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Intoxications from organic solvents

How do organic solvents work?

How do organic solvents work?

In this short video we illustrate how organic solvents work. Organic solvents dissolve fat. Here we watch two dishes. One contains water, the other contains white spirit. White spirit is a mixture of organic solvents which for instance is used in paint. When oil is added to the water, you see that the oil gathers in bubbles at the top, and the fat does not dissolve in the water. When oil is added to the white spirit, the oil immediately disappears, as it dissolves into the white spirit. This is how organic solvents work – they dissolve fat. This is relevant for humans because our nervous system is normally protected by fat tissue. The organic solvents remove this protection and harm the nerves and the brain.

Organic solvents and health effects

In the video above, one fantastic quality of organic solvents is illustrated: These substances dissolve fat easily, and can therefore be used to remove oil or grease, as for cleaning purposes. Water does not have this quality, and the fat remains as a bubble on the top of the water surface.

Another great quality of organic solvents, which we cannot see, is that they evaporate quickly in the air. This means that they disappear after they have done their job. For instance when we are painting a wall, we may use an organic solvent based paint. This paint consists of pigments dissolved in organic solvents. The solvents make it possible to put the paint up on the wall. With its fantastic qualities, the solvents disappear, they evaporate easily, and the color is back, stuck on the wall as we want it to be.

However, these two qualities of the organic solvents make them dangerous to human beings. By the evaporation, we inhale the solvents easily, and become exposed to them. We inhale the organic solvents. From the lungs, the organic solvents are transferred to the blood, and the blood transports organic solvents to different parts of the body. Organic solvents can also be absorbed from the skin, but this exposure uptake is normally rather small. The quality of dissolving fat makes it possible for organic solvents to reach parts of the body which normally are protected from chemicals. Parts of the nervous system, for instance, are normally protected by fat tissue and a special protection called the “blood brain barrier”. This is a barrier that separates the circulating blood from the fluid from the brain, formed by brain endothelial cells. Due to this protection, very few substances can come in contact with the nervous system. Organic solvents are exceptions. They enter the fat protection and they cross the blood-brain barrier. The substances can affect our nervous system in a very negative way. Very few chemicals can influence the brain and nervous system like this; organic solvents are dangerous exceptions.

However, be aware that the organic solvents are not stored in the body for very long periods. They may disappear from the body after minutes or hours. A few of these substances stay in the body longer, if the exposure is high, but not more than 1-2 weeks. The organic solvents are excreted from the body by the exhaled air or via urine/faeces.

Types of organic solvents

Organic solvents (most often called “solvents”) are a large group of chemical compounds, mainly hydrocarbon compounds. Workers, who can be exposed to organic solvents at work, are for instance those producing products that contain these solvents, like paints, varnishes and plastics. In addition, workers are exposed to organic solvents during manual work where the organic solvents are used, for instance during painting, degreasing, graphic work, floor laying and cleaning. Examples of organic solvents that are common in use are shown in the table below:

Solvent Example of usage
Acetone Paint and lacquer, plastic products and degreasers.
Butanol Paint and lacquer. The manufacture of artificial leather, perfume, plastic products.
Ethanol The production of drugs, explosives, plastic materials, synthetic rubber, varnish, glue.
Glycol ethers Plastic industry and manufacture of paints, varnishes and soaps. Found in hydraulic oils and in antifreeze liquids.
Methanol The production of celluloid, plastic, industrial colors and paint strippers. Is also used as fuel.
Methyl-ethyl-ketone Glue and lacquer, degreasers and cleansers.
Styrene Plastic production.
Toluene The chemical industry, rubber industry, the pharmaceutical industry, in the paint and glue.
Trichloroethylene (“tri”) Plastic industry, degreasers, thinners.
White Spirit Thinner for paint and varnish. Degreasing and cleaning.
Xylene Ink, rubber, glue, varnish and paint. Commonly used in the chemical industry.

One type of organic solvent is acetone – here is the chemical formula and acetone in a bottle

One type of organic solvent is acetone – here is the chemical formula and acetone in a bottle. © Colourbox

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Occupational Health in Developing Countries

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