Cordierite (Mg2[Al4O3(SiO3)5])

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions (no analytical monitoring of the test concentrations, no GLP).

Qualifier:

equivalent or similar to guideline

Guideline:

other: in analogy to the rules of the Dutch Standard Organization (NEN Nederlands Normalisatie Institut, 6502, 1980)

GLP compliance:

no

Analytical monitoring:

no

Details on sampling:

No data shown

Vehicle:

not specified

Details on test solutions:

No data shown

Test organisms (species):

Daphnia magna

Details on test organisms:

The test organisms were 1 day old and were obtained from standard laboratory cultures

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

Test Concentrations in mg/L Hardness after 72hr in mg CaCO3 and MgSO4/L
- 220
10 220
32 220
100 205
320 150

Test temperature:

The test temperature was 19 +/-1 °C during the experiment.

pH:

No data shown

Dissolved oxygen:

No data shown

Salinity:

No data shown

Nominal and measured concentrations:

The test concentrations were nominal.

Details on test conditions:

Lighting was circadiac with renewing rate of 3 times per week under semi-static test conditions. Numeber of organisms per group was 25.

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

NAS-b

Basis for effect:

mortality

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

NAS-a

Basis for effect:

reproduction

Following effect concentrations were observed or calculated (in mg/L): 
          
NAS-a   LC50 was observed at  680*mg/L with a NOEC of 320*mg/L

The Effects on reproduction (EC50) was observed 175*mg/L with a NOEC of 10 mg/L

            
 NAS-b:   LC50 >10000*mg/L with a NOEC>10000*mg/L

The Effects on reproduction (EC50) was 530*mg/L with a NOEC of 320 mg/L

The results marked with * may have been affected by hardness changes of the test medium.

Validity criteria fulfilled:

not applicable

Conclusions:

The long-term toxicity tests for NAS-a and NAS-b show low toxicity to the tested species Daphnia magna. The results from the long-term toxicity study may have been affected by changes in hardness in water. hardness decresed to 28mg CaCO3 and MgSO4/L at 1000mg NAS-b/L, but no mortality was observed at this concentration. Therefore the NOEC for NAS-b may be the result of both the toxicity and the lower hardness of the test medium. Fifty per cent mortality was observed at >1000mg/L for NAS-b and at 680 mg/L for NAS-a. Effects on reproductions were observed on fifty per cent of the population (EC50) at 175mg/L with a NOEC of 10 mg/L for NAS-a.

Executive summary:

The long-term toxicity of sodium aluminium silicate (NAS-a and NAS-b) to the fresh water invertebrate species Daphnia Magna was examined in accordance to the Dutch Standard Organization (NEN Nederlands Normalisatie Institut, 6502, 1980). The test was conducted during 21 days on 25 organisms per group from stndardized cultures. The tests were conducted under controlled temperature conditions at 19 ± 1°C with a circadiac light:dark cycle. Dosing was performed under static conditions. Mortality and effects on reproduction were the measured endpoints during the test showing low toxicity to the tested species Daphnia magna. The long-term LC50 and the NOEC for sodium aluminium silicate, NAS-b, was > 1000 mg/L and 680 mg/L and 320 mg/L for NAS-a. In addition, effects on reproductions were observed on fifty per cent of the population (EC50) at 530 mg/L with a NOEC of 320 mg/L for NAS-b and 175mg/L and 10 mg/L for NAS-a. A decrease in hardness was observed at 1000 mg NAS-b/L (28mg CaCO3 and MgSO4/L). Although there was a decrease in hardness in the test solution of NAS-b, no mortality was observed at this concentration. Therefore the NOEC for NAS-b may be the result of both the toxicity and the lower hardness of the test medium.

Description of key information

The long-term LC50 and the NOEC for sodium aluminium silicate, NAS-b, was > 1000 mg/L and 680 mg/L and 320 mg/L for NAS-a. In addition, effects on reproductions were observed on fifty per cent of the population (EC50) at 530 mg/L with a NOEC of 320 mg/L for NAS-b and 175mg/L and 10 mg/L for NAS-a. Both read-across substances are not considered to cause long-term toxicity to the aquatic invertebrate Daphnia Magna.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1 000 mg/L

Additional information

The long-term toxicity of the read across substance, sodium aluminium silicate (NAS-a and NAS-b)  to the fresh water invertebrate species Daphnia Magna was determined in accordance to the Dutch Standard Organization (NEN Nederlands Normalisatie Institut, 6502, 1980). Dosing was performed under static conditions. The exposed invertebrate was monitored over a period of 21 days to determine the concentration that killed 50% of the tested species (LC50) and effects on reproduction. The test showed low long-term toxicity to the tested species Daphnia magna. The long-term LC50 and the NOEC for sodium aluminium silicate, NAS-b, was > 1000 mg/L and 680 mg/L and 320 mg/L for NAS-a. The data generated for NAS-a were unreliable due to the uncontrolled changing in the conditions of the media during the experiment. Effects on reproductions were observed on fifty per cent of the population (EC50) at 530 mg/L with a NOEC of 320 mg/L for NAS-b and 175mg/L and 10 mg/L for NAS-a. A decrease in hardness was observed at 1000 mg NAS-b/L (28mg CaCO3 and MgSO4/L). Although there was a decrease in hardness in the test solution of NAS-b, no mortality was observed at this concentration. Therefore the NOEC for NAS-b may be the result of both the toxicity and the lower hardness of the test medium. The read-across substance is not considered to have long-term toxicity effects to aquatic invertebrates. Read-across between the registered substance and the test substances (NAS-a and NAS-b) is considered justified owing the structural similarity of the two substances. The registered substance and NAS-a will release silicon, aluminium, and respectively magnesium and sodium. As NAS-a and NAS-b are more water soluble than Cordierite, its aquatic toxicity represents the worst case scenario.