Tall oil, sodium salt

Endpoint summary

Description of key information

Skin sensitisation

The following information is taken into account for any hazard/risk assessment:

No sensitisation data are available for Tall Oil Soap therefore good quality data for the related substance Crude Tall Oil have been read across. Crude Tall Oil was found to be sensitising in a murine local lymph node assay (LLNA) carried out in accordance with OECD Test Guideline 429 and in compliance with GLP (Weber, 2005).

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vitro

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Reference 2

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13.09.05 to 16.11.05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Winkelman GmbH
- Age at study initiation: approximately 8 weeks
- Weight at study initiation: 16.4-21.6 g
- Housing: Individually in Makrolon Type II cages.
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: Five days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 (average)
- Humidity (%): 64.8 (average)
- Air changes (per hr): No data
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: From: 14.09.05 To: 19.09.05

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

10, 25 and 50 % (v/v) equivalent to doses of 15, 37.5 and 75 mg, respectively.

No. of animals per dose:

Five

Details on study design:

RANGE FINDING TESTS:
- Compound concentration: 100 and 50%
- Irritation: No local skin irritation with either dose. There was a slight increase in ear thickness at the highest dose, but not at the lower dose.
- Lymph node proliferation response: Not measured.


MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA
- Criteria used to consider a positive response: if the test substance induces a three-fold or greater increase in 3HTdR incorporation into lymph node cells of test lymph nodes relative to that recorded for control lymph nodes, as indicated by the stimulation index, together with the consideration of dose response.


TREATMENT PREPARATION AND ADMINISTRATION: The test substance (25 µl/ear) was administered in three concentrations to the dorsal surfaces of the ears of the animals of the test substance groups. In a manner identical to that of animals in the treatment groups animals of one negative control group and one positive control group were treated with acetone/olive oil and hexyl cinnamic aldehyde, respectively. Each animal was treated for three consecutive days. Three days after the last administration the proliferation of the lymphocytes of the draining lymph nodes was measured by the determination of the amounts of incorporated 3HTdR (20 µCi of 3HTdR administered to mice via the tail vein).
Approximately 5 hours after 3HTdR injection all animals were sacrificed by carbon dioxide asphyxiation and the draining auricular lymph nodes were rapidly excised. The lymph nodes of each group were pooled in PBS. A single cell suspension (SCS) of lymph node cells (LNC) was prepared by gentle mechanical disaggregation of the pooled lymph nodes. The SCSs were then transferred into centrifuge tubes and LNC were pelleted by centrifugation. Afterwards supernatants were removed by aspiration. Then the LNC were resuspended and washed twice with PBS. After the final washing the supernatants were removed leaving just a small volume (<0.5 mL) and macromolecules were precipitated by incubation with 5 % trichloroacetic acid (TCA) at 4°C overnight. Each precipitate was pelleted by centrifugation and resuspended in 1 mL TCA. This suspension was transferred into scintillation vials containing 10 mL scintillation cocktail and 3HTdR incorporation was determined with a β-scintillation counter.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

No data

Positive control results:

Application of 25% HCA in AOO resulted in an SI of 5.3. This result proves the sensitivity of the strain of animals used and the reliability of the experimental technique.

Key result

Parameter:

SI

Value:

0.9

Test group / Remarks:

low dose group

Key result

Parameter:

SI

Value:

2.6

Test group / Remarks:

medium dose group

Key result

Parameter:

SI

Value:

2.9

Test group / Remarks:

high dose group

Key result

Parameter:

SI

Value:

1

Test group / Remarks:

negative control group

Key result

Parameter:

SI

Value:

5.3

Test group / Remarks:

positive control group

Key result

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Low, medium and high dose: 4338, 13098 and 19314. Negative control: 4955 Positive control: 26402

Interpretation of results:

Category 1 (skin sensitising) based on GHS criteria

Conclusions:

In a good quality Local Lymph Node Assay (reliability score 1) conducted according to OECD test guideline 429, and GLP, Crude Tall Oil (CAS 8002-26-4) was regarded as a skin sensitiser. It is considered valid to read across this result to the related substance Tall Oil Soap.

