New challenges in marine pollution monitoring

There is abundant evidence that anthropogenic activities have polluted all compartments of the oceans, from the poles to the tropics, by different physical, chemical, and biological stressors. Chemical pollution is particularly tackled here with focus on legacy pollutants and newly emerging man-made compounds (xenobiotics) or anthropogenic forcing in the increase of natural chemical substances. It has been estimated that more than 100,000 chemicals are currently on the market [ECHA (European Chemicals Agency), 2017], and thousands of new substances are being introduced every year due to industrialization, intensive agriculture, and urban development. This has led to a continuous flow of chemical products to the oceans that have the potential to alter the structure of ecosystems by causing changes in the biotic communities that constitute them. Traditionally, the assessment of marine chemical pollution would exclusively be based on chemical analysis of a limited set of potential pollutants in selected environmental matrices, and a comparison between their levels with those found in pristine areas not being subjected to direct human pressures. However, such chemical assessment of pollution only offers a partially suitable approach to the question of how marine organisms and ecosystem functioning are affected by pollutants. This can only be answered by means of an integrated assessment including both chemical analyses and biological tools that quantitatively link the levels of pollutants with their ecological effects, including new contaminants for which no analytical techniques have yet been developed. Ideally, we aim to detect disturbances caused by pollutants before ecosystems are affected. So we need sensitive indications for pollution effects that provide an early warning to allow taking measures to avoid ecological damage. As for this concern a unique effort based on a European consensus, has been developed by ICES/OSPAR (Davies and Vethaak, 2012). A new challenge in marine pollution monitoring is also based on the harmonization of two European Union directives for the protection of the marine environment, the Water Framework Directive (WFD, 2000/60/CE) and the Marine Strategy Framework Directive (MSFD, 2008/56/CE). The latter established a legislative context demanding the use of effect-based tools for the assessment of pollution. These two directives were constructed according to two different strategies to assess the status of continental and coastal water ecosystems, following either a risk assessment approach (WFD) or an ecosystem approach (MSFD