Trichloroacetic acid

Toxicity to aquatic plants other than algae

Administrative data

Endpoint:

toxicity to aquatic plants other than algae

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: Test method was similar to OECD guideline 221. However, no data on analytical monitoring. No data on GLP.

Data source

Reference

Reference Type:

publication

Title:

Haloacetic acids in the aquatic environment. Part I: macrophyte toxicity.

Author:

Hanson ML, Solomon KR

Year:

2004

Bibliographic source:

Environmental Pollution 130 (2004) 371-383

Report date:

2003

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 221 (Lemna sp. Growth Inhibition Test)

Deviations:

not specified

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Trichloroacetic acid

EC Number:

200-927-2

EC Name:

Trichloroacetic acid

Cas Number:

76-03-9

Molecular formula:

C2HCl3O2

IUPAC Name:

trichloroacetic acid

Details on test material:

- Name of test material (as cited in study report): TCA
- Analytical purity: 99.7 %

Sampling and analysis

Analytical monitoring:

not specified

Test solutions

Vehicle:

yes

Details on test solutions:

The acid solutions were titrated to the required growth media pH with sodium hydroxide.

Test organisms

Test organisms (species):

Lemna gibba

Details on test organisms:

L. gibba was cultured axenically according to the methods outlined in Greenberg et al. (1992) with Hunter’s media containing 10 g/L sucrose. Culturing was conducted in a laminar flowhood.

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

7 d

Test conditions

Test temperature:

25 ± 2 ºC

Nominal and measured concentrations:

Nominal concentrations: 3, 10, 30, 100, 200, 400, and 800 mg/L.

Details on test conditions:

Approximately 10 days prior to a L. gibba toxicity test, plants were transferred from growth media containing sucrose to media without sucrose. This
was done so that the plants would switch from heterotrophic to autotrophic energy production.
L. gibba testing was conducted according to the methods outlined in Greenberg et al. (1992) with growth chamber conditions maintained under standard conditions for this test.
The growth chamber was a model E7H Controlled Environments chamber.
Light was maintained for 24 h at approximately 6200 lux.
Each test solution was transferred to a 10-mL plastic Petri dish (Fisher Scientific) and two plants, each with four fronds, for a total of eight fronds, were introduced and monitored.
Test solutions were changed on day 3 and 5 to maintain consistent levels of the compound under study.

- Control: n=6
- Exposed plants: n=3

The endpoints monitored were frond number, colony number, wet mass, frond mass, frond growth rate and chlorophyll a, chlorophyll b, and total chlorophyll concentrations. Pigment concentrations were determined simultaneously by extraction in ACS grade N,N'- dimethyl formamide (Fisher Scientific, Fair Lawn, NJ, USA) using the method and calculations outlined by Porra et al. (1989) and measured with a PU8620 Series UV/visible Spectrophotometer (Philips Analytical, Natick, MA, USA) on a fresh-weight basis.

Reference substance (positive control):

not specified

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

864.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: (95% CL = 575.2-1153.3)

Effect concentrations 2

Duration:

7 d

Dose descriptor:

other: EC25

Effect conc.:

215.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: (95% CL = 129.6-302.0)

Effect concentrations 3

Duration:

7 d

Dose descriptor:

EC10

Effect conc.:

53.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: (95% CL = 10.8-96.9)

Details on results:

The most sensitive endpoint was the Frond number and pigments was the least sensitive endpoint.

Any other information on results incl. tables

The EC50 was 864.3 (575.2 -1153.3) mg/L (basis for effect: growth rate).

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Remarks:

(No data on control results)

Conclusions:

The EC50 was 864.3 (575.2 -1153.3) mg/L (basis for effect: growth rate).

Executive summary:

Laboratory tests were conducted with the macrophyte Lemna gibba to assess the toxicity of Trichloroacetic acid.

The EC50 was 864.3 (575.2 -1153.3) mg/L (basis for effect: growth rate).

The most sensitive endpoint was the Frond number and pigments was the least sensitive endpoint.