Technical Expertise > Chemical Testing

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Standard Testing Methods
Liaison with Contract Laboratories

Standard Testing Methods

Testing of substances underpins key areas of national and international legislation concerned with placing and maintaining products in the market place. Results from physico-chemical, ecotoxicity and biodegradation tests are required for registration/notification and risk assessment of new substances and for risk assessment of existing substances. The core set of properties needed to make a basic evaluation of a substance is commonly referred to as the 'base set'.

A reliable understanding of chemical properties of a test substance is vital because:

Standardised test methods for the determination of the intrinsic properties of chemicals have been developed, and have been adopted as part of the core legislation for chemical assessment. The standardised methods are thorough, and stipulate specific details regarding test conditions and analytical methods. In some cases a particular approach may be recommended for substances that are volatile or relatively insoluble. These types of standards are important for the reliability and acceptability of the result and for the purposes of comparing results. The principles and most details of standard test protocols were originally developed through and published by OECD as test guidelines, and have been subject to peer review prior to full publication. The OECD guidelines are now freely available from the OECD. Click here to view them.

A degree of latitude is permitted and essential within the guidelines to allow for when testing 'difficult' substances - substances which are hard to test or analyse because of their properties and hence behaviour in the test or analytical system. Examples are highly volatile, insoluble or adsorbing substances. Specific guidance has been published on this subject. Click here to view.

The statutory EU standardised Test Methods for determining the hazardous properties of chemicals are contained in Annex V of Dir 67/548/EEC on the Classification, Packaging and Labelling of Dangerous Substances. Annex V is divided in three parts: Part A - physicochemical properties, Part B - human health effects, Part C - environmental effects, ecotoxicity and environmental fate (e.g. toxicity to fish, Daphnia or algae, bioconcentration, biodegradability). These same methods are implemented in Article 13 of the REACH Regulation.

Additionally, adherence to the principles of Good Laboratory Practice (GLP) ensures an audit trail for test data and enhances confidence in the reliability of the result and conclusions. New toxicological and ecotoxicological data generated for REACH must be conducted according to GLP, although this is not a requirement for physicochemical or substance characterization studies.

PFA scientists have considerable experience of conducting and managing regulatory test programmes gained from working in a GLP-compliant test laboratory. Now, in our capacity as consultants, we can bring this experience to bear in designing, placing and monitoring studies in contract testing laboratories on behalf of our clients. We have well-established links with some of the most highly regarded testing laboratories in the UK and Europe.

A particularly important aspect of the service we provide is that we bring our detailed understanding of the data needs of specific regulations to designing test protocols that will satisfy these needs. Our understanding is particularly important when dealing with what are commonly referred to as 'difficult substances'. It can be particularly frustrating and expensive for a sponsor with limited knowledge of testing options to find that the test protocol that they sign up to does not match the specific properties of the test substance and consequently does not provide the right data. Our objective is to avoid this unsatisfactory scenario occurring.

Liaison with Contract Laboratories

Contract laboratories have an important role in providing companies with the data required to meet regulatory requirements. The benefit of using contract skills is widely recognised.

Setting up contract studies in physical chemistry, ecotoxicology and toxicology requires a series of actions:

It is important to get the process right: in-depth knowledge of the regulatory guidelines and requirements of the study, and the properties of the test substance, are necessary. This process can be time-consuming - often requiring input equivalent to 20% of the basic study cost. This is expedient, however. Should difficulties arise from inappropriate study design, the costs of bringing the project back on track can be significantly higher and in exceptional circumstances repeat testing using a revised protocol may be necessary.

PFA have had first-hand experience of setting up contract studies and can perform all of the tasks associated with running contract studies on behalf of the client. Because the contract laboratory can liaise with our experts, their effectiveness is improved.

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Department APS, University of Sheffield