Vegetation, soils, on-site disturbances, and watershed land use and land cover were assessed at 81 coastal tidal wetland sites using the New England Rapid Assessment Method. Condition indices (CIs) were derived from various combinations of the multi-dimensional data using principal component analyses and a ranking approach. Nested within the 81 wetlands was a set of ten reference sites which encompassed a range of watershed development and nitrogen loadings. The reference set of coastal tidal wetlands was previously examined with an intensive assessment, which included detailed measures of vegetation, soils, and infauna. Significant relationships were found between most of the rapid assessment CIs and the intensive assessment index. Significant relationships were also found between rapid assessment CIs and the developed lands in a 1-km buffer around the coastal wetlands. The regression results of the rapid assessment CIs with the intensive assessment index suggest that measures of vegetation communities, marsh landscape features, onsite marsh disturbances, and watershed natural lands can be used to develop valid CIs, and that it is unnecessary to make finer scale measurements of plant species and soils when evaluating ambient condition of coastal tidal wetlands in southern New England. However, increasing the survey points within coastal tidal wetland units when using a rapid assessment method in southern New England would allow for more observations of vegetation communities, marsh landscape features, and disturbances. Nevertheless, more detailed measures of hydrology, soils, plant species, and other biota may be necessary for tracking restoration or mitigation projects. A robust and standardized rapid assessment method will allow New England states to inventory the ambient condition of coastal tidal wetlands, assess long-term trends, and support management activities to restore and maintain healthy wetlands.

In the inner Bristol Channel and Severn Estuary, most contaminated stations were in muddy, depositional areas of the estuary, particularly along the Welsh coast between the Rivers Taff and Usk, and also on the English coast between Avonmouth and Severn Beach. Some deeper areas, dominated by sand and mixed sediments, also showed contaminant concentrations in excess of those predicted from sediment texture, organic matter, and aluminium or iron concentrations.Concentrations of lead, copper, chromium, nickel and zinc have decreased in the muddy sediments since the 1970s, but only lead has decreased in sand. With the exception of zinc, which is high in the Severn, trace element concentrations were comparable to those from other British estuaries.Landward of the proposed barrage, contaminants are associated with the sub-estuaries and muddy areas at their confluence with the main estuary. Post-barrage effects on contaminants will be focused in these muddy areas. However, fine sediment deposition on what are now sandy areas would increase their contaminant burden unless calcium build-up from the resulting molluscan fauna has the antagonistic effect of contaminant dilution in the sediment.

Wardrop, J.A.,* AGC Woodward-Clyde; Smith, J.P.,* Maxus Southeast Sumatra; Palmer, Don, Marine Science Laboratories; Seignior, Michael, AGC Woodward-Clyde; Fucik, Ken, SeaCrest Laboratories; Giroletti, Mark, BHP Laboratories; and Leeder, John, Amdel Abstract Dispersants are a valuable tool in oil spill management but also one that causes considerable concern amongst environmental groups. Some of these concerns are based on observations dating back to the Torrey Canyon oil spill of 1967 and are consequently dismissed on the basis that the dispersant and the manner in which they are used have changed considerably since then. However, it must be stated that chemically dispersed oil is generally toxic, even if the dispersant themselves have a low toxicity. Consequently environmental damage may result from their use. The decision on whether to use dispersant or not depends then on the relative damage that can be expected from dispersed oil compared to undispersed oil. In order to evaluate this potential, it is necessary to determine the efficiency of dispersant on an oil and the influence of chemical dispersant on the behaviour and toxicity of oil, both at sea and on shorelines. The paper discusses a systematic approach to the testing of dispersant and oils in order to better predict and assess possible environmental and operational benefits. The use of the procedures in the testing of two paraffinic Indonesian crude oils is discussed. The broader scientific information currently available suggests a number of areas in which additional data is required. Introduction The use of chemical dispersant remains one of the most controversial aspects of spill control and this controversy is based largely upon concerns about dispersant toxicity and increased environmental damage from dispersed oil. Some of the public concerns hark back to the ‘Torrey Canyon’ oil spill (U.K., 1967). Following this spill large volumes of industrial degreasers and cleaning agents were used on oiled shorelines. Not surprisingly, the use of these products, together with harsh cleaning methods such as scouring, resulted in a lot of damage to shoreline communities. However, these products were not dispersant and had toxicities far greater than the dispersant that were produced in the following years. In the following decades formulations continued to be refined and both efficiency and toxicity have been improved. Recent reviews have assessed decades of research and agree that, carefully used, dispersant are a valid spill control option. P. 291^

Recent attention to bioremediation of stranded oil on shorelines has identified some of the conditions under which nutrient addition to oil may prove successful. However, relatively little is known of the interactions between substrate texture and natural biodegradation rates to determine the residual hydrocarbon content and composition. The effects of varying shoreline energy levels on the balance of physical versus biological oil removal rates from a range of sediment substrates was investigated in a series of oil spill field experiments in southwest Britain. Two oil types (medium fuel oil mousse and lightly weathered Nigerian crude oil) were used on five shore types (coarse sand to salt marsh). Hydrocarbons were determined in the sediment at intervals up to a year. Selected extracts were analysed by gas chromatography (aliphatics). In a further phase, the contribution to the removal process made by treatment of the stranded oil with chemical dispersant was assessed. Results indicated that on shores where the most rapid physical removal occurred, biodegradation was minimal during the short time scale involved. On shores where oil persisted more than 20 days, biodegradation was more noticeable when oil concentration in the sediment was less than about 1 percent. These data show that physical processes (waves, tides, evaporation) remain the dominant removal mechanism across a range of shore types. The use of chemical dispersant on stranded oil appeared to accelerate physical removal of oil, but may have slowed down biodegradation rates. It would seem, however, that the stage at which biodegradation becomes quantitatively important may be reached more quickly if shoreline countermeasures (including dispersant use) are successful in accelerating physical removal.