SURFACE-ACTIVE SUBSTANCES IN THE EASTERN MEDITERRANEAN

During the EGAMES expedition in the Eastern Mediterranean in July 1993 , surface active substances (SAS) were determined in seawater samples from the Ionian and Aegean Seas using a.c. voltammetry. Measurements w ere made on unfiltered samples on board of the excursion ship and conc entrations of SAS were estimated using a calibration graph prepared wi th an arbitrary standard surfactant, Triton-X-100. The concentrations of SAS in the Aegean Sea ranged from 0.07 to 0.21 mg/L in surface wate rs (0.5 m), and from 0.07 to 0.35 mg/L at a 5 m depth. In the Ionean S ea, samples were collected only at a 0.5 m depth and the concentration s of SAS were from 0.08 to 0.18 mg/L. Qualitatively, more hydrophobic organic material was present in the Aegean Sea, while in the more turb ulent waters of the Eastern Mediterranean and in the open waters of th e Ionian Sea more hydrophilic and/or conditionally hydrophobic substan ces were present.