Amorphous condensation products of orthophosphoric acid and sodium carbonate (3-6 : 1)

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September 22, 2005-October 8, 2005

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)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The concentrations of the test substance were analyzed in control and test solutions at 0 and 48 hrs. 10mL of samples was taken from test solution and filtered using 0.45μm syringe filter.

Details on test solutions:

1. Culturing and dilution water : M4 medium
2. Test solution preparation
1) Range-finding test concentration : Each 1 mL of stock solutions was added to 99 mL of test medium to give exposure level of
0.1, 1, 10 and 100mg/L (without pH adjustment). The pH of 100 mg/L test solution was 3.65. Therefore, pH of 10 and 100 mg/L test solution were adjusted to pH 8.0 (equivalent to the pH level of 0.1 mg/L test solution) by adding 1N-NaOH. Precipitation of the test substance was observed in the pH adjusted 100mg/L test solution.
2) Definitive test : Each 1 mL of stock solutions (2,500, 5,000, 10,000, 20,000 and 40,000 mg/L) was added to 99 mL of test
medium to give exposure level of 29, 61, 81, 157 and 376 mg/L and then pH were adjusted to 8.0 ± 0.2. Only the dilution water was used for the control. Precipitation of the test substance was observed in the test solution 81, 157 and 376 mg/L.

Test organisms (species):

Daphnia magna

Details on test organisms:

Name : Daphnia magna Straus
Source : The ecotoxicology Research Team, Korea Institute of Toxicology (KIT), KRICT, Deajeon, Korea (origin: the Institute of
Ecological Chemistry, GSF, Germany)
Test organism : First-instar Daphnia magna neonates (< 24 hours old)
Photoperiod : 16 hours of continuous artificial light and 8 hours of continuous darkness with 30 minutes dawn and dusk transition periods.
Temperature : 18~22 °C during the culture period.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

265 mg/L (as CaCO3)

Test temperature:

20.4± 0.3 °C

pH:

7.50 to 8.14

Dissolved oxygen:

8.4 ~ 8.9 mg/L (% saturation: 92~98 %)

Nominal and measured concentrations:

Nominal test concentrations: 0, 25, 50, 100, 200 and 400 mg/L
Mean measured test concentrations: 0, 29, 61, 81, 157 and 376 mg/L

Details on test conditions:

Light intensity : Between 650 and 660 Lux.
Feeding and aeration : Without feeding and aeration during 48 hours of exposure period.
Experimental design : Thirty daphnids (three replicates)
Criteria of effect : The symptoms of intoxification and immobilisation were examined daily. The criterion of immobilisation employed in this study was an inability to swim for approximately 15 seconds after gentle agitation.

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 376 mg/L

Nominal / measured:

meas. (geom. mean)

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 376 mg/L

Nominal / measured:

meas. (geom. mean)

Details on results:

No immobilisation and adverse effects was observed in control. The number of immobilised daphid at 157 and 376 mg/L was one each at 24 hours. At 48 hours, one daphnid at 157 mg/L and 3 daphnids at 376 mg/L were immobilized (Table 1). Any abnormal behaviors of the daphnids were not observed in each treatment group during the test period (Table 2). All results were expressed in terms of measured concentration. The EC50 values and other parameters were shown in Table 3.

Conclusions:

The 48hr-EC 50 values of Phosphoric acid (CAS No. 7664-38-2) to Daphnia magna was determined as > 376 mg/L. The no-observed effect concentration (NOEC) was estimated to be 81 mg/L.

Executive summary:

The study was conducted to assess the acute toxicity of phosphoric acid (CAS No. 7664 -38 -2) to Daphnia magna. The study was conducted in accordance with the OECD Guidelines for the Testing of Chemical No. 202. " Daphnia sp., Acute Immobilisation Test (Adopted: 13th April 2004)".

Thirty daphnids (less than 24 hours old) per treatment level, in three replicates of 10 each, were exposed to measured concentration of 29, 61, 81, 157 and 376 mg/L of test substance and control for 48 hours under static conditions. The incidence of immobilization was recorded for each treatment level at 24 and 48 hours. The following values, expressed in terms of measured concentrations, were derived from the test.

parameter/Exposure period	24 hours	48 hours
EC50	> 376 mg/L	> 376 mg/L

The concentrations were expressed as geometric means of measured concentration obtained at the beginning (0hr) and end (48 hrs) of the test.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

key study

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

This read-across is based on the hypothesis that source and target substances have similar properties because of structural similarity and that the target chemical (Amorphous condensation products of orthophosphoric acid and sodium carbonate (3-6 : 1)) hydrolyse to orthophosphoric acid and the sodium dihydrogen phosphate. The sodium dihydrogen phosphate has no identified hazardous properties. The orthophosphoric acid is source substance and is identical to the hydrolysis product of constituent A (metaphosphoric acid) of the target substance.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The concentrations of the test substance were analyzed in control and test solutions at 0 and 48 hrs. 10mL of samples was taken from test solution and filtered using 0.45μm syringe filter.

