Benzene (also commonly referred to as benzene) is an organic chemical that occurs in liquid and colorless form. Highly flammable, benzene at room temperature easily evaporates into the air (volatile), with a characteristic sweetish and aromatic odor: from this characteristic derives the name of the class of "aromatic" chemical compounds of which it is the progenitor. chemical structure, it consists of a hexagonal ring with 6 carbon atoms (due to its specific characteristics called aromatic ring) linked to 6 hydrogen atoms (its chemical formula is in fact C6H6).
Component of petroleum derivatives and crude oil (the one just extracted from wells and not yet processed) is present in the air practically everywhere due to:
- natural events (forest fires or gas leaks from volcanoes)
- human and industrial activities that use crude oil and its derivatives as fuel or for the production of lubricants, solvents and adhesives
- motor vehicle exhaust gases, fueled by petrol. In fact, benzene, together with other substances such as toluene and xylene, is added to unleaded petrol as an anti-knock agent in place of the previously used tetraethyl lead and eliminated for its toxic effects. Benzene makes up about 80% of total emissions into the air where, in a few days, it degrades by reacting with other compounds. Wind and rain, in turn, help to dilute and reduce the levels of benzene in the air. fall back and lay on the ground
Furthermore, benzene can also contaminate water due to the diffusion in the environment of substances derived from petroleum or due to the presence of harmful and illegal discharges produced by specific industrial plants (such as chemical industries or foundries).
Indoors (often referred to with the English word indoor), benzene can be emitted by:
- cigarette smoke
- domestic combustion due to the use of fireplaces, stoves, incense sticks, deodorants, room diffusers
- products used for the construction of buildings or for the finishing of the buildings themselves (paints, glues, adhesives, solvents)
- proximity to high traffic areas which can favor the penetration of the benzene present externally into the internal environments
- car parks, garages and underground garages which, especially if not ventilated, can have high concentrations of benzene in the air
Known for its toxicity, benzene has been classified by the International Agency for Research on Cancer (IARC) in group 1, among the substances with a sure ability to generate cancer (carcinogenicity) in man.Sources of exposure
Sources of exposure
The exposure of the population to benzene occurs mainly through the inhalation of:
- smoke active tobacco. Twice as much benzene concentrations were measured in the blood of people who smoke as in non-smokers.It has been calculated that smoking 20 cigarettes a day breathes (inhales) a greater quantity of benzene than those who frequent busy streets even for several hours a day
- polluted air present in outdoor environments (often referred to with the English word outdoor). Pollution is caused by motor vehicle exhaust and emissions from industries using fuels or chemical reagents that can emit benzene
- polluted air present in indoor environments (often referred to with the English word indoor). Pollution is determined by the existence of “sources” inside the buildings due to the release of benzene from building materials, furnishing elements, detergents and detergents, paints, glues, domestic combustion. A significant contribution is also due to passive tobacco smoke: in the homes where smokers live, in fact, the levels of benzene in the air are generally 10-20 micrograms per cubic meter, while in homes where no smokers live, the measured values are much lower than 10 micrograms per cubic meter
- polluted air present inside a vehicle (which is considered an environment indoor, heavily dependent on the quality of the outdoor air). In fact, driving in traffic causes, for the same time, an exposure of about 3-4 times higher than the environmental one
All these sources represent about 99% of the total exposure to benzene, so the contribution of water and food is very low (equal to 1%).
There is also the possibility of occupational exposure to benzene, for example, in chemical industries or foundries. Over time, the use of open industrial cycles in the production of consumer products (plastics, resins, pesticides, drugs, paints, adhesives and adhesives) has been very limited and today it is mainly used as a raw material in closed cycle processes. The Italian law, with the legislative decree n. 81 of 2008, protects the health of workers, establishing a maximum occupational exposure value of 3.25 milligrams per cubic meter.Effects on health
Effects on health
Acute benzene poisoning does not occur frequently. Mostly it is associated with inhaling high levels of benzene (much higher than those normally found in our environment). Inhaled benzene is readily absorbed into the lungs. It accumulates in adipose tissue, bone marrow, blood and liver, where it is metabolized to be eliminated in the urine and exhaled air. The effects of poisoning are:
- headache (headache)
- acceleration of the heartbeat (tachycardia)
- eye irritation
- death, in the most serious cases
The "targets" of acute benzene intoxication in the human body are, therefore, the nervous system and the heart.
Drinking alcohol increases the toxic effects of benzene on the human body.
On the other hand, periods of exposure of longer duration and low doses of benzene have effects on the blood (hematopoietic system). In fact, benzene causes toxicity to the bone marrow (producer of blood cells), causing a reduction in red and white blood cells with consequent anemia. It can also cause bleeding and effects on the immune system, thus increasing the risk of getting an infection.
Long-term exposures (chronic) benzene can also cause various forms of leukemia: acute myeloid leukemia, non-Hodgkin's lymphoma, chronic lymphocytic leukemia and multiple myeloma.
Health effects in children to date are believed to be similar to those seen in adults.
It is important to know that those who have had acute benzene poisoning have a higher risk of getting leukemia; it is therefore advisable to carry out the necessary blood tests frequently and regularly, and always under medical advice and supervision.Prevention and useful advice
Prevention and useful advice
Limiting people's exposure to benzene as much as possible can be considered the most important preventive action for the entire population and especially for workers at risk. Even quitting smoking, in addition to determining beneficial effects on health, can certainly contribute to limiting the risks associated with exposure to benzene both for the smoker and for people subject to passive smoking, especially in indoor environments (indoor) and by car.
To decrease the levels of benzene present in indoor environments (indoor), it is certainly a good idea:
- ventilate the houses preferably opening the windows further away from the busiest streets or, in any case, during the hours when traffic is less
- avoid staying and resting in environments where products such as incense sticks are used, deodorants and perfume diffusers, and in rooms where building materials or coatings have just been used
Vehicle traffic is an important source of exposure to benzene, even in the open air. Decreasing traffic levels, for example by walking or cycling for short trips or using public transport more, is certainly a correct choice. and a valid alternative to reduce exposure to benzene.
In our country, the concentration levels of benzene in outdoor environments are regularly checked by specific control units with the aim of following and verifying (to monitor) the air quality regularly.
The legislative decree n. 155 of 2010, indicates the limit value in 5 micrograms per cubic meter, to be calculated on an annual basis.
There are also European Union laws (such as EU regulation no. 305 of 2011) which regulate the trade in construction products, providing for a specific assessment in relation to the possible emission of some harmful substances, including benzene.
The World Health Organization (WHO) has estimated that by inhaling every day (indoor And outdoor) for a lifetime of 0.17 micrograms per cubic meter of benzene, you will have a 1 in 1 million risk of contracting a cancer disease.Bibliography
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