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Environmental fate & pathways

Additional information on environmental fate and behaviour

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Administrative data

Endpoint:
additional information on environmental fate and behaviour
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study does not contain information relevant for risk assessment of TiO2; However, the study is well documented and meets generally accepted scientific principles, and is therefore considered as supporting information.
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
publication
Title:
Vertical transport and plant uptake of nanoparticles in a soil mesocosm experiment
Author:
Gogos, A. et al.
Year:
2016
Bibliographic source:
J Nanobiotechnol (2016) 14:40

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
In a non-standardized pot test with red clover and wheat, natural soil blended with quartz sand was spiked with food grade E171 TiO2 by mixing the particle powder into the soil at beginning of the test. Plants were grown for 14 weeks (red clover) or 12 weeks (wheat), after which soil core samples were collected and titanium soil concentrations were measured using an energy-dispersive XRF spectrometer. Furthermore, leachates were collected after watering at week 13 (red clover) and week 11 (wheat) and analysed for titanium concentrations by means of ICP-OES.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: bulk
Details on test material:
- Name of test material (as cited in study report): Titanium dioxide E171 (Sachtleben Chemie GmbH, Germany)
- Purity: no information
- Crystalline phase: anatase
- Primary particle size (TEM, n=52): 92 ± 31 nm (Fraction < 100 nm: 69 %)
- Coating: no
- Surface area: no information
- Surface charge: no information
- Particle size distribution: no information
- Shape: no information

Results and discussion

Any other information on results incl. tables

VERTICAL SOIL DISTRIBUTION OF TI

- only the highest exposure concentration (1000 mg TiO2 /kg) was analytically accessible using XRF

- actual dry weight Ti-exposure concentrations were mostly slightly higher (2.5-7.6 %) than initial nominal concentrations predicted from native and added amounts, however these differences were not significant, indicating a rather reliable spiking method

- no statistically significant differences were found between Ti concentrations in different soil layers (0-5, 5-10, 10-15 cm); a tendency to slightly higher concentration in the lowest layer (10 -15 cm) was observed for the E171 treatment

LEACHING OF TI

- amount of Ti in leachate in all treatments was very low (≤ 0.0001 % of initial spiked Ti amount), presumably because the added water amount was too low to initiate quantitative elution

- Ti concentration in leachate for the 1000 ppm TiO2 treatment was significantly elevated (ca. 40 -105 µg Ti/L) compared the control (< 25 µg Ti/L) in the wheat experiments

Applicant's summary and conclusion

Conclusions:
In a non-standardized pot test with red clover and wheat, natural soil blended with quartz sand was spiked with food grade E171 TiO2 powder (primary particle size: 92 ± 31 nm). Soil cores sampled after 12 weeks for wheat experiments showed no statistically significant differences in Ti concentrations for the different soil depths (0-5, 5-10, 10-15 cm). After watering the pots to 110% water holding capacity, leachate analysis at week 11 (wheat) showed a significant increase of the Ti concentrations for the highest concentration tested (1000 mg TiO2/kg soil) compared to the control. However, it has to be considered that only 0.0001% of the applied Ti was found in the leachate.