When the adsorption processes affecting the migration rates of organic solutes in groundwater systems are considered in detail, it can be shown that the use of multiple tracers should allow accurate calculation of the groundwater velocity even when all the tracers are retarded to some extent by interactions with mineral surfaces in the aquifer and even when the extent of that retardation is not known beforehand. It should be required only that the tracers be members of a series of compounds whose surface interaction energies vary regularly, this condition being met, for example, by compounds in the series C2ClnF6−n Experimental studies aimed at testing this concept show that two series of tracers behave as expected on laboratory columns (limestone and sand), thus indicating the fundamental validity of the approach. Further, the nature of the interactions between the mineral surfaces and the tracer molecules can be shown in these cases, at least, to be nonspecific, the strength of the interaction depending only on the polarizability of the tracer molecule. It seems likely that other satisfactory tracers can be selected using this criterion and that the approach should be applicable even to systems involving many different mineral surface types.
Seawater samples collected at four stations in the Gulf of Maine, three on the Scotian Shelf, and at a single station in the Sargasso Sea (Sept.‐Oct., 1977) were analyzed for CCl3F‐content using a rapid gas Chromatographic technique carried out on board ship. The concentrations observed in the Gulf average 2.9 × 10−12moles/liter, corresponding to significant supersaturation with regard to the overlying atmospheric concentrations and surface temperatures. Not all the excess can be attributed to prior equilibration at the colder temperatures prevailing at higher latitudes, and it seems likely that waste disposal activities may contribute to the local excess. Lower concentrations are observed at stations on the Scotian Shelf and in the Sargasso Sea, with observed stratifications in the CCl3F concentrations being well‐correlated with previously described oceanographic features.
In order to place new emphasis on marine pollution prevention in the complex field of tanker operations, the author developed, and is currently conducting, a Shipboard Pollution Control Indoctrination and Training Program. This program, presented on-board during passage, covers all aspects of ship operations at sea and in port which have pollution potential. Through the use of movies, slides, formal and informal discussion sessions the officers and crew are given a better understanding of the economic, legal and technical factors of marine pollution; good operating practices are reviewed; the ship/terminal relationship is explored; the policies and programs of management are emphasized; personnel are prepared for more effective action should an incident occur; and the overall pollution control posture of the vessel and terminals is evaluated. Meetings with management are held before and after the shipboard session as a result of which comprehensive pollution control programs are instituted or updated based to a great extent upon the feedback from the ships and recommendations of the author. Based upon experiences with independent, oil company and government contract tanker operators, and government agencies functioning in the field, 1) details of the program and its reception are reviewed, 2) observations are presented relative to conditions and particular problem areas encountered, 3) suggestions for further concerted efforts in the direction of pollution prevention are set forth and, 4) further desirable actions in the direction of education and training are outlined.
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