Field-portable X-ray Fluorescence Analysis Research Articles

Lead exposure from households and school settings: influence of diet on blood lead levels.

Lead is known as a potent toxicant to human health, particularly for children while their central nervous system is developing. The aim of this study was to investigate the associations between blood lead levels (BLLs) and lead exposure in the children's diet, home, and school environments. A cross-sectional study was conducted with 153 children aged 1-4years, in four day care centers (DCCs), where a high prevalence of lead exposure was previously found. Lead determination by graphite furnace atomic absorption spectrometry (GF-AAS) was performed for venous blood, drinking water collected in the DCCs, and the 24-h diet (n = 64). Environmental screenings were conducted to evaluate lead concentrations in the tableware, buildings, and playground items in all DCCs and children's homes (n = 18) by using a field-portable X-ray fluorescence analyzer (FP-XRF). The BLL mean was 2.71μgdL-1. Means for 24-h lead concentrations in the diet were 1.61 and 2.24μgkg-1 of body weight (BW) in two DCCs. Lead concentrations in the water supply were lower than 2μgL-1. More than 11% of the DCCs' environmental analyses presented lead concentrations higher than or equal to 1mgcm-2, as defined by the USEPA. The diet was not found to be a risk factor for lead exposure, but households and DCC settings raised concern. Children's exposure to lead in DCC environments, where they spend the most part of their weekdays, appeared to be relevant. Graphical abstract ᅟ.

Use of a Field Portable X-Ray Fluorescence Analyzer for Environmental Exposure Assessment of a Neighborhood in Cairo, Egypt Adjacent to the Site of a Former Secondary Lead Smelter

The objectives of this study are to demonstrate for the first time the use of a field portable X-Ray Fluorescence Analyzer (XRF) in a multi-media environmental survey and to use the survey results to determine if residual lead from a once-active secondary lead smelter in Cairo, Egypt, still posed a health risk to the residents when comparing results with US EPA standards. Results were analyzed to determine if relationships among the variables indicated that there were residual impacts of the former smelter. Samples collected inside and near a total of 194 dwellings were analyzed. The mean floor dust lead loading was 7.48 μg lead/ft2. Almost 10% of the dwellings had at least one floor dust wipe sample that exceeded the United States Environmental Protection Agency's (USEPA) interior settled dust lead level of 40 μg lead/ft2. The median paint lead level was 0.04 mg lead/cm2. 17% of the dwellings had at least one interior paint sample that exceeded the USEPA standard of 1.0 mg lead/cm2. Mean soil lead concentration in the study area was 458 ppm and 91 ppm outside the study area. Four of nine composite soil samples exceeded the US EPA limit for bare soil in play areas. Lead concentrations in samples collected in locations outside the study area did not exceed the limit. The highest concentration was in the plot closest to the smelter and may represent residual impact from the former smelter. Statistically significant relationships were not detected between interior floor dust lead loading and either interior paint lead loading or exterior dust lead concentration. Thus, no significant exposure from the former smelter was indicated by these analyses. This may have resulted from the time elapsed since the closing of the smelter and/or the relatively low paint lead levels. Further study is needed in other areas of Egypt near former and active lead smelters. Elevated levels of mercury and arsenic detected in soil samples do not appear to be related to the smelter but warrant further study.

An assessment of field-portable X-ray fluorescence analysis for nickel and iron in laterite ore (New Caledonia)

The aim of this work was to determine how in-situ portable XRF (pXRF) analysis of ores (in this study, nickel and iron) may be consistent with data obtained from well-prepared samples analysed by conventional XRF methods, and to investigate potential sources of error in field measurements due to different chemical composition, moisture content and particle size. For this study, 201 samples of saprolite and laterite, sieved at 125 μm, were selected for their Ni and Fe contents (from 0.119 to 5.225 % Ni and from 4.7 to 37.2 % Fe for saprolite samples and from 0.38 to 2.94 % Ni and from 21.5 to 55.55 % Fe for laterite samples), compressed to make powder pellets and used to calibrate the pXRF. It is shown that for these two elements, pXRF can correlate extremely well (r 2 > 0.98, relative standard error <7 %) with conventional laboratory results when samples are suitably prepared (dried, pulverized and pelletized). Laboratory analysis of a few artificially wetted samples shows that both Ni and Fe estimated concentrations are directly proportional to moisture content. In the field, two experiments were conducted, one on an air-dried drill-core and the second directly on the pit face. The results indicate that because of sample heterogeneity, Ni and Fe contents are better estimated in the laterite layer than in the saprolite layer. Despite the many challenges associated with field conditions, pXRF can provide useful benefits for a number of applications in the mining sector.

