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Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

key study

Study period:

From September 29, 2015 to October 07, 2015

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The test was performed on a similar substance. The complete justification for the read across approach is attached at section 13.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

M4 medium

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISMS
- Source: RCC Ltd.
- Age at study initiation (mean and range, SD): Young daphnids, aged less than ‘24’ hours old

ACCLIMATION
- Acclimation period: one day prior to the experiment in the test area
- Type and amount of food: were fed with algae suspension

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

Not available

Hardness:

220 mg/l

Test temperature:

20.7- 20.8 °C

pH:

7.69 - 7.88

Dissolved oxygen:

7.63 – 7.78 mg/l

Salinity:

Not available

Nominal and measured concentrations:

NOMINAL: 0.30, 0.60, 1.20, 2.40, 4.80, 9.60, and 19.20 mg/l were fixed in a geometric series with a separation factor of 2.0.

Details on test conditions:

TEST SYSTEM
- No. of organisms per vessel: 10 daphnids
- Test vessel: 100 ml Glass Beaker
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: volume of 50 ml
- Aeration: no
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 4 replicates

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: M4 Medium

RANGE-FINDING STUDY: yes
100.03 mg of the test item was dissolved and made up to 500 ml using M4 medium to prepare a stock (1 mg/ 5ml) which was used to prepare the required test concentrations of 0.001, 0.01, 0.1, 1, 10, 50, and 100 mg/l. All the test concentrations were prepared for 200 ml (0.0002, 0.002 ,0.02, 0.2, 2, 10, and 20 mg/200 ml). From the stock solution, 1 µl, 10 µl, 100 µl, 1 ml, 10 ml, 50 ml and 100 ml was taken and made up to 200 ml each to prepare the required concentrations viz., 0.001, 0.01, 0.1, 1, 10, 50 and 100 mg/l respectively. From the above prepared concentrations, 50 ml ofthe test solution was transferred into each replicate beaker. Thus, 4 replicates were maintained for control and treatment.

Reference substance (positive control):

yes

Remarks:

Potassium Dichromate Pure

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

4.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

1.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

Based on the test results, the EC50 in Daphnia magna observed for a period of 24 hour was calculated as 24.07 mg/l with upper confidence limits of 43.27 mg/l and lower confidence limits of 18.27 mg/l and regression equation Y = 0.8956 +2.9711 log (x). The EC50 in Daphnia magna observed for a period of 48 hour was calculated as 4.40 mg/l with upper confidence limits of 6.64 mg/l and lower confidence limits of 2.93 mg/l and regression equation Y = 2.7293+3.5279 log (x). The no observed effect concentration (NOEC) and the low observed effect concentration (LOEC) for 24 hours was calculated as 4.80 mg/l and 9.60 mg/l respectively.The no observed effect concentration (NOEC) and the low observed effect concentration (LOEC) for 48 hours was calculated as 0.60 mg/l and 1.20 mg/l respectively.

Results with reference substance (positive control):

Based on the test results, the EC50 of Potassium Dichromate Pure in Daphnia magna observed for a period of ‘24’ hour was calculated as 1.72 mg/l with upper confidence limits of 2.12 mg/l and lower confident limits of 1.40 mg/l and regression equation Y = 4.0957 + 3.8604 log (x). At ‘48’ hour, the EC50 was calculated as 1.33 mg/l with upper confidence limits of 1.63 mg/l and lower confidence limits of 1.08 mg/l and regression equation Y = 4.5239 + 3.8769 log (x).

Reported statistics and error estimates:

ECSO with 95% confidence limits for 24 and 48 hour was calculated using Finney Probity analysis.

Validity criteria fulfilled:

yes

Conclusions:

The EC50 in Daphnia magna observed for a period of 48 hour was calculated to be 4.40 mg/l

Executive summary:

Acute Immobilization Toxicity Study inDaphnia magnawas conducted in accordance with OECD Guideline 202. Based on the results of the range finding experiment, main experiment was conducted with a range of concentrations viz., 0.30, 0.60, 1.20, 2.40, 4.80, 9.60 and 19.20 mg/l. Forty daphnids with four replicates (10 daphnids in each replicate) for each test concentration and control group were maintained. The test item was formulated with M4 medium. The daphnids with brood chambers were acclimatized one day prior to the exposure in M4 medium. After the exposure on day 0, daphnids were observed for immobilisation at approximately 24 hour and 48 hour and the respective data was recorded.

