Asbestos In Soils Research Articles

Asbestos-Environment Pollution Characteristics and Health-Risk Assessment in Typical Asbestos-Mining Area.

Asbestos has been confirmed as a major pollutant in asbestos-mining areas that are located in western China. In general, asbestos-fibre dust will is released into the environment due to the effect of intensive industrial activities and improper environmental management, such that the health of residents in and around mining areas is jeopardised. A typical asbestos mining area served as an example in this study to analyse the content and fibre morphology of asbestos in soil and air samples in the mining area. The effects of asbestos pollution in and around the mining areas on human health were also assessed based on the U.S. Superfund Risk Assessment Framework in this study. As indicated by the results, different degrees of asbestos pollutions were present in the soil and air, and they were mainly concentrated in the mining area, the ore-dressing area, and the waste pile. The concentration of asbestos in the soil ranged from 0.3% to 91.92%, and the concentration of asbestos fibres in the air reached 0.008-0.145 f·cc-1. The results of the scanning-electron microscope (SEM) energy suggested that the asbestos was primarily strip-shaped, short columnar, and granular, and the asbestos morphology of the soils with higher degrees of pollution exhibited irregular strip-shaped fibre agglomeration. The excess lifetime cancer risk (ELCR) associated with the asbestos fibres in the air of the mining area was at an acceptable level (10-4-10-6), and 40.6% of the monitoring sites were subjected to unacceptable non-carcinogenic risks (HQ > 1). Moreover, the waste pile was the area with the highest non-carcinogenic risk, followed by the ore dressing area, a residential area, and a bare-land area in descending order. In the three scenarios of adult offices or residences in the mining area, adults' outdoor activities in the peripheral residence areas, and children's outdoor activities, the carcinogenic-and non-carcinogenic-risk-control values in the air reached 0.1438, 0.2225 and 0.1540 f·cc-1, and 0.0084, 0.0090 and 0.0090 f·cc-1, respectively. The results of this study will lay a scientific basis for the environmental management and governance of asbestos polluted sites in China.

Environmental Assessment of Friable Asbestos from Soil to Air Using the Releasable Asbestos Sampler (RAS).

The objectives of this study are to examine the feasibility of the releasable asbestos sampler (RAS) equipment for laboratory tests as an alternative to activity-based sampling (ABS), and to apply the equipment controlled by wind velocity and water contents in the field to asbestos-contaminated soils. Two asbestos-contaminated mines (the Jecheon mine and the Jongmin-ri mine) were selected. At each mine, 21 surface soils (0~15 cm) were sampled, the asbestos concentrations were analyzed, and then three representative sites, containing 0.25%, 0.50%, and 0.75% of asbestos in soils, were chosen to evaluate the amount of releasable asbestos by the modified RAS with wind velocity and water contents. The results showed that the levels of releasable asbestos from soil to air increased with higher wind velocities and lower water content. In addition, the application of risk assessment of releasable asbestos in the soils as an alternative to the activity-based sampling (ABS) method was established at each site, and an estimation of the excess lifetime cancer risk (ELCR) was also calculated. According to the calculation, the estimated ELCR values did not exceed the threshold value (1 × 10-4) in the Jecheon mine for all the soils, while some samples from the Jongmin-ri mine exceeded the threshold value. Therefore, proper remediation work is needed to control friable asbestos from soils to air in the vicinity of the mines.

Soil-pH and cement influence the weathering kinetics of chrysotile asbestos in soils and its hydroxyl radical yield

Chrysotile asbestos is a toxic and carcinogenic mineral that has been used in a variety of industrial and consumer applications. Much of the fiber- and cement-containing asbestos waste has ended up in terrestrial environments. Chrysotile weathering in soils and the potential for natural attenuation have, however, hardly been examined yet. Here we explored how soil properties influence the dissolution rate of chrysotile, the release of the carcinogenic metals chromium and nickel, and the hydroxyl radical (HO•) generation by chrysotile fibers. Chrysotile dissolution rates in soil suspensions decreased with increasing soil-pH and were lower than reported rates in soil-free systems. Dissolved organic carbon did not markedly accelerate dissolution at circumneutral pH, whereas cement mixed with soil inhibited dissolution because of its alkalinity. The HO•-yield of incubated fibers in non-amended soils eventually decreased by 60–75%. The decline was fastest in an acidic podzol soil, yet was followed by a small rebound. Cement amendment induced the largest HO•-yield reduction (∼90%), presumably due to surface coating of the fibers. Overall, this work demonstrates that the potential for natural attenuation of chrysotile asbestos in soils critically depends on soil chemical parameters and the presence of cement in association with the fibers.

