Petroleum hydrocarbons in the Mediterranean Sea: A mass balance

Over three quarters of a million tonnes of oil were estimated to be introduced annually into the Mediterranean Sea from land-based and open-sea discharges. This paper is a critical assessment of data available through 1983 on the distribution of petroleum-derived hydrocarbon residues and the biogeochemical processes controlling the transport and fate of organic contaminants in this regional sea ecosystem. Inputs, outputs and ecosystem partitioning or inventories are computed and a complete mass balance model is proposed. The approach raises several implications with respect to strategies for the sampling and analysis of organic contaminants in ocean ecosystems. The report also provides a basis on which to evaluate the effectiveness of recent discharge regulations in reducing pollution loads in the Mediterranean. The agreement between calculated fluxes, inventories and input time scales demonstrates the usefulness of organic contaminants as markers for the development of global and ocean flux models.