Assessment of Environmental and Domestic Exposure to Tremolite in New Caledonia

Trace element contamination of soil and dust by a New Caledonian ferronickel smelter: Dispersal, enrichment, and human health risk

Metallurgical industries remain a considerable source of trace element contamination and potential human health risk. Determination of sources is a key challenge. With respect to the South Pacific's largest and longest operating metallurgic smelter in Nouméa, New Caledonia, determining the environmental impact and subsequent human health risk associated with local ferronickel smelting is complicated by natural geological enrichment of Ni and Cr. This study applies a multi-method and multi-matrix approach to disentangle smelter emissions from geogenic sources and model the consequent health risk from industrial activity. Dust wipes (n = 108), roadside soil (n = 91), garden soil (n = 15) and household vacuum dust (n = 39) were assessed to explore geospatial trace element (As, Cr, Cu, Fe, Mn, Ni, Pb, S, V and Zn) variations across outdoor and indoor environments. Enrichment factors (EF) identified elevated levels of smelter-related trace elements: S (EF = 7), Ni (EF = 6) and Cr (EF = 4), as well as Zn (EF = 4). Smelter-related elements in soil and dust deposits were negatively correlated with distance from the facility. Similarity of Pb isotopic compositions between dust wipes, surface soil and vacuum dust indicated that potentially toxic trace elements are being tracked into homes. Non-carcinogenic health risk modelling (Hazard Index, HI) based on 15 spatial nodes across Nouméa revealed widespread exceedance of tolerable risk for children (0-2 years) for Ni (HI 1.3-15.8) and Mn (HI 0.6-1.8). Risk was greatest near the smelter and to the north-west, in the direction of prevailing wind. Given the elevated cancer risk documented in New Caledonia, disentanglement of environmental from industrial sources warrants further attention to ensure community health protection. Our analysis illustrates how the confounding effects from complex environmental factors can be distilled to improve the accuracy of point source apportionment to direct future mitigation strategies.

Mesothelioma in immigrants from Turkey: Genes have a minor role

OBJECTIVE

To examine the incidence and epidemiology of malignant mesothelioma in immigrants from Karain where there is an extraordinarily high incidence of mesothelioma, Cappadocia, Turkey, to Stockholm, Sweden, and their children over 20 years of age born in Stockholm, i.e. two genetically similar populations with and without erionite exposure.

METHODS

This survey was conducted as a retrospective cohort study. Standardized average annual mesothelioma incidence rates (AAMIRs) and mesothelioma standardized incidence ratio (mSIR) were calculated. Cox regression analysis was used to determine the importance of different factors related to mesothelioma risk.

RESULTS

The cohort consisted of 337 people, 203 of whom were born and/or lived in Karain before immigrating to Sweden (erionite-exposed), and 134 who were born in Stockholm (erionite-unexposed). There were 69 deaths, 42 (61%) due to mesothelioma, and two patients with the disease who were still alive. Of these 44 patients, 22 were men. All mesothelioma patients were in the erionite-exposed group. In the age group 30-49 years, mesothelioma developed in 11 of 38 (29%) with erionite exposure, while there were no cases among 86 persons in the non-exposed group. For men, the AAMIR was 253.9 per 100,000 persons in the whole cohort, and for women, it was 350.9. The mSIR was 71.9 for men and 393.1 for women. Exposure to erionite exceeding 20 years and age over 40 years were associated with increased mesothelioma risk.

CONCLUSION

Exposure to erionite is the leading cause of mesothelioma in Karain villagers, and genetic factors are probably of minor importance.