Occurrence of asbestos in soils: state of the art

Occurrence of asbestos in soils: state of the art

Sampling, Analysis, and Risk Assessment for Asbestos and Other Mineral Fibers in Soil

ABSTRACT Asbestos may be present in soil as a natural occurrence or by contamination from asbestos-containing building materials, illegal dumping of asbestos, or other human activities. When trying to properly assess asbestos and other mineral fiber content in a sample by microscopy, soil is a problem matrix in all respects. Even defining the sample to be collected requires forethought and can greatly influence the final analytical result. Determining the sampling approach as well as the best sample preparation and analysis techniques are critical to obtaining accurate results in a metric that is useful to the end user. This article provides an overview of the various approaches that can be applied to assist those involved with asbestos in soil projects. There are many analytical techniques that can be applied for the determination of asbestos content in soil, including visual observation in the field, stereomicroscopy, polarized light microscopy, scanning electron microscopy, transmission electron microscopy, x-ray diffraction, and others. All of these techniques have their own inherent strengths and weaknesses. Fortunately all of the analysis options are complementary, and using multiple techniques can help to better characterize a sampling site and provide a more comprehensive assessment. Time and cost constraints will typically play a role in determining the final sampling and analysis plan.

Refinement of Sampling and Analysis Techniques for Asbestos in Soil

ABSTRACT Measuring the concentrations of asbestos in contaminated soils is challenging. Data are often highly variable. Variability in soil measurements has led to limitations in comparing results from sites nationally and difficulties in reproducing results, even from the same sites over time. The difficulties in collecting reproducible soil data limit the ability to extrapolate from concentrations in soil and compare to concentrations in air. This extrapolation is necessary if soil data are to be used in human health risk assessments. To address this substantial limitation of asbestos soil data, researchers from Environmental Protection Agency (EPA) regions and the National Exposure Research Laboratory are conducting a series of efforts to advance the use of data that are collected, processed, and analyzed using the most reproducible methods. These soil data, collected from a variety of sites across the country, will be compared to air data from activity-based sampling in an attempt to establish a quantitative relationship between asbestos soil concentrations and airborne fiber concentrations. This research plan summary provides an update on the EPA efforts under way and the challenges that lie ahead.

