Titanium 2-hydroxy-1,2,3-propanetricarboxylate (2:5)

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:

48 hours

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)

Specific details on test material used for the study:

Batch/Lot No. 115829/70
Appearance Clear, particulate free liquid
Purity (wt.%) 54.7
Storage conditions Room temperature (in sealed container)
Expiry date December, 2019

Analytical monitoring:

yes

Details on test solutions:

M4 medium was used as culturing and dilution water, and was prepared according to the method of OECD Guideline (2004). This test item was fully soluble in dilution water.

Test organisms (species):

Daphnia magna

Details on test organisms:

The ephippia was obtained from MicroBioTests Inc. Belgium (imported date: January 16, 2018). Daphnia has been cultured successively for a generation in invertebrate culture room, Environmental Toxicology Research Center, Gyeongnam Department of Environmental Toxicology and Chemistry, Korea Institute of Toxicology (KIT).
Brood stock of Daphnia magna were cultured under 16 h light: 8 h dark with 30 min transition period at 18-22 ºC in glass beakers containing three liters of M4 medium. Cultures were fed daily with a suspension of Pseudokirchneriella subcapitata and the amount (3 mL/L vessel/day) of the supplied algae was range of 6 x 106-107 cell/mL. 1 mL/L of YCT (Yeast, Chlorophyll and Tetramine, NeoEnbiz, Korea) was feed twice in a week. Culture conditions ensured that reproduction was by parthenogenesis.
Gravid adults were isolated 24 hours prior to initiation of the test. Young daphnids produced overnight (< 24 hours old) were used for testing.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

254 mg/L

Test temperature:

19.5-20.4 ºC

pH:

4.57-8.64

Dissolved oxygen:

7.67-8.95mg/L

Nominal and measured concentrations:

The measured concentrations were 7.85, 14.6, 26.6, 50.8 and 91.9 mg/L (81.8-91.9% of nominal concentration) for nominal concentrations of 9.6, 17.2, 30.9, 55.6 and 100 mg/L at 0 hour.

Details on test conditions:

TEST SYSTEM
Crystallizing dish containing 100 mL of test solution for each replicate was used for toxicity test.
20 daphnids, divided into four groups of five daphnids each, were used for each test concentration and control groups (dilution water).

OTHER TEST CONDITIONS
- Photoperiod: 16 hours of light and 8 hours of dark, including 30-minute dawn and dusk transition periods
- Light intensity: 1161-1268 lux.

RANGE-FINDING STUDY
The range-finding test was conducted at the nominal concentrations of 0.1, 1, 10 and 100 mg/L
by static system. 5 daphnids were exposed in each test vessel and immobilization was observed
during 48 hours. Based on the result of the range-finding test, no immobilization was observed in 0.1-10 mg/L
and 100% immobilization was observed in 100 mg/L of test solution.

Water quality parameters of pH, dissolved oxygen and temperature were measured in each surviving test vessel at 0 and 48 hours of the test.

Daphnia were examined daily for symptoms of intoxication and immobilization. The animals were considered to be immobilized if they were unable to swim for approximately 15 seconds after gentle agitation.

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

68.9 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

51.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

No remarkable phenomenon was observed in all test solutions throughout test period. There was no immobilization and symptoms of intoxication observed in control groups and 9.6, 17.2, 30.9, 55.6 mg/L of test solutions (mean measured concentrations: 7.28, 14.2, 27.3, 51.6 mg/L). 100% immobilization was observed in 100 mg/L (mean measured concentration: 91.9 mg/L)

Results with reference substance (positive control):

The 24hr-EC50 value (95% confidence limits) of Potassium dichromate to Daphnia magna were determined 1.83 mg/L (1.60-2.14 mg/L).

Reported statistics and error estimates:

EC50 value with 95% confidence limits and NOEC (No observed effected concentration) were analyzed by CETIS Version 1.8.7.15 (Tidepool Scientific Software, USA). Binomial/Graphical methods were applied to obtain the effective concentrations and Steel Many-One Rank Sum test were used for NOEC in this study.

