Toxic Effects of Solvents and Vapors

Solvents are liquid organic chemicals with variable lipophilicity and volatility, and nearly everyone is exposed to solvents during normal daily activities. Solvents undergo ready absorption across the lung, skin, and gastrointestinal (GI) tract. In general, the lipophilicity of solvents increases with increasing molecular weight, whereas volatility decreases. Solvents frequently are used to dissolve, dilute, or disperse materials that are insoluble in water. Most solvents are refined from petroleum for example gasoline, which is a complex mixtures that consist of hundreds of compounds.
Solvents are classified largely according to their molecular structure or functional group. Classes of solvents include aliphatic hydrocarbons, many of which are chlorinated (i.e., halocarbons); aromatic hydrocarbons; alcohols; ethers; esters/acetates; amides/amines; aldehydes; ketones; and complex mixtures
Most solvents enter the environment through evaporation during production, processing, storage, and transport activities. Winds dilute and disperse solvent vapors across the world and solvent contamination of drinking water supplies is a major health concern.
Toxicokinetic studies the uptake and disposition of chemicals in the body. Volatility and lipophilicity are two important properties of solvents that govern their absorption and deposition in the body. Lipophilicity can vary from quite water-soluble (e.g., glycols and alcohols) to quite lipid-soluble (e.g., halocarbons and aromatic hydrocarbons). Many solvents have a relatively low molecular weight and are uncharged. Thus, they pass freely through membranes from areas of high concentration to low concentration by passive diffusion.