圾填埋场底层土壤污染状况研究

通过钻孔取样对温州市杨府山垃圾填埋场底部及周边土层的污染状况的调查分析,结果表明,垃圾填埋场下方及周边垃圾渗滤液流经区域下方的浅层土壤已受到一定程度的污染,污染主要集中在表层填土层.主要是重金属污染和TS污染,原因与土壤结构有关,表层填土层相对松散,渗透系数较大.     

大连市城市中心区生活垃圾调查与分析

在统计、分析大连市城市中心区垃圾产生量以及不同类型垃圾所占比例的基础上,确定实验采样点数量和位置,进行垃圾成分和理化性质的分析.结果表明:大连市城市中心区垃圾主要来源于居民家庭和各种商业活动,垃圾含水率和密度高于全国平均水平,发热量基本满足垃圾焚烧处理要求.     

福州市与台北市生活垃圾收费制度比较

将福州市生活垃圾收费制度与台北市生活垃圾收费制度进行比较,结果表明:垃圾收费从量制在环境效益与公平方面优于定额制.     

上海市生活垃圾内河集装箱运输优势的探讨

对上海市生活垃圾的运输河道进行水质取样分析,讨论内河集装箱运输模式的优势及其改善水体状况的作用。     

某大型垃圾填埋场环境调查分析

选取某典型生活垃圾填埋场,经过1 a多在不同季节多次取样调查,对其排放污染物进行了分析。该垃圾填埋场渗沥液经处理后可达标排放;地下水和环境空气的检测指标存在超标现象;土壤的检测指标均达标。并提出了规范城市生活垃圾填埋场建设和加强垃圾填埋场管理的相关建议,以减少其对周边环境的影响。     

生活垃圾厌氧发酵制沼气研究

以天津市的居民生活垃圾、食堂垃圾、市场垃圾为实验原料,采用高温和中温发酵,研究了发酵过程中的累计产气量、pH、甲烷和二氧化碳浓度变化情况.初步总结和分析这些变化规律,并对垃圾厌氧发酵制沼气技术给予建议.     

韶关市生活垃圾填埋场投资估算

生活垃圾填埋场是一项投资规模大,涉及面广,不确定因素较多的基础设施工程,通过韶关市花拉寨生活垃圾填埋场投资估算的实例介绍了垃圾填埋场投资估算的方法.     

顶空自动进样气相色谱法测定水中三氯甲烷的不确定度评定

目的对全自动顶空气相色谱法测定水中三氯甲烷含量的不确定度进行评定。方法对全自动顶空气相色谱法测定水中三氯甲烷含量的测定过程进行全面的分析,通过数学模型分析并计算测量过程中的不确定度分量,最后计算出相对合成标准不确定度和相对扩展不确定度。结果根据实验过程分析,不确定度4个来源的结果分别为：①标准溶液稀释过程引入的不确定度1．7×10^-2;②曲线似合引人的不确定度0．7×10^-2;③样品重复性测定引入的不确定度2．0×10^-2;④取样体积引人的不确定度1．15×10^-3,合成扩展相对不确定度为5．4％（k=2）。结论标准溶液配制、曲线似合、样品重复性、取样体积这4个不确定度来源中,除了取样体积引人的不确定度最小,其他3项并不侧重哪方面,严格这3项的操作才是控制精度的根本。     

The variability of delivered dose of aerosols with the same respirable concentration but different size distributions

The influences of aerosol size distribution and breath tidal volume on respirable dose estimates were examined for mouth breathing using the ACGIH/ISO/CEN criterion for respirable-equivalent aerosols. Actual tissue doses predicted from a set of pulmonary empirical deposition equations, the Heyder-Rudolf equations, were compared with deposition assumed to occur under the penetration-based respirable dust sampling criterion. Deposition estimate errors ranged from approximately 1/10- to 10-fold, with aerosol mass median aerodynamic equivalent diameter and geometric standard deviation as well as tidal volume each showing a substantial influence under appropriate conditions. These findings demonstrate that reliance on respirable aerosol sampling data obtained with devices performing on a penetration-based sampling criterion may lead to erroneous dose-response relationships in exposure standard development as well as exposure misclassification errors during epidemiological studies. A more reliable dose estimate would be obtained using devices with collection efficiency performance closely matching the alveolar deposition prediction curves of Heyder and Rudolf. We believe that if it is not currently required, the development of a deposition-based aerosol sampling methodology will soon be required for the determination and quantification of inhaled aerosol-induced adverse health effects.     

