Iron hydroxide oxide yellow

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Daphnia magna

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

The test item was insoluble in water. Treatment in an ultrasonic bath (1 h) resulted in red-brown colouration of the flask content, indicating fine dispersal of the test item. After treatment on a magnetic stirrer for 24 h, the suspension was tested without filtration.

Validity criteria fulfilled:

yes

Remarks:

The immobilisation and other abnormalities in the controls did not exceed 10% by the end of the test. The dissolved oxygen concentration remained above 3 mg/L throughout the exposure period.

Conclusions:

For iron hydroxide oxide the observed 48 hour EC50 on Daphnia magna was >/= 100 mg/L. The determination was performed according to OECD Guideline 202.

Executive summary:

The determination was performed according to OECD Guideline 202 (Currenta 2008).

The Daphnia were exposed to a limit test concentration of nominally 100 mg/L of iron hydroxide oxide dissolved in water. Auxiliaries used to prepare the test media were an ultrasonic bath and a magnetic stirrer.

Observations were made on the swimming ability and the immobilisation rate, respectively, after 24 and 48 hours of exposure. The test item was insoluble in dilution water. Treatment in an ultrasonic bath (1 h) resulted in yellow-brown colouration of the flask content, indicating fine dispersal of the test item. After treatment on a magnetic stirrer for 24 h, the suspension was tested without filtration.

No toxic effects against daphnia were observed at a limit test concentration of 100 mg/L under static conditions.

Description of key information

For alpha iron hydroxide oxide the observed 48 hour EC50 on Daphnia magna was >/= 100 mg/L.

Additional information

Applying read-across to nanosized iron (hydr)oxides (see attachment "Read-across justification-environ assessment-iron oxides" and “Endpoint-specific read-across justification for nano forms of iron oxide, 2021” attached in IUCLID section 13), nanosized iron manganese trioxide is not considered acutely toxic to aquatic invertebrates. Fornano-alpha iron hydroxide oxide yellow, the observed 48-h EC50 value for the immobilization of Daphnia magna is > 100 mg/L, a concentration that is 100-fold above the corresponding OECD test limit.

Table: Acute toxicity of iron (hydr)oxides to aquatic invertebrates

Endpoint	Test species	Test results	Test material/ form	Reliability: Reference
Short-term toxicity to aquatic invertebrates	Daphnia magna	EC50 (48h): >100 mg/L nominal	diiron trioxide / powder	RL2: Neuhahn, 2008
	Daphnia magna	EC50 (48h): >100 mg/L nominal	iron hydroxide oxide yellow / nano, alpha	RL2: Neuhahn, 2008
	Daphnia magna	EC0 (48 h): >= 10 g/L nominal	triiron tetraoxide	RL2: Caspers, 2000

Acute toxicity of iron (hydr)oxide nanoforms to aquatic invertebrates was investigated in a reliable study with nano-alpha iron hydroxide oxide yellow according to OECD 202 (Neuhahn, 2008). Toxic effects to Daphnia magna were not observed at a limit test concentration of 100 mg/L, representing the respective OECD test limit for acute toxicity, under static conditions and an unbounded 48 h EC 50 value of > 100 mg/L (nominal) was derived.

Based on read-across to nanosized iron (hydr)oxides (see attachment "Read-across justification-environ assessment-iron oxides" and “Endpoint-specific read-across justification for nano forms of iron oxide, 2021” attached in IUCLID section 13), available data indicate a low potential for acute toxicity ofnanosized iron manganese trioxideto aquatic invertebrates (see table below).

Supportive information microsized iron (hydr)oxides

For microsized iron (hydr)oxides, the observed 48-h EC50 values for the immobilization of Daphnia magna range from > 100 mg/L to > 10,000 mg/L, a concentration that is 100-fold above the corresponding OECD test limit.