Chemical pollution of surface water poses a threat to the aquatic environment, with effects such as acute and chronic toxicity in aquatic organisms, accumulation of pollutants in the ecosystem and loss of habitats and biodiversity, and also poses a threat to human health. As a matter of priority, causes of pollution should be identified and emissions of pollutants should be dealt with at source, in the most economically and environmentally effective manner.

Pursuant to the second sentence of Article 191(2) of the Treaty on the Functioning of the European Union (TFEU), Union policy on the environment is to be based on the precautionary principle and on the principles that preventive action should be taken, that environmental damage should, as a priority, be rectified at source and that the polluter should pay.

Treating waste water can be very costly. In order to facilitate cheaper and more cost effective treatment, the development of innovative water treatment technologies could be stimulated.

Pursuant to Article 191(3) TFEU, in preparing its policy on the environment, the Union is to take account of available scientific and technical data, environmental conditions in the various regions of the Union, the potential benefits and costs of action or lack of action as well as the economic and social development of the Union as a whole and the balanced development of its regions. Scientific, environmental and socio-economic factors, including human health considerations, should be taken into account in developing a cost-effective and proportionate policy on the prevention and control of chemical pollution of surface waters, including in reviewing the list of priority substances in accordance with Article 16(4) of Directive 2000/60/EC. In view of that aim, the polluter pays principle underpinning Directive 2000/60/EC should be consistently applied.

The Commission has conducted a review of the list of priority substances in accordance with Article 16(4) of Directive 2000/60/EC and with Article 8 of Directive 2008/105/EC and has come to the conclusion that it is appropriate to amend the list of priority substances by identifying new substances for priority action at Union level, setting EQS for those newly identified substances, revising the EQS for some existing substances in line with scientific progress and setting biota EQS for some existing and newly identified priority substances.

The review of the priority substances list has been supported by an extensive consultation with experts from the Commission services, Member States, stakeholders and the Scientific Committee on Health and Environmental Risks.

The revised EQS for existing priority substances should be taken into account for the first time in river basin management plans covering the period 2015 to 2021. The newly identified priority substances and their EQS should be taken into account in the establishment of supplementary monitoring programmes and in preliminary programmes of measures to be submitted by the end of 2018. With the aim of achieving good surface water chemical status, the revised EQS for existing priority substances should be met by the end of 2021 and the EQS for newly identified priority substances by the end of 2027, without prejudice to Article 4(4) to (9) of Directive 2000/60/EC, which includes inter alia provisions for extending the deadline for achieving good surface water chemical status or achieving less stringent environmental objectives for specific bodies of water on the grounds of disproportionate cost and/or socio-economic need, provided that no further deterioration occurs in the status of the affected bodies of water. The determination of surface water chemical status by the 2015 deadline laid down in Article 4 of Directive 2000/60/EC should be based, therefore, only on the substances and EQS set out in Directive 2008/105/EC in the version in force on 13 January 2009 unless those EQS are stricter than the revised EQS under this Directive, in which case the latter should be applied.

Additional substances posing a significant risk to, or via, the aquatic environment at Union level have been identified and prioritised using the approaches specified in Article 16(2) of Directive 2000/60/EC and should be added to the list of priority substances. The latest available scientific and technical information has been taken into account in deriving the EQS for those substances.

The contamination of water and soil with pharmaceutical residues is an emerging environmental concern. In evaluating and controlling the risk to, or via, the aquatic environment from medicinal products, adequate attention should be paid to Union environmental objectives. In order to address that concern, the Commission should study the risks of environmental effects from medicinal products and provide an analysis of the relevance and effectiveness of the current legislative framework in protecting the aquatic environment and human health via the aquatic environment.

The derivation of EQS for priority hazardous substances usually involves higher levels of uncertainty than is the case for priority substances but such EQS still establish a benchmark to assess compliance with the objective of good surface water chemical status, as defined in Article 2(24) and points (ii) and (iii) of point (a) of Article 4(1) of Directive 2000/60/EC. However, in order to ensure an adequate level of protection for the environment and human health, the cessation or phasing-out of discharges, emissions and losses of priority hazardous substances should also be aimed at, in accordance with point (iv) of point (a) of Article 4(1) of Directive 2000/60/EC.