X-ray diffraction and field portable X-ray fluorescence analysis and screening of soils: project design

AbstractThis paper presents the preliminary results of a study investigating the application of laboratory X-ray diffraction (XRD) and field portable X-ray fluorescence (XRF) analysis of soils as screening methods for forensic comparison and generalized provenancing. The study area is the Buffalo–Niagara metropolitan region in New York, a glacially draped area of the northeastern USA. For the initial stages of this study, soils are being collected from publicly accessible areas (parks, playgrounds, etc.) for mineralogical and elemental analysis. Initially, minimal sample preparation is being applied to create specimens. An investigation of the published literature reveals that there are a number of different suggested approaches for forensic application of XRD data, not all of which appear to be appropriate to the task at hand. The data being generated in this study are being used to build a reference set for comparison studies. In addition, two simulated forensic samples were collected to test the usefulness of XRD and XRF screening for determining possible regional source areas. For one sample this method was reasonably successful in identifying the general source area, while the results for the second sample were somewhat less satisfactory. In future additional sample handing and analysis protocols will be added.

Analysis of Beverages for Hg, As, Pb, and Cd with a Field Portable X-Ray Fluorescence Analyzer

Analytical capabilities of a handheld X-ray tube analyzer for analysis of beverages were evaluated. Sets of standard solutions for the elements Hg, As, Pb, and Cd were prepared with mass fractions up to 5000 mg/kg. A thirst quencher beverage was spiked with these elements up to mass fractions of 2500 mg/kg. Portions of these solutions were placed in standard X-ray fluorescence (XRF) cells, as well as the original container, and analyzed by using a field portable Innov-X alpha-6000s XRF tube-type analyzer. Uncorrected analyzer output usually yielded qualitative or semiquantitative results for the spiked beverages in X-ray cells. Average correction factors applied to analyzer output yielded accurate (in terms of z-scores) quantitative results for As above 20 mg/kg and qualitative or semiquantitative results for the other elements. Weighted quadratic fit calibrations provided accurate quantitative or semiquantitative results for all elements at levels above 20 mg/kg. The instrument's preset X-ray overlap correction algorithm worked well for the beverage spiked with all four elements. Spiked beverages analyzed through the wall of the original polyethylene terephthalate container produced accurate results within measurement uncertainties after application of "container wall" correction factors.

Determination of Bromine in Regulated Foods with a Field-Portable X-Ray Fluorescence Analyzer

A field-portable X-ray fluorescence analyzer, factory-calibrated for soil analysis, was used to measure bromine (Br) mass fractions in reference materials, flour, bakery products, malted barley, selected U.S. Food and Drug Administration Total Diet Study foods, and other food products. By using a calibration based on instrumental neutron activation analysis results for Br in reference materials, accurate quantitative results, confirmed by z-scores, could be obtained for mass fractions of about 2-55 mg/kg. These results confirmed accuracy of results (with larger uncertainties) obtained by applying a simple correction factor to the analyzer's output value. Results showed that very short analysis times (<2 min) would be needed to screen foods for Br content at regulatory levels for brominated and enriched brominated flour (24 mg/kg Br) and whole wheat flour and bakery products (36 mg/kg Br). Feasibility for determination of Br in malted barley at the regulatory level (75 mg/kg Br) was demonstrated, but quantitative results at that level could not be assured because no reference material with a suitable mass fraction was available. Br mass fractions for all foods tested were well below regulatory levels.

Two and three-dimensional quantification of lead contamination in alluvial soils of a historic mining area using field portable X-ray fluorescence (FPXRF) analysis

Two- and three-dimensional element distributions in soils and sediments may be important for the identification of geomorphic processes and the reconstruction of landscape evolution. Field portable X-ray fluorescence (FPXRF) analysers provide new possibilities in the detection and quantification of these element distributions. Results from a research project studying the heavy metal contamination of alluvial soils in a historic mining area at the Vils River near Freihung (Eastern Bavaria, Germany) exemplify how FPXRF can be applied to quantify two- and three dimensional element distributions in a floodplain environment on different scales. The results show that two-dimensional lead distribution of topsoil bulk samples (0 to 20 cm depth) clearly depends on the geomorphology of the study area. Concentrations of more than 1000 mg kg − 1 lead are restricted to the river floodplain. On a fluvial terrace lead concentrations of the topsoils are consistently far below 500 mg kg − 1 . Within the floodplain environment the lead contamination is not homogeneously distributed but forms areas of higher and lower lead concentrations. Micro fluvial structures (channels, ridges) are polluted on different levels, depending on the composition of the sediments or the water contents. This demonstrates that accurate assessments of floodplain metal contamination can only be made if small scale spatial variability has been considered. Analysis of the three-dimensional lead distribution shows that concentrations of the in situ measurements range from 500–6000 mg kg − 1 subject to depth, geomorphology and distance from the Vils River. Although the absolute contents are higher, three-dimensional lead distribution derived from laboratory measurements is identical with the plotted results of the in situ investigations. By calculating a correction factor for further investigations, water content as one of the main causes for differing results between field and laboratory analyses can be diminished. In situ FPXRF analysis as a robust technique could be used to investigate metal contamination on floodplain soils at a range of spatial scales. It allows detailed sampling, which can yield important information on the geomorphological controls on metal contamination in such environments.