Asbestos knowledge and awareness level in central part of Anatolia

Background Asbestos-contaminated soil has been used by people for many years in the rural part of Anatolia. However, there is no program to control usage of asbestos in this region. Objective To determine the knowledge and awareness level about asbestos in a region where asbestos-related diseases are endemic due to environmental exposure to asbestos in the rural setting. Methods This study included 760 participants, recruited using non-probability sampling, who were classified into four groups according to residence and asbestos exposure type (urban, rural; asbestos-exposed, asbestos-unexposed). Asbestos knowledge and awareness was measured via the Asbestos Knowledge and Awareness Questionnaire (AKAQ). The cut-off value of questionnaire was determined by the K-means cluster analysis for sufficient and insufficient knowledge and awareness level. A multiple logistic regression analysis was performed to determine independent factors affecting sufficient knowledge and awareness of participants about asbestos. Results The median and mean score of the AKAQ in study group were 30 and 33.9, respectively. The urban asbestos-exposed group had a higher score than the urban asbestos-unexposed and both rural groups (p < 0.001). Factors affecting asbestos knowledge and awareness were education status (p = 0.035), asbestos exposure (p = 0.003) and living in the rural area (p = 0.005). Sufficient knowledge and awareness (score > 45) was higher among participants who had graduated from university and had asbestos exposure. Insufficient knowledge and awareness level was higher among participants living in rural areas. Conclusion In this region of Anatolia, knowledge and awareness level of asbestos was low among people at risk for environmental asbestos exposure. People should be aware of asbestos and its hazards by a well-designed training program and be monitored for asbestos-related diseases.

Environmental asbestos exposure and risk of mesothelioma

Mesothelioma is commonly considered an occupational disease occurring as a result of asbestos exposure in the workplace. Several avenues for environmental asbestos exposures have been described and may be associated with asbestos related disease, including mesothelioma. Worker take-home asbestos, or para-occupational exposure, has been well documented and is the most commonly reported pathway for asbestos exposure among mesothelioma cases that do not have history of occupational asbestos exposure. Observational studies have evaluated several communities with elevated mesothelioma incidence and environmental exposures attributed to local asbestos-related industries. Potential, but uncertain, mesothelioma risk also may be associated with general population asbestos exposure through contact with asbestos-containing commercial products, particularly housing materials that can be easily disturbed through normal activity. Finally, studies have described elevated mesothelioma incidence in several areas where populations are exposed to naturally occurring asbestos materials. These various environmental asbestos exposure pathways are poorly understood, and further studies should be pursued to evaluate their respective importance for population mesothelioma risk.

Sheep lymph-nodes as a biological indicator of environmental exposure to fluoro-edenite

A significantly increased incidence of pleural mesothelioma in Biancavilla (Sicily, Italy) has been attributed to exposure to fluoro-edenite (FE), a fibrous amphibole extracted from a local stone quarry. The lymph-nodes draining the pulmonary lobes of sheep grazing around the town were examined, to gain insights into fibre diffusion. The pasture areas of six sheep flocks lying about 3km from Biancavilla were located using the global positioning system. The cranial tracheobronchial and one middle mediastinal lymph-node as well as four lung tissue samples were collected from 10 animals from each flock and from 10 control sheep for light and scanning electron microscopy (SEM) examination. The lymph-nodes from exposed sheep were enlarged and exhibited signs of anthracosis. Histologically, especially at the paracortical level, they showed lymph-follicle hyperplasia with large reactive cores and several macrophages (coniophages) containing grey-brownish particulate interspersed with elements with a fibril structure, forming aggregates of varying dimensions (coniophage nodules). Similar findings were detected in some peribronchiolar areas of the lung parenchyma. SEM examination showed that FE fibres measured 8-41µm in length and 0.4-1.39µm in diameter in both lymph-nodes and lung tissue. Monitoring of FE fibres in sheep lymph-nodes using appropriate techniques can help set up environmental pollution surveillance.

Endemic malignant mesothelioma: exposure to erionite is more important than genetic factors

The village of Karain, Turkey, has the world's highest prevalence rate of malignant mesothelioma (MM). Environmental exposure to erionite is thought to cause the disease. However, it has also been suggested that the disease is mainly genetic. Residents in Karain village were traced from 1990 to 2006. Mineral samples were obtained from stones used in construction of their houses and any fibers present were identified. All women who had moved to the village as brides were traced and their cause of death determined. MM was the cause of death in 52 of 322 villagers, representing 50.5% of all deaths. Only 2 of 8 types of stones used in construction contained erionite, and these stones had been used almost exclusively in the mid-sections of the village, where MM was common. In houses not containing erionite, no cases of MM were observed. Sixty-four women came as brides to Karain from villages where erionite or asbestos is not found. Of the 16 women who have died, 11 (69%) died from MM. The extreme risk of MM in Karain is due to indoor exposure to erionite. The effect of genetic factors on mesothelioma development cannot be evaluated in this study, but is likely to be minor.