Determination of carbon disulfide at the workplace by sampling on charcoal tubes--problems and solutions

The aim of the study was to check the reliability and comparability of different analytical methods for ambient monitoring of carbon disulfide (CS2). A stationary sampling system, consisting of a charcoal sampling tube and pump, and two personal sampling systems, consisting of a charcoal sampling tube and a portable pump and of a diffusive charcoal sampler have been compared. The limits of quantification, within-series precision, between-series precision, recovery, and comparability of the methods were investigated. For passive sampling the recovery was determined by three different techniques. For a sampling time of 6 hours the limit of quantification was 0.2 ppm for the personal sampling and 0.01 ppm for the stationary sampling system. The within-series precision was between 5 and 8%. For personal sampling the between-series precision was between 9 and 12% using a passive sampler. The recovery ranged between 45 and 85% depending on the quotient of eluent volume and charcoal mass. The comparison of the two personal sampling methods in a field study using linear regression demonstrated with statistical certainty an excellent concordance of the methods. The study shows that particularly the method for determining air levels of carbon disulfide by passive sampling is associated with high systematic errors. If these errors are unknown or ignored they will result in highly underestimated exposure data for carbon disulfide.     

Methyltetrahydrophthalic anhydride in air--sampling and analysis.

Methyltetrahydrophthalic anhydride (MTHPA), an organic anhydride, is a sensitizing agent even at low air concentrations: no methods for its sampling and analysis have previously been reported. This paper outlines the use of Amberlite XAD-2 for sampling MTHPA vapour in air, followed by analysis using gas chromatography with flame ionization detection. The level of detection corresponds to a concentration in air of 10 micrograms m-3 for a 20 l. sampling volume. Up to 200 l. air has been sampled, at a sampling rate of 1 l. min-1, without detectable losses. The adsorption efficiency and the stability of the anhydride in the XAD-2 tubes were not influenced by a relative air humidity (RH) of 40%, but at RH 80% there was a loss of 18% at 50 l. air-sample volume. Results from sampling in XAD-2 tubes were 8% lower than those from parallel sampling in midget bubblers containing 10 ml 0.01 M sodium hydroxide.     

分光光度法测定工作场所空气中氨含量的不确定度分析

目的建立分光光度法测定工作场所空气中氨含量不确定度方式。方法依照JJF1059-1999《测量不确定度评定与表示》,建立数学模型,计算各不确定度分量和合成不确定度。结果标准溶液配制引入的标准不确定度分量为0.823%,由标准曲线求得样品溶液浓度引起的标准不确定度为0.062 8,样品取样与定容体积引起的标准不确定度为0.008 2,标准采样体积引入的标准不确定度为0.005 4,合成相对标准不确定度为0.06,扩展不确定度为0.38。结论该方法适用于分光光度法测定氨含量的不确定度评定。     

Performance of the surface air system air samplers

Two models of the surface air system (SAS) air sampler have been compared with the Bourdillon slit sampler. These tests show that the effective sampling volume remains nearly constant with an efficiency approximating to 100% over the range of particle sizes likely to be encountered in environmental sampling. At particle sizes below 4 micron the collection efficiency falls off and with 2 micron particles the efficiency is reduced to 50%. The high air flows, c.200 1 min-1 of the samplers are particularly suited to measurements of low levels of airborne micro-organisms.     