충남 서산 대로리 일대 토양 내 석면의 광물학적 특성

충남 서산 대로리 일대 토양 내 석면의 광물학적 특성

충청북도 제천시 폐석면광산 주변 토양에서 검출되는 각섬석의 크기 분포

본 연구는 석면형태와 비석면형태의 구분을 위하여 충청북도 제천시에 소재한 한 폐석면광산 지역의 토양 중 트레모라이트와 악티노라이트 섬유의 크기 특성을 파악하였다. 폐석면광산 주변지역의 토양과 트레모라이트 석면 암석을 채취하고, 투과전자현미경으로 길이 <TEX>$5{\mu}m$</TEX> 이상이며 길이대너비 비율이 3:1 이상인 섬유의 크기를 측정하여 알려진 석면형태와 비석면형태를 보이는 트레모라이트의 크기 분포와 비교하였다. 연구 결과 섬유의 너비는 기하평균으로 토양시료 <TEX>$1.2{\mu}m$</TEX>, 석면 암석 <TEX>$0.3-0.6{\mu}m$</TEX>, NIST 트레모라이트 <TEX>$1.3{\mu}m$</TEX>, HSL 트레모라이트 <TEX>$0.2{\mu}m$</TEX> 이었다. 길이대너비 비율은 기하평균으로 토양시료 7.3, 석면 암석 13.7-30.1, NIST 트레모라이트 7.2, HSL 트레모라이트 37.8 이었다. 토양시료는 알려진 석면형태의 트레모라이트 뿐만 아니라 비석면형태의 트레모라이트에 비해서도 가늘고 길이대너비 비율이 큰 섬유를 적게 함유하였다. 따라서 연구 대상 토양시료 중의 트레모라이트-악티노라이트는 전형적 석면형태로 분류할 수 없으며, 대부분은 광산 및 채석장으로부터 바람에 의해 비산된 석면으로 인한 오염의 결과가 아닌 것으로 추정된다. 토양 중 석면의 관리를 위해서 석면 오염 여부를 조사 시에는 감섬석의 크기 분포가 함께 고려되어야 한다. This study is for discrimination between asbestiform and non-asbestiform based on size characteristics of tremolite-actinolite fibers in soils from a closed asbestos mine, Jecheon, Chungcheongbuk-do, Korea. Soils and tremolite asbestos rocks were collected from a closed asbestos mine area. The dimensions of fibers with minimum <TEX>$5{\mu}m$</TEX> in length and 3:1 in aspect ratio were measured using transmission electron microscopy (TEM) and compared to the known tremolite populations ranging from asbestiform to non-asbestiform. The geometric means of width of soils, asbestos rocks and National Institute for Standard and Technology (NIST) and Health and Safety Laboratory (HSL) reference samples were <TEX>$1.2{\mu}m$</TEX>, <TEX>$0.3-0.6{\mu}m$</TEX>, <TEX>$1.3{\mu}m$</TEX> and <TEX>$0.2{\mu}m$</TEX>, respectively. The geometric means of aspect ratio of soils, asbestos rocks and NIST and HSL reference samples were 7.3, 13.7-30.1, 7.2 and 37.8, respectively. The population of tremolite-actinolite fibers from soils compared to known asbestiform and non-asbestiform tremolite was lack of thin and high aspect ratio fibers. Upper results suggest that tremolite-actinolite fibers in soils cannot be classified into a commercial grade asbestos. The tremolite-actinolite fibers do not mainly appear to be the result of contamination from distance asbestos sources by wind. For the management and control of asbestos in soils, size distributions of amphiboles should be incorporated into asbestos survey results of soils.

Development and In-situ Application of Asbestos Removal Equipment for Asbestos-contaminated Soils

The objective of this study is to develop removal equipments of fibrous materials including friable asbestos in soils. Asbestos removal equipment, was invented using artifical friability and its optimun working conditions were examined. Then, the suggested working conditions such as 200 rpm of rotation for brush, 3 m/s of inhale velocity and 0.1 m/s of moving equipment velocity were applied in the field. Soil samples were collected from various places including playground of elementary school, orchard and farmland and then analyzed with 20 retuning times in order to measure asbestos concentration before and after remediation. The collected asbestos from the soils by the developed equipment were 18.414 f/cc, 12.668 f/cc and 104.310 f/cc for playground, orchard and farmland respectively. Asbestos contents in soils were decreased from 1% to 0.5% with 50% removal effectiveness before and after soil remediation using the developed equipment. Additional facilities reducing soil water contents and disturbing the contaminated soil are suggested to improve the asbestos removal efficiency of the developed equipment.

Evaluation of a fluidized bed asbestos segregator preparation method for the analysis of low-levels of asbestos in soil and other solid media

The fluidized bed asbestos segregator (FBAS) is a sample preparation instrument that utilizes air elutriation to separate asbestos structures from heavier matrix particles and deposit these structures onto a filter which can then be analyzed by transmission electron microscopy (TEM) or other appropriate microscopic techniques. The performance of the FBAS preparation method was evaluated using a variety of performance evaluation (PE) standards that spanned different matrix materials (soil and vermiculite) and different types of asbestos (chrysotile and amphibole). Results for these PE standards show that there is an approximately linear relationship between the concentration of asbestos in the PE standard (as mass percent) and the mean concentration estimated by the TEM analysis following preparation by FBAS, expressed as asbestos structures captured on the filter per gram of test material (s g−1). Method detection limits achieved in these studies ranged from 0.002% to 0.005% by weight, which is approximately 100-times lower than the detection limits that are usually achieved using other analytical methods for asbestos in soil and other solid media. The FBAS unit is compact, fitting into a standard laboratory fume hood, and components of the unit are relatively easy to decontaminate or are disposable. The FBAS unit construction and operation costs are relatively low and sample throughput is high (up to 20 samples per day). Current research using the FBAS unit is ongoing and an inter-laboratory validation study is in progress.

