Strontium 3-hydroxy-4-[(1-sulfonato-2-naphthyl)azo]-2- naphthoate 5/2 hydrate

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

02 Jun 2010 - 03 Aug 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 070711
- Expiration date of the lot/batch: 07 July 2011
- Purity: 96.4 %
- Description: Red powder

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature in the dark

Analytical monitoring:

yes

Details on sampling:

Sampling:
Frequency: At the beginning and at the end of an interval of 48 hours (nominal days 0 and 2) and on days 5, 9 and 19 of the study.
Volume: 2 mL
Storage: Not applicable, samples were freshly analysed.

At the end of the test refreshment period, the replicates of both test groups were pooled before sampling. In addition, the filter containing the undissolved residue was kept and transferred for analytical investigation.

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)

The batch of R507-2 tested was a red powder with a purity >= 96.4 % and not completely soluble in test medium at the concentration tested.

Preparation of test solutions started with supersaturated solutions at loading rates of 100 mg/L applying a 5 to 6-minute treatment period with ultrasonic waves followed by 3 days of magnetic stirring. This resulted in a red dispersion containing a floating layer and precipitate. The dispersion was filtered through a 0.45 µm membrane filter (Whatman, RC55) to remove the larger undissolved particles. The filtered solutions were all clear and colourless and as such used for testing.

Test organisms (species):

Daphnia magna

Details on test organisms:

Species:
Daphnia magna (Crustacea, Cladocera) (Straus, 1820), at least third generation, obtained by acyclical parthenogenesis under specified breeding conditions.

Source:
In-house laboratory culture with a known history.

Reason for selection:
This system has been selected as an internationally accepted invertebrate species.

Validity of batch:
Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20 %, presence of males, ephippia or discoloured animals and there was no delay in the production of the first brood.

Characteristics:
For the test selection of young daphnia with an age of < 24 hours, from parental daphnids of more than two weeks old.

Test type:

semi-static

Water media type:

freshwater

Total exposure duration:

21 d

Hardness:

148 - 228 mg CaCO3 per litre

Test temperature:

19.4 - 20.3 °C

pH:

7.4 - 8.1

Dissolved oxygen:

7.1 - 9.3 mg/L

Details on test conditions:

Frequency of renewal: Three times a week

Test vessels: Volume: 60 mL (6 x 0 3.5 cm), all-glass covered with a Perspex plate.

Medium: M7
Experimental design: At the start of the experiment (nominal day 0) 20 neonate daphnids, less than one day old, per group were divided over twenty vessels each containing a minimum of 50 ml test medium.

Light: 16 h photoperiod daily; intensity at the start: 682-708 lux (9.4-10.3 µE.m-2.s-1; intensity at the end: 839-908 lux (10.9-12.1 µE.m-2.s-1)


Feeding: Daily, 0.25 mL of Chlorella pyrenoidosa suspension containing 1.66 x10e8 cells was added as feed for the daphnids. This daily ration corresponded to 0.2 mg C/Daphnia/day, which is the recommended value for daily feeding per daphnid in the reproduction test according to the OECD Guideline 211.

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mortality

Details on results:

The mean reproduction in the R507-2 test group was higher than the reproduction recorded in the control group. Mean reproduction numbers were 92.1 and 161.3 for the control and R507-2 test group, respectively. Historical data from 2009 (23 studies) showed a mean reproduction of the control animals of 120 ± 27 (mean ± SD). The value 161.3 of this study is in the range of mean ± 2SD (66 - 174). Furthermore, the maximum value among the historical data is 158 and this is very close to the value of this study. Therefore, the mean reproduction number in the R507-2 group is considered within the experimental fluctuations.

There were no recordings of immobile young or appearance of unhatched (aborted) eggs in either of the two test groups throughout the 21-day test period.

Statistical analysis for cumulative reproduction was not performed as no adverse effects were noted in the treatment group in comparison to the control.

Table: Average body lengths (mm) of parental daphnids with the standard deviation (SD) per group measured at the end of the test and the percentage reduction of body length relative to the control.

 

Test group R507-2 (mQ/1)	Average length (mm)	SD	% Reduction
Control	4.26	0.14	-
100*	4.63	0.13	0

* 0.45 µm filtered test solution.

Table: Effect parameters

Parameter	R507-2 Loading rate (mg/L)*
21-day LC50 (parental mortality)	>100
NOEC for parental mortality	100
21-day EC50 for reproduction	>100
21-day LOEC for reproduction	>100
21-day NOEC for reproduction	100
21-day LOEC for parental body length	>100
21-day NOEC for parental body length	100
Overall LOEC	>100
Overall NOEC	100

* 0.45 µm filtered test solution.

Conclusions:

Under the conditions of the present study R507-2 did not adversely affect reproduction, survival or growth of Daphnia magna in a 0.45 µm filtered solution prepared at a loading rate of 100 mg/L after 21 days of exposure (NOEC). The actual exposure concentration in the filtrate was below 0.03 mg/L, being the detection limit of the analytical method.

Executive summary:

Daphnia magna, 21 -day reproduction study with R507-2

The study procedures described in this report were based on the OECD guidelines for Testing of Chemicals: Guideline No. 211, 2008. In addition, the procedures were designed to meet the test methods and validity criteria of the ISO International Standard 10706, 2000, the Commission Regulation (EC) No 440/2008 Part C.20, 2008 and the OECD guidance document number 23, 2000.

