Alcohol Ethoxylates

244 Pages·2009·1.7 MB·English

Human & Environmental Risk Assessment on
ingredients of European household cleaning
products

Alcohol Ethoxylates

Version 2.0
September 2009

This version is based on the Version 1 (May 2007) where the equation 4.2 (page
24) has been corrected

All rights reserved. No part of this publication may be used, reproduced, copied, stored or
transmitted in any form or by any means, electronic, mechanical, photocopying, recording or
otherwise without the prior written permission of the HERA Substance Team or the involved
company.

The content of this document has been prepared and reviewed by experts on behalf of HERA
with all possible care and from the available scientific information. It is provided for
information only. Much of the original underlying data which has helped to develop the risk
assessment is in the ownership of individual companies.

HERA cannot accept any responsibility or liability and does not provide a warranty for any
use or interpretation of the material contained in this publication.
1
1. Executive summary
General
Alcohol ethoxylates (AE) are a major class of non-ionic surfactants which are widely
used in laundry detergents and to a lesser extent in household cleaners, institutional
and industrial cleaners, cosmetics, agriculture, and in textile, paper, oil and other
process industries.
Human health
The presence of AE in household detergents gives rise to a variety of possible
consumer contact scenarios including direct and indirect skin contact from its use in
laundry detergents, inhalation through the use of spray cleaners and oral ingestion
derived from residues deposited on dishes. The aggregate consumer exposure to AE
has been conservatively estimated to be at maximum 6.48 µg/kg bw/day.

A substantial amount of toxicological data and information in vivo and in vitro
demonstrates that there is no evidence for AEs being genotoxic, mutagenic or
carcinogenic. No adverse reproductive or developmental effects were observed. The
majority of available toxicity studies revealed NOAELs in excess of 100 mg/kg bw/d
but the lowest NOAEL for an individual AE was established to be 50 mg/kg bw/day.
This value was subsequently considered as a conservative, representative value in the
risk assessment of AE. The effects were restricted to changes in organ weights with
no histopathological organ changes with the exception of liver hypertrophy (indicative
of an adaptive response to metabolism rather than a toxic effect). It is noteworthy that
there was practically no difference in the NOAEL in oral studies of 90-day or 2 years
of duration in rats. A comparison of the aggregate consumer exposure and the
systemic NOAEL (taking into account an oral absorption value of 75%) results in a
Margin of Exposure of 5,800. Taking into account the conservatism in the exposure
assessment and the assigned systemic NOAEL, this margin of exposure is considered
more than adequate to account for the inherent uncertainty and variability of the
hazard database and inter and intra-species extrapolations.

AEs are not contact sensitizers. Neat AE are irritating to eyes and skin. The irritation
potential of aqueous solutions of AEs depends on concentrations. Local dermal effects
due to direct or indirect skin contact in certain use scenarios where the products are
diluted are not of concern as AEs are not expected to be irritating to the skin at in-use
concentrations. Potential irritation of the respiratory tract is not a concern given the
very low levels of airborne AE generated as a consequence of spray cleaner aerosols
or laundry powder detergent dust.

In summary, the human health risk assessment has demonstrated that the use of AE in
household laundry and cleaning detergents is safe and does not cause concern with
regard to consumer use.

Environment
The environmental risk assessment uses the “sum of toxic units” approach, in which
the ratio of the predicted environmental concentration (PEC) of each individual AE
homologue to the predicted no effect concentration (PNEC) of that AE homologue is
2
first calculated, and then the sum of these ratios, or “toxic units”, is calculated for all
AE homologues used in laundry cleaners and household cleaning products. Thus 230
different AE homologues, with hydrocarbon chain lengths from 8 to 18 and with
ethylene oxide chain lengths from 0 to 22, are considered in the AE environmental
risk assessment.

