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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

The category consists of alkyl sulfates with a predominantly linear alkyl chain length of C8-C18. Most chemicals of this category are not defined substances, but mixtures of homologues with different alkyl chain lengths (UVCBs). The most important common structural feature of the category members is the presence of a predominantly linear aliphatic hydrocarbon chain with a polar sulfate group, neutralized with a counter ion (i.e., Na+, K+, NH4+, or an alkanolamine cation). The hydrophobic hydrocarbon chain (with a length between C8 and C18) and the polar sulfate group confer surfactant properties and enable the commercial use of these substances as anionic surfactants. Common physical and biological pathways result in structurally similar breakdown products, and are, together with the surfactant properties, responsible for similar environmental behavior and essentially identical hazard profiles with regard to human health. The counter ion will not influence chemical reactivity and classification for the purpose of this assessment is not expected to be affected by the difference in counter ion (ref. OECD SIDS 2007, HERA Report 2002, Koennecker et al. 2011).

In aqueous environments the salts will dissociate, so that the counter ions will not fundamentally alter pathways of tissue disposition, metabolism, excretion, or target organs of toxicity. Accordingly no major differences were found in most of the endpoints between the compounds with different counter ions (ref. OECD SIDS 2007, HERA Report 2002, Koennecker et al. 2011). Moreover, several of the counter-ions have also been assessed in the OECD HPV Program and/or according to REACH Regulation (EC) No 1907/2006: triethanolamine (CAS 102-71-6), the ammonia category (CAS 7664-41-7; 1336-21-6; 7783-18-8; 12593-60-1) and ammonium salts, like ammonium sulfate (CAS 7783-20-2), chloride (CAS 12125-02-9) and bicarbonate (CAS 1066-33-7).

In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met. In particular for environmental fate and eco-toxicity, information shall be generated whenever possible including the use of information from structurally related substances. In this particular case the similarity of the alkyl sulfates category members is justified, in accordance with the specifications listed in Regulation (EC) No. 1907/2006 Annex XI, 1.5 Grouping of substances and read-across, is based on the scope of overlapping of composition, similar molecular structure, physico-chemical properties, toxicological, ecotoxicological profiles and supported by various QSAR methods.

 

Physico-chemical properties relevant for environmental fate of alkyl sulfates:

Physico-chemical characteristics of the substances in the category are similar, or follow regular patterns. The most important parameter influencing PC-properties is the varying length of the alkyl chain.

- Vapour pressure - as ionic substances, category members are characterized by low vapour pressures.

- Partition coefficient - as surfactants concentrate at hydrophilic/hydrophobic boundaries and do not equilibrate between phases, Pow is not a good descriptor of surfactant hydrophobicity and only of a limited predictive value for the partitioning of these compounds in the environment. Nevertheless, experimental Pow values have been obtained, usually as quotients of solubilities in octanol and in water. Partition coefficients are low (mostly negative values of log Pow) and they increase with the alkyl chain range.

- Water solubility - the solubility in water of the category members is high, in the range of 100-1000 g/L. Particular values decrease with the alkyl chain range.

 

Environmental fate and pathways of alkyl sulfates:

- All members of the alkyl sulfates category are well soluble in water.

- The substance is readily biodegradable. The same result was demonstrated in numerous studies for the whole category of alkyl sulfates.

- Abiotic degradation like hydrolysis is not a relevant for environmental pathway due to the chemical structure of the substances.

- All the substances in this category are essentially non-volatile, which implies that atmospheric photodegradation is irrelevant.

- As the log Pow-value is below 3, a potential for bioaccumulation can be excluded. The same trend is observed for all the other alkyl sulfates.

- Due to the low to moderate log Koc-values, it can be predicted that the sorption to sludge, sediments and soils will be relatively low.

- The members of alkyl sulfates category are unlikely to persist in the aquatic environment.

Table 1. Environmental fate and pathway: Alkyl Sulfates Category (overview):

ER - experimental result

RA - read-across

ID No.

Substance name

CAS No.

