Propanoic acid, 2-(4-chloro-2-methylphenoxy)-, 2-ethylhexyl ester, (2R)-

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 1999-08-04 to 2000-01-24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

MCPP-P DMA
Batch No.: 9158/7(91-1)
Purity: 76.6 %

Analytical monitoring:

yes

Details on sampling:

Sampling at 0 and 72 h. 15 - 20 mL aliquotes were collected from each prepared concentration.

Vehicle:

no

Details on test solutions:

The test substance was MCPP-P DMA. Based on a range finding test the definitive concentrations were set to 0, 5.6, 14.3, 35.8, 90, 224 mg/L nominal as MCPP-P acid. The test concentrations were measured at the beginning and the end of test exposure period as MCPP-P acid.

Test organisms (species):

Anabaena flos-aquae

Details on test organisms:

Anabaena flos-aquae (strain CCAP 1403/13B)
Source: Culture collection of Algae and Protozoa (CCAP), Ambleside, Cumbria, UK

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

no data

Test temperature:

23.4 - 25.2 °C

pH:

6.8 - 7.3

Dissolved oxygen:

no data

Salinity:

NA

Conductivity:

no data

Nominal and measured concentrations:

Equivalent to MCPP-P acid concentrations:
nominal: 0, 5.6, 14.3, 35.8, 90, 224 mg/L
measured: 0, 5.955, 14.3, 36.17, 91.35, 227.4 mg/L

Details on test conditions:

The test flasks were 250 mL Erlenmeyer flasks capped with foil lids. Three replicates and six controls were used. The medium was prepared according to guideline. Illumunation was provided by artifical fluorescent tubes at light intensity of 7610 lux. The alga growth inhibition was measured by cell counting after 24, 48 and 72 hours under microscope and Sedgewick-Rafter or Neubauer Counting Chambers depending on cell numbers present.

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

28.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: MCPP-P DMA

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

23.9 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: MCPP-P acid

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

7.21 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: MCPP-P DMA

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

5.956 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: MCPP-P acid

Reported statistics and error estimates:

The EC50-value and NOEC were calculated by probit transformation and regression analysis. According to OECD the 100 % inhibition observed in the highest exposure groups were not included in the EC50 estimation. The Pearson chi-squared goodness of fit test statistic was statistically significant at the 1 % level for AUG (0 - 72 h) and the growth inhibition curve for each of the concentration curves. As a result, the EC50 value reported can only be used as indicative of the EC50 as the probit fit to the data was not good, i.e. the data were not adequately spread over 0 % to 100%.

Validity criteria fulfilled:

yes

Conclusions:

For MCPP-P acid, the hydrolysis product of MCPP-P 2-EHE, a 72h-EC50 of 23.9 mg/L and a 72h-NOEC of 5.96 mg/L were determined on the alga Anabaena flos-aquae.

Executive summary:

The effect of MCPP-P DMA salf upon the growth of Anabaena flos-aquae a freshwater blue-green alga, was determined over a 72 h period, in a test based on procedures in OECD 201 (1984).

The nominal concentrations of MCPP-P DMA salt whole product tested were 268, 107, 43, 17, 6.7 and 0 mg/L corresponding to 224, 90, 36, 14, 5.6 and 0 mg/L MCPP-P acid, respectively.The measured concentration were 227.4, 91.35, 36.17, 14.30, 5.956 and 0 mg/L as MCPP-P acid. The EC50 and the NOEC were calculated and reported for both MCPP-P DMA and the MCPP-P acid.

The EC50 for the salt was determened to be 28.9 mg/L, where for the acid it was 23.9 mg/L. The NOEC based on the MCPP-P DMA salt was 7.21 mg/L and based on the MCPP-P acid was 5.956 mg/L.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please refer to section 13 for "Read Across justification".

Reason / purpose for cross-reference:

read-across source

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

28.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: MCPP-P DMA

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

23.9 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: MCPP-P acid

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

7.21 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: MCPP-P DMA

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

5.956 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: MCPP-P acid

Description of key information

For MCPP-P acid, the hydrolysis product of MCPP-P 2-EHE, a 72h-EC50 of 23.9 mg/L and a 72h-NOEC of 5.956 mg/L were determined on the alga Anabaena flos-aquae.

Key value for chemical safety assessment

EC50 for freshwater algae:

23.9 mg/L

EC10 or NOEC for freshwater algae:

5.956 mg/L

Additional information

The toxicity to aquatic algae and cyanobacteria was investigated with MCPP-P acid (read-across).

 

The effect of MCPP-P DMA salf upon the growth of Anabaena flos-aquae a freshwater blue-green alga, was determined over a 72 h period, in a test based on procedures in OECD 201 (1984).

The nominal concentrations of MCPP-P DMA salt whole product tested were 268, 107, 43, 17, 6.7 and 0 mg/L corresponding to 224, 90, 36, 14, 5.6 and 0 mg/L MCPP-P acid, respectively. The measured concentration were 227.4, 91.35, 36.17, 14.30, 5.956 and 0 mg/L as MCPP-P acid. The EC50 and the NOEC were calculated and reported for both MCPP-P DMA and the MCPP-P acid.

The EC50 for the salt was determined to be 28.9 mg/L, where for the acid it was 23.9 mg/L. The NOEC based on the MCPP-P DMA salt was 7.21 mg/L and based on the MCPP-P acid was 5.956 mg/L.