Interlab

Interlaboratory Exercise of the BlueWWater Project

The BlueWWater interlaboratory exercise is an initiative aimed at serving as a tool to evaluate and validate the analytical methods used by laboratories to detect emerging contaminants in wastewater and surface water. It is designed to help participants improve their techniques, identify areas for improvement, and strengthen confidence in their results.

Objective of the Exercise

Conducted in accordance with the guidelines of ISO 13528:2022 and the International Harmonized Protocol for Proficiency Testing of Analytical Chemistry Laboratories by IUPAC, the exercise aims to determine certain pharmaceutical and cosmetic substances in wastewater and receiving water bodies. These substances, even at very low concentrations, may pose risks to the environment and public health. Through this exercise, we aim to provide laboratories with the necessary tools to comply with the new requirements established by the Urban Wastewater Treatment Directive (UWWTD).

Compounds

Substances listed in Annex I, Part C, Table 3 of the UWWTD

Category 1 (substances that can be easily treated):

• Amisulpride
• Carbamazepine
• Citalopram
• Clarithromycin
• Diclofenac
• Hydrochlorothiazide
• Metoprolol
• Venlafaxine

Category 2 (substances that can be easily removed):

• Benzotriazole
• Candesartan
• Irbesartan
• Mixture of 4-methylbenzotriazole and 5-methylbenzotriazole

Matrices

• Water from wastewater treatment plants (WWTP): influent and effluent
• Surface water from the receiving environment: river water

Dates

• Sample distribution to participants: July 2025
• Sample analysis period: June to November 2025
• Report on participation results: June 2026

Participation and Requirements

Twelve laboratories from Spain and Portugal participated in the exercise, reporting results for the 12 compounds in the three matrices.

Results

• Exercise protocol (in Spanish, in Portuguese): This protocol aims to present the procedure established by INTECMAR, as the organizer of the exercise, for the proper implementation of the proficiency test among the participating laboratories.
• Sample homogeneity and stability protocol (in Spanish, in Portuguese): this protocol describes the statistical design and the methods followed to determine the sufficient homogeneity and stability of the proficiency test samples during the development of the exercise.
• Protocol for participants (in Spanish, in Portuguese): instructions sent to the laboratories participating in the exercise.

The exercise results report will be published soon.

Contact

For more information, contact interlaboratorio@intecmar.gal