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What methodologies exist in relation to environmental monitoring of asbestos?

Among these analytical techniques, microscopy is the most important tool used for the detection of fibrous morphology. For the counting of airborne fibers, microscopic techniques such as phase contrast microscopy (PCM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) are widely used. For the analysis of bulk asbestos such as asbestos in commercial products and building materials, polarized light microscopy (PLM), TEM and SEM are generally used. As non-microscopic techniques, X-ray diffraction (XRD) and differential thermal analysis (DTA) have also been adopted in several standard methods.

Different techniques have their own strong and weak points and different methods have their own applications. Therefore, care should be taken to select and apply a standard method. The following present a review of existing standard testing methods related to asbestos in air or bulk materials for the monitoring of asbestos in occupational settings (not presented).

Are asbestos substitutes available?

Considerable effort has been devoted to finding alternative fibers or minerals to replace asbestos fibers in their applications. Such efforts have been motivated by various reasons, typically, availability and cost, and more recently, health and liability concerns. The substitution of asbestos fibers by other types of fibers or minerals, must, in principle, comply with three types of criteria:

  • the technical feasibility of the substitution;
  • the gain in the safety of the asbestos-free product relative to the asbestos-containing product; and
  • the availability of the substitute and its comparative cost (from USGS Asbestos).

It is important to know that safer substitutes for asbestos products of all kinds have become increasingly available. These include fiber-cement products using combinations of local vegetable fibers and synthetic fibers, as well as other products that serve the same purposes. The WHO is actively involved in evaluating alternatives (from WBG good practice note).

What international legislation and regulations exist on the use of asbestos?

  1. The International Labour Organization (ILO) and the World Health Organization (WHO): Outline for the Development of National Programs for the Elimination of Asbestos-related Diseases (NPEAD), 2007
  2. WHO: Elimination of Asbestos-related Diseases, 2006
  3. ILO: Resolution concerning asbestos, 2006
  4. The United Nations Environmental Program (UNEP): Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal, 1989
  5. ILO: Convention concerning Safety in the Use of Asbestos, 1986 (No.162) and Recommendation concerning Safety in the Use of Asbestos, 1986 (No.172)
  6. UNEP and the Food Agriculture Organization (FAO): Rotterdam Convention on the Prior Informed Consent (PIC) Procedure for Certain Hazardous Chemicals and Pesticides in International Trade
  7. The European Parliament and the Council of the European Union: Council Directive on the Protection of Workers from the Risks related to Exposure to Asbestos at Work, 1983

Asbestos-related diseases

What is asbestosis?

What is the differential diagnosis for asbestosis?

What is asbestos related lung cancer?

What is pleural mesothelioma?

Mesothelioma is a malignancy located in the pleura, the peritoneum, the pericardium and the tunica vaginalis, all of which is normally lined by mesothelial cells.

In most mesothelioma cases, diffuse spread along the cavity is a characteristic feature. In the case of pleura, it is supposed that there are small nodules in the parietal pleura at the initial stage and immediately tumor begins to spread along the pleural surface, and as a result, diffuse pleural thickening is induced accompanied by adhesion between the parietal and visceral pleura. Finally, mesothelioma encloses the lung parenchyma, which is a classical gross feature of mesothelioma.

Occasionally (probably a few percent) mesothelioma forms a localized tumor with no diffuse spread pattern. Mesothelioma chiefly extends in the pleural cavity, however, sometimes it invades mainly to the chest wall, and as a result, it resembles a chest wall tumor. Although unusual, it is difficult to differentiate mesothelioma based on gross features, because the possibility that the tumor derives from chest wall (soft tissue or bone) or lung cannot be excluded.

In the case of peritoneum, most mesothelioma cases show diffuse thickening of the peritoneum or disseminated small nodules in the peritoneum. Rarely it may be noticed as a large nodule.

What is benign pleural effusion?

What is diffuse pleural thickening?

There are three categories as to the origin of diffuse pleural thickening caused by asbestos exposure: Asbestosis extends from the visceral pleura to the parietal pleura, benign asbestos pleural effusion is involved as a preceding lesion, and neither asbestosis nor benign asbestos pleural effusion is the origin.

What is pleural plaque (pleural thickening)?

What are the histological features of mesothelioma?

Why is the pathological diagnosis of mesothelioma, especially in developing countries, rather difficult?

When a small amount of pleurisy or ascites is found clinically with no significant thickening of pleura or peritoneum, the diagnosis of mesothelioma is very difficult. If the biopsy specimen consists of a small tissue sample, its pathological diagnosis is limited. A comprehensive judgement is warranted, including clinical examination, CT imaging as well as pathological findings, which in combination, contribute to an accurate diagnosis of mesothelioma.

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