Tetrachloro-μ-hydroxy(μ-methacrylato-O:O')dichromium

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
In aqueous media, the target substance complexation reaction products of Tetrachloro-μ-hydroxy(μ-methacrylato-O:O')dichromium, isopropylalcohol and water (CAS 15096-41-0) dissociates into the three compounds methacrylic acid (CAS 79-41-4), chromium trichloride (CAS 10025-73-7) and propan-2-ol (CAS 67-63-0). Hence, methacrylic acid, chromium trichloride and propan-2-ol will be present regardless whether the target substance itself or methacrylic acid, chromium trichloride and propan-2-ol, respectively, were used as test material. Moreover, dissociation of the target substance (CAS 15096-41-0) is to be expected in aquatic environmental systems, which allows the read across between the target substance (CAS 15096-41-0) and the source substance propan-2-ol (CAS 67-63-0).

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The purity of the source substance propan-2-ol which was used in the test with Daphnia magna (reference 6.1.3-5) is unknown. The target substance complexation reaction products of Tetrachloro-μ-hydroxy(μ-methacrylato-O:O')dichromium, isopropylalcohol and water (CAS 15096-41-0), has a purity of 100 % (w/w).

3. ANALOGUE APPROACH JUSTIFICATION
Experimental data i.e. acute toxicity studies with Daphnia magna were available for propan-2-ol. The source substance was tested in an study similar to OECD Guideline 202. This study revealed a 24-h LC50 > 10000 mg/L (nominal). The information given on propan-2-ol is considered to be sufficient to cover the required endpoint information for the target substance complexation reaction products of Tetrachloro-μ-hydroxy(μ-methacrylato-O:O')dichromium, isopropylalcohol and water (CAS 15096-41-0).

Reason / purpose for cross-reference:

read-across source

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

LC0

Effect conc.:

5 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
In aqueous media, the target substance complexation reaction products of Tetrachloro-μ-hydroxy(μ-methacrylato-O:O')dichromium, isopropylalcohol and water (CAS 15096-41-0) dissociates into the three compounds methacrylic acid (CAS 79-41-4), chromium trichloride (CAS 10025-73-7) and propan-2-ol (CAS 67-63-0). Hence, methacrylic acid, chromium trichloride and propan-2-ol will be present regardless whether the target substance itself or methacrylic acid, chromium trichloride and propan-2-ol, respectively, were used as test material. Moreover, dissociation of the target substance (CAS 15096-41-0) is to be expected in aquatic environmental systems, which allows the read across between the target substance (CAS 15096-41-0) and the source substance chromium trichloride (CAS 10025-73-7).

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The purity of the source substance chromium trichloride which was used in the test with Daphnia magna (reference 6.1.3-3) is unknown. The target substance complexation reaction products of Tetrachloro-μ-hydroxy(μ-methacrylato-O:O') dichromium, isopropylalcohol and water (CAS 15096-41-0), has a purity of 100 % (w/w).

3. ANALOGUE APPROACH JUSTIFICATION
Experimental data i.e. acute toxicity studies with Daphnia magna were available for chromium trichloride (CAS 10025-73-7). The source substance was tested in an study according to OECD Guideline 202. This study revealed an effect level 24-h EC50 of 111 mg CrCl3.6H2O/L . The information given on chromium trichloride is considered to be sufficient to cover the required endpoint information for the target substance complexation reaction products of Tetrachloro-μ-hydroxy(μ-methacrylato-O:O')dichromium, isopropylalcohol and water (CAS 15096-41-0).

Reason / purpose for cross-reference:

read-across source

Duration:

24 h

Dose descriptor:

EC0

Effect conc.:

11 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

chromium(III)

Basis for effect:

mortality

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

22 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

element

Remarks:

chromium(III)

Basis for effect:

mortality

Duration:

24 h

Dose descriptor:

EC0

Effect conc.:

55 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Remarks:

CrCl3.6H2O

Basis for effect:

mortality

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

111 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Remarks:

CrCl3.6H2O

Basis for effect:

mortality

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
In aqueous media, the target substance complexation reaction products of Tetrachloro-μ-hydroxy(μ-methacrylato-O:O')dichromium, isopropylalcohol and water (CAS 15096-41-0) dissociates into the three compounds methacrylic acid (CAS 79-41-4), chromium trichloride (CAS 10025-73-7) and propan-2-ol (CAS 67-63-0). Hence, methacrylic acid, chromium trichloride and propan-2-ol will be present regardless whether the target substance itself or methacrylic acid, chromium trichloride and propan-2-ol, respectively, were used as test material. Moreover, dissociation of the target substance (CAS 15096-41-0) is to be expected in aquatic environmental systems, which allows the read across between the target substance (CAS 15096-41-0) and the source substance methacrylic acid (CAS 79-41-4).

