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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
Not specified
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study, which is rated as reliability 2 because it is a read-across study.
Justification for type of information:
Please refer to IUCLID Section 13 for the read-across justification.
Reason / purpose:
read-across source
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES
- Melting point: <0 °C
- Boiling point: 258 °C
- Vapour pressure: Not measured
- Water solubility (under test conditions): Not measured
OTHER PROPERTIES (if relevant for this endpoint)
- Results of test for ready biodegradability: 8 % after 28 day
- Other:
Analytical monitoring:
no
Details on sampling:
Daily cell counts were made visually by means of direct microscopic examination with a hemocytometer.
Vehicle:
no
Details on test solutions:
Individual WAFs were prepared for each test level and renewed daily. Individual WAFs were prepared by adding a measured weight of test material to a measured volume of dilution water (1-L) in a glass vessel and stirring for 24 hours. Following the mixing period, the test solutions were allowed to stand for approximately 4 hours before the water phase was siphoned off. The siphoned water phase (i.e., WAF) was used for the aquatic toxicity test.
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
Cells taken from a log-growth phase in-house culture of Selenastrum capricornutum that was originally purchased from University of Texas at Austin alga collection.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Post exposure observation period:
No post exposure observation period specified.
Hardness:
Not specified
Test temperature:
Test temperature (ºC) - 24 + 1.
pH:
pH ranged from 7.6 - 8.1 at 0-hour and 9.0 - 9.7 after 96 hours.
Dissolved oxygen:
Not specified
Salinity:
Not applicable
Nominal and measured concentrations:
Control, 0.3, 3.3, 33, 330 and 3,300 mg/L WAF loading rates.
Details on test conditions:
A static test was conducted; i.e., there was no daily renewal of test solution. Three 100-mL replicates per treatment, inoculum ~10,000 cells/mL. The 250-mL Erlenmeyer flasks were stoppered with foam plugs to reduce entry of dust, etc. During the test all treatment and control flasks were randomly placed on an orbital shaker adjusted to approximately 100 cycles per minute under constant light (24 hours/day). Daily cell counts were made visually by means of direct microscopic examination with a hemocytometer.
Light: Cool-white fluorescent lights provided a light intensity of 370 to 380 foot-candles 24-h per day. Test temperature (ºC) - 24 + 1.
Dilution Water: Sterile enriched alga growth media adjusted to pH 7.5.
Particulate matter ranged from <10 mg/L at the start of the test to 29 mg/L at the end of the test. pH ranged from 7.6 - 8.1 at 0-hour and 9.0 - 9.7 after 96 hours.
Test Levels: Control, 0.3, 3.3, 33, 330 and 3,300 mg/L WAF loading rates.
Reference substance (positive control):
no
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
ca. 33 mg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
ca. 600 mg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
96 h
Dose descriptor:
EC0
Effect conc.:
ca. 870 mg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
Effects were determined to be algistatic based on the rapid re-growth of an aliquot of cells taken from 500 mg/L cultured in fresh control media.
Results with reference substance (positive control):
No data
Reported statistics and error estimates:
EL50s were calculated using Standard statistical methods from Stephan (1983)
Validity criteria fulfilled:
yes
Conclusions:
Endpoint: growth rate
Exposure period: 96 hour(s)
Unit: mg/l
NOEC: c = 33
EL50 : c = 600
EL0 : c = 870
Executive summary:

Study conducted to OECD test guidelines in compliance with GLP. Effects were determined to be algistatic based on the rapid re-growth of an aliquot of cells taken from 500 mg/L cultured in fresh control media.

 

Endpoint: growth rate

Exposure period: 96 hour(s)

Unit: mg/l

NOEC: c = 33

EL50 : c = 600

EL0 : c = 870

Read across to supporting substance, CAS No. 36878 -20 -3, by structural analogue.

Description of key information

Read across to supporting substance CAS 36878 -20 -3. Effects were determined to be algistatic based on the rapid re-growth of an aliquot of cells taken from 500 mg/L cultured in fresh control media. However the results do not trigger classification and labelling under Directive (EC) No 1272/2008 - the CLP Directive. 



 
  

  
  
  
    

oss to supporting substance CAS 36878 -20 -3. Effects were determined to be algistatic based on the rapid re-growth of an aliquot of cells taken from 500 mg/L cultured in fresh control media. However the results do not trigger classification and labelling under Directive (EC) No 1272/2008 - the CLP Directive.

 

 

Key value for chemical safety assessment

EC50 for freshwater algae:
600 mg/L
EC10 or NOEC for freshwater algae:
33 mg/L

Additional information

Read across to supporting substance, CAS No. 36878 -20 -3, by structural analogue. Substance structure attached under Illustration.

This substance has been supported under Environmental Protection Agency’s (EPA’s) High Production Volume (HPV) Challenge Program. The American Chemical Councils RAPA Panel, has derived a “Substituted Diphenylamines” category of chemicals for this substance, please refer to EPA reference 201-14700A located at

 

http://www.epa.gov/hpv/pubs/summaries/subdipha/c13378rt.pdf

Relying on several factors specified in EPA’s guidance document on “Development of Chemical Categories in the HPV Challenge Program,” in which use of chemical categories is encouraged, the chemicals constitute a chemical category on the following basis:

 

Structural Similarity. A key factor supporting the classification of these chemicals as a category is their structural similarity (see Figure 1). All share a common starting material; Diphenylamine (Benzenamine, N-phenyl-, CAS# 122-39-4), a common synthetic pathway, and all compounds in this category are diamines with various substitutions.

 

Similarity of Physicochemical Properties. The similarity of the physicochemical properties of these materials parallels their structural similarity. All are off-white to light brown solids or viscous liquids intended for use as antioxidants in finished rubber articles or as antidegradant additives that extend the useful life of heavy-duty industrial functional fluids used in high-speed, high-temperature and/or high-load applications. As a class, these amine-based antidegradant compounds are less migratory (more polymer-bound) and less staining than the Substituted p-Phenylenediamine antidegradants. The use of these materials requires that they be stable under high temperatures. Their low volatility is due to their low vapor pressure, highly viscous or solid form. The existing information for these materials indicates that they have low water solubility and high flash points.

 

Fate and Transport Characteristics. Members of this category have been shown to be not readily biodegradable, so additional testing is not needed. The lack of water solubility of the members of this category makes hydrolysis testing unnecessary. These materials have been shown not to partition to water or air if released into the environment due to their low water solubility and low vapor pressure.

 

Toxicological Similarity. Review of existing published and unpublished test data for Substituted Diphenylamines shows the aquatic and mammalian toxicity among the materials within this category are similar.

 

Aquatic Toxicology. Data on acute fish toxicity, acute invertebrate toxicity, and alga toxicity were reviewed. With increasing molecular weight, the toxicity to aquatic organisms decreases. These materials have high estimated log Kowvalues, such that acute toxicity is not expected at or below their low levels of water solubility. For the purposes of the HPV Program, additional testing was not proposed for the members of this category.

 

Conclusion. Based upon the data reviewed in “Substituted Diphenylamines” category of chemicals, the physicochemical and toxicological properties of the Substituted Diphenylamine category members are similar and follow a regular pattern as a result of that structural similarity. Therefore, the definition of a chemical category has been met, and read across is considered appropriate for the category of chemical.