The environmental concentrations in river water are determined from measured
effluent concentrations from European sewage treatment facilities, using recently
developed analytical methods able to measure environmental concentrations of
individual AE homologues with hydrocarbon chain lengths from 12 to 18 and
ethylene oxide chain lengths from 0 to 18. These homologues cover more than 80% of
the tonnage used in laundry cleaners and household cleaning products. Conservative
estimates have been made for the concentrations of the other AE homologues, and
these are included in the risk assessment. The total local AE concentration in river
water receiving sewage effluent (PEClocal ) is 1.01µg/l.
dissolved

The equilibrium partitioning method has been used to predict the concentrations of the
individual AE homologues in river sediment from the river water concentrations.
Maximum values for soil concentrations have been estimated from measured
concentrations of several representative European sewage sludges. The local
sediment, soil, and sewage treatment plant concentrations have been determined as
1.01mg/kg wet sediment, 0.24 mg/kg wet soil, and 9.8 µg/l respectively, with the
sewage treatment plant concentration determined from the measured AE effluent
concentrations.

Two complementary methods, both based on high quality chronic effects data, are
used to determine the toxicity of the AE homologues in river water. The deterministic
method uses a recently published QSAR for the species with the best high quality
chronic information, Daphnia magna, with an application factor of 10. The
probabilistic method uses a chronic QSAR, recently developed using data from 17
different species and an application factor of 1, to predict the NOEC values for each
AE homologue. Equilibrium partitioning is then used to determine the toxicity of AE
homologues in sediment and soil, with the soil values being supported by acute and
chronic single homologue data for some AE homologues.

Two risk assessments, one using the deterministic (D) method and one using the
probabilistic method (P), have been carried out for the environmental concentrations
of AE used in laundry cleaners and household cleaning products. The resulting risk
assessment ratio (PEC/PNEC value) for all the AE homologues in surface water is
0.041 with the deterministic method (D), and 0.024 with the probabilistic method (P).
Risk assessment ratios are 0.316(D) and 0.181(P) in sediment, 0.103(D) and 0.068(P)
in soil, and 0.007 in the sewage treatment plant, where a simple method assuming the
acute data for the most toxic AE mixture applies to all AE has been used. As all the
risk assessment ratios are below 1, there is no cause for concern in any of the
environmental compartments.
In summary, AE usage in laundry cleaners and household cleaning products is not a
cause for concern in the EU environment, as shown by consideration of surface water,
sediment, sewage treatment facilities, and soil.
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Table of contents
1. Executive summary....................................................................................................2
General.......................................................................................................................2
Human health.............................................................................................................2
Environment...............................................................................................................2
Table of contents............................................................................................................4
3. Substance characterisation.........................................................................................9
3.1 CAS number and grouping information..............................................................9
3.2 Chemical structure and composition....................................................................9
3.2.1. Chemical Structure.......................................................................................9
3.2.2 Physicochemical Properties........................................................................10
3.2.2.1. Solubility in water...............................................................................10
3.2.2.2. Melting point.......................................................................................13
3.2.2.3. Boiling Point.......................................................................................14
3.2.2.4. Vapour pressure data and Henry’s Law constant...............................15
3.2.2.5. Log K ,K , and K information for AE homologues.......................16
ow oc d
3.3 Manufacturing route and production volume....................................................18
3.4 Homologue distribution in HERA applications.................................................19
4. Environmental assessment.......................................................................................21
4.1. Environmental Exposure Assessment...............................................................21
4.1.1. Environmental Fate....................................................................................21
4.1.1.1. Partitioning between environmental compartments............................21
4.1.1.1.1. Adsorption to soil, sediment, and activated sludge......................21
4.1.1.1.2. Volatilisation................................................................................25
4.1.1.2. Biotic and abiotic degradability..........................................................25
4.1.1.2.1. Abiotic degradation in water, soil, sediment, and air..................26
4.1.1.2.2. Ready tests for ultimate aerobic biodegradability.......................26
4.1.1.2.3. Primary biodegradability in river water.......................................32
4.1.1.2.4. Primary biodegradation in sewage treatment...............................36
4.1.1.2.5. Anaerobic biodegradability..........................................................37
4.1.1.3. Removal in sewage treatment.............................................................39
4.1.1.4. Bioconcentration.................................................................................40
4.1.2. PEC Calculations.......................................................................................42
4.1.2.1. Determination of PEC values for the aquatic compartment...............45
4
4.1.2.1.1. Description of the effluent monitoring data.................................45
4.1.2.1.2. The alcohol cap............................................................................46
4.1.2.1.3. Determination of the local 90% effluentmatrix for C12 to C18 AE

