Solvents are used worldwide and in a lot of applications, such as paints, cosmetics, pharmaceuticals, household and industrial cleaners and inks. Although they provide efficient solutions for many daily situations, important drawbacks are related to the use of products that include solvents in their composition. One of the problems is that these chemicals contribute to air pollution. The solvents are commonly known as volatile organic compounds, which can take part in chemical reactions that lead to ozone formation.
Solvents can be classified in two major groups: water-based (aqueous) solvents and hydrocarbon-based (organic) solvents. The properties of organic solvents are influenced by factors such as the number of carbon atoms in the chain and the presence of single, double, or triple bonds between adjacent carbon atoms.
There are lots of studies that correlate relatively low-level exposure to organic solvents and solvent mixtures and neuropsychiatric diseases. Solvents such as carbon disulfide and toluene have been proved to be neurotoxic, which means that they can cause neuropsychological changes (anxiety, irritability and forgetfulness) when repeatedly inhaled. Aromatic compounds, especially the polycyclic aromatic hydrocarbons, present intermediate biodegradability since they are not so resistant to biological degradation. However, these compounds are of major concern due to their toxicity and tendency to bioaccumulate.