Commiphora myrrha, ext.

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-02-21 to 2018-XX-XX

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

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

none

Analytical monitoring:

yes

Remarks:

unspecific

Details on sampling:

In order to verify the maintenance of the WAFs during the ecotoxicological testing, chemical analyses in daphnids test solutions were performed:
- In fresh solutions at the beginning of the test (T = 0h) and after renewal (T=24h)
- In old solutions (T = 24h and T= 48h)
The test tube were pooled randomly (2*10mL) for chemical analyses.

Schedule analysis at initial time:
- T0h Control Fresh
- T0h 100.0 mg/L Fresh
All the “Fresh” solutions were analysed taken directly from the starting solutions without daphnids.

Schedule analysis at 24h:
- T24h Control Old
- T24h 100.0 mg/L Old

- T24h Control Fresh
- T24h 100.0 mg/L Fresh

Schedule analysis at final time:
- T48h Control Old
- T48h 100.0 mg/L Old

Vehicle:

no

Details on test solutions:

TEST ITEM PREPARATION
The test item was not soluble in the test medium, a special solubilisation protocol was carried out
before the experimentation, according to the OECD n°23 guidance document on aquatic toxicity te
sting of difficult substances and mixtures.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Daphnia magna Straus, clone number 5, from at least the third generation (i.e. the third brood)
obtained with a non-cyclic parthenogenesis reproduction.
The daphnids breeding was carried out in closed bottles placed in a climatic chamber free from any to
xic vapour and in medium M4.
Daphnids used in this experimentation were less than 24 hours old.
- Feeding during test: None

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

not applicable

Hardness:

250 mg.L-1 (as CaCO3).

Test temperature:

20.8 and 20.9°C

pH:

7.31 - 8.18

Dissolved oxygen:

> 60% of the air-saturation value

Salinity:

n.a.

Conductivity:

n.a.

Nominal and measured concentrations:

nominal: 0.6, 1.3, 2.9, 6.3, 13.7 and 30.0 mg.L-1.

Details on test conditions:

TEST DETAILS
- Test vessel: glass test tube
- Type: closed
- Renewal rate of test solution: Renewal of test solutions at 24h
- No. of organisms per vessel: 5
- Test medium: The medium M4 ELENDT was prepared from concentrated stock solutions in ultr
apure water as described in the guideline.
16h light : 8h dark

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

14.818 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

The 48-hour EL50 value was determined by the computer program ToxRat.
After 48 hours of exposure, immobilisation rates were 0% at 0.6, 1.3, 2.9 and 6.3 mg.L-1, 30% at 13.7 mg.L-1 and 100% at 30.0 mg.L-1.

Results with reference substance (positive control):

no data

Reported statistics and error estimates:

It was not possible to perform the ANOVA

Acute immobilisation of daphnids after 24 and 48 hours in the range-finding test (semi-static 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	5 5	0 0	0	0 0		0
1	1 2	5 5	0 0	0	0 0		0
10	1 2	5 5	0 0	0	4** 5		90
32	1 2	5 5	0 1	10	5 5		100
100	1 2	5 5	5 5	100	5 5		100

* WAF prepared at the given loading rate.

The WAFs were filtered since fine particles were observed in the mixing vessels.

** The surviving daphnia was very weak.

Validity criteria fulfilled:

yes

Conclusions:

Under the test conditions, 48h-EL50 of the test item is 14,818 mg/L.

Executive summary:

A study was performed to assess the acute toxicity of test item Essential oil of Commiphora myrrha to Daphnia magna. The method 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) 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 Loading rate), a statistically derived concentration which is expected to cause immobility in 50% of test animals within a period of 48 hours.

 

Following a preliminary range-finding test, twenty daphnids (four replicates, five daphnids per replicate) were exposed to Water Accommodated Fractions (WAFs) of the test item over a range of nominal loading values of 0.6, 1.3, 2.9, 6.3, 13.7 and 30.0 mg.L^-1 and to a control. The immobilisation 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 analysis of Total Organic Carbon (TOC) at start (t=0h), at t=24h (new and old solutions) and at the end of the test (t=48h).

The analytical results of this test showed that organic compounds in the loading rates of interest were found to be overall stable between the start and the end of each exposure period (t=0h-t24h_Oldand t=24h_Fresh-t=48h), within the ± 20% of the initial TOC concentrations values. After 48 hours of exposure, immobilisation rates were 0% at 0.6, 1.3, 2.9 and 6.3mg.L^-1, 30% at 13.7mg.L^-1and 100% at 30.0mg.L^-1.

The EL₅₀at the end of the test was as follows:

Time (h)	EL50(mg test item.L^-1)	95% confidence limits (mg test item.L^-1)
48	14.818	n.d.

n.d.: not determined due to mathematical reasons or inappropriate data

Statistical analyses were performed by the computer program ToxRat

Under the experimental conditions and based on nominal loading rates, the 48-hour EL₅₀ value was 14.818 mg.L^-1.

Description of key information

The toxic effect of test item Essential oil of Commiphora myrrha to the freshwater invertebrate Daphnia magna was investigated in a closed semi-static test usingWater Accommodated Fractions. Under the experimental conditions andbased on nominal loading rates, the 48-hour EL₅₀value was 14.818 mg.L^-1.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

14.818 mg/L

Additional information

For that endpoint, an experimental GLP study with the registered substance was available.

This study was performed to assess the acute toxicity of test item Essential oil of Commiphora myrrha to Daphnia magna. Themethod 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) 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 Loading rate), a statistically derived concentration which is expected to cause immobility in 50% of test animals within a period of 48 hours.

The 48–hr-acute toxicity of test item to D. magna was studied under semi-static conditions. Daphnids were exposed to control and test chemical at nominal concentration of 0.6, 1.3, 2.9, 6.3, 13.7 and 30.0 mg a.i./L for 48hr.  WAF was performed to obtain that range. Mortality/immobilization and sublethal effects were observed daily.  The 48– hour EL₅₀ was 14.818 mg/L.  

Based on the results of this study, test item would not be classified as aquatic acute 1 in accordance with the CLP classification system.

All the validity crietria were fulfilled. This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

 

Results Synopsis

Test Organism Age: 24hr

Test Type: Semi Static

EC₅₀:  14.818 mg/L                           

Endpoint(s) Effected:  immobilisation