When most of us think of paint, we think of the paint that stained our shirts when we used to make art projects or the paint that was used by artists like Van Gogh to make The Starry Night. However paint is used in many industries and for many different jobs, including paint manufacturers, house painters and auto body shop workers. These paint industry workers are exposed to vast amounts of paint every day and therefore need to concern themselves with knowing what chemicals are found in paint as well as their genotoxic effects. Paint is made up of thousands of chemical compounds including toluene, xylene and glycol ethers. Paint industry workers as well as painters are potentially exposed to these chemicals which may lead to DNA and chromosomal damage. Many studies have been done to evaluate genome damage induced in cells of paint industry workers.
Many different chemicals used to make paint can be potentially damaging to the human genome. Ingesting, inhaling or touching these chemicals can have many damaging effects. Toluene is a colorless, organic liquid that is used as a thinner in industrial paint. Toluene is the cause of that distinct paint smell that we recognize when we walk into a freshly painted house. Toluene is not classified as a carcinogenic solvent, yet its neurotoxicity is well recognized. Symptoms of toluene exposure include nose and eye irritation, dizziness, headaches and skin tingling sensations. Long term exposure can cause detrimental effects to the central nervous system. Another chemical used to make paint is xylene. Xylene is a colorless, flammable liquid that is used to enhance the staining of industrial paints. Like toluene, exposure to xylene can cause dizziness, nausea and the depression of the central nervous system.
Due to the limited information on the genotoxic effects associated with exposure to paint, researchers began to evaluate the DNA damage caused by occupational exposure to car paints. A study was done exercising both the quantification of cell-free DNA and the comet assay using a sample of 33 workers taken from car paint shops in South America. Cell-free DNA is an important biomarker for a non-invasive analysis of many diseases, such as cancer. Cell-free DNA is found circulating in the bloodstream and is seen as a specific tumor marker for the early prognosis of cancerous tumors. The comet assay is a simple method for measuring DNA strand breaks in eukaryotic cells. Cells which are damaged by radiation are embedded in agarose gel and are lysed with detergent and salts to form nucleoids containing supercoiled loops of DNA. The damaged DNA is separated from the intact DNA, the “head,” and generates a comet “tail.” By applying these two methods, it was concluded that there was a significant increase in the extent of DNA damage in the exposed individuals compared with the non-exposed individuals. By use of the comet assay, the damaged DNA was seen on the gel after electrophoresis and fluorescent staining. There was a greater amount of damaged DNA molecules with longer “tails” seen in the cells of individuals exposed to toluene. It was also found that with increasing exposure time to airborne toluene solvent vapors, there was a significantly greater amount of cell-free DNA. These findings provided useful information about the cell-free DNA levels in exposure to the toluene in paint, which contributes to the diagnosis of genotoxic damage in individuals occupationally exposed to car paints.
In addition, a study on sister chromatid exchange (SCE) was done to test for the genotoxicity of paint. Sister chromatid exchange is the exchange of genetic material between two identical sister chromatids. These exchanges involve the breakage of both DNA strands followed by an interchange of entire portions of DNA during the S phase. The formation of SCEs is correlated to DNA recombination repair and the induction of point mutations, gene amplification and toxicity by mutagens. This study investigated genetic damage in 30 workers who were exposed to the toluene in paint, compared to 30 control subjects, and used the sister chromatid exchange assay as a biomarker for genotoxicity. SCE frequency was found to be significantly higher in paint workers as compared to control individuals, showing the genotoxic risk of working with paint. The results also show that the amount of time exposed to toluene affects the risk of genotoxicity; the longer the individual is exposed to the toluene in paint, the greater the number of sister chromatid exchanges that individual will have, and therefore the greater the risk of DNA mutations.
Based on much research it seems unequivocal that paint can have many genotoxic effects. The toxic solvents found in paint, including toluene and xylene may adversely affect a person’s DNA and cause lasting damage to the body. A way to decrease the potential harms of exposure to great amounts of paint is to use paint that is made with toluene alternatives. One should also not deliberately sniff paint because the great concentration of toluene inhaled can have immediate effects on the breathing pathway. Paint should also be used in well-ventilated rooms so as to decrease the concentration of the toluene vaporized in the air. By having a well-ventilated room, the toluene particles will disperse over a larger space and have less of an effect on the individual. While abundant research has already been done on the effects of paint on chromosomal damage, there is still research presently being done to discover safer ways to utilize paint.