Executive summary:

Crude Tall Oil was diluted with acetone: olive oil (AOO), 4:1, v/v (10, 25 and 50% solutions) and was administered to three groups of five female CBA/Ca mice. Administration was performed epicutaneously to the dorsal surface of both ears, once per day on three consecutive days. The volume administered was 25 µl per ear. Positive (hexyl cinnamic aldehyde: HCA 25% in AOO) and negative (AOO) control substances were administered under identical conditions as the test substance. Five days after the first topical application, ³H-thymidine was intravenously administered to all mice via a tail vein. Approximately five hours later all animals were sacrificed, the draining auricular lymph nodes were excised, pooled for each group, and single cell suspensions were prepared. Then incorporation of ³H-methyl thymidine into the cells was determined and compared with the negative controls. The stimulation index (SI) was calculated as the ratio of the disintegrations per minute (DPM) of the dosed groups or of the positive control group to the DPM of the negative control group.

All animals survived until the end of the study, and no adverse effects were observed in any of the animals. Body mass gains were within the normal range for the strain, sex and age of the mice used. No skin irritating effects were observed in any of the groups. The SIs of the test substance were 0.9, 2.6 and 3.9 for the low, medium and high dose groups, respectively. The positive control group gave a SI of 5.3, thus demonstrating the validity of the test. According to the OECD test guideline a positive result should be regarded if the SI is equal to or greater than 3, together with consideration of the dose-response. Therefore it was concluded by the authors that Crude Tall Oil is sensitising to the skin.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

No sensitisation data are available for Tall Oil Soap, therefore, good quality data for the related substance Tall Oil have been read across. Crude Tall Oil was found to be sensitising in a murine local lymph node assay (LLNA) carried out in accordance with OECD Test Guideline 429 and in compliance with GLP (Weber, 2005). The stimulation indices of the test substance were 0.9, 2.6 and 3.9 for the low, medium and high dose groups, respectively. The positive control group gave a SI of 5.3, thus demonstrating the validity of the test. According to the OECD test guideline a positive result should be regarded if the SI is equal to or greater than 3, together with consideration of the dose-response. A concentration-dependent response was observed, therefore it was concluded by the authors that Tall Oil is sensitising to the skin.

Read-across justification:

Crude Tall Oil (CTO) is a UVCB substance comprising over eighty constituents, broadly described as fatty acids, rosin acids and neutrals. CTO is obtained from the neutralisation of Tall Oil Soap (TOS). TOS is obtained as a by-product from the Kraft Pulping process but contains the monosodium salts of the fatty acids and rosin acids, rather than the free acid. Since these are weak acids, and CTO has been shown in reliable, guideline studies to be non-corrosive and non-irritant, the toxicological behaviour of the sodium salts in vivo will be identical to that of the free acid constituents, because they will dissociate to the corresponding acid and Na⁺. Sodium is a ubiquitous, essential element in nature and will not contribute to the toxicology of Tall Oil Soap.

The sensitisation potential of abietic acid, breakdown products and other substances relevant to Tall Oil Distillates, which are also constituents of TOS was reviewed by the “Maximale Arbeitzplatz-Konzentration” (maximum workplace concentration) (MAK, 2013). The constituents included:15-hydroperoxyabietic acid methylester; 15-hydroperoxyabietic acid; 15-hydroperoxydehydroabietic acid methylester; 15-hydroperoxydehydroabietic acid; 7-oxodehydroabietic acid; abietic acid; abietyl alcohol; dehydroabietic acid; di(dehydroabietic acid-15-yl)peroxide; dihydroabietic acid; dismutated rosin; hydrated abietic acid; isopimaric acids; levopimaric acid; neoabietic acid; palustric acid; primaric acid; rosin acids; rosin;tetrahydroabietic acid; α-13,14-epoxyabietic acid methylester; α-epoxyabietic acid; β-13,14-epoxyabietic acid methylester; β-epoxyabietic acid (MAK, 2013).