Exposure time	24-hour	48-hour
EC50 values	68.9	68.9
95% confidence limits	51.6-91.9	51.6-91.9
NOEC	51.6	51.6

Unit: mg/L, geometric mean measured concentrations)

Cumulative immobilization of Daphnia magna

Nominal concentration (mg/L)	Mean measured concentration (mg/L)	No. of animals tested	Cumulative No. of immobilized daphnids (Initial population: 5 daphnids/replicate)
			24-hour						48-hour
			R1	R2	R3	R4	Total	%	R1	R2	R3	R4	Total	%
Control	ND	20	0	0	0	0	0	0	0	0	0	0	0	0
9.6	7.28	20	0	0	0	0	0	0	0	0	0	0	0	0
17.2	14.2	20	0	0	0	0	0	0	0	0	0	0	0	0
30.9	27.3	20	0	0	0	0	0	0	0	0	0	0	0	0
55.6	51.6	20	0	0	0	0	0	0	0	0	0	0	0	0
100	91.9	20	5	5	5	5	20	100	5	5	5	5	20	100

Rx : Replicate Number

ND: Not detected

Symptoms of intoxication of the test item toDaphnia magna

Nominal concentration (mg/L)	Mean measured concentration (mg/L)	Symptoms of Intoxication
		24-hour	48-hour
Control	ND	NOR (20)	NOR (20)
9.6	7.28	NOR (20)	NOR (20)
17.2	14.2	NOR (20)	NOR (20)
30.9	27.3	NOR (20)	NOR (20)
55.6	51.6	NOR (20)	NOR (20)
100	91.9	-	-

( ) : Number of daphnids

ND: Not detected

NOR: Normal

Measured concentrations of the test item in the test solution

Nominal concentration (mg/L)	Measured concentration (mg/L)		Mean measured concentration (mg/L)
	0-hour	48-hour
Control	ND	ND	NA
9.6	7.85 (81.8)	6.75 (70.3)	7.28 (75.8)
17.2	14.6 (84.9)	13.9 (80.8)	14.2 (82.6)
30.9	26.6 (86.1)	28.1 (90.9)	27.3 (88.3)
55.6	50.8 (91.4)	52.4 (94.2)	51.6 (92.8)
100	91.9 (91.9)	-	91.9 (91.9)

ND: Not detected

NA: Not available

( ) : % of nominal concentration

- Test solution was not analyzed because all daphnids were dead

Validity criteria fulfilled:

yes

Conclusions:

The 48-hr EC50 value (95% confidence limit) of Titanium citrate in Daphnia magna was 68.9 mg/L (51.6-91.9 mg/L), expressed in terms of the geometric mean measured concentration.

Executive summary:

The acute toxicity of Titanium citrate to Daphnia magna was studied according to OECD 202 “Daphnia sp., Acute Immobilization Test”. The test substance was soluble in dilution water and it was possible to prepare 100 mg/L of test

solution (highest concentration) by direct addition method. Titanium was analyzed for determination of test concentration and the concentrations of test solutions were calculated using measured concentration of titanium.

According to the stability test, the concentration was 101.4-102.9% of initial concentration. Therefore, the toxicity test was performed under static system.

The range-finding test was conducted at the nominal concentrations of 0.1, 1, 10 and 100 mg/L by static system. No immobilization was observed in 0.1-10 mg/L and 100% immobilization was observed in 100 mg/L of test solution. Therefore, the definitive test was performed with a control and nominal concentrations of 9.6, 17.2, 30.9, 55.6, 100 mg/L using a static system. The definitive test was performed for 48 hours and 20 daphnids were exposed for each

concentration with four replicates. The mean measured concentrations were 7.28, 14.2, 27.3, 51.6, 91.9 mg/L (0.66, 1.29, 2.48, 4.69, 8.36 mg/L as titanium) for nominal concentrations of 9.6, 17.2, 30.9, 55.6, 100 mg/L

during test period.

During 48 hours’ test period, no immobilization and toxic symptoms were observed in control and 9.6, 17.2, 30.9 and 55.6 mg/L of test solution (mean measured concentration: 7.28, 14.2, 27.3, 51.6 mg/L (0.66, 1.29, 2.48, 4.69 mg/L as titanium)) and 100% immobilization was observed in 100 mg/L (mean measured concentration: 91.9 mg/L (8.36 mg/L as titanium)).

The 48-hr EC50 value (95% confidence limit) of Titanium citrate in Daphnia magna was 68.9 mg/L (51.6-91.9 mg/L), expressed in terms of the geometric mean measured concentration.

Description of key information

At 100 mg/l, immobilisation was observed, but at low concentrations tested, there was limited effect

Under environmental conditions, diluted titanium citrate will dissociate leading to the formation of insoluble titanium salts such as carbonates, oxide and hydroxide.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

68 mg/L