Environmental and Health Assessment of Substances in Household Detergents and Cosmetic Detergent Products
13. Methods for ranking of substances and ingredients
| 13.1 | Environmental hazard assessment |
| 13.2 | Human health hazard assessment |
Comparison of the inherent environmental and toxicological properties of substances and
ingredients in detergents is frequently conducted in relation to formulation of new
products and environmental labelling. The methods presented in this Chapter are based on
internationally accepted principles for classification of single substances. A large
number of chemicals that are used in household detergents have been officially classified
on the basis of their potential toxicity to human health, whereas only very few of these
chemicals have been classified for their potential environmental hazards. The
implementation of the Directive 99/45/EC of the European Parliament and of the Council
implies that chemical preparations may be classified as dangerous for both human health
and for the environment. The methods for ranking of single substances are derived from the
criteria for the risk phrases (R-phrases) also forming the basis of the classification of
preparations in the Directive 99/45/EC. The relation between this Directive and the
ranking criteria implies that the ranking methods may contribute to the production and
request of products that will not be classified as dangerous for health or the
environment. However, the ranking is entirely based on the data evaluation by the authors
of this review, and the purpose has not been to recommend a classification of specific
substances. The ranking presented in this Chapter should be interpreted as a screening of
the potential hazards of the substances to health and the environment. Substitution of a
potentially hazardous substance identified on the basis of inherent properties is not
always the only solution, and substances may exist, where substitution is not attractive
for technical, economical, and even environmental and health based reasons. In such cases,
the ranking may be seen as a tool to identify substances for which a more thorough risk
assessment should be performed.
13.1 Environmental hazard assessment
The environmental hazard assessment is performed on the basis of the inherent properties of the substances. The method for environmental ranking of single substances is based on the weighting of R-phrases in the Directive 99/45/EC and follows commonly accepted criteria and data interpretation that are used for classification (Directive 67/548/EEC) and effects assessment for the aquatic compartment (EC 1996).
The inherent environmental properties are used for ranking of single substances in four main groups, i.e. environmental hazard classes 1-4, where class 4 contains the substances considered to have the lowest potential for environmental hazard (and vice versa). The environmental ranking system operates with a class 3A and a class 3. Class 3A contains substances with an acute aquatic toxicity corresponding to EC/LC50 £ 1 mg/l and for which other additional evidence suggests that the substances are environmentally less acceptable (than the substances in class 3) or that further investigations are necessary. Substances with an acute aquatic toxicity characterized by EC/LC50 £ 1 mg/l are placed in class 3A, if one or more of the following criteria apply:
| 1. | Limited ultimate biodegradability in aerobic tests for ready biodegradability (i.e. below pass level) due to sorption, toxicity or other inherent properties that preclude sufficient biodegradability under standard test conditions, provided that other convincing scientific evidence is available to demonstrate that the substance can be degraded to harmless products in the aquatic environment (> 70% within 28 days). The expert judgement of the scientific evidence may always be an issue of debate as long as no criteria have been defined for biodegradation simulation tests, their environmental relevance, and their technical quality. The substances with the above mentioned characteristics are, therefore, placed in class 3A, and a more thorough evaluation of the evidence proving a rapid degradation is recommended on a case by case basis. |
| 2. | Limited ultimate biodegradability under anoxic conditions as indicated by < 60% ThGP during 60 days in screening tests (e.g. ISO 11734), unless > 60% mineralization or complete primary degradation to harmless products is confirmed under relevant anoxic conditions. Recalcitrance under anoxic conditions may lead to an accumulation of the substance in aquatic sediments. Anaerobic biodegradability of surfactants is included in the criteria for environmental labelling (e.g., the Nordic Swan). |
| 3. | Indications for potential bioaccumulation in aquatic organisms as indicated by an experimentally determined BCF > 100 or a log Kow ³ 3.0. This additional criterion recognizes that indications for potential bioaccumulation may exist for some substances, although the evidence is not sufficient to fulfil the criteria for class 1. E.g., there are difficulties in the extrapolation from experimental data for defined model chemicals to more complex raw materials like, e.g., surfactants composed of several homologues and/or isomers. Such substances are placed in class 3A, because the potential bioaccumulation may imply a higher impact on the aquatic environment, e.g., when sub-lethal effects are considered. |
The criteria for environmental ranking of substances in the environmental hazard classes
1, 2, 3A, 3, and 4 are given below. Class 0 is used for substances for which the available
data are considered insufficient (Table 13.1).
Table 13.1
Criteria for environmental hazard assessment.