Some of the human data gave conflicting results; however, the overall conclusion is potential for slight sensitisation for purified abietic acid. Some particular interesting results from the review study by MAK (2013) include that humans with pre-existing allergy to gum rosin had high positive sensitisation response to 15-hydroperoxyabietic acid which was also observed in animals. Similarly, 15-hydroperoxyabietic acid methylester in small concentrations was a significant sensitiser to animals. Moreover, subjects with pre-existing allergies towards plastics and adhesives had high proportion of positive sensitisation responses to abietic acid and rosin. Furthermore, MAK (2013) conclude that abietic acid does not stimulate an immune response i.e. is not an allergen itself, however, when becoming metabolised into an immunologically reactive form or is in the form of one of the oxidation products, abietic acid is a potent sensitiser in humans as well as in animals.

The data reviewed is summarised in the tables below. The information included skin sensitisation results obtained from human data following patch test, case reports as well as in vitro/in vivo animal data.

Since TOS contains 10-40% rosin acid sodium salts (typical ca. 23%), and typically approximately 10% by weight of sodium abietate, the positive animal and human sensitisation data for these constituent types support the conclusion that TOS would be expected to exhibit skin sensitising potential.

Table : Sensitisation potential of rosin and abietic acid and its derivatives in humans having contact dermatitis

Substance tested:	Already known allergy/sensitisation towards:	Total number of subjects:	Sensitisation reaction:	Percentage of positive reaction (%):	Reference cited:[1]
Abietic acid	Native/modified rosin	41	26	63	Geier & Hausen, 2000
Rosin	n/a	5755	156	2.7	Scheuer et al., 1992
Abietic acid	n/a	4246	29	0.7	Scheuer et al., 1992
Abietic acid	Plastics and adhesives	142	2	1.4	Kanerva et al., 1997
Abietic acid	Plastics & adhesive	343	3 (of clinical relevance)	0.9	Tarvainen, 1995
Rosin	Plastics & adhesive	8	8	100	Tarvainen, 1995
7-oxodehydroabietic acid (purified)	Rosin	20	20	100	Sadhra et al., 1996, 1997
Abietic acid (95 %)	Rosin (unmodified)	35	21	60	Sadhra et al., 1996
Abietic acid (99 %)	Rosin (unmodified)	35	19	54	Sadhra et al., 1996
Dehydroabietic acid	Rosin (unmodified)	35	0	0.0	Sadhra et al., 1996
Levopimaric acid	Rosin (unmodified)	35	6	17	Sadhra et al., 1996
Palustric acid	Rosin (unmodified)	35	5	14	Sadhra et al., 1996
Neoabietic acid	Rosin (unmodified)	35	3	8.6	Sadhra et al., 1996
Pimaric acid	Rosin (unmodified)	35	2	5.7	Sadhra et al., 1996
Isopimaric acid	Rosin (unmodified)	35	0	0.0	Sadhra et al., 1996
Rosin	Rosin (unmodified)	35	32	91	Sadhra et al., 1996
Rosin acid	Rosin (unmodified)	16	10	63	Sadhra & Foulds, 1995
Abietic acid (20%)	Rosin (unmodified)	16	12	75	Sadhra & Foulds, 1995
15-hydroperoxyabietic acid	Gum rosin	24	17	71	Karlberg & Gafvert, 1996
15-hydroperoxyabietic acid	Gum rosin	44	25	57	Karlberg & Gafvert, 1996
α-epoxyabietic acid	Gum rosin	12	1	8.3	Karlberg & Gafvert, 1996
α-epoxyabietic acid	Gum rosin	12	3	25	Karlberg & Gafvert, 1996
β-epoxyabietic acid	Gum rosin	12	2	17	Karlberg & Gafvert, 1996
β-epoxyabietic acid	Gum rosin	12	5	42	Karlberg & Gafvert, 1996
7-oxodehydroabietic acid	Gum rosin	11	6	55	Karlberg & Gafvert, 1996
7-oxodehydroabietic acid	Gum rosin	11	8	73	Karlberg & Gafvert, 1996
15-hydroperoxydehydroabietic acid	Gum rosin	10	0	0.0	Karlberg & Gafvert, 1996
Di(dehydroabietic acid-15-yl)peroxide	Gum rosin	7	0	0.0	Karlberg & Gafvert, 1996
Abietic acid	(Moderate contact allergy to) rosin	14	7	50	Soderberg et al., 1990
Neoabietic acid	(Moderate contact allergy to) rosin	14	3	21	Soderberg et al., 1990
Dehydroabietic acid	(Moderate contact allergy to) rosin	14	0	0.0	Soderberg et al., 1990
Isopimaric acid	(Moderate contact allergy to) rosin	14	0	0.0	Soderberg et al., 1990
Levopimaric acid	(Moderate contact allergy to) rosin	14	0	0.0	Soderberg et al., 1990
Abietic acid	Contact dermatitis	390	9	2.3	Wahlberg, 1978
Rosin	Contact dermatitis	390	15	3.8	Wahlberg, 1978
Abietic acid	Contact dermatitis	45	3 (also positive to 20% colophony in ethanol)	6.7	Wikstrom, 1969
Rosin	Contact dermatitis	45	10	4.5	Wikstrom, 1969

