Registration Dossier

Ecotoxicological information

Short-term toxicity to fish

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
96 hours
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
GLP compliance:
not specified
Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Details on test organisms:
Young hatchery-purchased fry (6.2 + 0.7 cm; 1.7 + 0.7 g), acclimated for at least 3 weeks to the treated city water
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Hardness:
Tests were carried out using activated charcoal and ultraviolet light-treated Longueuil-city water, whose hardness generally stands between 100 to 150 mg L -I in CaCO 3 equivalents.
Test temperature:
15 +/- 0.1 deg C
pH:
pH (value not reported) was monitored periodically throughout the experiment.
Dissolved oxygen:
Aeration (7.5 cm 3 L -I min -1) of each test vessel. Dissolved oxygen (value not reported) was monitored periodically throughout the experiment.
Nominal and measured concentrations:
0 (control), 0.01, 0.1, 1, 10 and 100 mg/L Zr.
Details on test conditions:
Exposure vessels consisted of 60 L Rubbermaid containers lined with a polyethylene bag into which was placed a black-meshed Vexar (Dupont) cylinder (with lid) espousing the contour of the assay container.
Reference substance (positive control):
no
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 20 mg/L
Conc. based on:
element
Basis for effect:
mortality
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 54 mg/L
Nominal / measured:
nominal
Conc. based on:
other: Registered substance
Basis for effect:
mortality
Details on results:
100% mortality within 2 hr at 100 mg/L Zr (pH-3.0), but identical effect for dilution water adjusted to pH=3.0. In the 96-hr LCs0 bioassay with rainbow trout, low pH was entirely responsible
for toxicity at 100 mg/L Zr. At 10 mg L I Zr (pH = 6.7), the next highest test concentration used in the assay, no lethal effects were observed. The LC50 was therefore initially identified as being > 10 mg L -1 Zr. However, in a subsequent sublethal bioassay carried out at 0, 1, 5 and 20 mg/L Zr, no mortality was noted at the highest concentration tested. Hence, a 96-hr LC50 > 20 mg L -1 was finally reported.

The reported toxicity of zirconium 4+ ion was used to calculate the toxicity of the registered substance based on a 37% Zr w/w content

Conclusions:
The LC50 (96 hr) in rainbow trout (Salmo gairdneri) was reported to be >20 mg/L Zr, calculated to be 54 mg/l for the registered substance.
Executive summary:

The LC50 (96 hr) in rainbow trout (Salmo gairdneri) was reported to be >20 mg/L Zr. Although mortality was 100% at a higher dose of 100 mg/L Zr, this was attributed entirely to the effects of pH.

Description of key information

The LC50 (96 hr) in rainbow trout (Salmo gairdneri) was reported to be >20 mg/L Zr. Although mortality was 100% at a higher dose of 100 mg/L Zr, this was attributed entirely to the effects of pH.

The Zr4+ content of the anhydrous registered substance is ca 37%; using an assumed LC50 of 20 mg/l Zr 2 +, the product LC50 is estimated 54 mg/l

Key value for chemical safety assessment

LC50 for freshwater fish:
54 mg/L

Additional information

A figure of 54 mg/l is used for the CSR and classification of the anhydrous oxynitrate