Seawater Fluorescence Near Oil Occurrence

Petroleum and its related products pose a serious pollution risk to the world’s seas and require a simple, rapid detection method. This is a difficult task if the pollution is under the water surface. One common approach to oil detection is excitation-emission spectroscopy (EEMs) of seawater exposed to oil for analyzing the fluorometric index (FI o/w ) as a potential indicator of oil presence in the marine environment. In this paper, FI o/w was determined for both natural seawater and samples of the same water, but exposed to a relatively small portion of oil. The water samples were collected from the coastal and port waters of the Gdynia region (Southern Baltic Sea) from five stations, four times at two-week intervals. FI o/w indicates the changes between seawater sampled from the marine environment and the same seawater polluted with oil substances. Moreover, the obtained FI o/w values do not depend on the point and time of sampling. In all cases of seawater exposed to oil, significantly higher FI o/w values were observed than for unpolluted seawater. Moreover, the detection of oil by analyzing the value of FI o/w is efficient if the oil-to-water weight ratio is close to or above 5 × 10 −6 .