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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:
experimental study
Adequacy of study:
key study
Study period:
96 hours
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
according to guideline
Guideline:
other: Protocol for bioassessment of hazardous waste sites. EPA-600/2-83-05
Principles of method if other than guideline:
96 hours exposure period
GLP compliance:
no
Specific details on test material used for the study:
Chromium chloride used as a reference, but analysis and result all expressed as Cr3+
Analytical monitoring:
yes
Details on sampling:
Detaills not described
Vehicle:
no
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
Algal cells (10,OOO cells/ml) were exposed to the test solutions for 96 h. Algae cultured in algal assay medium served as the controls.
Test type:
static
Water media type:
freshwater
Remarks:
Natural water, contaminated with Chromium
Limit test:
no
Total exposure duration:
96 h
Remarks on exposure duration:
This exceeds normal guidelines for 72 hour exposure. This should not greatly impact on the results in since this is a satable inorganic substance.
pH:
Samples on which algal assays were performed were adjusted with 0.1 N NaOH, as necessary, to a final pH that ranged from 5.6 to 8.9
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
0.3 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
element
Remarks:
chromium
Basis for effect:
biomass
Key result
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
ca. 0.6 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
other: Cr (OH)3
Basis for effect:
biomass
Details on results:
The research using different contaminated waters resulted in an EC50 range of 0.229 - 0.360 mg/l with a mean of 0.265 mg/l CrThese have been rounded to 0.3 mg/l Cr.
Reported statistics and error estimates:
Linear regression analysis [9] was used to calculate the mean inhibitory concentrations (EC50) related to measured chromium concentrations.The difference in yields between the control and test flasks was calculated and reported as percent inhibition.
Validity criteria fulfilled:
not specified
Conclusions:
Water from a number of contaminated sources was assessed for toxicity and a relatively consistant EC50 determined of ca 0.3 mg/l CrThis equates to an estimated EC50 0.6 mg/l Cr (OH)3
Executive summary:

Peer reviewed research using scientifically valid methods determined the inhibitory concentrations of Cr3+ to algea

Estimed EC50 for Cr (OH)3 is 0.6 mg/l.

Description of key information

Key value for chemical safety assessment

EC50 for freshwater algae:
0.6 mg/L

Additional information

Based on Cr3+ EC50 0.3 mg/l