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Environmental fate & pathways

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Administrative data

Endpoint:
field studies
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Well documented method. No data on GLP.

Data source

Reference
Reference Type:
publication
Title:
Long-Term Exposure of Sitka Spruce Seedlings to Trichloroacetic Acid
Author:
Cape JN, Reeves NM, Schröder P, Heal R
Year:
2003
Bibliographic source:
Environ. Sci. Technol. 2003, 37, 2953-2957

Materials and methods

Principles of method if other than guideline:
This experiment reports the results from treating 4-year-old Sitka spruce (Picea sitchensis (Bong.) Carr) plants in a greenhouse over a growing season with Trichloroacetic acid supplied either to the soil or to the foliage at concentrations of 10 and 100 ng/mL. Chemical analysis used automated headspace gas chromatography (Perkin-Elmer HS40XL) with electron capture detection following thermal decarboxylation of TCA to give CHCl3.
GLP compliance:
not specified
Type of measurement:
Chemical analysis used automated headspace gas chromatography (Perkin-Elmer HS40XL) with electron capture detection following thermal decarboxylation of TCA to give CHCl3.
Media:
This experiment reports the results from treating 4-year-old Sitka spruce (Picea sitchensis (Bong.) Carr) plants in a greenhouse over a growing season with Trichloroacetic acid supplied either to the soil or to the foliage at concentrations of 10 and 100 ng/mL.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Trichloroacetic acid, TCA

Results and discussion

Any other information on results incl. tables

Similar uptake of Trichloroacetic acid by needles was observed for both modes of treatment, with significant accumulation of Trichloroacetic acid (300 ng/g dry wt) at the higher concentration. Larger concentrations in stem tissue were seen for the foliar-applied Trichloroacetic acid (280 ng/g) than for the soil-applied Trichloroacetic acid (70 ng/g), suggesting that direct stem uptake may be important. Six months after treatments stopped, Trichloroacetic acid concentrations in the needles of plants exposed to 100 ng/mL Trichloroacetic acid were still enhanced, showing that biological degradation of Trichloroacetic acid in needles was slow over the winter. By contrast, no significant enhancement of Trichloroacetic acid in soil could be detected in the directly treated soils even during the experiment. The protein content of needles treated with the higher concentration of Trichloroacetic acid either route was significantly smaller than for the controls, but there was no effect of Trichloroacetic acid on the conjugation of 1-chloro-2,4-dinitrobenzene in roots nor on the conjugation of 1,2-dichloro-4-nitrobenzene in needles.

Applicant's summary and conclusion

Conclusions:
Similar uptake of Trichloroacetic acid by needles was observed for both modes of treatment, with significant accumulation of Trichloroacetic acid (300 ng/g dry wt) at the higher concentration. Larger concentrations in stem tissue were seen for the foliar-applied Trichloroacetic acid (280 ng/g) than for the soil-applied Trichloroacetic acid (70 ng/g), suggesting that direct stem uptake may be important. Six months after treatments stopped, Trichloroacetic acid concentrations in the needles of plants exposed to 100 ng/mL Trichloroacetic acid were still enhanced, showing that biological degradation of Trichloroacetic acid in needles was slow over the winter. By contrast, no significant enhancement of Trichloroacetic acid in soil could be detected in the directly treated soils even during the experiment. The protein content of needles treated with the higher concentration of Trichloroacetic acid either route was significantly smaller than for the controls, but there was no effect of Trichloroacetic acid on the conjugation of 1-chloro-2,4-dinitrobenzene in roots nor on the conjugation of 1,2-dichloro-4-nitrobenzene in needles.
Executive summary:

Trichloroacetic acid has been implicated as an airborne pollutant responsible for adverse effects on forest health. There is considerable debate as to whether Trichloroacetic acid observed in trees and forest soils is derived from atmospheric deposition or from in situ production.

This experiment reports the results from treating 4-year-old Sitka spruce (Picea sitchensis (Bong.) Carr) plants in a greenhouse over a growing season with Trichloroacetic acid supplied either to the soil or to the foliage at concentrations of 10 and 100 ng/mL. Chemical analysis used automated headspace gas chromatography (Perkin-Elmer HS40XL) with electron capture detection following thermal decarboxylation of TCA to give CHCl3.

Similar uptake of Trichloroacetic acid by needles was observed for both modes of treatment, with significant accumulation of Trichloroacetic acid (300 ng/g dry wt) at the higher concentration. Larger concentrations in stem tissue were seen for the foliar-applied Trichloroacetic acid (280 ng/g) than for the soil-applied Trichloroacetic acid (70 ng/g), suggesting that direct stem uptake may be important. Six months after treatments stopped, Trichloroacetic acid concentrations in the needles of plants exposed to 100 ng/mL Trichloroacetic acid were still enhanced, showing that biological degradation of Trichloroacetic acid in needles was slow over the winter. By contrast, no significant enhancement of Trichloroacetic acid in soil could be detected in the directly treated soils even during the experiment. The protein content of needles treated with the higher concentration of Trichloroacetic acid either route was significantly smaller than for the controls, but there was no effect of Trichloroacetic acid on the conjugation of 1-chloro-2,4-dinitrobenzene in roots nor on the conjugation of 1,2-dichloro-4-nitrobenzene in needles.