Methods applied in studies of benthic marine debris

The ocean floor is one of the main accumulation sites of marine debris. The study of this kind of debris still lags behind that of shorelines. It is necessary to identify the methods used to evaluate this debris and how the results are presented and interpreted. From the available literature on benthic marine debris (26 studies), six sampling methods were registered: bottom trawl net, sonar, submersible, snorkeling, scuba diving and manta tow. The most frequent method used was bottom trawl net, followed by the three methods of diving. The majority of the debris was classified according to their former use and the results usually expressed as items per unity of area. To facilitate comparisons of the contamination levels among sites and regions some standardization requirements are suggested.     

Integrated use of biomarkers (acetylcholinesterase and antioxidant enzymes activities) in Mytilus galloprovincialis and Mullus barbatus in an Italian coastal marine area

The use of biomarkers to evaluate the biological effects of chemical pollutants in marine organisms represents a recent tool in the monitoring field responding to the need to detect and assess the effects of chemical contaminants on the biota. The aim of the present work was the field application of the integrated use of acetylcholinesterase (AChE) and antioxidant enzymes (catalase--CAT, glutathione peroxidase--GSH-Px), for detecting the possible exposure/effect induced by chemical pollutants in native marine organisms from a coastal marine area, represented by Salento Peninsula (Italy), that shows a coastline of high environmental value, but under constant urban pressure, including agriculture activities, widely diffused in the whole hinterland. Eight sampling stations were chosen: four not urbanized areas considered "uncontaminated" controls and four clearly exposed to anthropogenic impact. The bioindicator species studied were a sessile invertebrate, Mytilus galloprovincialis, and a benthic teleost fish, Mullus barbatus.AChE activity in M. galloprovincialis revealed significant differences among places; the minimum values observed (3.9+/-1.8 nmolmin(-1)mg(-1)) was about 50% reduced with respect to the maximum found (11.4+/-0.9 nmolmin(-1)mg(-1)). The reduction in AChE activity observed in two control stations could be explained by the leaching of pesticides into the sea from the agricultural lands. Moreover, the inhibition of AChE activity by heavy metals besides pesticides, can also explain the reduction of the enzymatic activity observed in an industrialized and harbour area. In M. galloprovincialis AChE activity showed a significant inverse correlation with catalase activity but not with glutathione peroxidase that did not significantly change in animals sampled from the eight stations. Also in M. barbatus AChE activity showed significant differences among places; it was inversely correlated with liver GSH-Px activity, but not with catalase activity, that did not show any significantly variation in animals sampled in the different stations.In conclusion, the integrated use of AChE and antioxidant enzymes (catalase or glutathione peroxidase) in M. galloprovincialis and M. barbatus, two species living in different compartment of marine coastal ecosystem, can find a useful application within the framework of marine coastal environment monitoring programs for detecting the possible exposure/effect induced by chemical pollutants, including pesticides, on living marine organisms.     

Hepatic ethoxyresorufin O-deethylase (EROD) activity in flounder (Platichthys flesus) from contaminant impacted estuaries of the United Kingdom: continued monitoring 1999-2001

The determination of hepatic ethoxyresorufin O-deethylase (EROD) has been used to assess the induction of the mixed function oxygenase system (MFO) of flounder (Platichthys flesus) in UK estuaries. Induction of the MFO system denotes possible exposure to certain organic contaminants (e.g. polycyclic aromatic hydrocarbons, polychlorinated biphenyls) and its measure has been incorporated in national monitoring programmes. This study presents EROD monitoring data from 5 UK estuaries taken between 1999 and 2001 and builds on data from previous years. The results reveal that for all sampled estuaries EROD values have been significantly (p < 0.05) elevated on the majority of occasions in comparison with the reference estuary, the Alde in Suffolk, UK. However, the limited temporal scale of the reported monitoring does not allow any conclusions to be drawn with respect to trends in the data. Possible factors influencing the data (size, gender, seasonality, reproductive status, etc.) are discussed and recommendations for continued monitoring are made.     

The use of chemical dispersants to combat oil spills at sea: A review of practice and research needs in Europe

In order to better understand the practice of dispersant use, a review has been undertaken of marine oil spills over a 10 year period (1995-2005), looking in particular at variations between different regions and oil-types. This viewpoint presents and analyses the review data and examines a range of dispersant use policies. The paper also discusses the need for a reasoned approach to dispersant use and introduces past cases and studies to highlight lessons learned over the past ten years, focussing on dispersant effectiveness and monitoring; toxicity and environmental effects; the use of dispersants in low salinity waters; response planning and future research needs.