环境空气中氡检测实验室间比对及其结果评价

[目的]建立环境空气中氡检测实验室间比对方法,有助于实验室发现检测结果的系统误差,从而提高技术水平,确保检测结果准确可靠。[方法]通过对被测环境空气氡浓度稳定性试验和均匀性试验,选择适合比对试验的稳定条件。6家实验室的7台氡检测仪,分别依据国家标准《环境空气中氡的标准测量方法》（GB／T 14582--1993）和卫生部行业标准《空气中氡浓度的闪烁瓶测量方法》（GBZ／T155--2002）及《利用实验室间比对的能力验证——第1部分：能力验证计划的建立和运作》（GB／T15483．1—1999）规定的比对程序进行环境空气中氡浓度检测,比对结果采用稳健统计方法进行评价。[结果]比对试验统计结果显示中位值（M）217Bq／m^3、稳健变异系数（RobustCV）14．3％、标准四分位间距（NormIQR）31．1Bq／m^3、最大值（MAX）236Bq／m^3、最小值（删）85Bq／m^3、变动范围（R）151Bq／m^3。7台氡检测仪中,有5台比对结果满意,1台结果有问题（Z比分数-2．28）,1台结果不满意（Z比分数-4．24）。[结论]环境空气中氡浓度检测实验室间比对结果表明．不同检测方法、不同型号检测仪器的枪测结果具有可咖．性．     

Intercomparison of retrospective radon detectors.

We performed both a laboratory and a field intercomparison of two novel glass-based retrospective radon detectors previously used in major radon case-control studies performed in Missouri and Iowa. The new detectors estimate retrospective residential radon exposure from the accumulation of a long-lived radon decay product, (210)Pb, in glass. The detectors use track registration material in direct contact with glass surfaces to measure the alpha-emission of a (210)Pb-decay product, (210)Po. The detector's track density generation rate (tracks per square centimeter per hour) is proportional to the surface alpha-activity. In the absence of other strong sources of alpha-emission in the glass, the implanted surface alpha-activity should be proportional to the accumulated (210)Po, and hence to the cumulative radon gas exposure. The goals of the intercomparison were to a) perform collocated measurements using two different glass-based retrospective radon detectors in a controlled laboratory environment to compare their relative response to implanted polonium in the absence of environmental variation, b) perform collocated measurements using two different retrospective radon progeny detectors in a variety of residential settings to compare their detection of glass-implanted polonium activities, and c) examine the correlation between track density rates and contemporary radon gas concentrations. The laboratory results suggested that the materials and methods used by the studies produced similar track densities in detectors exposed to the same implanted (210)Po activity. The field phase of the intercomparison found excellent agreement between the track density rates for the two types of retrospective detectors. The correlation between the track density rates and direct contemporary radon concentration measurements was relatively high, considering that no adjustments were performed to account for either the residential depositional environment or glass surface type. Preliminary comparisons of the models used to translate track rate densities to average long-term radon concentrations differ between the two studies. Further calibration of the retrospective detectors' models for interpretation of track rate density may allow the pooling of studies that use glass-based retrospective radon detectors to determine historic residential radon exposures.     

生活饮用水中卤代烃检测能力的实验室问比对评估

[目的]通过实验室间比对有效评价和监控疾控系统实验室的检测技术水平,确定和核查实验室实施新方法检测的能力。[方法]该研究比对试验项目为生活饮用水中卤代烃7个组分的定量检测,参试实验室按照国家标准《生活饮用水标准检验方法有机物指标》（GB／T5750．8—2006）、《利用实验室间比对的能力验证——第1部分：能力验证计划的建立和运作》（GB／T15483．1—1999）和《利用实验室间比对的能力验证——第2部分：实验室认可机构对能力验证的选择和使用》（GB／T15483．2—1999）规定的比对程序,分别检测A、B两个比对样品。通过统计分析,判定各参试实验室的检测能力。[结果]参加水中卤代烃检测项目的实验室共51个。其中,除1个实验室仅检测了三氯甲烷和四氯化碳项目外,其余50个均完成7个项目的比对。分析结果显示,比对试验结果的稳健变异系数（Robust CV）大部分〈10．0％,结果的平均满意率为77．3％（｜Z｜≤2,结果满意）,平均有问题率为9．4％（2〈｜Z｜〈3,结果有问题）,平均不满意率为13.3％（｜Z｜≥3,结果不满意）。检测的水中卤代烃7个组分中,四氯化碳的结果满意率最高,为84．3％;一氯二溴甲烷结果满意率最低,为70．0％;二氯一溴甲烷不满意率最高,为22．0％;三氯乙烯不满意率最低,为6．0％。[结论]检测生活饮用水中7种卤代烃能力的实验室间比对结果表明,该次参试实验室的检测能力基本处于受控和可比状态。     

