Organochlorine contaminants in microlayer and subsurface water of Alexandria Coast, Egypt

The surface microlayer of seawater is a potential enrichment site for hydrophobic organic compounds. Concentrations of pesticides and congeners of polychlorinated biphenyls (PCBs) in the microlayer and subsurface waters of Alexandria coast were assessed. A 0.22 m(2) screen was used to collect microlayer samples at 12 stations in June 1997. The samples were analyzed by gas chromatography with electron capture detection (GC-ECD) and confirmed by GC with mass spectrometry. Ten organochlorine pesticides and 10 PCB congeners were measured. The surface microlayer was enriched 2- to 3-fold in pesticides and PCBs. The most contaminated locations studied were Abu-Quir Bay and the Eastern Harbor. This study provides the first record of residues of PCB congeners in the studied areas and the first data about microlayer enrichment at Alexandria's Mediterranean Coast.