Lithium carbonate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1996-08-14 to 1997-02-02-04

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)

Version / remarks:

1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OTS 797.1300 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Samples were analyzed for lithium in triplicate using a FLM-AAS method developed and validated by the FMC Corporation. Measured concentrations of lithium carbonate were calculated by multiplying measured lithium concentrations by 5.3240.

Vehicle:

no

Details on test solutions:

A primary stock solution (5000 mg wm/L) was prepared for the definitive test by adding 1.2500 g of neat test substance to 250 mL volumetric flask, bringing it to volume with deionized water and sonicating for approximately 50 minutes to ensure homogeneity. Test solutions were prepared by adding appropriate volumes of the primary stock to the appropriate volume of dilution water (total volume 1 liter). A dilution water control was maintained concurrently with the test solutions.

Test organisms (species):

Daphnia magna

Details on test organisms:

Water fleas will be neonates (i.e. <24 hours old) obtained by isolating gravid females from the culture water in food-free dilution water < 24 hours prior to beginning the test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No

Hardness:

c(CaCO3) = 56 mg wm/L

Test temperature:

19.0 °C to 20.3 °C

pH:

pH 8.5 to 10.2

Dissolved oxygen:

7.2 to 8.9 mg/L (79 to 98 % of saturation)

Nominal and measured concentrations:

Nominal concentrations: 5.0, 10, 20, 40, and 80 mg/L
Measured concentrations: 0.0, 4.76, 9.84, 20.0, 43.7 and 82.8 mg/L

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

33.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Remarks:

Li2CO3

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 20.0 - 42.7 mg wm/L

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

20 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Remarks:

Li2CO3

Basis for effect:

mobility

Details on results:

The 48-hour EC50 was 33.2 mg/L (based on mean measured concentrations) with 95 % confidence limits of 20.0 and 43.7 mg/L. The no-observed-effect-concentration (NOEC) was 20.0 mg/L, based on the lack of mortality and sublethal effects at this and all lower test concentrations.

Reported statistics and error estimates:

The EC50 values were estimated by a computer program (Wheat, 1989) using the following statistical methods: moving average angle, probit, logit, and non-linear interpolation. Confidence limits for EC50 values determined by non-linear interpolation were calculated by binomial probability. The method selected for reporting the test results was determined by the characteristics of the data, i.e. the presence or absence of 0 % and 100 % mortality and the number of concentrations in which mortalities between 0 and 100 % occurred.

Mortality of the water flea, Daphnia magna, during a 48 -hour exposure to lithium carbonate under static conditions:

Mean Measured Concentration (mg/L)	Cumulative Number Dead (Percent Mortality)
	24 Hour		48 Hour
Control	0	(0)	0	(0)
4.76	0	(0)	0	(0)
9.84	0	(0)	0	(0)
20.0	0	(0)	0	(0)
43.7	9	(45)	17	(85)
82.8	15	(75)	20	(100)

Calculated EC50 values, based upon measured concentrations, for the water flea, Daphnia magna, exposed to lithium carbonate under static conditions:

Exposure Period (Hour)	EC50Value^a	LCL^b	UCL^c	Slope	Method Used
24	53.3	43.1	67.8	4.43	Probit
48	33.2	20.0	43.7	-.-^d	Binomial

a EC50 values and confidence limits expressed in mg wm/L.

b Lower 95 percent confidence limit.

c Upper 95 percent confidence limit.

d The slope cannot be calculated using this method.

Validity criteria fulfilled:

yes

Conclusions:

The 48-hour EC50 in Daphnia magna was 33.2 mg lithium carbonate/L (based on mean measured concentrations) with 95 % confidence limits of 20.0 and 43.7 mg lithium carbonate/L.
The NOEC was 20.0 mg lithiumcarbonate/L, based on the lack of mortality and sublethal effects at this and all lower test concentrations.

Executive summary:

A static freshwater toxicity test was conducted to determine the acute toxicity of lithium carbonate to the water flea, Daphnia magna according to OECD Guideline 202. Mean measured concentrations of lithium carbonate ranged from 4.76 to 82.8 mg/L and from 95 to 109 % of nominal. All test solutions appeared clear and colourless and concentrations remained stable throughout the test. Mortality of the water flea exposed for 48 hours to lithium carbonate ranged from 0 % at test concentrations lower than 20.0 mg/L to 100 % at 82.8 mg/L. Control mortality was 0 %. The 48-hour EC50 was 33.2 mg lithium carbonate/L with 95 % confidence limits of 20.0 and 43.7 mg/L. The NOEC was 20.0 mg lithium carbonate/L, based on a lack of significant mortality and sublethal effects observed at this and all lower test concentrations. Based on these data, the calculated EC50 for lithium ion was 6.24 mg/L and the NOEC was 3.76 mg/L.

Description of key information

The 48-hour EC50 in Daphnia magna was 33.2 mg lithium carbonate/L (based on mean measured concentrations) with 95 % confidence limits of 20.0 and 43.7 mg lithium carbonate/L. The NOEC was 20.0 mg lithium carbonate/L, based on the lack of mortality and sublethal effects at this and all lower test concentrations.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

33.2 mg/L

Additional information

A static freshwater toxicity test was conducted to determine the acute toxicity of lithium carbonate to the water flea, Daphnia magna according to OECD Guideline 202. Mean measured concentrations of lithium carbonate ranged from 4.76 to 82.8 mg/L and from 95 to 109 % of nominal. All test solutions appeared clear and colourless and concentrations remained stable throughout the test. Mortality of the water flea exposed for 48 hours to lithium carbonate ranged from 0 % at test concentrations lower than 20.0 mg/L to 100 % at 82.8 mg/L. Control mortality was 0 %. The 48-hour EC50 was 33.2 mg lithium carbonate/L with 95 % confidence limits of 20.0 and 43.7 mg/L. The NOEC was 20.0 mg lithium carbonate/L, based on a lack of significant mortality and sublethal effects observed at this and all lower test concentrations. Based on these data, the calculated EC50 for lithium ion was 6.24 mg/L and the NOEC was 3.76 mg/L.