Waterborne radon in seven Maine schools

This study investigated the transfer coefficient of radon from water to air in kitchens and bathrooms for seven schools located in Maine. Simulations occurred in water use rooms containing multiple airborne radon detectors. Quantities measured included radon concentration in water (10-960 Bq L(-1), 260-26,000 pCi L(-1)), air (0-3 Bq L(-1), 0-80 pCi L(-1)), volume of water used, emissivities (0.04-0.98), and ventilation rates (0.012-0.066 min). Using these parameters provides the means for calculating the transfer coefficient and by which dose due to waterborne radon can be estimated in other schools. Transfer coefficient values calculated for kitchens and baths ranged from 9.6 x 10(-6) to 2.0 x 10(-2). Multiple detectors showed that the radon concentration varied throughout a room. These measurements represent the first of this type to be done in schools in Maine.     

陕西省饮用水中锰检测能力验证结果分析

目的 为了了解并提高陕西省各水质检测机构对水中锰检测的整体水平和技术能力.方法 选用自制锰能力验证样品,样品的均匀性采用"单因子方差分析"法进行评定;样品的稳定性通过"t检验"法进行评定;采用稳健统计技术"Z比分数"的统计方法对饮用水中锰的检测结果进行分析.结果 样品共发放至全省各相关机构136家实验室,锰检测结果(含...     

Interlaboratory comparison of different alpha-particle and radon sources: cell survival and relative biological effectiveness.

Alpha radiation-induced cell killing was determined in four different laboratories in order to: 1) measure interlaboratory variability and 2) compare the effects of radon and radon daughter exposures with the effects of 238Pu (an often-used model for radon exposure). The results suggest that differences in handling from laboratory to laboratory can affect both low and high linear energy transfer responses and should be considered when comparing results from different laboratories.     

辐射危害控制中人工放射性核素的γ能谱分析比对

目的：通过组织全国省、直辖市疾病预防控制中心对γ能谱进行比对,提高实验室放射性核素检测水平,促进放射性核素γ能谱测量的发展,保证检测质量。方法：由中国疾病预防控制中心辐射防护与核安全医学所组织2011年全国放射性核素γ能谱分析方法比对,样品为含有241Am、137Cs和60Co放射性核素的Al2O3粉末样品,要求参加比对的25家单位测量其中的241Am、137Cs和60Co的比活度。结果：本次比对共提交71个结果,参加单位全部采用高纯锗（HPGe）探测器。根据判定程序,对上报结果进行了判定与处理,23家合格,其中2家满足优秀条件,2家由于刻度源与测量仪器原因未能提交全部结果。整个比对合格率为92%,优秀率为8%。结论：经过比对绝大部分单位的整体检测能力得到了明显的提高。本次比对既检验了各单位分析放射性核素的水平,又进一步提高了利用γ能谱测量样品的能力。     

A new certified reference material (GBW10037) of vitamin B3 in infant formula

Concentration of vitamins in infant formula needs to be checked in order to ensure healthy growth and development of infants. A new certified reference material (CRM) of vitamin B₃ (nicotinamide) in infant formula (no. GBW10037) was developed by applying LC–IDMS (liquid chromatography–isotope dilution mass spectrometry) method and LC–UV (liquid chromatography–ultraviolet) method. The relative expanded uncertainty of nicotinamide was 5.6%. The methods were validated by an international intercomparison for determination of nicotinamide in the formula. In the intercomparison, the result by these methods approached the median, and the uncertainty was the smallest among all the participants. The new CRM of vitamin B₃ in infant formula is capable of validating analytical measurements of laboratories, for ensuring accuracy, traceability, reliability and comparability of analytical results from different laboratories.     