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.

Pleural plaques related to "take-home" exposure to asbestos: An international case series

Context:

While a large number of studies indicate the risks of high-level exposures to asbestos in the workplace setting, a relatively small number of studies describe the risk of pleural disease related to “take-home” asbestos brought into the household by workers exposed to asbestos. Consequently, the risk of pleural disease in family members of asbestos-exposed workers is likely underappreciated.

Case presentations:

Two families of siblings, one in Israel and one in the US, were evaluated because of their significant exposures to asbestos brought into the home by family members with heavy occupational exposures. Two of the four children of an asbestos cement debagger in Petach Tikvah, Israel and two children of a pipe lagger in a naval shipyard near Seattle, Washington, manifested benign pleural disease without parenchymal disease, despite having no occupational exposure to asbestos.

Discussion:

These cases illustrate that “take-home” asbestos exposure may lead to pleural disease at higher rates than commonly realized.

Relevance to clinical practice:

Providers should recognize that due to the potential for “take-home” exposures, asbestos-related disease in a patient may be a marker for disease in household contacts. Patients with family members heavily exposed to asbestos should be strongly encouraged to quit smoking in an effort to reduce any further carcinogenic exposures. Additionally, workplace control and regulation of asbestos use should be emphasized to protect both workers and their families.

10th Anniversary Critical Review: Naturally occurring asbestos

Asbestos is a naturally occurring mineral in the Earth's crust, and it is not confined to the historic and current asbestos mining areas, but rather quite commonly encountered in certain geological environments across the world. That diseases developed as a result of high exposures suffered by miners and asbestos products workers is incontrovertible. In addition, asbestos contamination as a result of past production and use is considered a serious issue where remediation is normally required. However, the risk to health of living on soil and rock where asbestos is encountered as a result of the natural occurrence of small quantities of asbestos minerals is less obvious. The picture becomes even less clear when the minerals are subject to intensive investigation, since our generally accepted definitions of asbestos are themselves put to the test. The discovery of asbestos or related minerals has consequences beyond any immediate risks to health, including profound effects on the value of and ability to use or enjoy property. This review examines the issue of naturally occurring asbestos (NOA) as it has developed in the United States of America and elsewhere, including some superficial insights into the reactions of communities to the presence of NOA. These responses to 'contamination' by nature deserve further in-depth study.

Monitoring and identification of airborne asbestos in unorganized sectors, India

Rajasthan state in India is credited to cater more than 90% of total production of asbestos in this country, of which around 60% is processed there in unorganized sectors including milling and manufacturing of asbestos-based products. Unorganized asbestos units particularly mills showed unhealthy occupational conditions, therefore industrial hygiene study was carried out focusing on the prevalence of asbestos fibres in air at work zone area of asbestos milling units. Fibre levels were in the range of 2.00-5.09f/cm(3) and 4.07-15.60f/cm(3) in unorganized asbestos mills of Rajasthan located at Beawer and Deogarh districts, respectively. Like asbestos concentration, fibre type and length are also vital factors in the health risk assessment of industrial workers. Phase contrast and polarized light microscopic study of asbestos fibres showed their amphibole nature registering about 90% as tremolite and rest as anthophyllite. Fibre length measured micrometrically were sub-grouped in <10microm, 11-20microm, 21-30microm and >30microm. About 30-40% fibres belonged to sub-group <10microm. It is concluded that unorganized asbestos mills bear poor industrial unhygienic conditions reflected specifically from their manyfold higher fibre concentrations than the Indian and International standards. Poor industrial unhygienic conditions are attributable to obsolete milling technology, lack of pollution control devices and escape from regulatory control.