Absolute of Boswellia Carterii (Burseraceae) obtained from exudate by hexane treatment and subsequent ethanol extraction

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2017-08-29 to 2017-11-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Principles of method if other than guideline:

Not relevant.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

No data.

Analytical monitoring:

yes

Details on sampling:

Duplicate samples for analysis were taken from the control and all test solutions at the start (t=0h), at t=24h (new and old solutions) and at the end of the test (t=48h). Concentration of dissolved organic material was checked by analysis of Total Organic Carbon (TOC) in the control medium and the WAFs. TOC analysis was not performed in compliance with the OECD GLP principles but was adapted to fit the specific parameters of the test item, in accordance with ISO 17025.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
The study was carried out using WAFs (Water Accommodated Fractions). The WAFs (for fresh media at t=0h and t=24h) were prepared under closed conditions and by slow-stirring.
The mixing vessels were cylindrical glass bottles sealed with screw caps and fitted with a drain port near the bottom for drawing off the WAFs. The volume of each mixing vessel was approximately 1 L. A magnetic stirring bar was placed in each mixing vessel completely filled with test water (with a minimum of headspace). After heating of the test item sample to approx. 50°C for about 4 hours, the loading rates of the test item were weighed in glass flasks (approximate volume: 100 mL) filled with minimum headspace with test water (from the mixing vessel) and were immediately sealed with screw caps after weighing. After having tried different methods for the preparation of the WAFs in the preliminary study, the following protocol has been selected for the final test: each glass flask was placed in a water bath for 10-15 minutes at approx. 50°C, followed by sonication for approx. 10 minutes. Based on experience on similar substances, the heating/sonication step is a method allowing to remove the paste fragments stuck to the glass of the flasks and to extract the soluble fraction of the test item as much as possible.
Then the mixing vessels were carefully filled with the contents of the glass flasks and thereafter were closed immediately. The mixing was initiated with the vortex in the centre extending maximally around 10% vessel depth from the top to the bottom of the vessel. After 24 +/- 2 hours of gentle stirring in the dark at room temperature, the WAFs were allowed to stand for 1 hour before use. The first 100 mL were removed via the drain port. Then the WAFs were filtered and added into test vessels that were immediately sealed with screw caps after introduction of daphnids. No small bubble was observed in the test vessels. The test solution in test vessels was observed to be clear and colourless. The test was carried out without adjustment of the pH.

Controls: Test water without test substance but treated in the same way as the test substance solution.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Species: Daphnia magna (Straus), clone 5
- Sex: Female
- Origin: LIEBE - CNRS UMR 7146 - UFR SciFA - Université de Lorraine Campus Bridoux - Bât. IBISE, 8, rue du Général Delestraint - 57070 METZ, bred in the Laboratoires des Pyrénées et des Landes.
- Validity of batch: Daphnids originated from a healthy stock, showing no signs of stress such as mortality, presence of males, ephippia or discoloured animals.
- Age at test start: < 24 hours old
- Reason for selection: Characteristic and common representative of freshwater zooplankton which has been selected as an internationally accepted invertebrate species.
- Breeding conditions: Daphnids were cultured in the Laboratoires des Pyrénées et des Landes under similar temperature and light conditions as used in the test. The cultivation of the parental daphnids was performed in all-glass vessel containing test water. Cultures were maintained at a density of 1 adult daphnid per 25 mL of culture medium. Daphnids were fed at least three times a week with a suspension of algal cells (Pseudokirchneriella subcapitata) up to 0.1-0.2 mg C.Daphnia.-1day.-1. The water was changed three times a week. These culture conditions maintained the daphnids in the parthenogenetic reproductive stage.
- Feeding during test: No feeding

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Remarks on exposure duration:

None

Post exposure observation period:

No data

Hardness:

Total water hardness was approximately 250 mg/L (as CaCO3)

Test temperature:

20°C ± 2°C

pH:

8.14-8.61

Dissolved oxygen:

7.82-8.68 mg test item.L-

Salinity:

No data.

Conductivity:

No data.

Nominal and measured concentrations:

Nominal : 100 mg/L (loading rate of the substance)

Details on test conditions:

TEST SYSTEM
- Test vessels: All-glass test tubes of approximately 20 mL capacity sealed with screw caps. Each test vessel was uniquely identified with study code, replicate number, date of experimentation and treatment group.
- Aeration: No aeration of the test solutions occurred throughout the test.
- Renewal rate of test solution: A semi-static test was performed with renewal of test solutions after 24 h (because of the properties of the test item)
- No. of daphnids: 20 per treatment group (control and loading rate of 100 mg.L-1), divided into 4 groups of 5 animals
- Loading: 5 daphnids per vessel each completely filled with test solution and without headspace.
- Number of replicates: 4 replicates with daphnids per treatment group.
- Introduction of Daphnids: Daphnids were introduced into the test vessels each completely filled with test solution and without headspace immediately after filling the test vessels with test solutions.

