Substitution warning
The substitution of harmful chemicals is an
important part of the Harmonised Mandatory Control Scheme
(HMCS). The UK is obliged to implement the policy to replace
chemical substances identified as candidates for
substitution.
These substances are flagged with a substitution warning
on the product template.
Why might an offshore chemical be marked with a substitution warning?
If it:
- is on the OSPAR List of chemicals for priority action, or
- the List of chemicals of possible concern, or
- is considered by the authorising authority to be of equivalent
concern for the marine environment;
or
- is inorganic and has a LC50
or EC50 less than 1 mg/l;
or
- has a biodegradation of:
- <20% in OECD 306, marine BODIS or any other accepted marine
protocols, or
- <20% in 28 days in freshwater (OECD 301 and 310), or
- if half-life values >60 and 180 days from simulation tests
in marine water and sediment respectively (e.g. OECD 308,
309);
or
- meets two of the following three criteria:
- biodegradation:
- <60% in 28 days in OECD 306, marine BODIS or any other
acceptable marine protocol, or in the absence of valid results for
such tests (<60% in 28 days (OECD 301B, 301C, 301D, 301F, 310,
freshwater BODIS), or
- <70% in 28 days (OECD 301A, 301E), or
- bioaccumulation:
- BCF >100 or Log Pow ≥3 and molecular
weight <700, or
- if the conclusion of a weight-of-evidence expert judgement
under Appendix 3 of OSPAR Agreement 2008-5 is negative, or
- toxicity:
- LC50 <10mg/l or EC50 <10mg/l.
A reliable value of Log Pow cannot be calculated for
surfactants and therefore cannot be used to indicate whether a
surfactant might bioaccumulate. OSPAR requires regulatory
authorities to take a precautionary approach where data are
ambiguous or missing. So substitution warnings will be applied to
those surfactants that have a molecular weight of <700 and are
either:
- less than 60% or 70% biodegradable in 28 days (according to the
test protocol), or
- have an EC50/LC50 <10 mg/l
unless Cefas is satisfied that other evidence submitted by the
supplier indicates that the substance should not bioaccumulate.
Assessing bioaccumulation of surfactants
Under the HMCS pre-screening scheme the potential for a
substance to bioaccumulate is assessed according to its
Log Pow. It is not appropriate to
determine Log Pow values for surfactants
with the standard OECD test methods (OECD 107 Shake Flask and OECD
117 HPLC). This is due to the intrinsic properties of surfactants
(surface binding, accumulation at interfaces, emulsion formation)
and their resulting inability to partition between two phases.
The HOCNF also allows the BCF for a substance to be reported.
This value is determined experimentally in a full bioconcentration
test utilising either fish or a bivalve mollusc (OECD 305 and ASTM
E1022). Conducting these tests with surfactants is technically
challenging but may be possible in many cases by applying the
guidance in the following OECD documents:
- OECD series on testing and assessment No. 27: Guidance document
on the use pf the harmonised system for the classification of
chemicals which are hazardous for the aquatic environment
- OECD series on testing and assessment No. 23: Guidance document
on aquatic toxicity testing of difficult substances and
mixtures.
In the absence of any relevant scientifically robust data on a
substance from the standard OECD tests described above, Cefas will
apply the precautionary principle assuming the substance will
bioaccumulate. However, if there is robust scientific evidence (for
example from biodegradation studies, toxicokinetic studies,
including metabolism, residue or monitoring studies) that indicates
a substance is unlikely to bioaccumulate, Cefas will evaluate these
data and apply expert judgement.
During the risk-assessment process, operators are required to
consider the selection of products both in terms of the magnitude
of their Risk Quotient (RQ) and the presence of hazardous
substances, including candidates for substitution. Operators are
required to provide a robust defence for the continued use of
products that have a high RQ or contain candidates for
substitution.
Chemical suppliers must consider the advice they provide to
operators that justifies continued use of any product containing
candidates for substitution. In addition, suppliers should consider
a managed approach to the replacement of any undesirable
components, leading to the reformulation and re-certification of
products.
Cefas is happy to explain any substitution warning assigned to a
product, and to discuss any approach you may be considering in
addressing these issues.
Operators are encouraged to select products without a
substitution warning. Therefore, a supplier may wish to seek
alternatives at the product-development stage. However, there may
be good technical reasons why a particular substance cannot
immediately be substituted. The supplier should highlight these to
operators so that they can include this information in their
justification for continued use of the product.