Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

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:
August 30 - September 03, 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study has been performed according to ISO guidelines and according to GLP principles.
Principles of method if other than guideline:
ISO 10253: Water quality - Marine growth inhibition test
with Skeletonema costatum and Phaeodactylum tricornutum.


OECD 2000: Guidance Document on aquatic toxicity testing of
difficult substances and mixtures. OECD Environmental Health
and Safety Publications Series on Testing and Assessment
No. 23. ENV/JM/MONO(2000)6.


ISO 8245: Water Quality - Guidelines for the determination
of total organic carbon (TOC) and dissolved organic carbon
(DOC).
GLP compliance:
yes
Analytical monitoring:
yes
Details on test solutions:
Identity and concentration of auxiliary solvent for dispersal: Test medium: ISO 10253 medium based on filtered (0.45
µm)natural seawater (salinity 34.4 S).


Separate WAF's were prepared for 5 loading rates (100-180-
320-560-1000 mg/l) in the dark at 21°C. After 23 h WAF's
were filtered through Wathman GF/C glass fibre filters to
remove non-settling suspended material.
Test organisms (species):
other: Skeletonema costatum, strain NIVA BAC 1 (marine alga)
Test type:
static
Water media type:
saltwater
Limit test:
no
Total exposure duration:
72 h
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
other: loading rate
Basis for effect:
growth rate
Remarks on result:
other: TOC at 1000 mg/l loading rate is 72.0 mg/l
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
180 mg/L
Nominal / measured:
nominal
Conc. based on:
other: loading rate
Basis for effect:
growth rate

Comments:
TOC analysis:

control seawater: 6.0 mg TOC/l

100 mg/L WAF: 10.0 mg TOC/l

1000 mg/l WAF: 72.0 mg TOC/l

The results show that less than 10% of the test substance
partitioned to the water phase as dissolved organic matter,
assuming that the carbon content of the test substance is
70% by weight.

The WAFs with loading more than 180 mg/l caused a
significant inhibition of the growth throughout the
experiment. The loading causing 50% reduction of the average
growth rate (ErL50) was >1000 mg/l. The average growth rate
was higher than in the control at 180 mg/l but
significantly lower at 320 mg/l. Thus the no observable
effect loading (NOEL) is 180 mg/l.

Validity criteria fulfilled:
yes
Conclusions:
Radiagreen EBL (Pentaerythritol mono oleate base Polyol) caused a significant effect on the growth of the marine alga Skeletonema costatum in water accommodated fractions at loading rates above 180 mg/l.

Description of key information

The study was performed according to ISO Guideline 10253 and GLP prinicples.

Key value for chemical safety assessment

EC50 for marine water algae:
1 000 mg/L
EC10 or NOEC for marine water algae:
180 mg/L

Additional information

The inhibitory effect of Radiagreen EBL (Radia 7853) on the growth of the marine diatom Skeletonema costatum, strain NIVA BAC1, has been investigated. The test was performed according to ISO 10253: Marine algal growth inhibition test with Skeletonema costatum and Phaeodactylum tricornutum. The test was performed on water accommodated fractions (WAF) of the test substance. The loading rates were 100 - 1000 mg/l. Growth was monitored by daily counting of cell numbers. Significant reduction of the growth rate of S. costatum was observed at WAF-loadings above 180 mg/l (=NOEC). The growth rate inhibition was less than 50% at the highest loading (1000 mg/l), so the EC50 is >1000 mg/l, or expressed as measured TOC >72.0 mg/l, which is above the water solubility limit of the substance.