Long-term toxicity to aquatic invertebrates

Long-term toxicity to aquatic invertebrates

Administrative data

Purpose flag:

key study

Study result type:

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

Study well conducted with standard guidelines and chemical analysis. No GLP no analytical certificates and no raw data.

Data source

Reference

Reference Type:

publication

Title:

Comparison of hardness and chloride regulated acute effects of sodium sulfate on two freshwater crustaceans.

Author:

Soucek, D.J.

Year:

2007

Bibliographic source:

Environmental Toxicology and Chemistry, Vol. 26, No. 4, pp. 773–779

Materials and methods

Test guideline

Qualifier:

according to

Guideline:

other guideline: ASTM E 1295-01 (2002)

Principles of method if other than guideline:

Three-brood survival/reproduction bioassays were performed according to the above mentioned guideline. 
Long-term measurement of reproduction rate was performed as follows. Organisms were cultured according to US EPA methods with the only modification being that the culture water contained an elevated sodium sulfate concentration of 1000 mg SO4 2-/l. Cultures were initiated simultaneously using the same cohort of neonates produced by animals cultured in MHRW. Neonates to start a new generation were selected from animals that had produced at least three broods and had not reproduced on the previous day. Five generations were cultured in each treatment.

GLP compliance:

no data

Test materials

Identity of test material same as for substance defined in section 1 (if not read-across):

no

Test material identityopen allclose all

Test material identity 1

Identifier:

CAS number

Identity:

7757-82-6

Test material identity 2

Identifier:

EC number

Identity:

231-820-9

Test material identity 3

Identifier:

EC name

Identity:

sodium sulphate

Details on test material:

Anhydrous sodium sulfate
purity: 99% 
Fisher Scientific

Analytical monitoring:

yes

Details on sampling:

No details given

Vehicle:

no

Details on test solutions:

Three-brood survival/reproduction bioassays: six sulfate concentrations, including a control
Long-term measurement of reproductive rate (5 generations): control, 1000 mg SO4 2-/l

Test organisms

Test organisms (species):

Ceriodaphnia dubia

Details on test organisms:

TEST ORGANISM
- Source: in-house culture according to US EPA methods. Initially obtained from Aquatic Research Organisms, Hampton, NH
- Age at study initiation: less than 24h

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Remarks:

differs per test

Test conditions

Hardness:

92 ± 2 mg CaCO3/l

pH:

8.0 ± 0.1

Details on test conditions:

Three-brood survival/reproduction bioassay:

TEST SYSTEM
- Test vessel:
- Type: open
- Material, size, headspace, fill volume: 50 ml glass beakers
- Renewal rate of test solution (frequency/flow rate): daily
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10
- Feeding: as in culture according to US EPA methods

TEST MEDIUM / WATER PARAMETERS
- Type of water: Moderately Hard Reconstituted Water (MHRW) and Reformulated Moderately Hard Reconstituted Water (RMHRW)
RMHRW had similar hardness but a different Ca:Mg ratio and chloride concentration from MHRW.

TEST DURATION
Until at least 60% of the test organisms had produced three broods. This was 7 days in all cases.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): number of young and survival of parent animals were counted daily.


Long-term measurement of reproductive rate:

TEST SYSTEM
- Test vessel:
- Type: open
- Material, size, headspace, fill volume: 50 ml glass beakers
- Renewal rate of test solution (frequency/flow rate): daily
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 20
- No. of vessels per control (replicates): 20
- Feeding: as in culture according to US EPA methods

TEST MEDIUM / WATER PARAMETERS
- Type of water: Moderately Hard Reconstituted Water (MHRW)

TEST DURATION
Five generations

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): total number of neonates produced per animal after 8 days. Neonates were counted and removed daily.

