Chloroacetic acid

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 Oct - 21 Oct 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP - Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Circular on Test Methods of New Chemical Substances (Japan), Alga, growth inhibition test

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Chloroacetic acid

EC Number:

201-178-4

EC Name:

Chloroacetic acid

Cas Number:

79-11-8

Molecular formula:

C2H3ClO2

IUPAC Name:

chloroacetic acid

Test material form:

solid: crystalline

Details on test material:

- Name of test material (as cited in study report): Chloroacetic acid
- Physical state: non colored crystalline
- Analytical purity: 100%
_ Vapour pressure: 1 hPa at 20°C
-Water solubility: 45% at 20 °C
- Lot/batch No.: 610C2140
- Stability under test conditions: stable, verified by IR.
- Storage condition of test material: in the cool and dark

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0.02, 0.03, 0.59, 0.10, 0.17, 0.300 mg/L
- Sampling method: Test water was sampled from all vessels and mixed in one sample for each concentration. These samples were centrifuged (3000 rpm, 10 min).

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test item was soluted in medium to prepare Stock solution I (1000 mg/L). Stock solution I was diluted with medium to prepare stock solution II (1 mg/L). Stock solution II was diluted with medium to make series of concentrations.

Test organisms

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Strain: ATCCC22662
- Source (laboratory, culture collection): American Type Culture Collection
- Age of inoculum (at test initiation): 5 days
- Method of cultivation:

ACCLIMATION
- Acclimation period: 5 days
- Culturing media and conditions (same as test or not): same as test

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 d

Test conditions

Test temperature:

22.2 - 23.0 °C

pH:

8.1 - 9.8

Nominal and measured concentrations:

Nominal concentration: 0.02, 0.034, 0.059, 0.100, 0.170, 0.300 mg/L
Mean measured concentration: 0.0182, 0.0331, 0.0586, 0.107, 0.179, 0.316 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flask
- Type (delete if not applicable): closed with air permeability silicone cap
- Material, size, headspace, fill volume: glassm 300 mL,
- Initial cells density: 5 x 1000 cells/mL
- Control end cells density: 2098000 ± 206000 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no adjustment
- Photoperiod: continuously
- Light intensity and quality: 75 μE/m2/s

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter

TEST CONCENTRATIONS
- Range finding study: performed twice.
- Test concentrations:
Range finding study I
Growth inhibition after 72 hours were 2, -1, 1, 7 and -2% in 0.008, 0.009, 0.01, 0.015, and 0.02 mg/L, respectively.
Range finding study II
Growth inhibition after 72 hours were -31, -39, -30, 34, 97, 99, 99% in 0.015, 0.02, 0.03, 0.04, 0.2, 0.3, and 0.4 mg/L, respectively.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.158 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 0.152 - 0.164 mg/L

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.066 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 0.05 - 0.088 mg/L

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.033 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.033 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no abnormalities
- Unusual cell shape: not observed.
- Colour differences: not observed.
- Aggregation of algal cells: not observed.
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: Test water was always colorless during the test.

Reported statistics and error estimates:

After confirmation of equality of variance, 1-way ANOVA and Dunnet multiple comparison test was performed. In case of no statistical siginificant, the highest concentration was regarded as NOEC.

Any other information on results incl. tables

Table 1. Measured concentration of the test substance in test cultures

Nominal concentration (mg/L)	Measured concentration (mg/L) (percent of nominal)				Mean (a) measured concentration (mg/L)
	0 hour	24 hours	48 hours	72 hours
Control	< 0.0003	< 0.0003	< 0.0003	< 0.0003	-
0.0200	0.0218 (109)	0.0209 (105)	0.0185 (93)	0.0098 (49)	0.0182 (91)
0.0340	0.0370 (109)	0.0373 (110)	0.0346 (102)	0.0195 (57)	0.0331 (97)
0.0590	0.0623 (106)	0.0623 (106)	0.0604 (102)	0.0448 (76)	0.0586 (99)
0.100	0.111 (111)	0.107 (107)	0.109 (109)	0.093 (99)	0.107 (107)
0.170	0.184 (108)	0.175 (103)	0.183 (108)	0.172 (101)	0.179 (105)
0.300	0.328 (109)	0.313 (104)	0.317 (106)	0.310 (103)	0.316 (105)

(a): time weighted mean