Biodegradability

Adsorption/Desorption [log Koc]

# 1

Sodium dodecyl sulfate

151-21-3

ER: readily biodegradable 95% (28d)

ER: 2.5 – 2.65

# 2

Sulfuric acid, mono-C12-13 (branched and linear)-alkyl esters, sodium salts

1231880-35-5

RA from 91783-23-2: readily biodegradable 95.3% (28d)

RA from 151-21-3, 3026-36-9: 2.5– 2.8

# 3

Sulfuric acid, mono-C12-14 (even numbered)-alkyl esters, sodium salts

85586-07-8

RA from 68585-47-7: readily biodegradable 75.7% (28d)

RA from 151-21-3, 1191-50-0: 2.5 – 3.19

# 4

Sulfuric acid, mono-C12-14 (even numbered)-alkyl esters, ammonium salts

90583-11-2

RA from 68585-47-7: readily biodegradable 75.7% (28d)

RA from 151-21-3, 1191-50-0: 2.5 – 3.19

# 5

Sulfuric acid, mono-C12-16 (even numbered)-alkyl esters, sodium salts

73296-89-6

ER: readily biodegradable 100% (28d)

RA from 151-21-3, 1191-50-0 : 2.5 – 3.19

# 6

Sulfuric acid, mono-C12-18 (even numbered)-alkyl esters, sodium salts

68955-19-1

ER: readily biodegradable 93% (28d)

RA from 151-21-3, 1191-50-0: 2.5 – 3.19

# 7

Sodium etasulfate

126-92-1

ER: readily biodegradable 89.35% (28d)

RA from 142-31-4: 1.88 – 2.0

# 8

Sodium octyl sulfate

142-31-4

ER: readily biodegradable 93.5% (29d)

ER: 1.88 - 2.0

# 9

Sodium nonyl sulfate

1072-15-7

RA from 142-87-0: readily biodegradable 92% (30d)

RA from142-31-4, 142-87-0: 1.88 - 2.25

# 10

Sodium decyl sulfate

142-87-0

ER: readily biodegradable 92% (30d)

ER: 2.09 - 2.25

# 11

Lithium dodecyl sulfate

2044-56-6

RA from 151-21-3: readily biodegradable 95% (28d)

RA from 151-21-3: 2.5 - 2.65

# 12

Sodium 2-butyloctyl sulfate

94200-74-5

ER: readily biodegradable 100% (28d)

RA from 151-21-3: 2.5 - 2.65

# 13

Sulfuric acid, mono-C8-10 (even numbered)-alkyl esters, sodium salts

85338-42-7

RA from 142-31-4, 142-87-0: readily biodegradable 92% (30d)

RA from 142-31-4, 142-87-0: 1.88 - 2.25

# 14

Sulfuric acid, mono-C10-12 (even numbered)-alkyl esters, sodium salts

85049-86-1

RA from 142-87-0, 151-21-3: readily biodegradable 95% (28d)

RA from 142-87-0, 151-21-3: 2.09 - 2.65

# 15

Sulfuric acid, mono-C8-14 (even numbered)-alkyl esters, ammonium salts

90583-10-1

ER: readily biodegradable 96% (28d)

RA from 142-31-4, 142-87-0, 151-21-3, 1191-50-0: 1.88 - 3.19

# 16

Sulfuric acid, mono-C8-14 (even numbered) -alkyl esters, compds. with triethanolamine

85665-45-8

ER: readily biodegradable 92% (30d)

RA from 142-31-4, 142-87-0, 151-21-3, 1191-50-0: 1.88 - 3.19

 

# 17

Sulfuric acid, mono-C8-14 (even numbered)-alkyl esters, ammonium salts, compds. with triethanolamine

96690-74-3

RA from 85665-45-8, 90583-10-1: readily biodegradable 92% (30d)

RA from 142-31-4, 142-87-0, 151-21-3, 1191-50-0: 1.88 - 3.19

# 18

Sulfuric acid, mono-C8-18 (even numbered)-alkyl esters, magnesium salts, compds. with triethanolamine

