Biogeochemistry of Volatile Organic Compounds in Marine Experimental Ecosystems and the Estuarine Environment-Initial Results

Abstract

Volatile organic compounds comprise an important group of organic components in the aquatic environment. Compounds in this class are generally too volatile to be handled by conventional solvent extraction, though not volatile enough for procedures used to analyze gaseous hydrocarbons (Brooks and Sackett 1973). A complex mixture of volatile compounds having diverse functional groups has been found in seawater (Gschwend 1979, Schwarzenbach et al. 1979a, Sauer 1980). Most volatiles are derived from anthropogenic activities (petroleum usage and exhausts, industrial solvents, etc.). Therefore, the highest concentrations of volatiles have generally been found in areas near urban and industrial sources (Stieglitz et al. 1976, Zurcher and Giger 1976, Giger et al. 1978, Sauer 1980). Coastal seawater contains less volatiles (Gschwend 1979, Schwarzenbach et ale 1979a, Helz and Hsu 1978, Sauer et al. 1978, Sauer 1980), while concentrations found in the open ocean are near the limits of detection (Giger 1977, Sauer 1980). Although detailed data on spatial and temporal distributions of many volatile compounds are limited, concentrations of volatiles clearly decrease during transport away from the source areas,through estuaries and the coastal zone, and into the open ocean. What the removal processes are (e.g., evaporation, adsorption onto particulates and subsequent sedimentation, degradation) and the extent to which each is important for a given volatile compound are the subjects of current research.