BIOASSAY-DIRECTED CHEMICAL-ANALYSIS OF GENOTOXIC COMPONENTS IN COASTAL SEDIMENTS

Organic extracts of coastal sediments collected off-shore from Barcelona were submitted to a three-level bioassay-directed chemical fractionation, including gel permeation chromatography (GPC) and normal-phase (NP) and reversed-phase (RP) liquid chromatography (LC). The chemical characterization, directed by the Salmonella microsome mutagenicity assay (TA98+S9, TA98NR+S9, and TA98/1,8DNP+S9), was carried out by capillary GC (CGC) coupled to selective detection systems and by CGC-MS techniques. The mutagenic activity recovered among the GPC fractions was concentrated (78-98%) in the second fraction (GPC-2), which was further fractionated by NP-LC. The mutagenicity among the 35 NP-LC-collected fractions exhibited a three-modal distribution, the highest level being recovered in the intermediate-polarity fractions (10-15%), which were further fractionated by RP-LC. Detailed chemical analysis of the mutagenic fractions led to the identification of 140 aromatic compounds, 57 of them classified as mutagenic or belonging to mutagenic chemical classes, among them, 1-nitropyrene, 6-nitrochrysene, and 6-nitrobenzo[a]pyrene were positively identified for the first time in a coastal sediment.