TEST MEDIUM / WATER PARAMETERS
- Test water: Reconstituted water (Elendt M4 medium), as prescribed by OECD Guideline 202.

OTHER TEST CONDITIONS
- Photoperiod: 16 h light : 8 h dark

EFFECT PARAMETERS MEASURED:
- Immobility: Immobility and abnormal behaviour were determined by visual observation after 24 and 48 hours. Immobile animals were eliminated from the vessels as soon as they were discovered. Daphnids were considered to be immobile if they were not able to swim within 15 seconds after gentle agitation of test vessels.
- pH and dissolved O2: At start (t=0h), at t=24h (new and old solutions) and at the end of the test (t=48h) from all treatment group.
- Temperature of Medium: Measured continuously in a temperature controlled vessel next to the test vessels, over the entire study period, beginning at the start of the test.

TEST CONCENTRATIONS
- Range finding study: Ten daphnids per concentration (5 per vessel, in duplicate) were exposed to the nominal loading rates 1, 10, 32, 100 mg.L-1 and to a control. Two method of preparation for the WAFs have been tried: heating/sonication and solvent conditions. Both conditions showed no daphnids immobilisation at every tested concentrations.
- Results used to determine the conditions for the definitive study: After the range-finding study, it has been decided to do a limit tests with a loading rate of 100 mg test substance/L for the final test.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

24 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

The evaluation was based on the nominal WAFs concentrations.
After 24 and 48 hours of exposure, no immobilisation of the test animals was observed in the control and the loading rate of 100 mg.L-1, confirming the observations of the range-finding test. Based on these results, the 24 and 48-hour EL50 values were therefore > 100 mg.L-1.

Results with reference substance (positive control):

On August 17, 2017 (most recent test), the 24h-EC50 was 0.92 mg.L-1. Hence, the sensitivity of the clone of Daphnia magna was in agreement with OECD 202 (expected 24h-EC50: 0.6 mg.L-1 to 2.1 mg.L-1) at this time.

Reported statistics and error estimates:

Not applicable (limit test).

Analytical results

Concentration of dissolved organic material in the control and the loading rate of 100 mg/L was checked by TOC analysis at start (t=0h), at t=24h (new and old solutions) and at the end of the test (t=48h).

Due to the complex nature of the substance, it was difficult to well solubilize the substance in the water medium (heating, sonication, mixing without headspace …). Even if the TOC analyses indicated that very few organic compounds were found (around 2 mg Carbon/L) throughout the test in the WAFs at 100 mg/L, analytical results showed that WAFs concentrations were overall stable between the start and the end of each exposure period (t=0h-t24h_Old and t=24h_Fresh-t =48h). It should be noted that a WAF is by definition a complex mixture for which the individual concentration of each constituent differs due to its properties (e.g. solubility, adsorption, volatilisation, bioaccumulation…). Due to these differences, interactions between certain constituents of the mixture may occur and affect the behaviour of a given constituent which consequently would not react in the same way that if it was alone in the mixture.Therefore, and since the test item was a UVCB substance, the results were based on the nominal test loading rates.

Acute immobilisation of daphnids after 24 and 48 hours in the final test

Nominal concentration*(mg test item.L^-1)	Replicate	Number of daphnids exposed	Response at 24h		Response at 48h
			Number	Total %	Number	Total %
Control	1 2 3 4	5 5 5 5	0 0 0 0	0	0 0 0 0	0
100	1 2 3 4	5 5 5 5	0 0 0 0	0	0 0 0 0	0

* WAF prepared at the given loading rate.

Validity criteria of the study

Controls: In the control, no daphnids became immobilised nor trapped at the surface of the water nor showed signs of stress.

Dissolved [0₂]_: Dissolved oxygen concentration at the end of the test was ≥ 60% of the air-saturation value in controls and test vessels (see Table 3). 

Thus the validity criteria have been fulfilled in the present study.

Validity criteria fulfilled:

yes

Conclusions:

Under the experimental conditions and based on nominal loading rates, the 48-hour EL50 was estimated to be higher than 100 mg/L.

Executive summary:

A study was performed to assess the acute toxicity of test item OLIBANUM RESINOIDE to Daphnia magna. The method followed was designed to be compliant with OECD Guideline for Testing of Chemicals No. 202, “Daphnia sp., Acute Immobilisation Test”, referenced as Method C.2 of Commission Regulation No. 440/2008 (amended byCommission Regulation (EU) 2016/266)(2) and with the “Guidance document on aquatic toxicity testing of difficult substances and mixtures” (OECD No. 23).

