OCNS ecotoxicology testing
Ecotoxicity data are required for offshore chemical products to help assess the potential environmental risk in the marine environment.
The OCNS requires bioaccumulation and biodegradation data, and aquatic toxicity data from three trophic levels (algae, crustacea and fish) to predict the potential ecosystem risk and, in turn, rank the product by Hazard Quotient (HQ).
The registration of a new chemical product will require a full set of ecotoxicity data on all components (except PLONORs [PDF, 176 KB] and those on the REACH (EC 1907/2006) Annex IV).
When completing the HOCNF for the mandatory or conditional toxicity tests, all toxicity fields must be completed. Where a value was not determined this should be stated on the HOCNF and a reason given.
Bioaccumulation data must be provided for all organic substances, with the exception of surfactants. This can be estimated by measuring Log Pow using the standard OECD test methods (OECD 107 Shake Flask and OECD 117 HPLC) or calculating the partitioning of the substances between water and n-octanol (Pow).
Reliable methods are now available for calculation of Log Pow for many types of organic substances and often laboratory testing can be avoided. Calculations should be fully validated and justified.
BCF data are also relevant. A BCF value can be determined experimentally in a full bioconcentration test utilising either fish or a bivalve mollusc (OECD 305 and ASTM E1022).
Biodegradability data must be provided for all relevant organic substances. For complex mixtures, individual information for all deliberately added substances is required.
Data from OECD 306, marine BODIS and other acceptable marine protocols can be submitted. In the absence of valid results for such tests data from OECD 301A-301F, OECD 310 and freshwater BODIS may be acceptable.
If the substance is found not to be readily biodegradable, or if a ready aerobic biodegradation test has not been performed, it will be assumed that the substance is persistent in aerobic conditions unless a simulation test (e.g. OECD 308, OECD 309) is performed, which indicates the opposite.
Aquatic ecotoxicity data
- OSPAR recommends test species Skeletonema costatum, or another suitable algae species if unavailable.
- The test protocol for Skeletonema costatum is ISO/DIS 10253.
- The value that is used should be growth rate EC50, not the value for biomass.
- OSPAR recommends test species Acartia tonsa, or another suitable crustacean species if unavailable.
- The test protocol for Acartia tonsa is ISO TC 147/SC5/WG2.
- OSPAR recommends the test species Scophthalmus maximus (juveniles); or Cyprinodon variegatus (juveniles). The recommended test protocol is the PARCOM Protocol 1995 part B.
- Limit tests are recommended to reduce the numbers of fish used in testing. Please see separate guidance.
- If a full fish test is required, the test protocol for the Scophthalmus maximus test (or other suitable species) - PARCOM Protocol 1995 Pt B - is recommended.
- Fish-toxicity data may not be required for a component when a substance's dataset (algae/crustacean toxicity, biodegradation and/or Log Pow/BCF) indicate that a substitution warning will be applied, regardless of the fish test result. The supplier is therefore advised to seek guidance from Cefas before commissioning tests.
Toxicity-test data for a fish test 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. This will only be the case if the individual substance data "drives" the HQ for the product.
Sediment-reworker-ecotoxicity data are not mandatory but are required in the following circumstances:
Where a component has at least one of the following conditions a sediment reworker test must be carried out:
- are "sinkers"; or
- have a Log Pow >4; or
- are in any other way known to adsorb to particles or end up in the sediment; or
- contain surfactants.
OSPAR recommend test species Corophium volutator, for which the protocol is PARCOM Protocol 1995 Pt A.
Cefas also actively encourages the use of literature data, where possible, providing that the data meet certain requirements. Please see the FAQs on OCNS toxicity-test data for more information.
Further detail about the test species applicable for the data submitted can be found in the downloadable document Criteria for accepting alternative toxicity data to support an HOCNF application (PDF, 13.9 KB).