OCNS Toxicity Test Data
What tests need to be carried out for surface-active substances?
For substances classified as surface-active (surfactants) you will need to provide data from biodegradation, algae, crustacean and fish toxicity tests as well as data from a sediment re-worker toxicity test for product registration. No log Pow testing is required.
If you are unsure of whether a substance is surface active, you should carry out a surface tension test as per guideline
When can the fish test be waived?
Fish toxicity data may not be required for a substance if testing another species has already identified a substance for substitution. However, this waiver is at the discretion of the competent authority.
It should be noted that toxicity-test data for fish might reduce the penalty factor applied by CHARM when only two other species tests are available, and hence reduce the Hazard Quotient (HQ) and banding for a product. However, this will only be the case if the substance is the “driving” component in the product.
Can literature data be used to support the HOCNF submission?
Literature data can be used if the information is summarised and it meets the following criteria:
- the laboratory, which conducted the study, is Good Laboratory Practice (GLP) accredited (or accredited to an equivalent standard, i.e. USEPA). Evidence such as a copy of the GLP certificate or a link to the laboratory website must be provided
- the experiments are conducted to accepted internationally recognised protocols (i.e. OECD, ISO)
The summary should include:
- evidence that the laboratory was GLP-accredited
- test duration, appropriate to study protocol
- test species, appropriate to study protocol
- test result(s) using appropriate endpoints for protocol
- the full literature reference
The source of information should be easily accessible, by Cefas.
Cefas also accept Klimisch 2 data from non-GLP accredited sources.
For additional information, please see Criteria for accepting alternative toxicity data (PDF, 13.9 KB) and section 4 and 8 of the OCNS Toxicity Test Data FAQ.
What other types of toxicity data are accepted for completing the HOCNF?
Other information may be considered, when used in a weight-of-evidence approach.
Such information could include:
- data from in vitro or in vivo studies that have not been generated in accordance with the latest accepted version of the validated test method or to GLP (or equivalent)
- Quantative structure-activity relationship (QSAR) model outputs
- Simultaneous Autoregressive model outputs (SAR), read-across and category approaches
Cefas reserve the right to accept or reject literature data and weight of evidence as part of the registration process if the information is not clear or not relevant. Chemical suppliers should be prepared to provide more evidence or more detailed explanations if required by the assessor.
How is the No Observed Effect Concentrations (NOEC) used during chemical assessment in the CHARM model?
NOEC values can be used in the determination of Predicted No Effect Concentrations (PNECs) during Hazard Quotient calculation.
A No Observed Effect Concentration (NOEC) result reflects the lowest concentration that was tested and had no effect during a toxicity test.
What is limit testing and is it likely to affect the ranking of my company's products?
Where there is no existing fish-toxicity test data, it is recommended that a limit test is conducted using the LC50 or EbC50 of the most sensitive test species of the other taxonomic groups tested. If no significant mortality occurs in this limit test, it is unnecessary to undertake a full toxicity test and the endpoint of the fish test should be reported as greater than the concentration tested (> limit concentration).
Most substances exhibit a fairly similar degree of toxicity to both algae and crustacean, but there are occasions where a substance appears to be much more toxic to one class of organism. Should the apparent toxicity be found to be due to a physical effect, such as chelation, and not toxicity, OSPAR recommends that the limit test should be conducted at the LC50 or EbC50 of the other species that was tested.
Limit testing should be introduced to reduce the numbers of fish used in testing substances for HMCS. Results will only affect the ranking of products where the substance on which the HQ is based is more toxic to fish than to algae or crustaceans.
Why do surface active substances and substances which sink or have a log Pow of >4 require sediment re-worker testing?
If a substance is surface active it will interact with all surfaces not just oil or water. Surface active substances are often used because they are designed to coat pipelines and provide protective layers. Or be used in formation to create either water or oil wet conditions by interacting with the formation surface. This means that the substance will adhere to particulate matter, a surprising amount of which is found in the water column. Eventually the particles will sink to the seabed and form part of the substrate, the particles will routinely be cleaned/ eaten by sediment re-workers to remove food items and therefore toxicity testing is required.