Analyzing spatial and temporal (222)Rn trends in Maine

Prolonged radon exposure has been linked to lung cancer. Cancer registry data indicates excess risk for age-adjusted lung cancer in Maine. Maine's mean residential radon activity exceeds the EPA maximum contaminant level (MCL). This paper describes the application of spatial autocorrelation methods to retrospective data as a means of analyzing radon activity in Maine. Retrospective air and well water radon activity data, sampled throughout Maine between 1993 and 2008, are standardized and geocoded for analysis. Three spatial autocorrelation algorithms-local Getis-Ord, local Moran, and spatial scan statistic-are used to identify spatial, temporal, and spatiotemporal radon activity clusters and/or outliers. Spatial clusters of high air- and well water-Rn activity are associated with Maine's Lucerne and Sebago granitic formations. Spatial clusters of low air- and well water-Rn activity are associated with Biddeford Granite and the metamorphic bedrock formation Silurian Ordovician Vassalboro. Space-time analysis indicates that most spatial clusters persist over the period of sampling. No significant temporal clusters are identified. Persistent spatial variations in radon may help to better understand and predict radon-related health risks associated with Maine residences.     

土壤中90Sr测量的实验室间比对结果

目的 检验参比单位土壤中⁹⁰Sr的分析能力,以提高各单位的检测水平和测量数据准确度。方法 组织全国辐射环境监测实验室开展土壤中⁹⁰Sr的分析能力比对。结果 参加本次比对有20个实验室,比对结果可以接受的占80%,不可以接受的占20%。结论 比对整体结果良好。但土壤中⁹⁰Sr的分析仍存在一些问题,需要进一步研究。     

Diagnosis of diabetes mellitus: limited use for portable blood-glucose measuring devices

In the Netherlands, guidelines for the diagnosis of diabetes mellitus are confusing and differ from the international guidelines. Capillary blood-glucose testing using a blood-glucose device is allowed used as a diagnostic tool, although this test is imprecise. The Dutch laboratories measure blood-glucose concentrations by a more precise accurate method, but sometimes measure glucose levels in capillary whole blood and sometimes in venous plasma. These results are not comparable, because the results of capillary measurements are lower than the plasma measurements. In daily practice, health-care professionals are using different methods and are often not aware of the differences in glucose values that may result. They do not realise that glucose devices and laboratory glucose measurements may differ and that capillary- and plasma-glucose values are not interchangeable. Uniformity within the Dutch laboratories with regard to the glucose measurements is urgently needed, as is revision of the Dutch guidelines concerning the diagnosis of diabetes mellitus. This should be based solely on venous plasma-glucose values determined in a laboratory. Portable blood-glucose devices should not be used as a diagnostic tool for diabetes mellitus. These should only be used for blood-glucose control monitoring during treatment or as a screening tool.     

Final results of the Austrian Radon Project

The Austrian Radon Project started in 1992 and ended in 2001. The Austrian Radon Project had two aims: firstly, finding areas of enhanced indoor radon concentration for future radon mitigations, and, secondly, defining areas with elevated radon risk where radon safe construction is necessary for new houses. The project was based on systematic indoor measurements in randomly selected houses using different types of detectors. Successful intercomparison tests were made in a radon chamber, but simultaneous measurements by different detectors normally used in homes deviated sometimes up to a factor of two. We have to assume that this results from manipulations of the detectors by the inhabitants. The mean radon concentration in Austrian homes was found to be 99 Bq m(-3). A radon potential was derived from the results of the measurements and the information received from questionnaires. This radon potential was defined as an expected radon concentration in a standard situation and characterizes the radon risk from ground sources with all the influences of different living situations eliminated. A mean radon potential was computed for every municipality and the information is displayed as a map. The uncertainty and the reliability of the classification of municipalities according to the radon potential are discussed in more detail and compared with results from Switzerland.     

