Registration Dossier

Ecotoxicological information

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:
2009
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Test article name : Sesbania grandiflora dry purified extract
Chemical class : Botanical extract
Preparation date : April, 2009
Expiry date : April, 2011
Physical form at 20°C : Powder
Colour : Pale brown
Storage conditions : The product was stored at room temperature, in well ventilated room, in its own original container
Safety precautions : Routinely hygienic procedures

Sampling and analysis

Analytical monitoring:
yes

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Study design

Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h

Test conditions

Test temperature:
the ambient temperature under the lights was continuously measured by the mean of a data logger. It was in the range 23.1 – 24.5 °C during the test period..
pH:
in the range 7.63 – 7.91 and 7.69 for control

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
46.63 mg/L
Basis for effect:
cell number
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
79.5 mg/L
Basis for effect:
growth rate

Any other information on results incl. tables

In the negative control the cell density increased on average by a factor of 91. This value complies with the validity criteria of the test according to the mentioned guidelines, such as the coefficient of variation of daily growth rates (21.4%) and the coefficient of variation of average growth in replicates control cultures during the test period (5.7%).

 

In the test item solution the algal growth rate (r) after 72 hours of exposure was inhibited by a minimum value of 0.5% for the nominal concentration of 10.00 mg/L to a maximum value of 71.2% for the highest concentration, compared to the negative control. The yield (y) decreased by a minimum value of 0.2% for the nominal concentration of 3.16 mg/L, to a maximum value of 97.1% for the highest concentration, compared to the negative control.

The effect of the three lowest concentrations, 1.00, 3.16 and 10.00 mg/L, was assessed to be not significant in comparison with control after 72 hours of exposure for both the end-points (Dunnett’s Multiple Comparison and Bonferroni Adjusted test analysis).

Applicant's summary and conclusion

Conclusions:
Endpoint 72 h EC10 (mg/L) 72 h EC20 (mg/L) 72 h EC50 (mg/L)
Yield 19.66 (11.30 – 25.73) 28.32 (22.90 – 32.92) 46.63 (42.87 – 50.45)
Growth rate 34.73 (31.00 - 38.06) 49.89 (47.16 – 52.45) 79.50 (77.74 – 81.27)