Reference substance (positive control):

no

Results and discussion

Effect concentrationsopen allclose all

Effect concentrations 1

Duration:

7 d

Endpoint:

LOEC

Effect conc.:

1 329 mg/L

Nominal / measured:

no data

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks (e.g. 95% CL):

Test medium is MHRW

Effect concentrations 2

Duration:

7 d

Endpoint:

EC50

Effect conc.:

1 698 mg/L

Nominal / measured:

no data

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks (e.g. 95% CL):

Test medium is MHRW

Effect concentrations 3

Duration:

7 d

Endpoint:

LOEC

Effect conc.:

3 277 mg/L

Nominal / measured:

no data

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks (e.g. 95% CL):

Test medium is MHRW

Effect concentrations 4

Duration:

7 d

Endpoint:

LC50

Effect conc.:

3 030 mg/L

Nominal / measured:

no data

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks (e.g. 95% CL):

Test medium is MHRW

Effect concentrations 5

Duration:

7 d

Endpoint:

LOEC

Effect conc.:

1 828 mg/L

Nominal / measured:

no data

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks (e.g. 95% CL):

Test medium is RMHRW

Effect concentrations 6

Duration:

7 d

Endpoint:

EC50

Effect conc.:

2 156 mg/L

Nominal / measured:

no data

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks (e.g. 95% CL):

Test medium is RMHRW

Effect concentrations 7

Duration:

7 d

Endpoint:

LOEC

Effect conc.:

4 436 mg/L

Nominal / measured:

no data

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks (e.g. 95% CL):

Test medium is RMHRW

Effect concentrations 8

Duration:

7 d

Endpoint:

LC50

Effect conc.:

3 611 mg/L

Nominal / measured:

no data

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks (e.g. 95% CL):

Test medium is RMHRW

Details on results:

From a graph it can be seen that the lowest test concentration of approx. 1109 mg/l (which is given in the graph as 750 mg SO4 2-/l) did not give a significant effect, therefore 1109 mg/l can be taken as the NOEC.

Long-term measurement of reproductive rate:
C. dubia cultured in 1000 mg SO4 2-/l produced significantly fewer neonates than in the control.
Combining the 5 generations the overal mean number of neonates produced per animal after 8 days in MHRW was 62.2 ± 6.6 and for MHRW with 1000 mg SO4 2-/l it was 50.6 ± 5.3.

Reported statistics and error estimates:

Three-brood survival/reproduction bioassay:
Three tests were conducted in each water type to obtain average values for percent survival and reproduction. For survival Fisher's Exact test was used to compare treatments to controls and for reproduction Dunnett's test was used.

Long-term measurement of reproductive rate:
Repeated-measures ANOVA was used to test the difference between the treatment and control, and if that difference varied from generation to generation.

Any other information on results incl. tables:

The results in the publication are given as mg sulfate ion, these values were converted to mg sodium sulfate.

It is not known whether nominal or measured concentrations are use for the results. It is written that analyses were performed to confirm sulphate concentrations, but no details are given in the publication whether or not measured concentrations were similar to nominals.

Applicant's summary and conclusion

Conclusions:

Sodium sulfate is not toxic to C. dubia in the long-term experiments. The LOEC for reproduction in MHRW was 1329 mg/l, which was the lowest result obtained in this test. The NOEC (taken from a graph) is 1109 mg/l. 
Over 5 generations reproduction was significantly lower in 1000 mg SO4 2-/l compared to the control.
The test was found to be valid with restrictions because the study was well conducted with standard guidelines and chemical analysis. No GLP no analytical certificates and no raw data were documented.

Executive summary:

Three-brood survival/reproduction bioassays were performed according to standard ASTM guidelines. Mortality and reproduction were checked daily and LOEC-, LC50- and EC50 values were determined.

Long-term measurement of reproduction rate was performed as follows. Organisms were cultured according to US EPA methods with the only modification being that the culture water contained an elevated sodium sulfate concentration of 1000 mg SO4 2-/l. Cultures were initiated simultaneously using the same cohort of neonates produced by animals cultured in MHRW. Neonates to start a new generation were selected from animals that had produced at least three broods and had not reproduced on the previous day. Five generations were cultured in each treatment.

Sodium sulfate is not toxic to C. dubia in the long-term experiments. The LOEC for reproduction in MHRW was 1329 mg/l, which was the lowest result obtained in this test. The NOEC (taken from a graph) is 1109 mg/l.

Over 5 generations reproduction was significantly lower in 1000 mg SO4 2-/l compared to the control.

Validity criteria fulfilled:

no data

Information on Registered Substances comes from registration dossiers which have been assigned a registratio