Chromium (III) hydroxide

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

fish early-life stage toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

72 days

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

As with all inorganic salts, the significance for toxicity or environmental assessment is the presence of specific ions that will form when in solution or when in biological systems.In the case of Cr III salts, the counter ion will have an effect on solubility and this is itself dependant on the type of media being used and in particular the pH of that media. It is generally accepted that in the case of metal salts, testing with salts that are soluble in the respective test media will ensure maximum exposure of the metal ions. This will include chlorides and nitrates as being more soluble and will indeed have relevance when dissolved in acid media, such as if ingested.Read-across to other chromium III salts is therefore considered valid as long as the exposure in the test system is greater than wold be expected for the substance under review for registration.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 210 (Fish, Early-Life Stage Toxicity Test)

Principles of method if other than guideline:

Exposure lasted 72 d for newly fertilized eggs and 58 d for the exposure started at the eyed stage. These exposures continued to 30 d post-swimup.

GLP compliance:

no

Analytical monitoring:

yes

Details on sampling:

Samples for chromium analysis were taken weekly from each concentration, and daily samples were takenfrom selected concentrations

Vehicle:

no

Details on test solutions:

Nominal concentrations of trivalent chromium rangedfrom 0.277 to 25.0 mg/lThe 50% replacement time of test water in the aquaria was approximately 25 min

Test organisms (species):

Salmo sp.

Details on test organisms:

Named in report as steelhead trout Salmo gairneri

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 d

Remarks on exposure duration:

Exposure lasted 72 d for newly fertilized eggs and 58 d for the exposure started at the eyed stage. These exposures continued to 30 d post-swimup.

Hardness:

Mean 25 mg/l as Ca Carbonate

Test temperature:

Mean 12.8 C

pH:

7.0 - 7.5

Dissolved oxygen:

Saturated

Nominal and measured concentrations:

Ten replicates, including 0 mg/l controlMean measured treatement concerntrations 5 - 271 mg/l

Reference substance (positive control):

no

Key result

Duration:

72 d

Dose descriptor:

other: NOAEC

Remarks:

Survival

Effect conc.:

ca. 150 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Cr III

Basis for effect:

mortality

Duration:

72 d

Dose descriptor:

NOEC

Effect conc.:

ca. 30 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

element

Remarks:

Cr III

Basis for effect:

weight

Details on results:

Slight reductions in survival at lower concentations, but not considered significantThe biological significance of the small reductions in percent survival and growth observed at 48 and 89 ug/l is uncertain

Validity criteria fulfilled:

not specified

Conclusions:

The NOAEC for survival is concluded to be 157 ug/l and in view of statistically uncertain reductions in length and weight occurring at 45 and 89 ug/l, the NOEC is concluded to be 30 ug/l

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

150 µg/L

Additional information

Headline NOAEC 150 ug/l is based on survival and vigour, but statistically uncertain reductions in length and weight occurred at 45 and 89 ug/l

Chromium III is available in natural waters and is an essential element. The metal therefore goes through biotransformation processes and is not accumulative.

Based on these charcteristics, classification as Aquatic Chronic 3 is proposed.