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首页> 外文学位 >Microenvironmental air and soil monitoring of contaminants: An evaluation of indoor and outdoor levels in Chihuahua City.
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Microenvironmental air and soil monitoring of contaminants: An evaluation of indoor and outdoor levels in Chihuahua City.

机译：污染物的微环境空气和土壤监测：对吉娃娃市室内和室外水平的评估。

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摘要

Like most of the cities around the world Chihuahua City suffers atmospheric and soil pollution. This is a problem that requires immediate attention from both public authorities and the scientific community. Although it is known that high levels of heavy metals are present in the airborne particulate matter, soil and dust in many urban regions, the information about personal exposure to these pollutants in Chihuahua City is nonexistent. This study focuses on the analysis and characterization of lead and arsenic in the airborne and soil particulate matter present in the interiors of households and their surrounding outdoor environments in the southern part of Chihuahua City. The sampling area chosen for this study was located in the southern part of Chihuahua City. An atmospheric sampling point selected by the Centro de Investigacion en Materiales Avanzados (CIMAV) was selected as a geographical center, with a 2 km radius forming the sampling area. The households selected for analyses were located on Lombardo Toledano Street, a high-traffic street. The main objectives of this study were to establish the maximum exposure level in outdoor and indoor environments for particulate matter less than 10 mum (PM 10), Pb, and As, to determine the background level of Chihuahua City for these same elements, to determine the isotopic ratios of Pb206 and Pb207 in the indoor and outdoor atmospheric samples, and to verify if the source of the pollution is from anthropogenic and/or natural sources. Additionally, a comparison of the analytical data from X-ray fluorescence (XRF) versus the analytical data from inductively coupled plasma with optical emission spectroscopy (ICP-OES) was conducted. The comparison of these techniques was based on sample preparation, speed of analysis, and accuracy of results. In the case of sample preparation, two extraction techniques were performed for a comparison of the extraction/leaching of Pb and As from the samples. These microwave-assisted extraction techniques used either concentrated nitric acid (HNO3) or aqua regia (a mixture of HNO3 and HCl, in 1:4 ratio) for elemental extraction. Statistical tools such as F-test, paired-data test, t-test and ANOVA were used to compare the analytical results between ICP-OES and XRF and the indoor/outdoor sampling study.;This study concluded that no statistical differences existed between the indoor and outdoor levels in the studied households for Pb and As concentrations. The results also showed that the most important sources of PM10 and Pb in the indoor environment were the transport and resuspension of external dust. The result further indicated that the inorganic As is associated with the fine particulate matter and is for the most part naturally occurring. In general the hypothesis that the exposure to environmental particulate matter, Pb and As is the same for indoor and outdoor environments can be accepted for the majority of the sampling houses. The isotopic ratios for the indoor samples were somewhat larger than the corresponding outdoor isotopic Pb sample ratios, reaching background levels from several regions around the world. The outdoor Pb isotopic ratios are similar to those found in the polluted-zones from smelting activities. The digestion of soil using HNO3 and aqua regia did not affect the extraction of Pb and As. The analytical techniques XRF and ICP-OES produced similar results for the determination of As in soil samples. However, these techniques produced different results for Pb determinations. These differences were, more than likely, associated to the digestion/extraction methodology. XRF techniques can successfully substitute other analytical techniques such as ICP-OES in the quantification of some trace elements in soil samples.
机译：像世界上大多数城市一样，吉娃娃市也遭受着大气和土壤污染。这个问题需要公共当局和科学界立即关注。尽管众所周知，许多城市地区的空气中颗粒物，土壤和尘埃中都含有大量的重金属，但在奇瓦瓦市尚没有有关个人接触这些污染物的信息。这项研究的重点是分析和表征奇瓦瓦州南部家庭内部及其周围室外环境中存在的空气和土壤颗粒物中的铅和砷。本研究选择的采样区域位于奇瓦瓦市的南部。由材料研究中心（CIMAV）选择的大气采样点被选为地理中心，半径为2 km。选定进行分析的住户位于人流密集的街道隆巴多·托莱达诺街上。这项研究的主要目的是确定室外和室内环境中小于10微米（PM 10），Pb和As的颗粒物的最大暴露水平，以确定这些相同元素的奇瓦瓦州背景水平，以确定室内和室外大气样品中Pb206和Pb207的同位素比，并验证污染源是否来自人为和/或自然来源。另外，对来自X射线荧光（XRF）的分析数据与来自具有光发射光谱法（ICP-OES）的电感耦合等离子体的分析数据进行了比较。这些技术的比较基于样品制备，分析速度和结果准确性。在样品制备的情况下，进行了两种萃取技术，用于比较样品中铅和砷的萃取/浸出。这些微波辅助萃取技术使用浓硝酸（HNO3）或王水（HNO3和HCl的混合物，以1：4的比例）进行元素萃取。使用F检验，配对数据检验，t检验和ANOVA等统计工具比较ICP-OES和XRF与室内/室外采样研究之间的分析结果。室内和室外的铅和砷浓度水平。结果还表明，室内环境中PM10和Pb的最重要来源是外部灰尘的运输和再悬浮。结果进一步表明，无机As与细颗粒物质有关，并且大部分是天然存在的。通常，大多数采样室都可以接受这样的假设，即室内和室外环境对环境颗粒物Pb和As的暴露相同。室内样品的同位素比值比相应的室外同位素Pb样品比值稍大，达到了世界上几个地区的背景水平。室外铅同位素比值与冶炼活动在污染区发现的比率相似。用硝酸和王水消化土壤不会影响铅和砷的提取。 XRF和ICP-OES分析技术在测定土壤样品中的As时产生了相似的结果。但是，这些技术对于Pb的测定产生了不同的结果。这些差异很可能与消化/提取方法有关。 XRF技术可以成功地替代其他分析技术，例如ICP-OES，以定量分析土壤样品中的某些微量元素。

著录项

  • 作者

    Delgado-Rios, Marcos.;

  • 作者单位

    The University of Texas at El Paso.;

  • 授予单位 The University of Texas at El Paso.;
  • 学科 Atmospheric Sciences.;Environmental Sciences.
  • 学位 Ph.D.
  • 年度 2007
  • 页码 109 p.
  • 总页数 109
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 语言学;
  • 关键词

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