Quality of HIV laboratory testing in Tanzania: a situation analysis

Tanzania is scaling up prevention, treatment, care and support of individuals affected with HIV. There is therefore a need for high quality and reliable HIV infection testing and AIDS staging. The objective of this study was to assess laboratories capacities of services in terms of HIV testing and quality control. A baseline survey was conducted from December 2004 to February 2005 in 12 laboratories which were conveniently selected to represent all the zones of Tanzania. The questionnaires comprised of questions on laboratory particulars, internal and external quality control for HIV testing and quality control of reagents. Source and level of customer satisfaction of HIV test kits supply was established. Of 12 laboratories, nine used rapid tests for screening and two used rapid tests for diagnosis. In the 12 laboratories, four used double ELISA and five used single ELISA and three did not use ELISA. Confirmatory tests observed were Western Blot in three laboratories, DNA PCR in two laboratories, CD4 counting in seven laboratories, and viral load in two laboratories. Although all laboratories conducted quality control (QC) of the HIV kits, only two laboratories had Standard Operating Procedures (SOPs). Internal and external quality control (EQC) was done at varied proportions with the highest frequency of 55.6% (5/9) for internal quality control (IQC) for rapid tests and EQC for ELISA, and the lowest frequency of 14.3% (1/ 7) for IQC for CD4 counting. None of the nine laboratories which conducted QC for reagents used for rapid tests and none of the five which performed IQC and EQC had SOPs. HIV kits were mainly procured by the Medical Store Department and most of laboratories were not satisfied with the delay in procurement procedures. Most of the laboratories used rapid tests only, while some used both rapid tests and ELISA method for HIV testing. In conclusion, the survey revealed inadequacy in Good Laboratory Practice and poor laboratory quality control process for HIV testing reagents, internal and external quality control.     

浙江省水质中砷汞检测能力验证计划结果分析

目的:为了提高实验室检测结果的准确性与可比性,以及检验机构的整体能力,识别实验室间存在的差异。方法:采用国际通用的稳健统计用"Z比分数"的统计方法对水中砷、汞的检测结果进行分析。结果:此次质控样品共发放至全省各相关的检验机构中心共189家实验室,其中砷检测结果满意的有137家,满意率为78.7%;汞检测结果满意的有100家,满意率为76.9%。结论:全省检验机构的汞、砷总体检测能力较高,部分实验室技术质量水平有待提高。     

安徽省饮用水中铅镉检测能力验证结果分析

摘要:目的　为了提高水质检测实验室检测结果的准确性与可比性以及检验机构的整体能力,识别水质检测实验室间存在的差异。方法　选用自制铅镉标准样品,分别采用F检验和∣x-y∣≤ 0.3σ准则法检验样本的均匀性和稳定性,采用稳健统计技术“Z比分数”的统计方法对饮用水中铅、镉的检测结果进行分析。结果　此次样品共发放至全省各相关的检测机构86家实验室,其中铅检测结果满意的有 77家,满意率为 89.5%（77/86）;镉检测结果满意的有62家,满意率为87.3%（62/71）。结论　全省水质检测实验室铅镉总体检测能力较高,部分实验室检测技术水平有待提高。     

Enhancing toxicity test performance by using a statistical criterion

Aquatic toxicity tests are laboratory experiments that measure the biological effect (e.g., growth, survival, reproduction) of effluents, receiving waters, or storm water on aquatic organisms. These toxicity tests must be performed using the best laboratory practices, and every effort must be made to enhance repeatability of the test method. We evaluated the generated reference toxicant test data for insurance of a level of quality assurance for tests over time within a laboratory and among laboratories. We recommend the reporting and evaluation of the percent minimum significant difference (PMSD) value for all toxicity test results. The minimum significant difference (MSD) represents the smallest difference between the control mean and a treatment mean that leads to the statistical rejection of the null hypothesis (i.e., no toxicity) at each concentration of the toxicity test dilution series. The MSD provides an indication of within-test variability, and smaller values of MSD are associated with increased power to detect a toxic effect. We recommend upper and lower PMSD bounds for each test method in order to minimize within-test variability and increase statistical power. To ensure that PMSD does not exceed an upper bound, testing laboratories may need to increase replication, decrease variability among replicates, or increase the control mean performance.     