 

Table : Sensitisation potential of rosin, abietic acid and its derivatives in humans in case reports

 

Substance tested:	Already known allergy/sensitisation towards:	Sensitisation reaction:	Percentage of positive reaction (%):	Total number of subjects:	Reference cited:^[1]
Abietic acid	Colophonium allergy	Test: 13   Control: 11	11   0	85   0	Karlberg et al., 1991
Abietic acid	Rosin	10	0	0.0	Karlberg et al., 1985
Rosin	Rosin	13	13	100	Foussereau et al., 1980
Abietic acid	Rosin	13	7	54	Foussereau et al., 1980
Dihydroabietic acid	Rosin	12	3	25	Foussereau et al., 1980
Dehydroabietic acid	Rosin	10	4	40	Foussereau et al., 1980
Tetrahydroabietic acid	Rosin	11	1	9.0	Foussereau et al., 1980
Hydrated abietic acid	Rosin	9	2	20	Foussereau et al., 1980
Abietyl alcohol	Rosin	12	9	75	Foussereau et al., 1980
Dismutated Rosin (disproportionated rosin)	Rosin	11	2	18	Foussereau et al., 1980

Table : Sensitisation potential of abietic acid and its derivatives in animals

Substance tested:	Total number of subjects:	Sensitisation reaction:	Percentage of positive reaction (%):	Reference cited:^[1]
Abietic acid (non-purified)	Test: 20   Following challenge with rosin: 20	1   8	5   40	Karlberg et al., 1980
Abietic acid (99.8 %) purity	20	0	0	Karlberg et al., 1985
7-oxodehydroabietic acid	20	4	20	Karlberg et al., 1988b
7-oxodehydroabietic acid	Test (1 %): 20 Test (5%): 20 Petrolatum: 20 Control: 20	4 8 11 1	20 40 55 5	Karlberg et al., 1988b
Abietic acid (1 %)	10	4	40	Hausen et al., 1989
Abietic acid (10 %)	10	4	40	Hausen et al., 1989
Abietic acid methylester (1 %)   Abietic acid methylester (10 %)	10     10	5     10	50     100	Hausen et al., 1989
Dehydroabietic acid (1 %) Dehydroabietic acid (5 %) Dehydroabietic acid (10 %)	10   10   10	0   2   0	0   20   0	Hausen et al., 1989
Isopimaric acid (in the form of piperidine salt)	10	0	0	Hausen et al., 1989
Levopimaric acid in the form of salt (1 %) Levopimaric acid in the form of salt (5 %) Levopimaric acid in the form of salt (10 %)	10   10   10	3   7   6	30   70   60	Hausen et al., 1989
Neoabietic acid in the form of piperidine salt (1 %)   Neoabietic acid in the form of piperidine salt (5 %)   Neoabietic acid in the form of piperidine salt (10 %)	8     8     8	0     1     2	0     13     25	Hausen et al., 1989
Tetrahydroabietic acid (1 %)   Tetrahydroabietic acid (10 %)	10     10	3     5	30     50	Hausen et al., 1989
Palustric acid	10	4	40	Hausen & Hessling, 1990
Pimaric acid	10	0	0	Hausen & Hessling, 1990
Sandaracopimaric acid	10	1	10	Hausen & Hessling, 1990
13,14-epoxyabietic acid	10	6	60	Hausen & Hesslinh, 1990