A limit test was performed following the results of a range-finding test. Twenty daphnids (four replicates, five daphnids per replicate) were exposed to Water Accommodated Fractions (WAFs) of the test item at a nominal loading rate of 100 mg test item/L and to a control.The immobility of the daphnids was determined in a closed semi-static 48-hour test by visual observation after 24 and 48 hours.Concentration of dissolved organic material in the control and the WAFs was checked by TOC analysis at start (t=0h), at t=24h (new and old solutions) and at the end of the test (t=48h).

Even if the TOC analyses indicated that very few organic compounds were found (around 2 mg Carbon/L) throughout the test in the WAFs at 100 mg/L, analytical results showed that WAFs concentrations were overall stable between the start and the end of each exposure period.

After 24 and 48 hours of exposure, no immobilisation of the test animals was observed in the control and the loading rate of 100 mg/L. Under the experimental condtions and based on nominal loading rates, the 48-hour EL50 was estimated to be higher than 100 mg/L. Moreover, the highest loading rate without observed effects was estimated to be at least 100 mg/L.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Read-across from a study performed on the analogue substance Resinoid of Boswellia Carterii (Burseraceae) obtained from exudate by hexane extraction.
The registered substance (target) and the source substance are natural extracts belonging to the group of Natural Complex Substances (NCS): UVCB sub-type 3, where the source is biological, and the process is refinement (ECHA Guidance on Identification and naming of substances under REACH, version 2.1 – May 2017, Section 4.3.1 and EFEO/IFRA Guidelines on substance identification and sameness of natural complex substances (NCS) under REACH and CLP, version of August 5, 2015).
The source substance Olibanum Resinoid and the registered substance have the same botanical origin: Boswellia Carterii (Burseraceae). They have the same related EC and CAS numbers as well as the same EC description. Compositions are not well defined but the registered substance is obtained from the source substance Olibanum resinoid by extraction with ethanol and elimination of the solvent. The source substance Olibanum resinoid contains all the constituents available from the extraction of the registered substance. Overall, the registered substance is expected to have its composition, and then its ecotoxicological behaviour, covered by Olibanum resinoid data. Therefore, we consider as reliable the read across from olibanum resinoid dossier to this dossier.

Reason / purpose for cross-reference:

read-across source

Specific details on test material used for the study:

N/A

Duration:

24 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

The evaluation was based on the nominal WAFs concentrations.
After 24 and 48 hours of exposure, no immobilisation of the test animals was observed in the control and the loading rate of 100 mg.L-1, confirming the observations of the range-finding test. Based on these results, the 24 and 48-hour EL50 values were therefore > 100 mg.L-1.

Results with reference substance (positive control):

On August 17, 2017 (most recent test), the 24h-EC50 was 0.92 mg.L-1. Hence, the sensitivity of the clone of Daphnia magna was in agreement with OECD 202 (expected 24h-EC50: 0.6 mg.L-1 to 2.1 mg.L-1) at this time.

Reported statistics and error estimates:

Not applicable (limit test).

Analytical results

Concentration of dissolved organic material in the control and the loading rate of 100 mg/L was checked by TOC analysis at start (t=0h), at t=24h (new and old solutions) and at the end of the test (t=48h).

Due to the complex nature of the substance, it was difficult to well solubilize the substance in the water medium (heating, sonication, mixing without headspace …). Even if the TOC analyses indicated that very few organic compounds were found (around 2 mg Carbon/L) throughout the test in the WAFs at 100 mg/L, analytical results showed that WAFs concentrations were overall stable between the start and the end of each exposure period (t=0h-t24h_Old and t=24h_Fresh-t =48h). It should be noted that a WAF is by definition a complex mixture for which the individual concentration of each constituent differs due to its properties (e.g. solubility, adsorption, volatilisation, bioaccumulation…). Due to these differences, interactions between certain constituents of the mixture may occur and affect the behaviour of a given constituent which consequently would not react in the same way that if it was alone in the mixture.Therefore, and since the test item was a UVCB substance, the results were based on the nominal test loading rates.

Acute immobilisation of daphnids after 24 and 48 hours in the final test

Nominal concentration*(mg test item.L^-1)	Replicate	Number of daphnids exposed	Response at 24h		Response at 48h
			Number	Total %	Number	Total %
Control	1 2 3 4	5 5 5 5	0 0 0 0	0	0 0 0 0	0
100	1 2 3 4	5 5 5 5	0 0 0 0	0	0 0 0 0	0

* WAF prepared at the given loading rate.