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The source substance which was used in the most reliable test with species (reference 6.1.3-1), had a analytical purity of 99.72 %. The target substance complexation reaction products of Tetrachloro-μ-hydroxy(μ-methacrylato-O:O')dichromium, isopropylalcohol and water (CAS 15096-41-0), has a purity of 100 % (w/w). Thus, the purity of the test materials is comparable.

3. ANALOGUE APPROACH JUSTIFICATION
Experimental data i.e. acute toxicity studies with Daphnia magna were available for methacrylic acid. The source substance was tested in an study according to US EPA OTS 797.1300. This study revealed a 48-h EC50 > 130 mg/L (measured, not specified). The information given on methacrylic acid is considered to be sufficient to cover the required endpoint information for the target substance complexation reaction products of Tetrachloro-μ-hydroxy(μ-methacrylato-O:O')dichromium, isopropylalcohol and water (CAS 15096-41-0).

Reason / purpose for cross-reference:

read-across source

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

210 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Description of key information

The 72-h EC50 (growth rate) of the structural analogue chromium trichloride (CAS 10025-73-7) was determined to be 111 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

111 mg/L

Additional information

No data on toxicity to aquatic invertebrates was availbale for the substance itself. In aqueous media, the substance dissociates into the three compounds methacrylic acid (CAS 79-41-4), chromium trichloride (CAS 10025-73-7) and propan-2-ol  (CAS 67-63-0). Thus, dissociation of the target substance (CAS 15096 -41 -0) is to be expected in aquatic environmental systems. Therefore, a read across between the target substance (CAS 15096-41-0) and the source substances methacrylate (CAS 79-41-4), chromium trichloride (CAS 10025-73-7) and propan-2-ol (CAS 67-63-0) was conducted. The available studies were assesseed in a weight of evidence approach.

 

Data were available of a short-term toxicity of the structural analogue methacrylic acid (CAS 79-41-4) was assessed according to guideline US EPA OTS 797.1300. The test flow-through test system contained six sets of four test chambers (1 L) designated as control, and concentration level 1 through level 5. Nominal test item concentrations were: 7.2, 14, 30, 60 and 120 mg/L. Dilution water was a blend of reverse osmosis water and ABC laboratory well water. 10 organisms were assigned to each of the four replicate test chambers (40 daphnids per concentration). Water quality measurements were recorded at 0 and 48 hours. Mean measured test item concentrations (sampling at 0 and 48 hrs) were: 6.7, 13, 32, 62 and 130 mg/L. In result, tthe 48-h EC50 for the structural analogue methacrylic acid was >130 mg/L.

 

In a valid study published by Severdrup et al, 2001(reference 6.1.3-1) using Acartia tonsa (Copepoda) in a semi-static test, the 96 hr EC50 of the test substance was determined to be 210 mg/L.

 

In a study with performed by the German BGA (Kuhn et al, 1989) in total 73 investigations were carried out in order to determine the NOEC of 73 environmentally relevant substances in the 21-d Daphnia reproduction test. As range finding test, acute tests were performed with 24 hours duration. The test was conducted in line with the provisional procedure proposed by the Federal Environmental Agency (Umweltbundesamt) (as of 1 January 1984). Daphnia magna Straus was used as the test organism. The concentrations of substances in the test preparations were chemically quantified. For chromium(III), tested as chromium trichloride hexahydrate, the EC 0 were 11 mg Cr/L (equivalent to 55 mg CrCl3.6H2O mg/L) and the EC 50 found was 22 mg Cr/L and 111 mg CrCl3.6H2O/L respectively (reference 6.1.3-3).

 

The short-term toxicity of the structural analogue propan-2-ol (CAS 67-63-0) published by Bringmann and Kuhn was assessed in a study similar to OECD Guideline 202 using 24-h-old animals from a clone of Daphnia magna. The test medium was tap water free from chlorine, saturated with oxygen, hardness 16° dH (German), pH 7.6 - 7.7, temperature 20 - 22°C. In result, the 24-h LC50 of propan-2-ol was determined to be > 10000 mg/L (reference 6.1.3-5).

 

Conclusion

The lowest 48-h EC50 value of 111 mg/L was determined for the structural analogue chromium trichloride (CAS 10025-73-7). Based on a worst case approach, the 72-h EC50 of the target substance is considered to be 111 mg/L.