Details on test solutions:

1. Culturing and dilution water : M4 medium
2. Test solution preparation
1) Range-finding test concentration : Each 1 mL of stock solutions was added to 99 mL of test medium to give exposure level of
0.1, 1, 10 and 100mg/L (without pH adjustment). The pH of 100 mg/L test solution was 3.65. Therefore, pH of 10 and 100 mg/L test solution were adjusted to pH 8.0 (equivalent to the pH level of 0.1 mg/L test solution) by adding 1N-NaOH. Precipitation of the test substance was observed in the pH adjusted 100mg/L test solution.
2) Definitive test : Each 1 mL of stock solutions (2,500, 5,000, 10,000, 20,000 and 40,000 mg/L) was added to 99 mL of test
medium to give exposure level of 29, 61, 81, 157 and 376 mg/L and then pH were adjusted to 8.0 ± 0.2. Only the dilution water was used for the control. Precipitation of the test substance was observed in the test solution 81, 157 and 376 mg/L.

Test organisms (species):

Daphnia magna

Details on test organisms:

Name : Daphnia magna Straus
Source : The ecotoxicology Research Team, Korea Institute of Toxicology (KIT), KRICT, Deajeon, Korea (origin: the Institute of
Ecological Chemistry, GSF, Germany)
Test organism : First-instar Daphnia magna neonates (< 24 hours old)
Photoperiod : 16 hours of continuous artificial light and 8 hours of continuous darkness with 30 minutes dawn and dusk transition periods.
Temperature : 18~22 °C during the culture period.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

265 mg/L (as CaCO3)

Test temperature:

20.4± 0.3 °C

pH:

7.50 to 8.14

Dissolved oxygen:

8.4 ~ 8.9 mg/L (% saturation: 92~98 %)

Nominal and measured concentrations:

Nominal test concentrations: 0, 25, 50, 100, 200 and 400 mg/L
Mean measured test concentrations: 0, 29, 61, 81, 157 and 376 mg/L

Details on test conditions:

Light intensity : Between 650 and 660 Lux.
Feeding and aeration : Without feeding and aeration during 48 hours of exposure period.
Experimental design : Thirty daphnids (three replicates)
Criteria of effect : The symptoms of intoxification and immobilisation were examined daily. The criterion of immobilisation employed in this study was an inability to swim for approximately 15 seconds after gentle agitation.

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 376 mg/L

Nominal / measured:

meas. (geom. mean)

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 376 mg/L

Nominal / measured:

meas. (geom. mean)

Details on results:

No immobilisation and adverse effects was observed in control. The number of immobilised daphid at 157 and 376 mg/L was one each at 24 hours. At 48 hours, one daphnid at 157 mg/L and 3 daphnids at 376 mg/L were immobilized (Table 1). Any abnormal behaviors of the daphnids were not observed in each treatment group during the test period (Table 2). All results were expressed in terms of measured concentration. The EC50 values and other parameters were shown in Table 3.

Conclusions:

The 48hr-EC 50 values of Phosphoric acid (CAS No. 7664-38-2) to Daphnia magna was determined as > 376 mg/L (read-across). The no-observed effect concentration (NOEC) was estimated to be 81 mg/L (read- across).

Executive summary:

The study was conducted to assess the acute toxicity of phosphoric acid (CAS No. 7664 -38 -2) to Daphnia magna. The study was conducted in accordance with the OECD Guidelines for the Testing of Chemical No. 202. " Daphnia sp., Acute Immobilisation Test (Adopted: 13th April 2004)".

Thirty daphnids (less than 24 hours old) per treatment level, in three replicates of 10 each, were exposed to measured concentration of 29, 61, 81, 157 and 376 mg/L of test substance and control for 48 hours under static conditions. The incidence of immobilization was recorded for each treatment level at 24 and 48 hours. The following values, expressed in terms of measured concentrations, were derived from the test.

parameter/Exposure period	24 hours	48 hours
EC50	> 376 mg/L	> 376 mg/L

The concentrations were expressed as geometric means of measured concentration obtained at the beginning (0hr) and end (48 hrs) of the test.

Description of key information

The 48hr-EC 50 values of Phosphoric acid (CAS No. 7664-38-2) to Daphnia magna was determined as > 376 mg/L (read-across). The no-observed effect concentration (NOEC) was estimated to be 81 mg/L (read- across).