OCNS ecotoxicology testing

Tests required under the Offshore Chemical Registration

Each chemical substance is assessed on a “case by case” basis. More specific advice related to the test data required can be provided by the OCNS team once the types of substances that will be in the formulation are known. The OCNS team can discuss the suitability of each test approach before testing is commissioned.

Note: tests are required on all substances, unless they:

  • Are on the PLONOR list or
  • Are on the REACH Annex IV or
  • Satisfy the particular REACH Annex V criteria specified in the HOCNF Guidelines. 

Bioaccumulation data

Bioaccumulation data must be provided for organic substances.

Bioaccumulation testing can be carried out by: 

  • measuring the Log Pow using:
    • the standard OECD 117 HPLC test method. In order for this method to be applicable, Log Pow values must be in the range 0 to 6. The HPLC is not suitable for strong acids and bases, metal complexes, substances reacting with the eluent or surface-active agents
    • the standard OECD 107 Shake Flask method, which is applicable when, Log Pow values are
      between -2 and 4 (occasionally up to 5)
  • measuring the Bioconcentration factor (BCF) which is relevant for all deliberately added substances with a Log Pow >3 and can be determined experimentally in a full bioconcentration test when a substance is fully water miscible utilising either fish (OECD 305) or a bivalve mollusc (ASTM E1022). A filter feeding organism such as a bivalve mollusc would be more appropriate for substances that give rise to suspended particles
  • reliable computational methods for the calculation of Log Pow (to avoid laboratory testing). The calculations should be fully validated and justified (for more information see QSAR and ‘Read-Across’)

A substance of high molecular weight is less likely to bioaccumulate. OSPAR has agreed to recognise MW 700 as a limit for bioaccumulation. However, if Log Pow test results are not available because substance has a MW>700 and Cefas will apply the precautionary principle assuming the substance will bioaccumulate by using the range (0.1 -6.1) in the CHARM calculations. In this situation sediment reworker test data is required to assess the product and calculate the HQ.

Biodegradation data 

Biodegradability data must be provided for all relevant organic substances.

The following biodegradation protocol test data are accepted by Cefas

Please note that  freshwater biodegradation data will undergo an adjustment factor of 0.7 under CHARM, this factor is not applied during pre-screening. When submitting, freshwater data suppliers must quote the test result obtained as the results of these tests are automatically adjusted by CHARM and will incur a double penalty if they have already been adjusted.

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

Test requirements:  


  • OSPAR recommends test species Skeletonema costatum, or another suitable algae species if unavailable, a list of alternate species can be found in the test guidelines
  • The test protocol for Skeletonema costatum is ISO/DIS 10253 
  • The value that should be used to fill in the HOCNF is growth rate EbC50, not the value for biomass ErC50


OSPAR recommends test species Acartia tonsa, or another suitable crustacean species if unavailable (a list of alternate species can be found in Criteria for accepting alternative toxicity data to support an HOCNF application (PDF, 13.9 KB).

  • The test protocol for Acartia tonsa is ISO TC 147/SC5/WG2
  • The value that should be used to fill in the HOCNF is LC50 and NOEC


  • 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.

Fish-toxicity data may not be required for a component when a substance's dataset (algae/crustacean toxicity, biodegradation and/or Log Pow/BCF) indicates 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 (this will not be the case if other substances in the product dictate the HQ).

Sediment reworker

Sediment reworker ecotoxicity data is not mandatory but is required in the following circumstances, where a component has at least one of the following conditions are "sinkers"; or

  1. Have a Log Pow >3; or
  2. Have a Koc>1000; or
  3. Contain surfactants

* OSPAR recommend test species Corophium volutator, for which the protocol is PARCOM Protocol 1995 Pt A.

* The recommended test protocol is PARCOM Protocol 1995 Pt A.

* The value that should be used to fill in the HOCNF is LC50 and NOEC.

Further detail about the test species applicable can be found in the downloadable document Criteria for accepting alternative toxicity data to support a HOCNF application (PDF, 13.9 KB)


Additional laboratory testing guidance can be found in the Laboratory testing guidance document