Environmental hazard class |
Explanations |
Class 0 |
The available data are insufficient |
Class 1 |
Acute aquatic toxicity: EC/LC50 £ 1 mg/l. The substance is not readily degradable, or the log Kow ³ 3.0 unless the experimentally determined bioconcentration factor (BCF) £ 100. |
Class 2 |
Acute aquatic toxicity: 1 mg/l < EC/LC50 £ 10 mg/l. The substance is not readily degradable, or the log Kow ³ 3.0 unless the experimentally determined bioconcentration factor (BCF) £ 100. |
Class 3A |
Acute aquatic toxicity: EC/LC50 £ 1 mg/l. The substances in this class have inherent properties that either make them less acceptable compared to the substances in class 3 or imply a need for further investigations. Substances with EC/LC50 £ 1 mg/l are placed in class 3A, if one or more of the following criteria apply: Ultimate biodegradability in ready biodegradability tests below the specified pass level provided that other convincing scientific evidence demonstrates rapid degradation to harmless products in the aquatic environment. Limited ultimate biodegradability under anoxic conditions as indicated
by Indications for potential bioaccumulation in aquatic organisms, but the data are considered insufficient to fulfil the criteria for class 1 (e.g. technical surfactants composed of several homologues and/or isomers). |
Class 3 |
Acute aquatic toxicity: EC/LC50 £ 1 mg/l. or: Acute aquatic toxicity: 10 mg/l < EC/LC50 £ 100 mg/l. The substance is not readily degradable. or: The substance is not readily degradable. The log Kow ³ 3.0 unless the experimentally determined bioconcentration factor (BCF) £ 100. or: The substance does not comply with the criteria mentioned above, but it is considered potentially hazardous to the aquatic environment on the basis of available evidence. |
Class 4 |
The substance does not comply with the criteria mentioned above, and it is not con-sidered hazardous to the aquatic environment on the basis of available evidence. |
The EU Technical Guidance Document recommends that the lowest of the relevant available
toxicity data (EC50 or LC50) is used for risk assessment, and that the effect
concentration is expressed as the arithmetic mean if more than one EC/LC50 value is
available for the same species (EC 1996). In order to obtain a high level of compliance
with internationally accepted criteria, the following approach was applied in the
environmental ranking presented in Table 13.5.
The EC/LC50 were derived by an evaluation of the available data describing the acute aquatic toxicity towards a number of commonly accepted species.
Algae
Selenastrum capricornutum (Pseudokirchneriella subcapitata)
Scenedesmus subspicatus
Chlorella sp.
Skeletonema costatum
Phaeodactylum tricornutum
Microcystis aeruginosa
Crustaceans
Daphnia magna
Daphnia pulex
Ceriodaphnia
Acartia tonsa
Brine shrimp (Artemia salina)
Scud (Gammarus pulex)
Nitocra spinipes
Mysid shrimp (Mysidopsis bahia)
Fish
Rainbow trout (Oncorhynchus mykiss)
Fathead minnow (Pimephales promelas)
Zebra fish (Danio rerio)
Bluegill sunfish (Lepomis macrochirus)
Medaka, Rice fish, Red killifish (Oryzias latipes)
Carp (Cyprinus carpio)
Golden orfe (Leuciscus idus melanotus)
Guppy (Poecilia reticulata)
Turbot (Scophthalmus maximus)
The geometric mean value was calculated if more than one EC/LC50 value was available for the same species. The geometric mean was preferred instead of the arithmetic mean, because the geometric mean implies that extreme toxicity values (‘outliers’) have less influence on the calculated mean value.
The effect concentrations (EC50 or LC50) that were obtained for the most sensitive species within one of the three trophic levels, algae, crustaceans, and fish, were used for the environmental ranking.
13.2 Human health hazard assessment
The ranking of human health effects are based on the EU-classification system. In this system classification of chemical substances and the assignment of R-phrases are performed on the basis of the inherent properties of the substances. The following different effect types are taken into consideration:
 | Acute toxicity |
| Corrosive/irritative effect |
| Organ toxicity |
| Allergy/sensibilization |
| Genotoxicity |
| Carcinogenicity |
| Reproductive toxicity |
| Neurotoxicity |
For substances classified in accordance with the EU-classification criteria (Annex 1), the official classification is used as guidance for the human health ranking. For substances, that are not officially classified, the human health ranking in this Chapter is based on the inherent toxicological properties of the substances.
The inherent toxicological properties are used for ranking of single substances in five "acute" health hazard classes (1-5) and five "subchronic/chronic" health hazard classes (A-E), where the classes 5 and E contain substances being considered to have the lowest potential for human health hazards (and vice versa).
The health hazard classes 1-5 describe the acute toxicological properties which cover acute toxicity, corrosive/irritative effects and organ toxicity. These toxicological effects are termed "acute effects". The health hazard classes A-E decribe chronic toxicological properties which cover allergy, neurotoxicity, carcinogenicity, genotoxicity and reproductive toxicity. These toxicological effects are termed "subchronic/chronic effects".
