[No public or meaningful name is available]

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

key study

Reason / purpose for cross-reference:

read-across source

Duration:

21 d

Dose descriptor:

EL10

Effect conc.:

ca. 4.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

other: EL20

Effect conc.:

ca. 5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Key result

Duration:

21 d

Dose descriptor:

EL50

Effect conc.:

ca. 7.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

EL50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

immobilisation

Duration:

21 d

Dose descriptor:

LOELR

Effect conc.:

ca. 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Duration:

21 d

Dose descriptor:

NOELR

Effect conc.:

ca. 3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Details on results:

All validation criteria were achieved during the test.

No significant mortalities occurred at any test concentrations throughout the test, therefore, the 21-day EL50 (immob) value based on nominal loading rates was observed to be greater than 10 mg/L loading rate WAF.

There was significant effect on size and color of the daphnids in that all of the surviving daphnids on Day 21 at the loading rate of 10 mg/L were markedly smaller and paler in color than control daphnids. After 21 days the length of each surviving adult was determined and demonstrated that there were statistically significant differences (P>= 0.05) between the control and the 10 mg/L loading rate WAF test group in terms of length of the daphnids after 21 days exposure to the test item.

At loading rate WAF test groups 0.010 to 3.2 mg/L there were no statistically significant differences when compared to the control after 21 days in terms of the number of live young produced per adult. The 10 mg/L test group showed a statistically significant difference from the control after 21 days in terms of producing fewer numbers of live young per adult.

An assessment made at each media renewal showed the "filial" daphnids produced by all the test groups were in the same general condition as the young produced by the controls over the duration of the test. Numbers of unhatched eggs and dead young were low in all control and treatment groups surviving to maturation.

The Maximum Acceptable Toxicant Loading Rate (MATL) was calculated to be 5.7 mg/L.

Analysis of freshly prepared 3.2 and 10 mg/L loading rate WAFs on days 0, 3, 7, 14, and 20 showed measured concentrations ranged from 0.0237 to 0.0523 mg/L and 0.0732 to 0.118 mg/L, respectively. Analysis of the expired test solutions for 3.2 and 10 mg/L loading rate WAFs on days 1, 4, 8, 15, and 21 showed measured concentrations ranges from less than the limit of quantitation (LOQ), determined to be 0.016 mg/L, to 0.0252 mg/L and less than the LOQ to 0.0917 mg/L, respectively. The dissolved test item may have been more than one or several components of the test item. Given that toxicity cannot be attributed to a single component or mixture of components but to the test item as a whole, the results were based on nominal loading rates only.

Reported statistics and error estimates:

Statistical analysis:

EL50 (immob) values up to Day 21 of the test were estimated by inspection of the data.

EL50 (repro) values after 21 days were calculated by the Linear Interpolation method using the ToxCalc computer software package.

LOEL and NOEL were estimated by the numbers of live young produced per adult over the duration of the test for the control and each test group were compared using one-way analysis of variance incorporating Bartlett's test for homogeneity of variance and the WIlliams test for differences between treatment means when several dose levels are compared with a zero dose control. Results from the control and each test groups daphnia length data, were compared using one way analysis of variance incorporating Bartlett's test for homogeneity of variance and Dunnett's multiple comparison procedure for comparing several treatments with a control. All statistical analyses were performed using SAS computer software package.

Summary of Findings Following the Exposure of Daphnia magna for 21 Days

 

 

LoadingRatemg/L	% Survival of P1	Number of Live Young
		Total	Per Parent Surviving to the End of the Test
Control	90	821	91
0.010	100	982	98
0.032	100	999	100
0.10	90	969	96
0.32	100*	844	94
1.0	100	1046	105
3.2	90	950	105
10	80	200	25

 * One accidental adult mortality, therefore results based on 9 adult daphnia

LoadingRatemg/L	NumberofDeadYoung		NumberofUnhatchedEggs
	Total	PerFemale(cumulative)	Total	PerFemale(cumulative)
Control	0	0	0	0
0.010	0	0	0	0
0.032	0	0	0	0
0.10	0	0	0	0
0.32	0	0	0	0
1.0	0	0	0	0
3.2	0	0	0	0
10	0	0	0	0

Validity criteria fulfilled:

yes

Conclusions:

Daphina magna were exposed to the test item for 21 days and did not result in any significant mortalities at all the test concentrations employed during the test. The 21 day EL50 (immobilization) value, based on nominal test concentrations for the parental Daphnia generation (P1) was estimated to be greater than 10 mg/L loading rate WAF. The 21 -Day EL50 (reproduction) value, based on nominal test concentrations was 7.8 mg/L loading rate WAF. The "lowest observed effect loading rate" (LOEL) and the "no observed effect loading rate" (NOEL) based on nominal loading rates were 10 and 3.2 mg/L, respectively. The "maximum acceptable toxicant loading rate" (MATL) was calculated to be 5.7 mg/L loading rate WAF.

Executive summary:

Introduction

 

A study was performed to assess the chronic toxicity of the test item to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (2004) No 211, "Daphnia magna Reproduction Test" referenced as Method C.20 of Commission Regulation (EC) No. 440/2008 and the US EPA Draft Ecological Effects Test Guidelines OCSPP 850.1300 "Daphnid Chronic Toxicity Test".