What data from other sources that is not test data can be submitted for chemicals registration?
In some cases, toxicity test data can be substituted by non-test data such as;
- Good Quality Literature Data
- Weight of Evidence
- Quantitative Structure Activity Relationship (QSAR)
For more information please see: Common sources of non-test data
What is Cefas looking for when asking for a QSAR validation?
The following information is required by Cefas for the justification of QSAR use:
- What steps were taken to validate the QSAR and was this a scientifically appropriate way of validating the QSAR?
- Does the target chemical fit the profiles of the chemicals that the QSAR was validated against? - This information needs to be assessed and therefore provided; stating that a QSAR is widely accepted and has been peer reviewed since EVERY SINGLE QSAR model run is different. A QSAR platform may remain the same but be valid for one type of chemical and not another.
Why are QSARs not suitable for describing surfactants and / or UVCBs?
Generally, surfactants and UVCBs have aspects of their structure which are ‘unknown’; either the structures themselves are ambiguous, or the proportions within the mixture. While this is classed under OSPAR as a ‘substance’ and treated as a single entity. In addition to this, surfactants are often very complex with different groups next to each other or at different distances, all of which contribute to the uncertainty about the structure. A representative ‘structure’ cannot be used because the chemical may have different forms with varying toxicity. QSARs models are used to describe discrete chemical forms using measured data endpoints. Inferences cannot easily be made as to what a different form or proximity of one functional group to another may have on the level of toxicity shown by the chemical. One example of where a simple change in the chemical structure orientation showed severe effects on human health is thalidomide, which would not have ordinarily have presented a modelled negative outcome.
Another reason why QSARs cannot normally be used in the determination of either Log Pow or toxicity of surfactants is that in normal chemicals which act as ‘narcotics’ this is a toxic property which is directly related to the Log Pow. However log Pow cannot be accurately measured for UVCBs and surfactants as it is often inappropriate. Surfactants partition to both water and oil phases and/ or interact with the column matrix used in Log Pow determination. UVCBs are unsuitable for measurement using Log Pow because depending on the method of manufacture and the physical conditions during manufacture the composition changes within certain tolerances. However, to achieve a consistent ‘substance’ composition excess of some of the starting chemicals may remain unreacted, these might have partitioning to water or oil and cause major peaks at the detector such that not all the peaks are fully detected. There are also other structural effects that may reduce the detection of the eluted chemical fraction and therefore provide an error in the measurements undertaken.
Can the REACH dossier by used for offshore chemical product registration?
Substances registered under REACH have a dossier with the PBT data. The dossiers are available with the REACH registration number and can be freely accessed through the ECHA website. However, to use the data you must comply with the REACH agreement regarding use of that data and legal terms of agreement with the website. Generally, unless supplier have a letter of access to the test dossier the data from the ECHA website must not be used for commercial purposes.
When supplier have access to REACH dossier test report Cefas can accept it during chemical registration process if:
- the substance has been fully REACH registered,
- the data/ report has been assessed as being Klimisch 1 (reliable without restrictions) of Klimisch 2 (reliable with restrictions)
- the HOCNF has been filled in correctly with the test report date as it appears in the REACH dossier with the laboratory report id and a link to the exact report. Adjustments are made to the data if the purity of the substance is <100%
Which chemical substances are exempt and the persistence, bioaccumulation and toxicity (PBT) test data are not required for offshore chemical product registration?
The Annex V describes substances that can be exempt from OCNS registration, some of which (items 8 & 9) relate to naturally occurring, non-hazardous substances and are equivalent to the PLONOR list. However sometimes the PBT data is required.
To establish it expert judgement is carried out by Cefas team based on the guidance provided by ECHA.
During this process, the supplier may be required to provide additional supplementary information in a separate document to the HOCNF.
The document itself should highlight the reasons why the supplier believes that data requirements should be waived, and use literature to provide weight to the argument, for more information see ‘Weight of Evidence approach’.
If the qualifying criteria for exempt substance are not met it will not be accepted for registration without PBT data.