Organohalogens of natural or unknown origin in surface water and precipitation

Abstract

Abstract Information about the occurrence and chemical character of adsorbable organic halogens (AOX) in surface water and precipitation is reviewed and updated with results from on‐going studies. There is now very strong evidence that the widespread occurrence of AOX in unpolluted aquatic environments is primarily caused by naturally halogenated humic substances; and, recently, the first chlorinated structural elements in aquatic fulvic acids were identified. Despite the considerable amounts of high‐molecular‐weight organohalogens in humus‐rich surface waters, the concentrations of specific low‐molecular‐weight organohalogens are generally low. This is illustrated by chromatograms obtained by combining different enrichment procedures for trace organics in water with GC‐AED analysis (gas chromatography with atomic emission detection) of chlorinated and brominated compounds. On‐going studies of the chemical character of AOX in precipitation have shown that the compounds responsible for the major fraction o...