in European sewage treatment effluent........................................................47
4.1.2.1.4. Determination of the total local surface water concentration......48
4.1.2.1.5. Determination of the dissolved local surface water concentration
......................................................................................................................49
4.1.2.1.6. Extrapolation to C8-11 and EO 19-22 AE homologues.............51
4.1.2.1.7. Determination of the regional background contribution to
PEClocal values.................................................................................52
dissolved
4.1.2.1.8. Determination of PEClocal ...............................................56
dissolved
4.1.2.2 Determination of PEClocal .......................................................57
sediment
4.1.2.3. Determination of local concentrations in the sewage treatment plant60
4.1.2.4. Determination of local concentrations in the terrestrial environment 61
4.1.2.4.1 Determination of local concentrations in sewage sludge.............61
4.1.2.4.2 Determination of PEC ...............................................................64
soil
4.1.2.5 Summary of PEC Values.....................................................................65
4.2. Effects assessment............................................................................................66
4.2.1. Aquatic effects...........................................................................................66
4.2.1.1. Acute ecotoxicity information for alcohol ethoxylates.......................66
4.2.1.1.1. Acute toxicity to algae.................................................................67
4.2.1.1.2. Acute toxicity to Invertebrates.....................................................75
4.1.1.1.3. Acute toxicity to fish....................................................................84
4.2.1.2. Chronic QSARs for alcohol ethoxylates and their use in deriving
PNEC ........................................................................................................91
aquatic
4.2.1.2.1. Chronic eco-toxicity data for alcohol ethoxylates.......................91
4.2.1.2.2. Development of the chronic daphnia QSAR...............................97
4.2.1.2.3. Development of the chronic algal QSAR....................................99
4.2.1.2.4. Development of the chronic fish QSAR....................................101
4.2.1.2.5. Development of the mesocosm QSAR......................................101
4.2.1.2.6. Development of the probabilistic chronic QSAR......................101
4.2.1.2.7. Extension of the chronic Daphnia and probabilistic QSARs to C8,
and EO21 and 22........................................................................................104
4.2.1.2.8. PNEC determination for aquatic species...................................106
4.2.2. Alcohol ethoxylate toxicity to sediment organisms.................................115
4.2.3 Alcohol ethoxylate toxicity to sewage treatment plant organisms...........117
4.2.4. AE toxicity to terrestrial species..............................................................119
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4.2.4.1. PNEC calculated using equilibrium partitioning..........................119
soil
4.2.4.2. Acute soil toxicity data for AE commercial products and homologues
........................................................................................................................121
4.2.4.3. Chronic soil toxicity data for AE homologues.................................127
4.2.5 Summary of PNEC Information Location................................................128
4.3 Risk assessment...............................................................................................129
4.3.1. Risk assessment for aquatic species.........................................................129
4.3.2 Risk assessment for sediment species.......................................................131
4.3.3 Risk assessment for STP micro-organisms...............................................133
4.3.4 Risk assessment for terrestrial species......................................................133
4.3.5. Risk assessment summary........................................................................135
5. Human health assessment......................................................................................137
5.1 Consumer exposure..........................................................................................137
5.1.1 Product types.............................................................................................137
5.1.2 Consumer contact scenarios......................................................................137
5.1.3 Consumer exposure estimates...................................................................137
5.1.3.1 Direct skin contact from hand-washing laundry................................138
5.1.3.2 Direct skin contact from pre-treatment of laundry............................138
5.1.3.3 Direct skin contact from hand dishwashing.......................................139
5.1.3.4 Direct skin contact from surface cleaners..........................................139
5.1.3.5 Indirect skin contact from wearing clothes........................................140
5.1.3.6 Inhalation of detergent dust during washing processes.....................141
5.1.3.7 Inhalation of aerosols from cleaning sprays......................................142
5.1.3.8 Oral exposures to alcohol ethoxylates...............................................142
5.1.3.9 Accidental or intentional overexposure.............................................143
5.1.3.10 Total exposure..................................................................................143
5.2 Hazard assessment...........................................................................................144
5.2.1 Summary of the available toxicological data............................................144
5.2.1.1 Acute toxicity.....................................................................................144
5.2.1.1.1 Acute oral toxicity.......................................................................144
5.2.1.1.2 Acute inhalation toxicity.............................................................149
5.2.1.1.3 Acute dermal toxicity..................................................................150