85586-38-5

RA from 142-31-4, 142-87-0, 151-21-3, 1191-50-0, 68955-20-4, 90583-18-9, 68140-10-3, 68955-19-1: readily biodegradable > 77% (30d)

RA from 142-31-4, 142-87-0, 151-21-3, 1191-50-0, 1120-01-0: 1.88 - 3.9

# 19

Sulfuric acid, mono-C12-14 (even numbered)-alkyl esters, potassium salts

1268005-68-0

RA from 151-21-3, 1191-50-0, 90583-18-9, 73296-89-6: readily biodegradable 79.8% (28d)

RA from 151-21-3, 1191-50-0: 2.5 – 3.19

# 20

Sulfuric acid, mono-C12-14 (even numbered)-alkyl esters, compds. with triethanolamine

90583-18-9

ER: readily biodegradable 77% (30d)

 

RA from 151-21-3, 1191-50-0: 2.5 – 3.19

# 21

Sulfuric acid, mono-C16-18 and 18 unsaturated (even numbered)-alkyl esters, sodium salts

1394155-71-5

RA from 68955-20-4: readily biodegradable 77% (30d)

Recalculation based on RA from 142-31-4, 142-87-0, 151-21-3, 1191-50-0: 3.5 - 3.9

# 22

Sulfuric acid, mono-C16-18 (even numbered)-alkyl esters, sodium salts

68955-20-4

ER: readily biodegradable 77% (30d)

Recalculation based on RA from 142-31-4, 142-87-0, 151-21-3, 1191-50-0: 3.5 - 3.9

# 23

Sodium tetradecyl sulfate

1191-50-0

ER: readily biodegradable 79.1% (29d)

ER: 3.13 - 3.19

# 24

Sodium hexadecyl sulfate

1120-01-0

--

--

# 25

Sodium octadecyl sulfate

1120-04-3

--

--

# 26

Sulfuric acid, monotallow alkyl esters, sodium salts

68140-10-3

ER: inherently biodegradable 99.2% (21d)

Recalculation based on RA from 142-31-4, 142-87-0, 151-21-3, 1191-50: 3.912

# 27

Sulfuric acid, mono-C10-16 (even numbered)-alkyl esters, sodium salts

68585-47-7

ER: readily biodegradable 75.7% (28d)

RA from 142-31-4, 142-87-0, 151-21-3, 1191-50-0, 1120-01-0: 1.88-3.515

# 28

Sulfuric acid, mono-C10-16 (even numbered)-alkyl esters, ammonium salts

68081-96-9

--

--

# 29

Sulfuric acid, mono-C10-16 (even numbered)-alkyl esters, magnesium salts

68081-97-0

--

--

# 30

Sulfuric acid, mono-C12-15-alkyl esters, sodium salts

68890-70-0

--

--

# 31

Sulfuric acid, mono-C12-13-alkyl esters, sodium salts

91783-23-2

ER: readily biodegradable 95.3% (28d)

RA from 151-21-3, 3026-36-9: 2.5 – 2.8

# 32

Sulfuric acid, mono-C12-13-alkyl esters, potassium salts

91783-22-1

--

--

# 33

Sulfuric acid, mono-C12-14-alkyl esters, magnesium salts

90583-23-6

--

--

# 34

Sulfuric acid, mono-C12-16-alkyl esters, ammonium salts

90583-12-3

--

--

# 35

Sulfuric acid, mono-C13-15 (odd numbered)-alkyl esters, sodium salts

86014-79-1

--

--

# 36

Sulfuric acid, mono-C14-18 (even numbered)-alkyl esters, sodium salts

68081-98-1

--

--

# 37

Sulfuric acid, mono C14-18 and C18-unsatd. (even numbered) alkyl esters, sodium salts

90583-31-6

--

--

# 38

Sulfuric acid, coco alkyl mono-ester, ammonium salts

90989-98-3

--

--

# 39

Sulfuric acid, palm kernel-oil mono-ester, ammonium salts

223705-48-4

--

--

# 40

Sulfuric acid, mono C14-18 and C16-18-unsatd. (even numbered) alkyl esters, sodium salts

85681-68-1

--

--