DISTRIBUTIONS OF RIVER-TRANSPORTED HALOGENATED BIPHENYLS AND TERPHENYLS IN COASTAL ENVIRONMENTS

The sedimentary distribution of chlorinated hydrocarbons in a coastal area of the Bay of Biscay which receives the discharges of six rivers: Deba, Urola, Oria, Urumea, Oyarzun and Bidasoa, has been studied by gas chromatography (GC) coupled to electron capture detection (ECD) and negative ion chemical ionization mass spectrometry (MS-NICI). Four replicates of six sample transects, each encompassing three water depth levels, have been obtained with four R/V cruises distributed in one year cycle. The resulting seventy-two samples have shown the predominance of chlorinated hydrocarbon mixtures equivalent to Aroclor 1260. These hydrocarbons exhibit a spatial distribution that depends on the pollution load introduced by each river and the particle-size composition of the marine sediments, two factors that determine the PCB variation along the coast and along each transect, respectively. In addition to the major PCB mixture, significant amounts, or even predominance, of Aroclor 1254-type hydrocarbons have been found in Deba, Urola, Oria and Bidasoa Rivers, occurring together with a PCT mixture equivalent to Leromoll 141. The composition of these PCT hydrocarbons has been studied by GC-MS-NICI.