No immobilization was observed in the control and in the daphnids exposed to 0.30 and 0.60 mg/l test concentrations throughout the experimental period. At the end of 24 hour, no immobility was observed in daphnids exposed to 1.20, 2.40 and 4.80 mg/l concentration whereas, 7/40 and 14/40 immobility was observed in daphnids exposed to 9.60 and 19.20 mg/l concentrations respectively. Thus, the percent immobilisation at the end of 24 hour was recorded to be 0 % in the control and in the daphnids exposed to 0.30, 0.60, 1.20, 2.40 and 4.80 mg/l concentrations whereas, 17.5 % and 35 % was observed in daphnids exposed to 9.60 and 19.20 mg/l concentrations respectively. At the end of 48 hour, 3/40, 7/40 and 14/40 immobility was recorded in the daphnids exposed to 1.20, 2.40 and 4.80 mg/l concentrations whereas, 39/40, 40/40 cumulative immobility was observed in daphnids exposed to 9.60 and 19.20 mg/l concentration. Thus the percent cumulative immobilisation at the end of 48 hour was recorded to be 0 % in the control and in the daphnids exposed to 0.30, and 0.60 mg/l test concentrations whereas, 7.5 %, 17.5 %, 35 %, and 97.5 % was observed in daphnids exposed to 1.20, 2.40, 4.80 and 9.60 mg/l concentrations and 100 % was observed in daphnids exposed to 19.20 mg/l concentration. 

Analytical verification of the test item in the dilution water (M4 medium) samples were performed in the test item concentrations of low (0.30 mg/l), intermediate (2.40 mg/l) and high (19.20 mg/l) at 0 hour and 48 hour. The mean recoveries data are given below:

- 0 Hour - Mean Recovery results: 97.28 %, 97.18 % and 98.32 % for 0.3 mg/l, 2.40 mg/l and 19.20 mg/l concentrations respectively

- 48 Hours - Mean Recovery results: 95.78 %, 94.31 % and 96.73 % for 0.3 mg/l, 2.40 mg/l and 19.20 mg/l concentrations respectively

Based on the test results, the EC50 in Daphnia magna observed for a period of 24 hour was calculated as 24.07 mg/l with upper confidence limits of 43.27 mg/l and lower confidence limits of 18.27 mg/l and regression equation Y = 0.8956 +2.9711 log (x). The EC50 in Daphnia magna observed for a period of 48 hour was calculated as 4.40 mg/l with upper confidence limits of 6.64 mg/l and lower confidence limits of 2.93 mg/l and regression equation Y = 2.7293+3.5279 log (x). The no observed effect concentration (NOEC) and the low observed effect concentration (LOEC) for 24 hours was calculated as 4.80 mg/l and 9.60 mg/l respectively.The no observed effect concentration (NOEC) and the low observed effect concentration (LOEC) for 48 hours was calculated as 0.60 mg/l and 1.20 mg/l respectively.

The EC50 inDaphnia magnaobserved for a period of 48 hours was calculated to be 4.40 mg/l with upper confidence limits of 2.93 mg/l.

The no observed effect concentration (NOEC) and the low observed effect concentration (LOEC) for 48 hours was calculated as 0.60 mg/l and 1.20 mg/l respectively.

Description of key information

The EC50 in Daphnia magna observed for a period of 48 hour was calculated to be 4.40 mg/l

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

4.4 mg/L

Additional information

No tests are available on short-term toxicity to invertebrates performed on the substance in itself nevertheless, one test is available on a similar substance. The complete evaluation and justification of the read across approach is attached at section 13.

Acute Immobilization Toxicity Study in Daphnia magna was conducted in accordance with OECD Guideline 202. Based on the results of the range finding experiment, main experiment was conducted with a range of concentrations viz., 0.30, 0.60, 1.20, 2.40, 4.80, 9.60 and 19.20 mg/l.

No immobilization was observed in the control and in the daphnids exposed to 0.30 and 0.60 mg/l test concentrations throughout the experimental period. At the end of 24 hour, no immobility was observed in daphnids exposed to 1.20, 2.40 and 4.80 mg/l concentration whereas, 7/40 and 14/40 immobility was observed in daphnids exposed to 9.60 and 19.20 mg/l concentrations respectively. Thus, the percent immobilisation at the end of 24 hour was recorded to be 0 % in the control and in the daphnids exposed to 0.30, 0.60, 1.20, 2.40 and 4.80 mg/l concentrations whereas, 17.5 % and 35 % was observed in daphnids exposed to 9.60 and 19.20 mg/l concentrations respectively. At the end of 48 hour, 3/40, 7/40 and 14/40 immobility was recorded in the daphnids exposed to 1.20, 2.40 and 4.80 mg/l concentrations whereas, 39/40, 40/40 cumulative immobility was observed in daphnids exposed to 9.60 and 19.20 mg/l concentration. Thus the percent cumulative immobilisation at the end of 48 hour was recorded to be 0 % in the control and in the daphnids exposed to 0.30, and 0.60 mg/l test concentrations whereas, 7.5 %, 17.5 %, 35 %, and 97.5 % was observed in daphnids exposed to 1.20, 2.40, 4.80 and 9.60 mg/l concentrations and 100 % was observed in daphnids exposed to 19.20 mg/l concentration. 

The EC50 in Daphnia magna observed for a period of 48 hours was calculated to be 4.40 mg/l with upper confidence limits of 2.93 mg/l.

The no observed effect concentration (NOEC) and the low observed effect concentration (LOEC) for 48 hours was calculated as 0.60 mg/l and 1.20 mg/l respectively.