Validity criteria of the study

Controls: In the control, no daphnids became immobilised nor trapped at the surface of the water nor showed signs of stress.

Dissolved [0₂]_: Dissolved oxygen concentration at the end of the test was ≥ 60% of the air-saturation value in controls and test vessels (see Table 3). 

Thus the validity criteria have been fulfilled in the present study.

Validity criteria fulfilled:

yes

Conclusions:

Under the experimental conditions and based on nominal loading rates, the 48-hour EL50 was estimated to be higher than 100 mg.L-1.

Executive summary:

A study was performed to assess the acute toxicity of test item OLIBANUM RESINOIDE to Daphnia magna. The method followed was designed to be compliant with OECD Guideline for Testing of Chemicals No. 202, “Daphnia sp., Acute Immobilisation Test”, referenced as Method C.2 of Commission Regulation No. 440/2008 (amended byCommission Regulation (EU) 2016/266)(2) and with the “Guidance document on aquatic toxicity testing of difficult substances and mixtures” (OECD No. 23).

A limit test was performed following the results of a range-finding test. Twenty daphnids (four replicates, five daphnids per replicate) were exposed to Water Accommodated Fractions (WAFs) of the test item at a nominal loading rate of 100 mg test item/L and to a control.The immobility of the daphnids was determined in a closed semi-static 48-hour test by visual observation after 24 and 48 hours.Concentration of dissolved organic material in the control and the WAFs was checked by TOC analysis at start (t=0h), at t=24h (new and old solutions) and at the end of the test (t=48h).

Even if the TOC analyses indicated that very few organic compounds were found (around 2 mg Carbon/L) throughout the test in the WAFs at 100 mg/L, analytical results showed that WAFs concentrations were overall stable between the start and the end of each exposure period.

After 24 and 48 hours of exposure, no immobilisation of the test animals was observed in the control and the loading rate of 100 mg/L. Under the experimental condtions and based on nominal loading rates, the 48-hour EL50 was estimated to be higher than 100 mg/L. Moreover, the highest loading rate without observed effects was estimated to be at least 100 mg/L.

The result of this study performed on an analogue is used for the registered substance.

Description of key information

Based on a read-across from an experimental GLP study performed on the analogue substance "Resinoid of Boswellia Carterii (Burseraceae) obtained from exudate by hexane extraction" according to the OECD 202 guideline, the following result has been extrapolated to the registered substance:

-       48h-EL50 > 100 mg/L (nominal loading rate)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

For that endpoint, a study on the registered substance was not available. Therefore, in order to assess the acute toxicity of the registered substance to aquatic invertebrates, the results from an experimental OECD 202 study performed on the analogue substance "Resinoid of Boswellia Carterii (Burseraceae) obtained from exudate by hexane extraction" have been used.

In this study, the toxic effect of the test item to the freshwater invertebrate Daphnia magna was investigated in a closed semi-static test using Water Accommodated Fractions. The method followed was designed to be compliant with OECD Guideline for Testing of Chemicals No. 202, “Daphnia sp., Acute Immobilisation Test”, referenced as Method C.2 of Commission Regulation No. 440/2008 and with the “Guidance document on aquatic toxicity testing of difficult substances and mixtures” (OECD No. 23). The criterion measured was the EL50 (Median Effective Concentration), a statistically derived loading rate which is expected to cause immobility in 50% of test animals within a period of 48 hours.

A limit test was performed following the results of a range-finding test. Twenty daphnids (four replicates, five daphnids per replicate) were exposed toWater Accommodated Fractions (WAFs) of the test item at a nominal loading rate of 100 mg test item/Land to a control.The immobility of the daphnids was determined in a closed semi-static 48-hour test by visual observation after 24 and 48 hours.Concentration of dissolved organic material in the control and the WAFs was checked by TOC analysis at start (t=0h), at t=24h (new and old solutions) and at the end of the test (t=48h).

Even if the TOC analyses indicated that very few organic compounds were found (around 2 mg Carbon/L) throughout the test in the WAFs at 100 mg/L, analytical resultsshowed that WAFs concentrations were overall stable between the start and the end of each exposure period. After 24 and 48 hours of exposure, no immobilisation of the test animals was observed in the control and the loading rate of 100 mg/L. Under the experimental condtions and based on nominal loading rates, the 48-hour EL50 was estimated to be higher than 100 mg/L. Moreover, the highest loading rate without observed effects was estimated to be at least 100 mg/L.

This study respected the requirements of the guideline and the validity criteria were successful. This study was therefore considered acceptable for that endpoint and the read-across justification is provided in the related iuclid study record.