冲击式二级采样对呼吸粉尘与总粉尘浓度比值的影响

为了验证冲击式二级粉尘采样对呼吸性粉尘与总粉尘浓度比值的影响，作者采用瞬时定点采样方法测定作业场所空气中呼吸性粉尘浓度与总粉尘浓度。结果表明，在采样体积相同的条件下，呼吸性粉尘的比值与总粉尘浓度间具有较好的从属共变关系（ｒ＞０．８），呼吸性粉尘的比值随着总粉尘浓度的升高而相应增大     

Blood sample volumes in child health research: review of safe limits

Objective

To determine paediatric blood sample volume limits that are consistent with physiological “minimal risk.”

Methods

A literature review was performed to search for evidence concerning the adverse effects of blood sampling in children and for guidelines on sampling volume in paediatric research. The search included Medline, EMBASE, other web-based and non-web-based sources and the bibliographies of the sources identified. Experts were also consulted.

Findings

Five studies and nine guidelines were identified. Existing guidelines specify paediatric blood sample volume limits ranging from 1% to 5% of total blood volume (TBV) over 24 hours and up to 10% of TBV over 8 weeks. The evidence available is limited and includes findings from non-randomized studies showing a minimal risk with one-off sampling of up to 5% of TBV.

Conclusion

The evidence available is consistent with the conclusion that all identified guidelines are within the limits of “minimal risk.” However, more and better evidence is required to draw firmer conclusions. Researchers and institutional review boards need to take into account the total sampling volume needed for both clinical care and research rather than for each alone. The child’s general state of health should be considered and extra caution should be observed particularly with children whose illness can deplete blood volume or haemoglobin or hinder their replenishment. Local policies must also address the appropriateness and local acceptability of collection procedures and of the blood volumes drawn.     

短时间采样溶剂解吸气相色谱法测定工作场所空气中苯的不确定度评价

目的建立短时间采样溶剂解吸-气相色谱法测定工作场所空气中苯的不确定度分析方法,以评价测定结果的质量,找出主要影响因素。方法根据标准GBZ/T 160.42-2007短时间采样溶剂解吸-气相色谱法测定工作场所空气中苯,建立不确定度的数学模型,系统分析、计算不确定度各分量。结果采用溶剂解吸-气相色谱法测定工作场所空气中苯,当苯浓度为4.14 mg/m3,其扩展不确定度为0.40 mg/m3(k=2)。其中采样体积、采样效率,解吸效率、标准溶液配制和标准系列测定对测量相对标准不确定度贡献较大。结论此方法评价短时间采样溶剂解吸-气相色谱法测定工作场所空气中苯的不确定度,适用于评估测定结果误差的主要来源。     

工作场所空气中正丙醇测定方法研究

目的 研究并建立适用于工作场所空气中正丙醇的定量检测方法。
方法 工作场所空气中正丙醇由活性炭管采集, 经体积比为1:100的异丙醇-二硫化碳混合溶剂解吸后, 经石英弹性毛细管柱HP-INNOWAX (30.0 m×0.53 mm×1.0μm)分离, 氢焰离子化检测器检测, 标准曲线法定量。
结果 正丙醇浓度在10~500 μg/mL范围内和峰面积呈线性关系, 回归方程y=2.12 x+1.96, 相关系数r=0.999 9(P < 0.05)。以3.0 L采样量计, 方法最低检出浓度0.09 mg/m3, 最低定量浓度0.30 mg/m3; 不同浓度加标样品测定结果的相对标准偏差为1.7%~3.6%, 解吸效率89.3%~94.7%, 采样效率> 96%, 100 mg活性炭对正丙醇的穿透容量为16 mg; 采样后的活性炭管在室温条件下至少可放置7 d。
结论 建立的工作场所空气中正丙醇溶剂解吸-气相色谱测定方法准确可靠、灵敏度高、稳定性良好, 适用于工作场所空气中正丙醇的现场检测。