The effectiveness of low-cost soil treatments to reduce soil and dust lead hazards: The Boston lead safe yards low cost lead in soil treatment, demonstration and evaluation

The Boston lead safe yards low cost lead in soil treatment, demonstration, and evaluation was developed to explore the viability and effectiveness of low-cost soil interventions to reduce exposure to soil lead hazards. Buildings that had been abated for lead to Massachusetts's deleading standards in the previous 5 yrs and met other program requirements were recruited for the evaluation. Following individual property assessments, yards were treated with application of ground coverings and ground barriers in 2000–2001 and followed up at 1 yr. The treatment cost ranged from $1095 to $5643 with an average of $2798. Soil lead levels at the building dripline, measured with a field-portable X-ray fluorescence analyzer (Niton Model 702 Spectrum Analyzer), dropped from 2021 PPM at baseline to 206 PPM at 1-yr follow-up. Most of the barrier treatments continued to block access to the lead-contaminated soil at 1 yr. At the follow-up, few properties with grass treatment had areas that were completely bare, but 28% had more than a small amount of treated areas bare. Treatments were effective in reducing entryway dust lead in the rear of the building if the residents reported they had maintained the yard treatments. Each additional yard work activity reported was predicted to lower 1-yr floor dust lead loading at the rear common/main and dwelling unit entries by about 20%. Each additional 100 ft 2 of yard treated was predicted to lower 1-yr floor dust loading at the rear dwelling unit entry by 19%. Treatments did not show a dust lead effect at 1 yr in the front entryway of the building, but the investigators believe that this may be due to the effect of resident cleaning overshadowing the treatment effect.

Portable lead analyzer to locate source of lead.

To investigate the sources of lead in the environment in children with elevated blood, with the help of a Field Portable X-Ray Fluorescence Analyzer. One hundred and seven school children were chosen for this study on a random basis, from Mangalore and Karnataka. Their blood lead was analyzed. Of the cases analyzed, 10 students whose blood lead level was more than 40 microg/dl were investigated using a field portable X-Ray Fluorescence Analyzer. This is the first time such a device has been available for this purpose in India. The 'likely' source of lead exposure could be determined in eight cases which was from the immediate environment of the children like 'lead-based' paint on surfaces in the house, on playground and other exterior equipment; lead storage batteries, contaminated dust and soil and other lead-containing substances. The use of an X-Ray Fluorescence Analyser appeared to be useful in determining the source of lead.

Results of field-portable X-ray fluorescence analysis of metal contaminants in soil and sediment

The US Environmental Protection Agency's Environmental Response Team (US EPA/ERT) has extensively used field-portable X-ray fluorescence (FPXRF) instruments for analyzing metals in soils and sediments at hazardous waste sites nationwide. The US EPA/ERT has used the Outokumpu Electronics Inc. (OEI) model X-MET 880 and the Spectrace Instruments model 9000 FPXRF analyzers. Instrument calibration methods, precision and detection limits are discussed. Both in-situ and prepared soil analysis are described. A statistical comparison of slopes (regression coefficients) is presented comparing AA/in-situ FPXRF and AA/prepared sample FPXRF regression results for data from a battery breakage and scrap metal site. The instruments' analytical capabilities are demonstrated by measurements of chemically analyzed samples from a variety of soil and waste matrices. Additionally, the US EPA's Quality Assurance/Quality Control (QA/QC) procedures for FPXRF analysis of soil and sediment samples is presented.

Statistical evaluation of field-portable X-ray fluorescence soil preparation methods

Traditional laboratory X-ray fluorescence (XRF) analysis has utilized sample preparation methods because the fixed nature of the instruments and absence of a surface probe precluded in-situ soil and sediment analysis. Currently, several field-portable XRF (FPXRF) instruments feature surface probes providing the option of in-situ soil and sediment analysis. In-situ FPXRF analysis can be a cost-effective near-real-time method to increase sampling densities due to the simplicity of the sample preparation. The following is a comprehensive statistical evaluation using current US EPA quality assurance guidelines for lead (Pb) data from a battery breakage site and zinc (Zn) and Pb data from a scrap metal site.