 

The batch of R507-2 tested was a red powder with a purity > 96.4 % and not completely soluble in test medium at the concentration tested.

 

The maximum soluble concentration of R507-2 in test medium was prepared by stirring a loading rate of 100 mg/L for three days. The obtained red dispersion was then filtered through a

0.45 µm membrane filter resulting in a clear and colourless solution.

 

The reproduction test was performed in a semi-static system, included 20 vessels for a 0.45 µm filtered R507-2 test group prepared at a loading rate of 100 mg/L and 20 vessels for an untreated control group. Each of the vessels contained one neonate (<24 h old) Daphnia magna in 50 ml test medium. The study duration was 21 days and the test solutions were renewed three times a week. The daphnids were fed on a daily basis with a Chlorella pyrenoidosa suspension. Every workday the condition of the parental daphnids was recorded, during the reproduction phase the number of living offspring, immobile young and appearance of unhatched (aborted) eggs was recorded. At the end of the test the lengths of the surviving parental daphnids were measured.

 

Analyses of duplicate samples taken from the freshly prepared solutions at 4 intervals showed that the measured concentrations in the filtrates were all below the Limit of Detection (LOD) of the analytical method (<0.03 mg/L).Consequently, it was decided to analyse samples taken from the spent solutions of one occasion only. As expected, the analysed concentration of this sample (taken on day 2) was still below the LOD. It was further demonstrated that the undissolved residue that was present on the filter was R507-2.

 

No mortality of parental daphnids was observed in the controls or in the R507-2 test group. All appeared healthy and survived the 21-day test period.

 

The mean reproduction in the R507-2 test group was higher than the reproduction recorded in the control group. Mean reproduction numbers were 92.1 and 161.3 for the control and R507-2 test group, respectively. No aborted eggs, unhatched eggs or immobile young were observed in the two test groups.

 

The mean length of the daphnids exposed to R507-2 after 21 days was slightly higher than the mean length obtained for the daphnia exposed to the control.

 

Test conditions were maintained within the limits prescribed by the protocol and the test was considered valid.

 

R507-2 did not adversely affect reproduction, survival or growth of Daphnia magna in a 0.45 µm filtered solution prepared at a loading rate of 100 mg/L after 21 days of exposure (NOEC). The actual exposure concentration in the filtrate was below 0.03 mg/L, being the detection limit of the analytical method.

In conclusion, due to the very low solubility of R507-2 in test medium concentrations causing adverse effects were not observed up to the limit of solubility.

Description of key information

Daphnia magna, 21 -day reproduction study with R507-2

The study procedures described in this report were based on the OECD guidelines for Testing of Chemicals: Guideline No. 211, 2008. In addition, the procedures were designed to meet the test methods and validity criteria of the ISO International Standard 10706, 2000, the Commission Regulation (EC) No 440/2008 Part C.20, 2008 and the OECD guidance document number 23, 2000.

 

The batch of R507-2 tested was a red powder with a purity > 96.4 % and not completely soluble in test medium at the concentration tested.

 

The maximum soluble concentration of R507-2 in test medium was prepared by stirring a loading rate of 100 mg/L for three days. The obtained red dispersion was then filtered through a

0.45 µm membrane filter resulting in a clear and colourless solution.

 

The reproduction test was performed in a semi-static system, included 20 vessels for a 0.45 µm filtered R507-2 test group prepared at a loading rate of 100 mg/L and 20 vessels for an untreated control group. Each of the vessels contained one neonate (<24 h old) Daphnia magna in 50 ml test medium. The study duration was 21 days and the test solutions were renewed three times a week. The daphnids were fed on a daily basis with a Chlorella pyrenoidosa suspension. Every workday the condition of the parental daphnids was recorded, during the reproduction phase the number of living offspring, immobile young and appearance of unhatched (aborted) eggs was recorded. At the end of the test the lengths of the surviving parental daphnids were measured.

 

Analyses of duplicate samples taken from the freshly prepared solutions at 4 intervals showed that the measured concentrations in the filtrates were all below the Limit of Detection (LOD) of the analytical method (<0.03 mg/L).Consequently, it was decided to analyse samples taken from the spent solutions of one occasion only. As expected, the analysed concentration of this sample (taken on day 2) was still below the LOD. It was further demonstrated that the undissolved residue that was present on the filter was R507-2.

 

No mortality of parental daphnids was observed in the controls or in the R507-2 test group. All appeared healthy and survived the 21-day test period.

 

The mean reproduction in the R507-2 test group was higher than the reproduction recorded in the control group. Mean reproduction numbers were 92.1 and 161.3 for the control and R507-2 test group, respectively. No aborted eggs, unhatched eggs or immobile young were observed in the two test groups.

 

The mean length of the daphnids exposed to R507-2 after 21 days was slightly higher than the mean length obtained for the daphnia exposed to the control.

 

Test conditions were maintained within the limits prescribed by the protocol and the test was considered valid.

 

R507-2 did not adversely affect reproduction, survival or growth of Daphnia magna in a 0.45 µm filtered solution prepared at a loading rate of 100 mg/L after 21 days of exposure (NOEC). The actual exposure concentration in the filtrate was below 0.03 mg/L, being the detection limit of the analytical method.

In conclusion, due to the very low solubility of R507-2 in test medium concentrations causing adverse effects were not observed up to the limit of solubility.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L