Poly(oxy-1,2-ethanediyl), α-[2-(dide- cylmethylammonio)ethyl]- .omega.- hydroxy-, propanoate (salt) (Bardap 26)

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

9/03/2001- 21/05/2001

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

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

Principles of method if other than guideline:

No applicable

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
No information provided.

Analytical monitoring:

yes

Details on sampling:

Samples to verify test concentrations were taken from the control and from each test group at 0 and 72 hours. The pH of each control and test flask was determined at initiation of the study and after 72 hours exposure. The temperature within the incubator was recorded daily.

Vehicle:

no

Details on test solutions:

Culture medium was prepared using reverse osmosis purified deionised water and pH adjusted to 7.5. A 148 mg/L stock solution of test substance was prepared, from which further dilutions were created and mixed with culture medium in order to give test concentrations of 0.0438, 0.0875, 0.175, 0.35 and 0.7 mg/L.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

-Test organism: Scenedesmus subspicatus
-Strain: CCAP 276/20
-Source: Institute fo frshwater ecology, Cumbria. Cultures maintained in laboratory by periodic replenishment of culture medium.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

Observations were made for 72 hours following exposure.

Hardness:

No information provided.

Test temperature:

24°C± 1°C

pH:

7.5-8.4

Dissolved oxygen:

No information provided.

Salinity:

No information provided.

Nominal and measured concentrations:

-Nominal concentrations: 0.0438, 0.0875, 0.175, 0.35 and 0.7 mg/L.
At 0 hours measured concentrations were found to be in the range of 88% to 104% of nominal concentrations with the exception of the 0.038 mg/L test sample (161%) and the 0.175 mg/L test sample(129%). Analysis of the test solutions after 72 hours showed a marked decline in test concentrations to between 31% and 59% of the nominal concentrations.

Details on test conditions:

TEST SYSTEM
- Test vessel: Conical flask
- Material, size, headspace, fill volume: 250 mL.
Three flasks each containing 100 ml of solution were prepared for the control and each treatment group.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Biomass production and growth rate.

TEST CONCENTRATIONS
- Test concentrations: 0, 0.0438, 0.0875, 0.175, 0.35 and 0.7 mg a.s./l

Reference substance (positive control):

not specified

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.044 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks:

Inhibition

Duration:

72 h

Dose descriptor:

other: EbC50

Effect conc.:

0.15 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks:

Inhibition

Key result

Duration:

72 h

Dose descriptor:

other: ErC50

Effect conc.:

0.34 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks:

Inhibition

Details on results:

This study indicated that the test substance was toxic to Scenedesmus subspicatus over 72 hours. The no-observed-effect concentration NOEC was found to be 0.044 mg/L. The 72hr EbC50 was estimated to be 0.15 mg/L and the 72hr ErC50 was estimated to be 0.34 mg/L. These results are based on the time-weight mean measured test concentrations due to the decline in measured test concentration over the 72-hour study period. This is considered to be due to adsorption of the test material to algal cells.

Results with reference substance (positive control):

No information provided.

Reported statistics and error estimates:

All statistical analyses were performed using the SAS computer software package. One way analysis of variance incorporating Bartlett's test for homogeneity of variance and Dunett's multiple comparison procedure were carried out on the area under the growth curve data at 72 hours for te control and all test groups to determine any statistically significant differences.

Table 1. Inhibition of Growth Rate and Biomass

Nominal concentration (mg a.s./l)	Area Under Curve at 72 hr	% Inhibition	Growth Rate	% Inhibition
0	1.49E+07	-	0.059	-
0.0438	1.44E+07	3	0.058	2
0.0875	1.18E+07	20	0.056	5
0.175	8.81E+06	41	0.048	19
0.35	5.09E+06	66	0.041	31
0.7	9.62E+05	94	0.026	56

Validity criteria fulfilled:

yes

Conclusions:

Based on concentration effect relationship observed, the no-observed-effect concentration (NOEC) was found to be 0.044 mg/L under the conditionsof this study. The EbC50 was found to be 0.15 mg/L and the ErC50 was found to be 0.34 mg/L.

Executive summary:

The effect of Bardap 26 (N,N-Didecyl-N-methylpoly(oxyethyl)ammonium Propionate) on the inhibition of algal growth was determined in a 72 hour growth inhibition test on Scenedesmus subspicatus, conducted in accordance with Directive 92/69/EEC, Method C3 and OECD Guideline No. 201. The test substance was dissolved in culture medium and the volume adjusted to give a 148 mg/L stock solution from which a series of dilutions were made. The test parameter used was the effect on biomass production and growth rate. The test was conducted at concentrations of 0, 0.0438, 0.0875, 0.175, 0.35 and 0.7 mg/L. Based on concentration effect relationship observed, the no-observed-effect concentration (NOEC) was found to be 0.044 mg/L., the EbC50 was found to be 0.15 mg/L and the ErC50 was found to be 0.34 mg/L.

Description of key information

One key study is available to assess the toxicity to aquatic algae. The study was conducted in accordance with Directive 92/69/EEC, Method C3 and OECD Guideline No. 201, with no deviations and compliant with GLP.

Scenedesmus subspicatus were exposed to Bardap 26 for 72 hours at concentrations of 0, 0.0438, 0.0875, 0.175, 0.35 and 0.7 mg/L. Based on concentration effect relationship observed, the no-observed-effect concentration (NOEC) was found to be 0.044 mg/L, the EbC50 was found to be 0.15 mg/L and the ErC50 was

found to be 0.34 mg/L. The ErC50 was used as the key EC50 value.

Key value for chemical safety assessment

EC50 for freshwater algae:

0.34 mg/L

EC10 or NOEC for freshwater algae:

0.044 mg/L

Additional information

The effect of Bardap 26 (N,N-Didecyl-N-methylpoly(oxyethyl)ammonium Propionate) on the inhibition of algal growth was determined in a 72 hour growth inhibition test on Scenedesmus subspicatus, conducted in accordance with Directive 92/69/EEC, Method C3 and OECD Guideline No. 201. The test substance was dissolved in culture medium and the volume adjusted to 500 ml to give a 200 ml/stock solution from which a series of dilutions were made. The test parameter used was the effect on biomass production and growth rate. The test was conducted at concentrations of 0, 0.0438, 0.0875, 0.175, 0.35 and 0.7 mg/L. Based on concentration effect relationship observed, the no-observed-effect concentration (NOEC) was found to be 0.044 mg/L,

the EbC50 was found to be 0.15 mg/L and the ErC50 was found to be 0.34 mg/L. The ErC50 was used as the key EC50 value as it is considered a robust measurement of toxicity than the EbC50.

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