석면 비산 장비를 이용한 토양 중 석면 비산 특성 및 위해성 평가

The objective of this study is to examine a releasable asbestos sampler developed for measuring friable asbestos from soil to air controlled by wind velocity and water contents. Asbestos contaminated soil with 3.75% at the Sinsuk-asbestos mine was sampled, air-dried and sieved to 100 mesh, then homogenized during 24 hours' agitation. Various wind velocities, 1 m/s, 2 m/s, 3 m/s, and 5 m/s, were applied to evaluate releasable characteristics of the releasable asbestos sampler. In addition, soils with 1.0%, 3.4%, 4.4%, 11.0%, 16.2%, and 20.0% of water contents were also examined the amount of friable asbestos by the releasable asbestos sampler. Collected soil and air samples were analyzed by polarized light microscopy (PLM) and phase contrast microscopy (PCM), respectively. Those contents were applied to calculate an excess life cancer risk (ELCR). This study also discussed the relationship with risk assessment by a weeding scenario of activity based sampling (ABS) and field applied releasable asbestos sampler. The result was shown that friability of asbestos in soil increased with wind velocity and decreased with water content. In comparison with ELCR results, over 10E-4 of cancer risk was found in condition on < 5% water content and > 3m/s wind velocity.

A Validated Approach for Assessing Exposure to Asbestos in Soil

A Validated Approach for Assessing Exposure to Asbestos in Soil

The health impact of nonoccupational exposure to asbestos: what do we know?

The objective of this study was to examine the epidemiological data that confirm the risks of pleural mesothelioma, lung cancer, and other respiratory damage associated with nonoccupational exposure to asbestos, in circumstances where exposure levels are usually lower than those found in the workplace: domestic and paraoccupational exposure to asbestos-containing material among people living with asbestos workers or near asbestos mines and manufacturing plants, environmental exposure from naturally occurring asbestos in soil, and nonoccupational exposure to asbestos-containing material in buildings. Studies concerning natural asbestos in the environment show that the exposure that begins at birth does not seem to affect the duration of the latency period, but the studies do not show whether early exposure increases susceptibility; they do not suggest that susceptibility differs according to sex. Solid evidence shows an increased risk of mesothelioma among people whose exposure comes from a paraoccupational or domestic source. The risk of mesothelioma associated with exposure as result of living near an industrial asbestos source (mines, mills, asbestos processing plants) is clearly confirmed. No solid epidemiological data currently justify any judgment about the health effects associated with passive exposure in buildings containing asbestos. Most of the studies on nonoccupational sources reported mainly amphibole exposure, but it cannot be ruled out that environmental exposure to chrysotile may also cause cancer. Nonoccupational exposure to asbestos may explain approximately 20% of the mesotheliomas in industrialized countries, but it is does not seem possible to estimate the number of lung cancers caused by these circumstances of exposure.

A Tiered Approach for the Assessment of the Human Health Risks of Asbestos in Soils

A tiered approach for the assessment of human health risks of soil contamination with asbestos has been developed. When in a specific tier the human health risk can not be rejected, the assessment in the following tier has to be performed. Because the risks of asbestos are caused by inhalation of asbestos fibers, the emission of fibers from soil to air is the determining factor. In Tier 0 of the tiered approach a generic soil quality standard is used. This Intervention Value is 100 mg/kg soil, dw asbestos equivalents (0.01% by weight), i.e. the sum of the concentration of chrysotile asbestos and ten times the concentration of amphibole asbestos, for bound (non friable) as well as for friable asbestos. Tiers 1 to 3 are site-specific. Tier 1 concerns a simple qualitative testing procedure, in which the potential or probability for emission of asbestos fibers from soil to air is assessed. In Tier 2 the respirable fraction in the soil and house dust, which relates to the potential site-specific exposure to humans, is determined and tested. Finally, when the risk can not be excluded, the concentration of asbestos fibers in outdoor and/or indoor air has to be measured and tested according to a standardized procedure, in Tier 3.

Mineralogical and microscopic evaluation of coarse taconite tailings from Minnesota taconite operations

