Asbestos and Health Risks
Asbestos is a bundle of fibres that occur naturally as a group of minerals. These specific fibres can be found in rocks and soils in almost every part of the world (Stayner et al., 2013). Asbestos consists mostly out of silicon and oxygen. However, asbestos contains also other elements. Asbestos can be ordered in two separate groups:
– Amphibole asbestos fibres are looking like needles. Within this group of asbestos, there are several subgroups such as amosite (brown asbestos), tremolite, actinolite, crocidolite (blue asbestos) and anthophyllite (Yano et al., 2001).
– Chrysotile asbestos, which is labelled as white asbestos, is one of the most common types of asbestos, especially in industrial applications and practices. Chrysotile asbestos fibres are wrapped around themselves in a spiral form. This is the reason why this type is also called curly or serpentine asbestos (Yano et al., 2001).
These types, described above, are both connected to several different clinical health effects.
Asbestos fibres are very helpful in several construction practices. Asbestos is strong, resistant to many chemicals and heat and it does not conduct electricity. Therefore, asbestos has been used in most buildings, roads and other industrial structures. For example, asbestos has been used to create cement textiles since the industrial revolution (Mai, 1980). This paper assesses the health effects of (diffusive) asbestos in roads and therefore these cement textiles are useful to assess too.
In the first half of the 20th century, there became to be a growing amount of evidence that proved that breathing the substance of asbestos caused harm to the lungs. Because of a lack of evidence at that time, exposure to asbestos in workplaces, for example, was not regulated. In England, in the 1930s, there were institutions that were taking steps towards the protection of people’s exposure to asbestos. However, during World War II, a large number of people was again exposed to very high levels of asbestos (Hillerdal, 2004).
Asbestos-related cancers were observed more and more during the second half of the 20th century. As a result of this, particular measures were taken to decrease people’s exposure to asbestos. This included particular exposure laws and standards that outlawed the use of asbestos in construction materials. Due to the upcoming laws and regulations among asbestos, there has been a large decrease in importing and using asbestos in construction practices in the Western-World since the 1970s, e.g. Western-Europe and the United States. Considering this, the exposure to asbestos in these parts of the world has decreased. Asbestos has been totally banned in the European Union since 2005 (Hillerdal, 2004). However, total removal of asbestos in existing buildings was not necessary. Yet, asbestos is still used in other parts of this world.
How is an asbestos exposition to people positioned?
People can be exposed in different ways:
– Swallowing asbestos: This is possible when people eat or take in contaminated substances. Water that flows through pipes which consist of asbestos is an example (Selikoff, 1968).
– Inhaling asbestos: However, most exposures come from the inhalation of asbestos fibres in the air. In this paper’s case, this can occur because of the diffusion of asbestos over the area near the roads for example. These fibres stay in the air over a very long period. Also, weather events can have an effect on the diffusion of these fibres (Selikoff, 1968).
Many people around the world are being exposed to relatively low levels of asbestos because it occurs naturally. An example of naturally occurring asbestos is because of the erosion of asbestos-containing rocks. In some areas, asbestos is also present in water and, as mentioned, in the air (Malcolm Harrington, 1978).
Asbestos and different cancers
Many people are stating that asbestos is causing cancer but how do we know this? Researches are using two different approaches to check whether asbestos is indeed causing cancer:
– Lab studies: In these kinds of studies animals are exposed to asbestos to see if this is causing cancer or other health-related problems. It is also possible to expose normal cells in a lab to asbestos to see if it causes the same changes as it does in cancer cells. It is always difficult to assess whether the same changes occur to humans, but it is a good measurement to check whether if it can possibly have effects on human health (NBCC, 2013).
– Studies in people: The other kind of studies looks at cancer rates in different groups of people. We can also call this cohort studies. In this kind of studies, there will be a comparison between the rate in a group which is exposed to asbestos and the rate in a group which is not exposed to asbestos. The outcome of these studies is not 100% certain because other factors in the groups can also have an effect (NBCC, 2013).
In most of the cases, one of the two cases is not enough. Therefore, in most studies are both study approaches being used to figure out if asbestos is causing cancer,
Evidence from both studies has indeed resulted in the fact that asbestos is increasing the risk for some types of cancer.
When people are inhaling asbestos fibres they can become stuck or these fibres can stick to mucus in the throat, trachea (windpipe) or bronchi (the breathing tubes in the lungs). They can also be coughed up and cleared out of the body. However, some of these fibres reach ends of the airways in the lungs or penetrate into the outer lines of the lungs, called the pleura. These fibres can eventually cause particular cancers such as mesothelioma.
Lung cancer
The inhalation of asbestos fibres is strongly associated with an increased risk of lung cancer. This risk is seen with all forms of asbestos. There are no particular safe types of asbestos in respect to lung cancer. Generally speaking, the larger the exposure to asbestos, the higher the risk of lung cancer. Most cases of lung cancer occur 15 years after the people’s first exposure to asbestos. Of course, there are factors that can speed up developing cancer such as smoking (Saracci, 1977).
Mesothelioma
This form of cancer is relatively rare. It affects the upper lining of some organs in the abdomen and the chest. This form of cancer is, obviously, closely linked with the exposure to asbestos. All forms of asbestos are able to cause this cancer. However, amphibole asbestos is causing it at lower levels than chrysotile asbestos (Røe & Stella, 2015).
The risk of getting mesothelioma increases with the amount of people’s exposure to asbestos. There is no safe level of asbestos in respect to the development of mesothelioma in human bodies (Røe & Stella, 2015).
This type of cancer takes a relatively long time to develop within a body. The time between first exposure and diagnosis is around 30 years. Unfortunately, the risk of getting mesothelioma is not dropping with the time after exposure. The risk is lifelong. The risk of getting mesothelioma is not increased due to smoking (Røe & Stella, 2015).
Other health problems
Besides the different cancers, mentioned above, there are also other health problems related to asbestos exposure. An example is a lung disease called asbestosis. When people are breathing in high levels of asbestosis, some of the fibres can become stuck in deep parts of the lungs. Due to this, it can be hard to breathe for these people. The average symptoms of asbestosis are for example a chronic cough and shortness of breath.
This illness will become noticeable after 10 to 20 years after asbestos exposure. Asbestosis can get worse over time, however, some people will actually feel particular symptoms and some people are not. For this illness no positive treatment is available.