Difluoroacetic 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:

weight of evidence

Reliability:

2 (reliable with restrictions)

Data source

Reference

Reference Type:

publication

Title:

Field level evaluation and risk assessment of the toxicity of dichloroacetic acid to the aquatic macrophytes Lemna gibba, Myriophyllum spicatum, and Myriophyllum sibiricum

Author:

Mark L. Hanson, Paul K. Sibley, Scott A. Mabury, Derek C.G. Muir, and KeithR. Solomona

Year:

2003

Bibliographic source:

Ecotoxicology and Environmental Safety 55 (2003) 46–63

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other:

Principles of method if other than guideline:

Plant Toxicity Lemna gibba, Myriophyllum spicatum, and Myriophyllum sibiricum on 14 days study of Organic Chemical Dichloro acetic acid

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Dichloroacetic acid

EC Number:

201-207-0

EC Name:

Dichloroacetic acid

Cas Number:

79-43-6

IUPAC Name:

dichloroacetic acid

Test material form:

other: Liquid

Details on test material:

- Name of test material (as cited in study report): Dichloroacetic acid
- Molecular formula (if other than submission substance): C2H2Cl2O2
- Molecular weight (if other than submission substance): 128.94
- Substance type: Organic
- Physical state: Liquid
- Impurities (identity and concentrations): -----

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Analysis of DCA residues was performed by ion chromatography
All samples were stored in the dark at 41C prior to analysis. Calibration was performed through the use of four external standard solutions, plus a quality control standard, and linear regression analysis. Standards and quality control samples were made up in field water obtained from a control microcosm.

Sampling and analysis

Analytical monitoring:

not specified

Test solutions

Vehicle:

not specified

Details on test solutions:

0, 10, 30, 100 mg/L of DCA

Test organisms

Test organisms (species):

other: Myriophyllum spicatum, M. sibiricum, and Lemna gibba

Details on test organisms:

The microcosms are approximately 1.2m deep witha water depthof 1m, a diameter of 3.9 m, a surface area of 11.95m2, water volume of approximately 12,000 L.

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

14 d

Test conditions

Hardness:

Hardness: 323 - 340 mg/L

pH:

pH : 7

Dissolved oxygen:

DO: 7.6-9.4mg/L

Reference substance (positive control):

not specified

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

30 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: M. spicatum

Effect concentrations 2

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: M. sibiricum

Effect concentrations 3

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

30 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: L. gibba

Effect concentrations 4

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: M. spicatum

Effect concentrations 5

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

30 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: M. sibiricum

Effect concentrations 6

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: L. gibba

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

The Nominal concentration of Dichloro acetic acid were 0, 10, 30 & 100 mg/L on Myriophyllum spicatum, M. sibiricum, and Lemna gibba. On which the NOEC & LOEC value was found to be on M. spicatum at Day 14 NOEC was 30 & LOEC 100mg/L., for M. sibiricum day 14 the NOEC 10 & LOEC on 30 mg/L and for L. gibba the NOEC on 14 days at 30 mg/L & LOEC was found to be at 100 mg/Lon Frond number.

Executive summary:

The Nominal concentration of Dichloro acetic acid were 0, 10, 30 & 100 mg/L on Myriophyllum spicatum, M. sibiricum, and Lemna gibba. On which the NOEC & LOEC value was found to be on M. spicatum at Day 14 NOEC was 30 & LOEC 100mg/L., for M. sibiricum day 14 the NOEC 10 & LOEC on 30 mg/L and for L. gibba the NOEC on 14 days at 30 mg/L & LOEC was found to be at 100 mg/Lon Frond number.