The contents of polycyclic aromatic hydrocarbons (PAH) were examined in surface sediments from the open Adriatic Sea. UV-fluorescence spectroscopy was used for the analysis, and continued emission spectra were scanned for the lower and higher aromatic fractions. The samples were collected in three seasons, December 1986, May 1987 and September 1987 on two transects between Yugoslavia and Italy. Higher values were found near the Italian coast. From spectral line shapes it is evident that there was no local source of pollution and that PAH are of petrogenic and pyrolytic origin. The spatial distribution of PAH contents is in good agreement with the dispersion pattern of recent sediments of the Adriatic Sea.

The impacts of oil and dispersed oil on freshwater ecosystems were examined in afield experiment conducted as part of the Freshwater Oil Spill Research Program. In July 1985, 3 m 3 of Normal Wells crude oil were spilled on each of two fen lakes. The slick on one lake was treated with the dispersant Corexit 9550. Corexit 9550 was effective in removing the oil from the water surface even though wave energy was very low. The oil or dispersed oil had little detectable short or long term impact on all water quality parameters measured, or on the microbial populations and activities in the water column and sediments of both lakes. Untreated oil caused more damage than the dispersed oil to floating aquatic plants and the shoreline vegetation, but new growth within the affected areas was observed one month after treatment. Seasonal regrowth of vegetation in all areas affected by the treatments appeared normal. Our results suggest that the best response to oil contamination in isolated fen lakes is no action at all. However, floating oil or oil washed ashore could pose a significant threat to indigenous wildlife or its habitats. Under these conditions, chemical dispersion may prove to be an effective alternative when conventional control and recovery measures are not feasible.

The use of a surface-drifting buoy equipped with an Argos transmitter to monitor the movement of an oil slick has been evaluated. It is concluded that such a buoy could act as a useful aid to aerial surveillance during oil spill incidents.

The application of fluorescence spectroscopic techniques to the uptake of aromatic hydrocarbons into the sandprawn, Callianassa kraussi, was examined. Animals were exposed to the water-soluble fraction of Qatar crude oil for up to 12 weeks, then depurated in clean seawater for up to 4 weeks. Fixed wavelength measurements showed the extent and rapidity of aromatic hydrocarbon accumulation into the hepatopancreas of C. kraussi These measurements, along with synchronous spectra, were useful in demonstrating differential accumulation of light and heavy aromatic hydrocarbons.

The distribution of oil degrading bacteria (ODB) and its ratios to viable heterotrophic bacteria (CFU) and direct counts (AODC) were examined in relation to the surface currents of the western Caribbean Sea. High ODB/CFU and ODB/AODC ratios were found, suggesting that chronic sources of hydrocarbons in the region may have a larger impact than those in the southern Gulf of Mexico, where previous studies have been performed. It was concluded that, in western Caribbean waters, the distribution of oil degrading bacteria, or its ratios to CFU or AODC, could be useful indicators of chronic oil inputs originating at the east of the Caribbean Sea, as well as their motions afterwards.

Recent increased human pressures on the environment have led to biological consequences in Lagos' coastal waters, notably in the Lagos lagoon and its drainage channel to sea. Two broad surveys were conducted in February and June 1985 and repeated in 1986 to obtain information on the distribution, habitats and communities in the Lagos lagoon in relation to environmental factors. The samples were used for biological, sediment particle size, organic matter, heavy metal and hydrocarbon analyses. A wide variety of sediments occurred throughout the study area. These ranged from fine, medium and coarse sands to admixtures of silt and clay which provided a wide selection of habitats. The western industrialized areas contained high levels of selected heavy metals. Petroleum hydrocarbon contamination was present in most samples. The percentage of total organic matter was closely associated with the sediment types and the influence of waste inputs. The distribution of several species was influenced by the salinity regime and nature of bottom deposits. Benthic macro-infauna was dominated by molluscs, which were most common in the shallow shoal sands of the northeastern portions of the study area. Species characteristic of stressed environments, notably Capitella capitata, Nereis sp. and Polydora sp., were more abundant in the polluted western industrialized portions. Several species showed seasonal population fluctuations. Diversity indices indicated that the communities exhibited high dominance with a small number of species.

A vertical selective migration of low and medium molecular weight hydrocarbons is demonstrated in the depth of a tropical forest soil heavily impacted by a crude oil spill. An identical pattern of horizontal migration is observed in the lateral zone of the polluted area and in the sediments of a shallow river which received the contaminated water runoff of the forest. The differential migration, which is attributed to the chromatographic properties of the media, resulted in the formation of a residual contaminant similar in composition to a gas-oil cut. The environmental contamination by this fraction extended far beyond the area initially polluted by the crude oil.

A sampling survey was carried out to measure the concentrations of certain chemicals which are discharged into the North Sea from chemical tankers following tank cleaning operations. The survey was carried out some 18 months after the implementation ofAnnex II of MARPOL and the results are compared with those obtained during a survey carried out before Annex II implementation. The measured concentrations were found to be extremely low and in many cases were below the limits of detection of the analytical technique. No evidence has been found to suggest that the North Sea needs to be declared a ‘Special Area’ for the purposes of Annex II. If chemical tankers comply with the provisions of Annex II, harmful concentrations of chemicals should not arise in the North Sea as a result of tank washing discharges.