Titanium carbide

Toxicity to terrestrial plants

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to terrestrial plants: short-term

Data waiving:

other justification

Justification for data waiving:

other:

Reference 2

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Docuemtation insufficient for assessment. No guideline followed. Exposure of plants via nutrient solution, no exposure via soil. Justification for read-across: Due to similar or lower transformation/dissolution results for titanium carbide (the target substance) than titanium trichloride (the source substance), the resulting toxicity potential would also be expected to be similar or lower, so read-across is appropriate. Therefore, the dose descriptors are expected to be sufficiently similar or higher for the target substance, and read-across to the source chemical is adequately protective. For more details refer to the attached description of the read-across approach.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Influence of Ti on yield of leaves, stems and roots of Phaseolus vulgaris was investigated in solution culture. The plants were exposed for a total of 21 days at Ti concentrations of 0, 10E-06 M, 10E-05 M, 10E-04 M with and without EDTA.
After exposure plants were divided into leaves, stems, and roots, washed in 1/10 N HCl and deionized water, dried, and weighed. Endpoint for the assessment of toxic effects was yield of the different plant parts.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Species:

Phaseolus vulgaris

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

- Common name: Bush bean
- Variety: C.V. Improved Tendergreen
- Source of seed: no data
- Prior seed treatment/sterilization: no data
- Historical germination of seed (germination of seed lot tested): no data
- Seed storage: no data

Test type:

other: plants are grown in solution culture and toxic effects are assessed

Study type:

laboratory study

Substrate type:

other: solution culture

Limit test:

no

Total exposure duration:

21

Nominal and measured concentrations:

Nominal Ti concentrations of 0, 10E-06 M, 10E-05 M, 10E-04 M.

Key result

Species:

Phaseolus vulgaris

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.048 other: mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

Ti

Basis for effect:

growth

Remarks:

yield of leaves, stems and roots

Species:

Phaseolus vulgaris

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

0.479 other: mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

Ti

Basis for effect:

growth

Remarks:

yield of leaves

Remarks on result:

other: 6.3 % reduction of yield in leaves (21.6 % reduction of yield in stems)

Species:

Phaseolus vulgaris

Duration:

21 d

Dose descriptor:

other: reduction of yield: 87.1 %, 71 %, and 93.6 % for leaves, stems, and roots, respectively

Effect conc.:

4.79 other: mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

Ti

Basis for effect:

growth

Remarks:

yield in leaves, stems and roots

Table 1: Effects of Ti addition and EDTA on yield of bush bean plants (dry weight basis).

			Yield [g/plant]			Reduction of yield compared to control [%] (calculated for samples without EDTA only)
Ti [M]	Ti [mg/L]	EDTA	Leaves	Stems	Roots	Leaves	Stems	Roots
0	0	+	0,7998	0,261	0,269	/	/	/
0	0	-	0,652	0,259	0,248	/	/	/
1,00E-06	0,0479	+	0,612	0,237	0,261	/	/	/
1,00E-06	0,0479	-	0,711	0,301	0,257	-9,05	-16,22	-3,63
1,00E-05	0,479	+	0,537	0,219	0,245	/	/	/
1,00E-05	0,479	-	0,611	0,203	0,257	6,29	21,62	-3,63
1,00E-04	4,79	+	0,112	0,09	0,018	/	/	/
1,00E-04	4,79	-	0,084	0,075	0,016	87,12	71,04	93,55

Validity criteria fulfilled:

not applicable

Conclusions:

Ti was highly toxic to Phaseolus vulgaris at 10E-04 M (= 4.79 mg/L) in solution culture.

Executive summary:

Influence of Ti on yield of leaves, stems and roots of Phaseolus vulgaris was investigated in solution culture. The plants were exposed for a total of 21 days at Ti concentrations of 0, 10E-06 M, 10E-05 M, 10E-04 M with and without EDTA. After exposure plants were divided to leaves, stems, and roots, washed in 1/10 N HCl and deionized water, dried, and weighed. Endpoint for the assessment of toxic effects was yield of the different plant parts.

Ti was highly toxic to Phaseolus vulgaris at 10E-04 M (= 4.79 mg/L) in solution culture. No adverse effects could be observed at 10E-06 M (= 0.0479 mg/L), whereas slight toxicity could be observed at 10E-05 M (= 0.479 mg/L).

Reference 3

Endpoint:

toxicity to terrestrial plants: short-term

Type of information:

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

Adequacy of study:

supporting study

Justification for type of information:

For details and justification of read-across please refer to the report attached in section 13 of IUCLID.

