CE03 - Interactions Humains-Environnement

Evaluating the asbestos risk in Sibate – ERASEd

ERASEd

Assessing the asbestos risk in Sibaté

To document original environmental exposure to asbestos and measure the knowledge of the risk.

The municipality of Sibaté is located in the department of Cundinamarca, south of Bogotá. Its total population is about 38,000 inhabitants. On the outskirts of this municipality there is an asbestos cement factory that has been manufacturing roofing for about 50 years. This factory has been (and continues to be) an important source of employment for the surrounding population. It seems clear that the exposures generated by this factory were multiple: occupational obviously, but certainly environmental and para-professional. Since December 2014, the local media have been reporting cases of asbestos-related diseases in this municipality: both in former workers of the plant and in people who simply lived nearby. The suspicions of an environmental contamination are real: several people have already died of mesothelioma, lung cancer and even asbestosis near this factory. Following interviews with relatives of victims, a strong suspicion of environmental pollution emerged: a probable massive pollution of the soil with asbestos.<br />It is the need to spatialize the «carcinogenic« hazard in an indirect way that constitutes the basis of ERASEd (objective 1). This need is coupled with the related need to measure the actual level of «social« impregnation of this risk at different scales (objective 2). These main objectives are broken down into specific tasks:<br />- to reconstitute the extension of the built-up area in the commune during the second part of the 20th century,<br />- to refine the danger zones with the help of a georadar,<br />- to mobilize the knowledge of the inhabitants in order to draw up a cartography of the filled sectors according to the residents,<br />- measure the knowledge of the risk within the different groups concerned,<br />- disseminate our results.

The localization of the danger zones will go through a series of three major works:
1) First, we will carry out an important compilation of topographic maps and cadastral maps available but - for the most part - not digitized at the Codazzi Institute of Bogota to trace the evolution of the urban zone at different times and to delimit a «safe« zone (built before the creation of the landfilled zones) and zones of potential danger.
2) We propose here to mobilize a geophysical technique : the georadar or ground penetrating radar (GPR). Ground penetrating radar is a technique that uses electromagnetic pulses to produce an image of the subsoil. The realization of punctual and regular measurements (defined with the help of a grid produced in a geographical information system) and/or continuous along determined transects will allow us to mark out this polluted fill.
3) We will mobilize the knowledge of the inhabitants in order to map the backfilled sectors according to their statements. The mobilization of inhabitants with a particular profile (at least 50 years old and having lived all their lives in Sibaté) will be ensured by the Colombian partners. Following the production of mental maps during workshops, we will produce a map of the frequency of mention - by the inhabitants - of the backfilled sectors.

The measurement of the knowledge of the risk within the different groups concerned will be done through :
1) A textual analysis of the Colombian press. The press reflects the existence of a debate, the emergence of an issue in the public square or the urban scene. Just like the different actors, the press privileges certain areas of threat, certain affected populations, certain specific actions that would show the existence of a risk even if it is not formulated. The objective of the research is thus to carry out a lexical analysis and to constitute a database georeferencing key words allowing to show the association which is made between the threat (in particular the asbestos), the risk or the sanitary crisis and places or urban territories.
2) A general population survey using «mental maps«. The mental maps of threats will aim to identify the major threats perceived by the actors.

Finally, two new related objectives have emerged:
1) mapping of asbestos cement roofs by using the RoofClassify plugin (under QGIS) using high-resolution Satellite imagery (Worldview 3),
2) the evaluation of the number of inhabitants who have come into direct contact with asbestos in the backfill by developing an agent-based model (platform GAMA).

Halfway through the ERASEd program, the preliminary mapping of asbestos-containing landfills (achieved through the use of available geographic information and the knowledge of local residents) now documents in an unprecedented manner an environmental contamination modality that has been little studied in the scientific literature. The atmospheric diffusion of asbestos fibers has, until now, mainly been studied from a source point generally industrial (factory or mine). Our work contributes to document the existence of «secondary« environmental exposure sources linked to industrial activity. This initial work may help explain the existence of particularly young cases of mesothelioma in the municipality of Sibaté.

The future perspectives correspond to the objectives to be fulfilled during the second part of the ERASEd program :
- to document the knowledge of asbestos risk in the general population in Sibaté,
- to map the asbestos cement roofs in the municipality
- to evaluate the populations in contact with asbestos at the time of the creation of the landfills,
- to communicate the results to the municipality in order to help it put in place a risk management plan.

Halfway through the project, 2 scientific communications were made as well as 2 conferences of scientific popularization (in English and in Spanish).
An article associating the French and Colombian partners was, moreover, published in the journal Environmental Research (Lysaniuk B., Cely-García M.F., Mazzeo A., Marsili D., Pasetto R., Comba P., Ramos-Bonilla J.P., Where are the landfilled zones? Use of historical geographic information and local spatial knowledge to determine the location of underground asbestos contamination in Sibaté (Colombia). Environmental Research, 2020, doi.org/10.1016/j.envres.20110182

ERASEd project - Assessing Asbestos Risk in Sibate

Asbestos is a generic term referring to silicates of fibrous texture all classified as "certain carcinogens" since 1977 by the International Agency for Research on Cancer (attached to the World Health Organization). In 2019, less than seventy countries have banned the use and marketing of products based on these fibers. In silence, Colombia remains a country producing and consuming asbestos when, at the same time, the main countries of the region ban, one after another, its use.

The municipality of Sibaté is located in the department of Cundinamarca, about twenty kilometers south of the Colombian capital Bogotá. Its total population is approximately 38,000. At the margins of this municipality is installed - for now fifty years - an asbestos-cement plant manufacturing both roofs and water pipes. This factory has been - and remains - an important source of employment for the surrounding populations. Despite this, it is clear that this plant generated various types of carcinogenic exposures: occupational obviously, but certainly environmental and domestic. It also seems - according to residents met by Colombian researchers - that part of the municipality was built on landfills provided by the plant. Since December 2014, the local media report cases of asbestos-related diseases in this municipality: both former factory workers and people just living nearby. Many people have already died of mesothelioma (known as asbestos cancer), lung cancer or even suffer from asbestosis near this plant. The rumor about the creation of the landfills, from materials supplied by the plant, was confirmed during a first phase carried out by partners of this project. Several soil samples have confirmed the presence of friable asbestos in the soil of Sibaté. While the risk is not yet socially constructed, the danger - i.e. the presence of asbestos at upper levels of the soil - is clear. By the constitution of a multidisciplinary and international team associating geographers (UMR PRODIG, France) and environmental engineering specialists (Universidad de Los Andes, Colombia), we propose to focus on two main objectives: to bound the landfills by mean of non-invasive methods; to measure risk awareness and identify major perceived threats by specific stakeholder groups in that community. We will implement several approaches to meet these objectives: analysis of land use changes, reconstruction of topographical changes, localization of a polluted stratum using geotechnical methods, participatory mapping and mental maps to locate elements “at risk”, textual analysis of the press, survey, and interviews.

The scientific scope of this project is protean: analysis of an unprecedented and undocumented situation, coherent mobilization of a set of mixed methods in a new context. The use of its results in the realization of an asbestos risk management plan would be the best valuation of this work.

Project coordination

Benjamin Lysaniuk (PRODIG)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

PRODIG PRODIG
Uniandes Universidad de Los Andes - Facultad de Ingenieria / Departamento de Ingenieria Civil y Ambiental

Help of the ANR 91,346 euros
Beginning and duration of the scientific project: October 2019 - 36 Months

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