INFLUENCE OF TIDE AND WAVES ON WASHOUT OF DISSOLVED NUTRIENTS FROM THE BIOREMEDIATION ZONE OF A COARSE-SAND BEACH - APPLICATION IN OIL-SPILL BIOREMEDIATION

Successful bioremediation of oil-contaminated beaches requires mainten ance of a sufficient quantity of growth-limiting nutrients in contact with the oiled beach material. A conservative tracer study was conduct ed on a moderate-energy, sandy beach on Delaware Bay to estimate the w ashout rate for dissolved nutrients from the bioremediation zone at di fferent stages during the lunar tidal cycle. When an aqueous solution of the conservative tracer (LiNO3) was applied to the beach surface in the upper intertidal zone at the full moon spring tide, it was comple tely removed within one day. When it was applied at neap tide, however , the tracer persisted in the bioremediation zone for several days. Th e amount of nutrient remaining in the bioremediation zone was highly c orrelated with the maximum extent to which the treated area had previo usly been submerged by water at high tide: submergence resulted in nea rly complete removal of dissolved compounds from the bioremediation zo ne. This high rate of nutrient washout was confirmed by daily monitori ng of nutrient concentrations in the bioremediation zone during an oil -spill bioremediation field study that was conducted on a nearby beach . (C) 1998 Elsevier Science Ltd. All rights reserved.