Class 1-3 and A-C are assigned to substances classified in accordance with the EU classification system. Class 4 and D are assigned to substances classified in accordance with the EU classification system, but also substances for which the evidence is too weak for classification, even though some evidence does exist. Class 5 and E include substances for which no evidence exists regarding human health or no concern exists based on existing evidence. Class 0 (acute effects) and 0 (chronic and sub-chronic effects) are assigned to substances for which there are no available data or the available data are not applicable in relation to the classification criteria.
The criteria for ranking the substances in the human health classes 1-5, A-E, and 0 are described in Table 13.2 and 13.3, respectively.
The health hazard class is stated for 100% pure substance, as well as for the substance diluted with a non-hazardous substance like water by use of the conventional method for product classification. However, it should be noted that the ranking of a substance in a health hazard class is a characterization of the health effect of a single substance and not a hazard assessment of a product containing the substances.
Table 13.2
Criteria for human health hazard assessment on acute, corrosive/irritative and organ
toxicity (acute effects)
Health hazard class |
Effect type |
Human health hazard criteria for acute effects |
||||
Class 0 |
All |
No data or available data not applicable to assessment of the human health hazard |
||||
Class 1 |
Acute toxicity |
Very high acute toxicity
|
||||
|
Corrosive/ Irritative effect |
Severely corrosive
|
||||
|
Organ toxicity |
Irreversible effects after a single exposure to low doses
|
||||
Class 2 |
Acute toxicity |
High acute toxicity
|
||||
|
Corrosive/ |
Corrosive
|
||||
|
|
Irritating to respiratory tract
|
||||
|
|
Severely damaging to eyes
|
||||
|
Organ toxicity |
Irreversible effects after a single exposure to medium doses
|
||||
Class 3 |
Acute toxicity |
Moderate acute toxicity
|
||||
|
Corrosion/ |
Irritating to skin and/or eyes
|
||||
|
Organ toxicity |
Irreversible effects after a single exposure to high doses
|
||||
Class 4 |
Acute toxicity |
Low acute toxicity
|
||||
|
Corrosive/ |
Mildly irritating to skin and/or eyes
|
||||
|
Organ toxicity |
No observed effect |
||||
Class 5 |
All |
No reason for concern with regard to health hazardous effects |
Table 13.3
Criteria for human health hazard assessment on allergy, neurotoxicity, carcinogenicity,
genotoxicity and reproductive toxicity (subchronic/chronic effects).
Health hazard Class |
Effect type |
Human health hazard criteria for subchronic/chronic effects |
||||
Class 0 |
All |
No data or available data not applicable to assessment of the human health hazard |
||||
Class A |
Allergy/ Sensibilisation |
Sensitising
|
||||
|
Neurotoxicity |
Severe effects after repeated or prolonged exposure of low doses
|
||||
|
Carcinogenicity |
Known carcinogenic to humans
|
||||
|
Genotoxicity |
Known mutagenic
|
||||
|
Reproductive Toxicity |
Known toxic to reproduction
|
||||
Class B |
Allergy/ Sensibilisation |
Sensitising
|
||||
|
Neurotoxicity |
Severe effects after repeated or prolonged exposure to medium doses
|
||||
| Carcinogenicity | Probably carcinogenic to humans
|
|||||
| Genotoxicity | Probably mutagenic
|
|||||
| Reproductive toxicity | Probably toxic to reproduction
|
|||||
| Class C | Neurotoxicity | Severe effects after repeated or prolonged
exposure to high doses
|
||||
| Carcinogenicity | Possibly carcinogenic to humans
|
|||||
| Genotoxicity | Possibly mutagenic
|
|||||
| Reproductive toxicity | Possibly toxic to reproduction
|
|||||
| Class D | Allergy/ Sensibilisation |
Sensitising Allergy has been found in a few isolated cases |
||||
| Neurotoxicity | No observed effect | |||||
| Carcinogenicity | Probably not carcinogenic to humans
|
|||||
| Genotoxicity | No observed effect | |||||
| Reproductive toxicity | No observed effect | |||||
| Class E | All subchronic/ chronic effects | No reason for concern with regard to health hazardous effects |
Table 13.4
Examples on human health ranking of substances.
Substance |
CAS No. |
Human health hazard classes |
|
pH regulators |
|
Acetic acid > 90% |
P64-19-7 |
1E |
Acetic acid, 25-90% |
|
2E |
Acetic acid, 10-25% |
|
3E |
Acetic acid < 10% |
|
4E |
Formic acid > 90% |
64-18-6 |
1E |
Formic acid, 10-90% |
|
2E |
Formic acid, 2-10% |
|
3E |
Formic acid, < 2% |
|
4E |
Table 13.5 Look here!
Ranking of substances in household detergents (gmv.: geometric mean value).