The quality and comparability of analytical results generated by laboratories appointed by competent authorities of the Member States to perform water chemical monitoring pursuant to Article 8 of Directive 2000/60/EC should be ensured. The EN ISO/IEC-17025 standard on general requirements for the competence of testing and calibration laboratories provides appropriate international standards for the validation of the methods of analysis used.

In order to fulfil validation requirements, all methods of analysis applied by Member States for the purposes of chemical monitoring programmes of water status should meet certain minimum performance criteria, including rules on the uncertainty of measurements and on the limit of quantification of the methods. To ensure comparability of chemical monitoring results, the limit of quantification should be determined in accordance with a commonly agreed definition.

Where there are no methods which comply with the minimum performance criteria, monitoring should be based on best available techniques not entailing excessive costs.

The calculation of mean values should take account of measurement results that are below the limit of quantification of methods of analysis. Rules to be used in this respect should be provided.

Technical operations to ensure the quality and comparability of analytical results should follow quality management system practices accepted at international level. For that purpose, the practices set out in EN ISO/IEC-17025 are appropriate. It is appropriate to ensure that laboratories performing chemical analysis demonstrate their competence through the participation in internationally or nationally recognised proficiency testing programmes and through the use of available reference materials. In view of harmonising practices at the Community level, the organisation of proficiency testing programmes should be based on relevant international standards. To that end, ISO/IEC guide 43-1 on proficiency testing by interlaboratory comparisons — Part 1: Development and operation of proficiency testing schemes provides an appropriate guide. The results of those programmes should be evaluated on the basis of the internationally recognised scoring systems. In this regard, ISO-13528 on statistical methods for use in proficiency testing by interlaboratory comparisons provides appropriate standards.

The Committee referred to in Article 21(1) of Directive 2000/60/EC was consulted on 15 May 2008 and delivered a positive opinion on the draft Commission Directive laying down, pursuant to Directive 2000/60/EC, technical specifications for chemical analysis and monitoring of water status. On 6 June 2008 the Commission submitted the said draft for scrutiny by the European Parliament and the Council. The European Parliament did not oppose the draft measures within the set deadline. The Council opposed the adoption by the Commission indicating that the proposed measures exceeded the implementing powers provided for in Directive 2000/60/EC. As a consequence, the Commission did not adopt the draft measures and submitted an amended draft of the concerned Directive to the Committee referred to in Article 21(1) of Directive 2000/60/EC. The Committee was consulted on the said draft by written procedure launched on 28 January 2009 and delivered a positive opinion.

The measures provided for in this Directive are in accordance with the opinion of the Committee referred to in Article 21(1) of Directive 2000/60/EC,