碱片-离子色谱法测定硫酸盐化速率影响因素

采用碱片-离子色谱法测定空气的硫酸盐化速率,方法在硫酸盐质量浓度为1.00~20.0 mg/L范围内线性良好(r≥0.999 0);碱片剪碎或不剪碎对空白碱片中硫酸根离子质量浓度的测定无明显影响,且高低两种加标浓度的回收率均在80.0%~120%之间;对于碱片实际样品,碱片剪碎更有利于硫酸根离子的快速溶出;随浸泡时间的延长,碱片中溶出的硫酸根离子质量浓度呈上升趋势,7 h硫酸根离子基本溶出完全,从保证结果质量和节省时间的角度考虑,确定最佳浸泡时间为3.5 h,建议碱片全部采取剪碎处理。     

Estimating Trophic State Proportions of a Regional Lake Population: Are Larger Samples Always Better?

During the summers of 1991–1994, the Environmental Monitoringand Assessment Program (EMAP) sampled 344 lakes throughout thenortheastern United States using a proportional stratified sampling design based on lake size. Approximately one-quarter ofthe 344 lakes were sampled each year (4 years) for totalphosphorus to determine the proportion (and associated95% confidence intervals) of the northeast lake population 1ha (11,076 ± 1,699 lakes) that was in oligotrophic,mesotrophic, eutrophic, or heupereutropic (4 classes) conditionaccording to the total phosphorus criteria of the North AmericaLake Manegement Society. Estimates for the second, third, andfourth yr were developed as cumulative of the previous yrsamples and the current yr samples for the northeast as a wholeand for each of its three ecoregions (4 regions). New confidence intervals were computed for each cumulative yrcondition estimate. This produced a total (4 years × 4classes × 4 regions) of 64 cumulative yr tropic conditionestimates. Confidence intervals for 21% of these estimates didnot shorten with increased sample size. This phenomena raisedquestions about the accuracy of estimates based on cumulativesampling procedures. We explain why and how the phenomenon comesabout with both straight random and proportional randomsampling. Further, we present an example of the effects thisphenomenon has on lake tropic state condition estimates in thenortheastern United States.     

环境空气中VOC_S在线监测法与SUMMA罐采样气相色谱-质谱法比对研究

定性比较了环境空气VOCs在线监测法和SUMMA罐采样GC-MS法的基本原理、检测化合物种类和适用范围,并对标样实验、日均浓度、小时浓度从统计学角度进行了定量比对.研究表明,VOCs在线监测法监测结果与实验室方法有较好可比性,可用于相关领域VOCs的连续监控.     

以江苏省河流湖泊为例探讨基于物种与面积关系确定大型底栖动物最适及高效采样量

以江苏省河流湖泊为研究对象,选取不同水体代表性点位,运用多生境采样法和形态学鉴定获取淡水大型底栖无脊椎动物的物种数及对应的采样面积,拟合实际结果的物种数与面积关系对数函数曲线。所研究采样量包括采样面积值、样方及样带数。研究发现,不同水体点位最适采样量面积为1.45~12.75 m²,样方及样带总数为6~16个,其要求十分耗时耗力。为解决这一问题,以物种数与面积关系对数函数的一阶导数曲线y≈1值为临界点,提出"高效采样量"概念,并提出3条采样原则供讨论。同时得到江苏地区高效采样量:涉水可过河流采样面积为1.36 m²,涉水不可过河流采样面积为1.5 m²,不可涉水河流和浅水湖泊采样面积为1.75 m²,均需采集4个样方,1个样带。     

Impacts of converting from leaded to unleaded gasoline on ambient lead concentrations in Jakarta metropolitan area

Total suspended particulate mater （TSP） concentrations were monitored for one year from July 2000 and for one year from April 2003 in Jakarta City. Thirteen elemental TSP components, aluminum （Al）, sodium （Na）, iron （Fe）, lead （Pb）, potassium （K）, zinc （Zn）, titanium （Ti）, manganese （Mn）, bromine （Br）, copper （Cu）, chromium （Cr）, nickel （Ni）, and vanadium （V） were analyzed by a sequential X-ray fluorescence spectrometer. Al, Na, Fe, K, and Pb were major components at most of the sampling locations in 2000. However, only Pb in 2003 dramatically decreased to one tenth. The phase-out of leaded gasoline began on July 1, 2001 in Jakarta City and lead content in gasoline decreased to one tenth, too. The decrease in Pb concentration was a result of the phase-out of leaded gasoline, as lead emissions mainly are exhaust gas from vehicles.     