Eighteen coarse taconite tailings samples were collected in 2000–2001 from five western Mesabi Range taconite (iron ore) operations located in northern Minnesota, i.e., EVTAC, Hibbing Taconite (Hibtac), USX Minntac, Ispat Inland (Minorca), and National Steel Pellet Company (NSPC), to test their physical, geological, chemical, and mineralogical properties [Zanko, L.M., Niles, H.B., Oreskovich, J.A., 2003. Properties and aggregate potential of coarse taconite tailings from five Minnesota taconite operations, Minnesota Department of Transportation, Local Road Research Board, St. Paul, MN, Report No. 2004-06 (also as Natural Resources Research Institute technical report, NRRI/TR-2003/44)]. The goal was to assemble a body of technical data that could be used to better assess the potential of using a crushed taconite mining byproduct like coarse tailings for more widespread construction aggregate purposes, primarily in roads and highways. An important part of the mineralogical assessment included X-ray diffraction (XRD) analyses and microscopic (polarized light microscopy, scanning electron microscopy, and transmission electron microscopy, i.e., PLM, SEM, and TEM, respectively) evaluation of the size and shape (morphological) characteristics of potentially respirable microscopic mineral particles and fragments. Quantitative mineralogy, based on XRD analyses, showed that the dominant mineral in all samples was quartz (55–60%), followed by much smaller amounts of iron oxides, carbonates, and silicates. Specialized microscopic analyses and testing performed by the RJ Lee Group, Monroeville, PA, on both pulverized (−200 mesh, or 0.075 mm) and as-is sample composites showed that no regulated asbestos minerals or amphibole minerals were detected in the western Mesabi Range samples. A small number (26) of non-asbestos and non-amphibole mineral cleavage fragments/mineral fibers were detected by SEM out of 1000 fields analyzed, but most were identified as minnesotaite and talc, silicate minerals common to the Biwabik Iron Formation. Amphibole minerals, absent in coarse tailings samples from the five western Mesabi Range taconite operations, were present in a single eastern Biwabik Iron Formation sample collected in 2003 for Lake County from the Cliffs Northshore operation in Silver Bay, MN. Importantly, the Superfund Method for the Determination of Releasable Asbestos in Soils and Bulk Materials [United States Environmental Protection Agency (USEPA), 1997. Superfund method for the determination of releasable asbestos in soils and bulk materials, EPA 540-R-97-028, U.S. Environmental Protection Agency, Washington], as modified by Berman and Kolk [Berman, D.W., Kolk, A.J., 2000. Modified elutriator method for the determination of asbestos in soils and bulk materials, Revision 1: Submitted to the U.S. Environmental Protection Agency, Region 8, May 23, 2000] failed to generate any protocol fibers, i.e., fibers longer than 5 μm and thinner than 0.5 μm, from either the western coarse tailings samples or the single eastern Biwabik Iron Formation sample. The combined findings suggest coarse tailings and other taconite mining byproducts should be treated with the same common sense safety and industrial hygiene approach practiced for all mineral-based materials that have the potential to generate respirable dust.

Asbestos in the natural environment

Chrysotile asbestos is a toxic and carcinogenic mineral that has been used in a variety of industrial and consumer applications. Much of the fiber- and cement-containing asbestos waste has ended up in terrestrial environments. Chrysotile weathering in soils and the potential for natural attenuation have, however, hardly been examined yet. Here we explored how soil properties influence the dissolution rate of chrysotile, the release of the carcinogenic metals chromium and nickel, and the hydroxyl radical (HO•) generation by chrysotile fibers. Chrysotile dissolution rates in soil suspensions decreased with increasing soil-pH and were lower than reported rates in soil-free systems. Dissolved organic carbon did not markedly accelerate dissolution at circumneutral pH, whereas cement mixed with soil inhibited dissolution because of its alkalinity. The HO•-yield of incubated fibers in non-amended soils eventually decreased by 60–75%. The decline was fastest in an acidic podzol soil, yet was followed by a small rebound. Cement amendment induced the largest HO•-yield reduction (∼90%), presumably due to surface coating of the fibers. Overall, this work demonstrates that the potential for natural attenuation of chrysotile asbestos in soils critically depends on soil chemical parameters and the presence of cement in association with the fibers.

Asbestos minerals in modern technology

In this review the main standard and novel analytical techniques and methods for sampling, sample preparation, detection and quantification of asbestos in soil and water are described, compared and discussed in terms of advantages and limitations. An overview of common analytical methods applied for identification and quantification of airborne asbestos is preliminary provided, as they have been widely studied, due to the well-known human pathologies related to fibers inhalation. Despite the presence of asbestos in soil and water may also constitute a health risk, it has been less investigated and regulated. For these environmental matrices, the methods adopted at international and national scale, covering the whole analytical process, from sampling to management of data, are reported in depth, highlighting their limitations like sensitivity, reliability and reproducibility. Finally, different promising novel/unconventional methods, that may substitute or support traditional ones for asbestos detection both in environmental and anthropic matrices, are presented and critically evaluated.