5.2.1.2 Corrosiveness/irritation......................................................................152
5.2.1.2.1 Skin irritation..............................................................................152
5.2.1.2.2 Eye irritation...............................................................................157
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5.2.1.3 Sensitization.......................................................................................162
5.2.1.4 Repeated dose toxicity.......................................................................164
5.2.1.4.1 Oral route....................................................................................164
5.2.1.4.2 Inhalation....................................................................................169
5.2.1.4.3 Dermal route.......................................................................................169
5.2.1.4.4 Other routes of exposure.............................................................170
5.2.1.5 Genetic toxicity..................................................................................173
5.2.1.5.1 In vitro.........................................................................................173
5.2.1.5.2 In vivo..........................................................................................175
5.2.1.6 Carcinogenicity..................................................................................176
5.2.1.7 Reproductive toxicity.........................................................................177
5.2.1.8 Developmental toxicity/teratogenicity...............................................178
5.2.1.9 Toxicokinetics....................................................................................181
5.2.1.10 Experience with human exposure....................................................183
5.2.1.10.1 Skin irritation............................................................................183
5.2.1.10.2 Allergic contact sensitization....................................................184
5.2.1.10.3 Toxicokinetics...........................................................................186
5.2.2 Identification of critical endpoints............................................................187
5.2.2.1 Overview on hazard identification.....................................................187
5.2.2.2 Rationale for identification of critical endpoints...............................189
5.2.2.3 Adverse effects related to accidental exposure..................................189
5.2.3 Determination of NOAEL or quantitative evaluation of data...................190
5.3 Risk assessment...............................................................................................190
5.3.1. Margin of exposure calculation...............................................................190
5.3.1.1 Exposure scenario: direct skin contact from hand-washed laundry...191
5.3.1.2 Exposure scenario: direct skin contact from pre-treatment of clothes
........................................................................................................................191
5.3.1.3 Exposure scenario: direct skin contact from hand dishwashing........191
5.3.1.4 Exposure scenario: direct skin contact from hard surface cleaning...191
5.3.1.5 Exposure scenario: indirect skin exposure from wearing clothes......191
5.3.1.6 Exposure scenario: inhalation of dust during washing process.........191
5.3.1.7. Exposure scenario: inhalation of aerosols from cleaning sprays......192
5.3.1.8 Exposure scenario: oral route from residues left on dinnerware.......192
5.3.1.9 Exposure scenario: oral route from accidental ingestion and eye contact
........................................................................................................................192
5.3.2 Risk characterisation..........................................................................193
7
5.3.3 Summary and conclusion..........................................................................195
6. References..............................................................................................................197
7. Contributors to this risk assessment.......................................................................225
Annex I - CAS Numbers............................................................................................226
Annex II – Rationale for structure-based category....................................................230
Structure of alcohol ethoxylates.........................................................................230
Mammalian toxicokinetics.................................................................................231
Toxicological profile..........................................................................................232
Acute oral toxicity..........................................................................................232
Eye irritation..................................................................................................233
Repeated dose....................................................................................................233
Conclusion.........................................................................................................234
References..........................................................................................................234
Annex IIB – Rationale for structure-based category – Environmental Data supporting
the Definition of the AE Category used in this HERA report...................................235
Annex III. EUSES Calculations for the Environmental AE Assessments.................239
A III.1 Data used as Input for EUSES Calculations.............................................239
A III.1.1. EPI Calculations.................................................................................239
AIII.1.2. LogKow, MW, and Koc information from the CSARA AE Workbook
(ERASM 2005b)................................................................................................242
AIII.1.3. Additional Information.......................................................................244
AIII. 2. Outputs from EUSES Calculations...........................................................244
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3. Substance characterisation

