The monitoring of chemical substances, as required by the MSFD, should allow for the seamless protection of waters against chemical hazards. EU Member States shall consider contaminants and their total releases (including losses, discharges or emissions) which may entail significant risks to the marine environment from past and present pollution in the marine region, sub-region or subdivision concerned.
A list of priority substances identified in EU coastal and territorial waters, as laid out in the Environmental Quality Standards Directive [2008/105/EC] and its amendment [2013/39/EU], is provided in the Water Framework Directive Strategy (WFD) on Priority Substances (PS). EU Member States may also identify in their coastal waters substances of national or local concern (River Basin Specific Pollutants) for control at the relevant level.
Furthermore, the MSFD provisions foresee the consideration of areas that are not covered by the WFD. Such contaminants include marine-specific substances and contaminants such as hazardous and noxious substances resulting from acute pollution events.
A close collaboration with Regional Sea Conventions is crucial, as contaminants cross national and EU borders. Lists of substances which potentially pose a risk to or via the aquatic environment have been also compiled under RSC and other international organizations:
While prioritization lists through the WFD and RSCs exist, there is need to also take recent or spatially limited contaminant issues into consideration. JRC is contributing to the identification and selection of MSFD relevant contaminants.
Chemical substances occurring in the marine environment might derive from specific sea-based human activities, such as shipping, antifouling agents, aquaculture, ammunition dumping, etc. Two recent publications review the literature to identify contaminants potentially released from these sea-based sources, providing an overview of the policies and frameworks for their management and regulation within the EU. This kind of information may contribute to the setting-up of approaches to marine pollution monitoring as well as help guide the identification of relevant substances for the implementation of the MSFD descriptor 8.
Additionally, the JRC has compiled in a single list more than 2700 substances (or groups of substances) coming from main lists of chemicals compiled by relevant global conventions, European legislation, European regional seas and dedicated research work. Although not all of these contaminants are of concern for the marine environment or for a particular MSFD region/sub-region/Member State, this general overview should help understand the different options and support further developments for the monitoring and assessment of chemical pollution in European marine waters. Discussion and collaboration between the different stakeholders and expert groups will be necessary for an efficient way towards an equally high level of protection for healthy and productive oceans. This compilation will also assist in using a harmonized nomenclature for the unambiguous identification of the substances of concern.
It may also serve as a basis for discussions about procedures for grouping/combining substances at European level. This is expected to facilitate consistency in the upcoming 2018 MSFD data reporting.
Moreover, the JRC is currently working on another report regarding the challenges and options for the identification of emerging contaminants in the marine environment. The aim of this report is to review methodologies in place to identify emerging contaminants and provide recommendations for harmonizing approaches in European marine waters. This is intended as a follow up of the previous work on marine chemical contaminants (Tornero and Hanke 2016) and the report on chemical lists mentioned above. Findings from these three works should foster collaboration among scientific and regulatory frameworks and contribute to a more robust assessment of chemical contaminants in the marine environment.

Pollution effects on the ecosystem components
The MSFD also considers the effects of pollution on the ecosystem components concerned, having regard to the selected biological processes and taxonomic groups where a cause/effect relationship has been established and needs to be monitored.
A technical report on effect-based tools was elaborated by the sub-group CMEP (Chemical Monitoring and Emerging Pollutants) in the context of the WFD.
Acute pollution effects
The occurrence, origin (where possible) and extent of significant acute pollution e.g. through oil and oil product slicks and their physical impact on biota should also be considered under MSFD. The European Maritime Safety Agency (EMSA) provides oil spill satellite surveillance to the EU coastal states. National aerial and vessel surveillance patrols can then target the area to verify the possible spill and potentially identify the polluter. This communication and verification process can be triggered through the MSFD.
Threshold values
Environmental Quality Standards (EQS) have been established for priority substances under the WFD. In absence of EQS for specific substances and/or matrices other than those specified, EU Member States could apply other assessment criteria agreed at regional or subregional level, such as those developed by Member States at national level or within RSC.