淮南市可吸入颗粒物研究的若干建议

由于可吸入颗粒物严重影响大气环境质量和人体健康,对其研究愈来愈受到重视.我国北京、南京、重庆等城市对可吸入颗粒物均做过系统的研究,而目前在淮南市仍是空白.总结近年来可吸入颗粒物方面的研究成果,对淮南市在此方面的研究提出若干建议,供研究者参考.     

民用燃料燃烧排放PM2.5和PM10中碳组分排放因子对比

在实验室中模拟民用燃料在家庭炉灶中的燃烧,应用稀释通道系统采集颗粒物,获得玉米秸秆、薪柴、蜂窝煤和块煤四种常用民用燃料燃烧排放PM10,PM2.5及载带碳组分的排放因子.结果表明,民用燃料燃烧排放的颗粒物以细颗粒为主, PM2.5占PM10的70%~90%.颗粒物排放因子最大的为块煤,其PM2.5和PM10的排放因子分别为9.837和11.929g/kg,分别是蜂窝煤的12.6和13.7倍;玉米秸秆和薪柴PM2.5和PM10的排放因子稍低于块煤,为7.359~10.444g/kg.4种燃料燃烧OC排放因子块煤最高,其在PM2.5和PM10中分别为5.29和5.19g/kg.薪柴燃烧EC的排放因子最高,其在PM2.5和PM10 中的排放因子分别为1.065和1.126g/kg.块煤两种粒径上EC的排放因子略低于薪柴.蜂窝煤EC的排放因子最低,比薪柴低300倍左右,玉米秸秆EC的排放因子也要比薪柴低10倍左右.碳组分是块煤,秸秆,薪柴排放颗粒物的主要成分,其含量在40%~60%之间,该值比蜂窝煤高3倍.四种燃料对应的OC/EC比值差异很大,薪柴和块煤燃烧排放颗粒该值为3~6,秸秆和蜂窝煤燃烧排放颗粒其值高达30~50.     

The importance of chorionic villus sampling after first trimester diagnosis of cystic hygroma

The prenatal diagnosis of The Turner Syndrome is described at a menstrual age of 12 weeks. Detection of cystic hygroma was followed by vaginal chorionic villous sampling (CVS) which revealed a 45,X karyotype. Early documentation of fetal karyotype in the presence of a cystic hygroma is essential for accurate diagnosis and genetic counselling.     

A Comparison of Precipitation Sensors Used on the Wet-Only Collectors

The variability in performance of three precipitation sensor types, mounted on three identical wet-only collectors, has been compared for eight months at a single site. The catch efficiencies, determined from the sample volumes, are relatively high for these three apparatuses, since they exceed 89% on average. The recorded data of openings and closings of collector lids reveal that the highest losses of collection efficiency, observed for rainfalls of low intensity and low amount, are largely imputable to design and running characteristics of each sensor. Ionic compositions between the samples of these three collectors are relatively close, although significant differences are especially found for H⁺, Ca²⁺, Mg²⁺ and K⁺, suggesting that these apparatuses are differently exposed to the dry deposition of soil particles. The RS 85 sensor seems to be the most suitable one of the three, since it ensures a high catch efficiency for all rain types and tends to limit the exposures of funnel to the dry deposition.     

临安区域大气本底站CO_2浓度特征及其碳源汇变化研究

通过分析2006年8月～2009年7月临安区域大气本底站Flask瓶采样获得的CO2浓度特征,结合碳追踪模式的模拟结果,研究了长三角地区碳源汇变化对CO2浓度的影响.结果表明,临安区域大气本底站的CO2浓度分布在368.3×10-6～414.8×10-6之间,具有较明显的季节波动变化特征,冬季高、夏季低,浓度年较差接近...