Abstract
Studies were carried out in experimental marine ecosystems to determine the fate and persistence of a series of volatile organic compounds in coastal seawater. A suite of aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated C2-hydrocarbons , and chlorinated aromatic hydrocarbons, covering a wide range of water solubilities, volatilities, and susceptibilities to biological degradation, was added to the water column of the mesocosms at concentrations typical of a moderately polluted estuary (0.2-4 micro g/L). Concentrations in the water column were followed for up to 2 months, under experimental conditions simulating winter, spring, and summer. Water column half-lives of the same compounds ranged from about 1 day to up to 4 weeks, depending on season and compound class. Volatilization appears to be the major process removing aromatic hydrocarbons, chlorinated C2-hydrocarbons, and chlorinated aromatic hydrocarbons during all seasons, with biodegradation also important for aromatic hydrocarbons in summer. Aliphatic hydrocarbons are quickly sorbed onto particulate matter and thus removed from the ' volatile ' pool; biodegradation also affects the alkanes. (Author 's abstract)