Reason / purpose for cross-reference:

reference to same study

Key result

Species:

Phaseolus vulgaris

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.048 other: mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

Ti

Basis for effect:

growth

Remarks:

yield of leaves, stems and roots

Species:

Phaseolus vulgaris

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

0.479 other: mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

Ti

Basis for effect:

growth

Remarks:

yield of leaves

Remarks on result:

other: 6.3 % reduction of yield in leaves (21.6 % reduction of yield in stems)

Species:

Phaseolus vulgaris

Duration:

21 d

Dose descriptor:

other: reduction of yield: 87.1 %, 71 %, and 93.6 % for leaves, stems, and roots, respectively

Effect conc.:

4.79 other: mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

Ti

Basis for effect:

growth

Remarks:

yield in leaves, stems and roots

Table 1: Effects of Ti addition and EDTA on yield of bush bean plants (dry weight basis).

			Yield [g/plant]			Reduction of yield compared to control [%] (calculated for samples without EDTA only)
Ti [M]	Ti [mg/L]	EDTA	Leaves	Stems	Roots	Leaves	Stems	Roots
0	0	+	0,7998	0,261	0,269	/	/	/
0	0	-	0,652	0,259	0,248	/	/	/
1,00E-06	0,0479	+	0,612	0,237	0,261	/	/	/
1,00E-06	0,0479	-	0,711	0,301	0,257	-9,05	-16,22	-3,63
1,00E-05	0,479	+	0,537	0,219	0,245	/	/	/
1,00E-05	0,479	-	0,611	0,203	0,257	6,29	21,62	-3,63
1,00E-04	4,79	+	0,112	0,09	0,018	/	/	/
1,00E-04	4,79	-	0,084	0,075	0,016	87,12	71,04	93,55

Validity criteria fulfilled:

not applicable

Conclusions:

Ti was highly toxic to Phaseolus vulgaris at 10E-04 M (= 4.79 mg/L) in solution culture.

Executive summary:

Influence of Ti on yield of leaves, stems and roots of Phaseolus vulgaris was investigated in solution culture. The plants were exposed for a total of 21 days at Ti concentrations of 0, 10E-06 M, 10E-05 M, 10E-04 M with and without EDTA. After exposure plants were divided to leaves, stems, and roots, washed in 1/10 N HCl and deionized water, dried, and weighed. Endpoint for the assessment of toxic effects was yield of the different plant parts.

This information is used in a read-across approach in the assessment of the target substance. For justification of read-across please refer to the attached read-across report (See IUCLID section 13).

Ti was highly toxic to Phaseolus vulgaris at 10E-04 M (= 4.79 mg/L) in solution culture. No adverse effects could be observed at 10E-06 M (= 0.0479 mg/L), whereas slight toxicity could be observed at 10E-05 M (= 0.479 mg/L).

Description of key information

Titanium carbide was not tested for toxicity to terrestrial plants and read-across to titanium trichloride (TiCl3) was used for this endpoint. Available results were obtained in solution culture of Phaseolus vulgaris. Ti was highly toxic at 4.79 mg/L, no effects on were observed at 0.479 mg Ti/L and 0.0479 mg Ti/L. Toxic effects are reported at concentrations much higher than realistically possible release of Ti ions from TiC (release was below the method detection limit of 0.4 µg/L in the T/D test). Thus TiC is considered to be non-hazardous to terrestrial plants. 

Additional information

Influence of Ti (applied as TiCl3) on yield of leaves, stems and roots of Phaseolus vulgaris was investigated in solution culture in the available supporting study (Wallace et al., 1977). The plants were exposed for a total of 21 days to Ti concentrations of 0, 10E-06 M, 10E-05 M, and 10E-04 M. Endpoint for the assessment of toxic effects was yield of the different plant parts. Ti was toxic to Phaseolus vulgaris at 10E-04 M (= 4.79 mg/L) in solution culture. No adverse effects could be observed at 10E-06 M (= 0.0479 mg/L), whereas slight toxicity could be observed at 10E-05 M (= 0.479 mg/L).

 

Due to reporting deficiencies and an unsuitable test system (solution culture), this study cannot be considered as a key study. Any other studies qualifying as a key study are not available. However, additional testing is not required as in accordance with REACH Annex IX, 9.4, column 2, the equilibrium partitioning method (EPM) based on aquatic data may be applied to assess the hazard to soil organisms in the absence of reliable toxicity data for terrestrial plants. A hazard for aquatic organisms was not identified, and thus no hazard is identified for soil organisms via EPM. In addition, the available supporting study does not indicate toxic effects for terrestrial plants at concentrations at which Ti ions are released from TiC (< 0.4 µg/L). Toxicity to Phaseolus vulgaris was observed at much higher concentrations of 4.79 mg Ti/L. Thus, release of ecotoxicologically relevant amounts of soluble Ti compounds are not expected.