15-hydroxydehydroabietic acid	10	0	0	Hausen et al., 1990
7-oxodehydroabietic acid (3 %)   7-oxodehydroxyabietic acid (10 %)	10     10	4     8	40     80	Hausen et al., 1990
α-13,14-epoxyabietic acid methylester (1 %)   α-13,14-epoxyabietic acid methylester (5 %)	15     15	13     15	86     100	Gafvert et al., (unknown year)
β-13,14-epoxyabietic acid methylester (0.2 %) β-13,14-epoxyabietic acid methylester (1 %) β-13,14-epoxyabietic acid methylester (5 %)	15   15   15	2   14   15	13   93   100	Gafvert et al., (unknown year)
15-hydroperoxyabietic acid	10	10	100	Gafvert et al., 1992
15-hydroperoxyabietic acid methylester (1 %) 15-hydroperoxyabietic acid methylester (5 %)	11   11	8   7	72   63	Karlberg et al., (unknown year)
15-hydroperoxydehydroabietic acid methylester (1 %)   15-hydroperoxydehydroabietic acid methylester (5 %)	15     15	13     14	86     93	Shao et al., 1995

[1]All references are cited in full in MAK, 2013.

Reference:
DFG, Deutsche Forschungsgeimenschaft. (2013).The MAK-Collection Part 1, MAK Value Documentations 2013.Wiley-VCH Verlag GmbH & Co. KGaA.

Justification for classification or non-classification

Several independent toxicologists have reviewed the available LLNA study with a view to whether Crude Tall Oil should be classified for skin and respiratory sensitisation based on these results. Their findings can be found in the following references: Mallett, A.K., (2006) A Regulatory Assessment of the Skin and Respiratory Sensitisation Potential of Crude Tall Oil. & Illing, P., (2005) Evaluation of Draft report 'Crude Tall Oil Skin Sensitisation Study (LLNA). The reviewers came to different conclusions regarding the need to classify, mainly due to the apparent weak skin sensitising potential of Crude Tall Oil. Illing (2005) concluded that since the criteria for classification do not differentiate between weak and moderate/strong sensitisers, Crude Tall Oil would probably require classification. However, this would be precautionary. Mallett (2006) noted that since most skin sensitisers are not respiratory sensitisers in humans, automatic classification of Crude Tall Oil as a respiratory sensitiser would be highly precautionary; the registrants do not consider that this classification is warranted.

On the basis of a reliable (reliability 1) murine local lymph node assay (LLNA) that was carried out in accordance with OECD Test Guideline 429 and in compliance with GLP with the related substance Crude Tall Oil (CTO), Tall Oil Soap is classified as Skin Sens. Cat.1B (H317: May cause an allergic skin reaction) in accordance with Regulation (EC) No 1272/2008.