Alcohol ethoxylates (AE) are a very widely used class of non-ionic surfactants.
Significant quantities of AE are converted to alcohol ethoxysulphates (AES) with the
remaining AE used primarily in household laundry detergents. AE have many
desirable characteristics such as rapid biodegradation, low to moderate foaming
ability, superior cleaning of man-made fibres and tolerance of water hardness. AE are
also used in lesser quantities in household cleaners, institutional and industrial
cleaners, cosmetics, agriculture, and in textile, paper, oil and other process industries.
Uses in household cleaning products, relevant to the HERA program of risk
assessments, include laundry detergents, hand dishwashing liquids, and various hard
surface cleaners. Chapter 5.1.1 details the household cleaning applications and typical
finished product concentration ranges of all AEs used in household products.

3.1 CAS number and grouping information

There are numerous CAS numbers describing AE. A comprehensive list is presented
in Annex I of this document. Although clearly important from a regulatory
perspective, the AEs covered in this assessment report are not characterized by CAS
numbers, but by a definition of their chemical structure in terms of the respective
carbon chain length and ethoxylation degree.

3.2 Chemical structure and composition

3.2.1. Chemical Structure

The AE family is defined for HERA purposes to be of the basic structure C AE .
x-y n
The subscript following the ‘C’ indicates the range of carbon chain units. AEs with
carbon unit range between C to C are most commonly used in household detergent
8 18
products. Further, AEs contain an ethylene oxide (E) chain attached to the alcohol.
The degree of ethylene oxide polymerization is indicated by a subscript which
indicates the average number of ethylene oxide units. In household products the
average ethylene oxide chain length commonly ranges between 3 and 12 units.
Two principle structures of AEs present in household cleaning products are presented
below.

O OH
H3C O O
Linear AE (C EO )
8 3

H C O OH
3
O O
CH3
Essential linear, methyl branched AE (C EO )
8 3

9
Further details on the structures included in the AE family are given in Section 3.3.,
with information concerning homologue distributions given in section 3.4.

3.2.2 Physicochemical Properties

The family of AE are composed of compounds that differ in chain length with respect
to the number of carbon units and the number of ethylene oxide units. The physico-
chemical properties of AE therefore span a broad range. Although very little specific
information is available concerning several of the physicochemical properties of
specific AE homologues, an extensive data set is available for the alcohols (the EO=0
homologues). In many cases it is possible to use the alcohol information to set upper
or lower limits for the specific physicochemical property for the other AE
homologues, and thus evaluate their chemical and physical chemical behaviour.

In general, information about several physicochemical properties of AE homologues
is necessary in order to carry out an environmental risk assessment according to the
principles of the EU TGD (2003), especially if the EUSES program is used to carry
out the assessment. The most important of these physicochemical properties are the
water solubility, the vapour pressure, the octanol/water partition coefficient or the
associated K 1 and K 2 values used to quantify adsorption onto various environmental
oc d
solids, and the Henry’s law constant, which quantifies the air/water partitioning
behaviour. However, melting point and boiling point information are also useful for
the environmental risk assessment. The experimentally available data are discussed
below. It is also possible to calculate these physical chemical properties for AEs,
using programs such as EPIWIN (US EPA 2000). Appendix III gives the physical
chemical properties calculated by EPIWIN for any AE isomers for which the
calculated value has been used in the HERA environmental AE assessment.

3.2.2.1. Solubility in water

The EU risk assessment protocol described in the TGD requires that information on
the solubility of a chemical be available, in order to ensure that aqueous
concentrations determined as part of the environmental risk assessment do not exceed
the solubility of the chemical in water, and to ensure that the chemical concentrations
used in eco-toxicity testing are below the limit of aqueous solubility. Although no
direct information is available for the other AE homologues, aqueous solubilities for
the alcohols (EO=0 homologues) have been collected as part of the long chain alcohol

1 K quantifies the adsorption onto organic carbon. It is useful for expressing
oc
adsorption onto environmental solids whose organic carbon content can be quantified,
and is used extensively in the EU TGD (2003) to describe adsorption to activated
sludge, suspended matter in surface waters, and solid particles in sediment and soil.
2 K quantifies the adsorption onto a specific solid type, such as sediment obtained
d
from a specific site. It incorporates the effects of hydrophilic and ionic or other
sorption mechanisms.
10