 

Methods

 

Based on the results of an acute toxicity test to Daphnia magna, (Harlan Laboratories Ltd, Study Number 0525/0979), Daphnia magna were exposed (10 replicates of a single daphnid per group) to Water Accommodated Fractions (WAFs) of the test item over a range of loading rates of 0.010, 0.032, 0.10, 0.32, 1.0, 3.2 and 10 mg/L for a period of 21 days. The test solutions were renewed daily.

 

The numbers of live and dead adult daphnia and young daphnids (live and dead) were determined daily. The daphnia were fed daily with a mixture of algal suspension and Tetramin® flake food suspension.

  

Results

 

Analysis of the freshly prepared 3.2 and 10 mg/L loading rate WAFs on days 0, 3, 7, 14 and 20 showed measured concentrations ranged from 0.0237 to 0.0523 mg/L and 0.0732 to 0.118 mg/L respectively. Analysis of the expired 3.2 and 10 mg/L loading rate WAFs on days 1, 4, 8, 15 and 21 showed measured concentrations ranged from less than the Limit of Quantification (LOQ), determined to be 0.016 mg/L, to 0.0252 mg/L and less than the LOQ to 0.0917 mg/L respectively.

 

Given that the toxicity cannot be attributed to a single component or a mixture of components, but to the test item as a whole, the results were based on nominal loading rates only.

 

Conclusion

Exposure of Daphnia magna to the test item resulted in no significant mortalities at all the test concentrations employed during the test. The 21 day EL50 (immobilization) value, based on nominal test concentrations for the parental Daphnia generation (P1) was estimated to be greater than 10 mg/L loading rate WAF. The 21 -Day EL50 (reproduction) value, based on nominal test concentrations was 7.8 mg/L loading rate WAF. The "lowest observed effect loading rate" (LOEL) and the "no observed effect loading rate" (NOEL) based on nominal loading rates were 10 and 3.2 mg/L, respectively. The "maximum acceptable toxicant loading rate" (MATL) was calculated to be 5.7 mg/L loading rate WAF.

Description of key information

Daphina magna were exposed to the test item for 21 days and did not result in any significant mortalities at all the test concentrations employed during the test. The 21 day EL50 (immobilization) value, based on nominal test concentrations for the parental Daphnia generation (P1) was estimated to be greater than 10 mg/L loading rate WAF. The 21 -Day EL50 (reproduction) value, based on nominal test concentrations was 7.8 mg/L loading rate WAF. The "lowest observed effect loading rate" (LOEL) and the "no observed effect loading rate" (NOEL) based on nominal loading rates were 10 and 3.2 mg/L, respectively. The

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

10 mg/L

Additional information

A study was performed to assess the chronic toxicity of the test item to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (2004) No 211, "Daphnia magna Reproduction Test" referenced as Method C.20 of Commission Regulation (EC) No. 440/2008 and the US EPA Draft Ecological Effects Test Guidelines OCSPP 850.1300 "Daphnid Chronic Toxicity Test".

 

Based on the results of an acute toxicity test to Daphnia magna, (Harlan Laboratories Ltd, Study Number 0525/0979), Daphnia magna were exposed (10 replicates of a single daphnid per group) to Water Accommodated Fractions (WAFs) of the test item over a range of loading rates of 0.010, 0.032, 0.10, 0.32, 1.0, 3.2 and 10 mg/L for a period of 21 days. The test solutions were renewed daily.

 

The numbers of live and dead adult daphnia and young daphnids (live and dead) were determined daily. The daphnia were fed daily with a mixture of algal suspension and Tetramin® flake food suspension.

  

Analysis of the freshly prepared 3.2 and 10 mg/L loading rate WAFs on days 0, 3, 7, 14 and 20 showed measured concentrations ranged from 0.0237 to 0.0523 mg/L and 0.0732 to 0.118 mg/L respectively. Analysis of the expired 3.2 and 10 mg/L loading rate WAFs on days 1, 4, 8, 15 and 21 showed measured concentrations ranged from less than the Limit of Quantification (LOQ), determined to be 0.016 mg/L, to 0.0252 mg/L and less than the LOQ to 0.0917 mg/L respectively.

 

Given that the toxicity cannot be attributed to a single component or a mixture of components, but to the test item as a whole, the results were based on nominal loading rates only.

Exposure of Daphnia magna to the test item resulted in no significant mortalities at all the test concentrations employed during the test. The 21 day EL50 (immobilization) value, based on nominal test concentrations for the parental Daphnia generation (P1) was estimated to be greater than 10 mg/L loading rate WAF. The 21 -Day EL50 (reproduction) value, based on nominal test concentrations was 7.8 mg/L loading rate WAF. The "lowest observed effect loading rate" (LOEL) and the "no observed effect loading rate" (NOEL) based on nominal loading rates were 10 and 3.2 mg/L, respectively. The "maximum acceptable toxicant loading rate" (MATL) was calculated to be 5.7 mg/L loading rate WAF.