Dissolved and particulate hydrocarbons in water from a spring sampling of the Var River Estuary (S. France)†

Abstract

To address questions of water quality monitoring and to investigate processes controlling the biogeochemical cycling of organics in estuarine and marine systems, we have used a resin adsorption apparatus with in‐line glass fiber filter for sampling “dissolved”; and “particulate”; organics. High resolution gas chromatographic analyses of water samples collected from the Var River and coastal Mediterranean show rivers are important sources of soluble pesticides and some PCB's. Percentage particle association was related to particle loading as predicted by sorption models. Total concentrations of PCB's resulted from river input superimposed on more widespread distributions consistent with atmospheric transport models. Petroleum products discharged to rivers and the sea surface plus atmospheric inputs of combustion products add to levels of biogenic sources making distributions highly variable. Distributions of hydrocarbons between physical‐chemical phases showed high percentage particle association of high boiling relatively insoluble components, while “dissolved”; material contained a larger proportion of low boiling unsaturated components at fairly constant concentration. This partitioning suggests different input sources or differential fractionation of components from the same general sources. We also noted the increase in relative importance in new unidentified halogenated hydrocarbon contaminants in coastal systems.