Scientific knowledge about the fate and effects of pollutants in water has evolved significantly over recent years. More is known about which compartment of the aquatic environment (water, sediment or biota, hereinafter ‘matrix’) a substance is likely to be found in, and therefore where its concentration is most likely to be measurable. Some very hydrophobic substances accumulate in biota and are hardly detectable in water even using the most advanced analytical techniques. For such substances, EQS should be set for biota. Nevertheless, in order to take advantage of their monitoring strategy and adapt it to their local circumstances, Member States should have flexibility to apply an EQS for an alternative matrix or, where relevant, an alternative biota taxon, for example sub-phylum Crustacea, paraphylum ‘fish’, class Cephalopoda or class Bivalvia (mussels and clams), provided that the level of protection afforded by the EQS and the monitoring system applied by the Member States is as good as that provided by the EQS and matrix laid down in this Directive.

Novel monitoring methods such as passive sampling and other tools show promise for future application, and their development should therefore be pursued.

The implementation of this Directive involves challenges which include the diversity of the possible solutions to scientific, technical and practical questions and the incomplete development of monitoring methods, as well as constraints on human and financial resources. To help address some of those challenges, the development of monitoring strategies and analytical methods should be supported by technical work by expert groups under the Common Implementation Strategy for Directive 2000/60/EC.

Persistent, bioaccumulative and toxic substances (PBTs) and other substances that behave like PBTs can be found for decades in the aquatic environment at levels posing a significant risk, even if extensive measures to reduce or eliminate emissions of such substances have already been taken. Some are also capable of long-range transport and are largely ubiquitous in the environment. Several such substances are among the existing and newly identified priority hazardous substances. For some of those substances there is evidence of long-term ubiquity in the aquatic environment at Union level, and those particular substances therefore need special consideration as regards their impact on the presentation of chemical status under Directive 2000/60/EC and as regards monitoring requirements.

As regards the presentation of chemical status under Section 1.4.3 of Annex V to Directive 2000/60/EC, Member States should be allowed to present separately the impact on chemical status of substances that behave like ubiquitous PBTs so that improvements in water quality achieved in relation to other substances are not obscured. In addition to the obligatory map covering all substances, additional maps, covering substances behaving like ubiquitous PBTs and separately covering the rest of the substances, could be provided.

Monitoring should be adapted to the spatial and temporal scale of the expected variation in concentrations. Given the widespread distribution and long recovery times expected for substances behaving like ubiquitous PBTs, Member States should be allowed to reduce the number of monitoring sites and/or the frequency of monitoring for those substances to the minimum level sufficient for reliable long-term trend analysis, provided that a statistically robust monitoring baseline is available.

The special consideration given to substances behaving like ubiquitous PBTs does not exempt the Union or the Member States from taking measures additional to those already taken, including at international level, to reduce or eliminate discharges, emissions and losses of those substances so as to achieve the objectives set out in point (a) of Article 4(1) of Directive 2000/60/EC.

Under Article 10(3) of Directive 2000/60/EC, where a quality objective or quality standard established pursuant to that Directive, to the Directives listed in Annex IX to Directive 2000/60/EC, or pursuant to any other Union legislation, requires stricter conditions than those which would result from the application of Article 10(2) of that Directive, more stringent emission controls are to be set accordingly. A similar provision has also been included in Article 18 of Directive 2010/75/EU. It follows from those Articles that the emission controls set under the legislation listed in Article 10(2) of Directive 2000/60/EC should be the minimum controls applied. Where those controls cannot ensure that an EQS is met, for example in the case of a substance behaving like a ubiquitous PBT, but stricter conditions would not either, even in conjunction with stricter conditions for other discharges, emissions and losses affecting the water body, such stricter conditions could not be considered as being required to meet that EQS.