Estimate of annual average radon concentration in the normal living area from short-term tests

Most residential radon guidelines refer to annual average radon concentration in the normal living area. However, decisions on whether a house needs mitigation are usually based on short term radon tests. Depending on where detectors are placed and when tests are performed, results of those measurements can differ significantly from the annual average radon concentration in the normal living area. We provide a practical method based on survey results in 5486 Canadian houses to estimate annual average radon levels from results of screening tests. The average ratio of radon concentration in the basement to that of the upper floors in a house is determined, and the average relative seasonal variations of radon levels in the basement and of the upper floors are identified. Based on these relative quantities, estimate factors are derived for four different combinations of detector location and the living area and tabulated for different calendar periods of radon testing. The annual average radon level can be estimated by multiplying the result of a short-term screening test with the appropriate estimate factor given in this study.     

An interlaboratory study on the use of steroid hormones in examining endocrine disruption

In recent years, there has been an increased use of the measurement of sex steroid hormone levels in the blood of animals exposed to chemicals as an indicator of reproductive impairment or an alteration in endocrine function. Although levels of hormones are often compared among animals and laboratories, there has been no study to examine the between-laboratory variability in actual steroid measurements. Therefore, we initiated a study with white sucker collected from a site receiving pulp mill effluent, previously documented as having reduced steroid levels, to address this issue. Samples of plasma and media from in vitro gonadal incubations were delivered to eight outside laboratories with the ability to measure steroid hormones. These laboratories ranged from well-established fish endocrine laboratories to wildlife toxicology laboratories, which have recently implemented the methods to measure steroid hormones. In this study, we have considered both the absolute measure of steroid content between laboratories as well as the ability to discriminate between reference and exposed populations as important criteria when evaluating the utility of these measures. Of the eight outside laboratories conducting the analyses, six detected identical site differences in circulating levels of testosterone and 17beta-estradiol to those documented by our Burlington laboratory (ON, Canada). However, the absolute value of the steroid hormones measured in the plasma varied significantly (plasma testosterone 0.6-23.1 ng/ml, 17beta-estradiol 77.6-1782.7 pg/ml) with coefficients of variation of 70.4% and 60.3% respectively. Similar results were demonstrated for the measurement of steroid hormones in media following in vitro gonadal incubation. Although there was a fair amount of variability in the absolute measure of steroid hormone levels, we would predict a far greater coherence of interlaboratory results through the sharing of reagents and the use of a common methodology between laboratories. These results are very promising, providing evidence for the inclusion of steroid hormones in monitoring endocrine disruption in wildlife species.     

2006年全国省级疾控中心食品中铅、砷含量实验室间比对结果分析

目的：为了提高实验室检测结果的准确性和可比性。方法：采用国际上通用的稳健统计,用“Z比分数”的统计方法对铅、砷的检测结果进行分析。结果：此次质控样品共发放至全国各省级疾控中心共31个实验室,其中有30个实验室按时提交了测定结果,占发送样品的96.8%。铅测定结果满意的实验室有24家,占80%;结果可疑的有5家,占16.7%;不满意结果的有1家,占3.3%。砷测定结果满意的实验室30家,占100%。结论：全国各省级疾病预防控制中心铅、砷总体检测能力较高,部分实验室技术质量水平有待提高。     

The measurement of activity-weighted size distributions of radon progeny: methods and laboratory intercomparison studies.

Over the past 5 y, there have been significant improvements in measurement of activity-weighted size distributions of airborne radon decay products. The modification of screen diffusion batteries to incorporate multiple screens of differing mesh number, called graded screen arrays, have permitted improved size resolution below 10 nm such that the size distributions can now be determined down to molecular sized activities (0.5 nm). In order to ascertain the utility and reliability of such systems, several intercomparison tests have been performed in a 2.4 m3 radon chamber in which particles of varying size have been produced by introducing SO2 and H2O along with the radon to the chamber. In April 1988, intercomparison studies were performed between direct measurements of the activity-weighted size distributions as measured by graded screen arrays and an indirect measurement of the distribution obtained by measuring the number size distribution with a differential mobility analyzer and multiplying by the theoretical attachment rate. Good agreement was obtained in these measurements. A second set of intercomparison studies among a number of groups with graded screen array systems was made in April 1989 with the objective of resolving spectral structure below 10 nm. Again, generally good agreement among the various groups was obtained although some differences were noted. It is thus concluded that such systems can be constructed and can be useful in making routine measurements of activity-weighted size distributions with reasonable confidence in the results obtained.