Dangerous Goods by Road
The classification of a mixture shall be based on summation of the concentrations of its classified
ingredients. The percentage of ingredients classified as "Acute" or "Chronic" will feed straight into the
summation method. Details of the summation method are described in 2.2.9.1.10.4.6.1 to
2.2.9.1.10.4.6.4.
Mixtures may be made of a combination of both ingredients that are classified (as Acute 1 and/or
Chronic 1, 2) and those for which adequate toxicity test data are available. When adequate toxicity
data are available for more than one ingredient in the mixture, the combined toxicity of those
ingredients shall be calculated using the following additivity formulas (a) or (b), depending on the
nature of the toxicity data:
(a) Based on acute aquatic toxicity:
where:
Ci = concentration of ingredient i (mass percentage);
L(E)C50i = LC50 or EC50 for ingredient i (mg/l);
n = number of ingredients, and i is running from 1 to n;
L(E)C50m = L(E)C50 of the part of the mixture with test data;
The calculated toxicity shall be used to assign that portion of the mixture an acute hazard
category which is then subsequently used in applying the summation method;
(b) Based on chronic aquatic toxicity:
where:
Ci = concentration of ingredient i (mass percentage) covering the rapidly degradable
ingredients;
Cj = concentration of ingredient j (mass percentage) covering the non rapidly
degradable ingredients;
NOECi = NOEC (or other recognized measures for chronic toxicity) for ingredient i
covering the rapidly degradable ingredients, in mg/l;
NOECj = NOEC (or other recognized measures for chronic toxicity) for ingredient j
covering the non-rapidly degradable ingredients, in mg/l;
n = number of ingredients, and i and j are running from 1 to n;
EqNOECm = equivalent NOEC of the part of the mixture with test data;
The equivalent toxicity thus reflects the fact that non-rapidly degrading substances are
classified one hazard category level more "severe" than rapidly degrading substances.
The calculated equivalent toxicity shall be used to assign that portion of the mixture a longterm
hazard category, in accordance with the criteria for rapidly degradable substances (Table
2.2.9.1.10.3.1 (b) (ii)), which is then subsequently used in applying the summation method.
When applying the additivity formula for part of the mixture, it is preferable to calculate the toxicity
of this part of the mixture using for each ingredient toxicity values that relate to the same taxonomic
group (i.e. fish, crustacea or algae) and then to use the highest toxicity (lowest value) obtained (i.e.
use the most sensitive of the three groups). However, when toxicity data for each ingredient are not
available in the same taxonomic group, the toxicity value of each ingredient shall be selected in the
same manner that toxicity values are selected for the classification of substances, i.e. the higher
toxicity (from the most sensitive test organism) is used. The calculated acute and chronic toxicity shall
then be used to classify this part of the mixture as Acute 1 and/or Chronic 1 or 2 using the same
criteria described for substances.
If a mixture is classified in more than one way, the method yielding the more conservative result shall
be used.
Summation method
Classification procedure
In general a more severe classification for mixtures overrides a less severe classification, e.g. a
classification with Chronic 1 overrides a classification with Chronic 2. As a consequence the
classification procedure is already completed if the results of the classification is Chronic 1. A more
severe classification than Chronic 1 is not possible; therefore, it is not necessary to pursue the
classification procedure further.
Classification for category Acute 1
First, all ingredients classified as Acute 1 are considered. If the sum of the concentrations (in %) of
these ingredients is greater than or equal to 25% the whole mixture shall be classified as Acute 1.
If the result of the calculation is a classification of the mixture as Acute 1, the classification
process is completed.
The classification of mixtures for acute hazards based on this summation of the concentrations of
classified ingredients is summarized in Table 2.2.9.1.10.4.6.2.2 below.
Table 2.2.9.1.10.4.6.2.2: Classification of a mixture for acute hazards based on summation of the concentrations
of classified ingredients
|
Sum of the concentrations (in %) of ingredients
classified as:
|
Mixture classified as: |
| Acute 1 × M a ≥ 25% | Acute 1 |
a For explanation of the M factor, see 2.2.9.1.10.4.6.4.
Classification for categories Chronic 1 and 2
First, all ingredients classified as Chronic 1 are considered. If the sum of the concentrations (in %)
of these ingredients is greater than or equal to 25% the mixture shall be classified as Chronic 1. If
the result of the calculation is a classification of the mixture as Chronic 1 the classification
procedure is completed.
In cases where the mixture is not classified as Chronic 1, classification of the mixture as Chronic 2
is considered. A mixture shall be classified as Chronic 2 if 10 times the sum of the concentrations
(in %) of all ingredients classified as Chronic 1 plus the sum of the concentrations (in %) of all
ingredients classified as Chronic 2 is greater than or equal to 25%. If the result of the calculation is
classification of the mixture as Chronic 2, the classification process is completed.
The classification of mixtures for long-term hazards based on this summation of the concentrations
of classified ingredients is summarized in Table 2.2.9.1.10.4.6.3.3 below.
Table 2.2.9.1.10.4.6.3.3: Classification of a mixture for long-term hazards based on summation of the
concentrations of classified ingredients
|
Sum of the concentrations (in %) of ingredients
classified as:
|
Mixture classified as: |
| Chronic 1 × M a ≥ 25% | Chronic 1 |
| (M × 10 × Chronic 1) + Chronic 2 ≥ 25% | Chronic 2 |
a For explanation of the M factor, see 2.2.9.1.10.4.6.4.
Mixtures with highly toxic ingredients
Acute 1 or Chronic 1 ingredients with acute toxicities well below 1 mg/l and/or chronic toxicities
well below 0.1 mg/l (if non-rapidly degradable) and 0.01 mg/l (if rapidly degradable) may
influence the toxicity of the mixture and are given increased weight in applying the summation
method. When a mixture contains ingredients classified as acute or Chronic 1, the tiered approach
described in 2.2.9.1.10.4.6.2 and 2.2.9.1.10.4.6.3 shall be applied using a weighted sum by
multiplying the concentrations of Acute 1 and Chronic 1 ingredients by a factor, instead of merely
adding up the percentages. This means that the concentration of "Acute 1" in the left column of
Table 2.2.9.1.10.4.6.2.2 and the concentration of "Chronic 1" in the left column of Table
2.2.9.1.10.4.6.3.3 are multiplied by the appropriate multiplying factor. The multiplying factors to
be applied to these ingredients are defined using the toxicity value, as summarised in
Table 2.2.9.1.10.4.6.4 below. Therefore, in order to classify a mixture containing Acute 1 and/or
Chronic 1 ingredients, the classifier needs to be informed of the value of the M factor in order to
apply the summation method. Alternatively, the additivity formula (see 2.2.9.1.10.4.5.2) may be
used when toxicity data are available for all highly toxic ingredients in the mixture and there is
convincing evidence that all other ingredients, including those for which specific acute and/or
chronic toxicity data are not available, are of low or no toxicity and do not significantly contribute
to the environmental hazard of the mixture.
Table 2.2.9.1.10.4.6.4: Multiplying factors for highly toxic ingredients of mixtures
a Non-rapidly degradable.
b Rapidly degradable.
Classification of mixtures with ingredients without any useable information
In the event that no useable information on acute and/or chronic aquatic toxicity is available for one or
more relevant ingredients, it is concluded that the mixture cannot be attributed (a) definitive hazard
category(ies). In this situation the mixture shall be classified based on the known ingredients only
with the additional statement that: "x percent of the mixture consists of ingredient(s) of unknown
hazard to the aquatic environment.