High-quality monitoring data, along with data on ecotoxicological and toxicological effects, are needed for the risk assessments that support the selection of new priority substances. The monitoring data collected from Member States, although significantly improved over the past years, are not always fit for purpose in terms of quality and Union coverage. Monitoring data are particularly lacking for many emerging pollutants, which can be defined as pollutants currently not included in routine monitoring programmes at Union level but which could pose a significant risk requiring regulation, depending upon their potential ecotoxicological and toxicological effects and on their levels in the aquatic environment.

A new mechanism is needed to provide the Commission with targeted high-quality monitoring information on the concentration of substances in the aquatic environment, with a focus on emerging pollutants and substances for which available monitoring data are of insufficient quality for the purpose of risk assessment. The new mechanism should facilitate the gathering of that information across Union river basins and complement monitoring data from programmes under Articles 5 and 8 of Directive 2000/60/EC and other reliable sources. In order to maintain monitoring costs at reasonable levels, the mechanism should focus on a limited number of substances, included temporarily in a watch list, and a limited number of monitoring sites, but should provide representative data that are fit for the purpose of the Union prioritisation process. The list should be dynamic and its validity in time should be limited, in order to respond to new information on the potential risks posed by emerging pollutants and to avoid monitoring substances for longer than necessary.

In order to simplify and streamline reporting obligations for the Member States, and increase coherence with other related aspects of water management, the notification requirements in Article 3 of Directive 2008/105/EC should be merged with the overall reporting obligations under Article 15 of Directive 2000/60/EC.

As regards the presentation of chemical status in accordance with Section 1.4.3 of Annex V to Directive 2000/60/EC, for the purposes of the update of the programmes of measures and of the river basin management plans to be carried out in accordance with Article 11(8) and Article 13(7) of Directive 2000/60/EC respectively, Member States should be allowed to present separately the impact on chemical status of newly identified priority substances and of existing priority substances with revised EQS, so that the introduction of new requirements is not mistakenly perceived as an indication that the chemical status of surface waters has deteriorated. In addition to the obligatory map covering all substances, additional maps, covering newly identified substances and existing substances with revised EQS, and separately covering the rest of the substances, could be provided.

It is important that environmental information on the status of Union surface waters and on the achievements of strategies against chemical pollution is made available to the public in a timely manner. With a view to strengthening access and transparency, a central portal providing information on the river basin management plans and their reviews and updates should be accessible to the public electronically in each Member State.

With the adoption of this proposal and submission of its report to the European Parliament and to the Council, the Commission has completed its first review of the list of priority substances as required under Article 8 of Directive 2008/105/EC. This has included a review of the substances listed in Annex III to that Directive, some of which have been identified for prioritisation. There is currently insufficient evidence to prioritise the other substances listed in Annex III. The possibility of new information regarding those substances becoming available means that they are not excluded from future review, as is the case for the other substances considered but not prioritised in the present review. Annex III to Directive 2008/105/EC has therefore become obsolete and should be deleted. Article 8 of that Directive should be amended accordingly, also regarding the date of reporting to the European Parliament and to the Council.

In order to react to relevant technical and scientific progress in the area covered by this Directive in a timely manner, the power to adopt acts in accordance with Article 290 TFEU should be delegated to the Commission in respect of the updating of the methods for applying the EQS laid down in the Directive. It is of particular importance that the Commission carry out appropriate consultations during its preparatory work, including at expert level. The Commission, when preparing and drawing up delegated acts, should ensure simultaneous, timely and appropriate transmission of relevant documents to the European Parliament and to the Council.

Since the objective of this Directive, namely that of achieving good surface water chemical status by laying down EQS for priority substances and certain other pollutants, cannot be sufficiently achieved by the Member States and can therefore, by reason of the need to maintain the same level of protection of surface water throughout the Union, be better achieved at Union level, the Union may adopt measures, in accordance with the principle of subsidiarity as set out in Article 5 of the Treaty on European Union. In accordance with the principle of proportionality, as set out in that Article, this Directive does not go beyond what is necessary in order to achieve that objective.

Directives 2000/60/EC and 2008/105/EC should therefore be amended accordingly,