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Short-term toxicity to aquatic invertebrates

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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
In this justification, the read-across (bridging) concept is applied. Please refer to a full version of Read-across statement attached in the section 13 "Assessment reports".

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The underlying hypothesis for the read-across is that the target and the source substance have similar toxicological properties (including the same target organs) due to their structural similarity, resemblance to their chemical reactivity, and therefore a similar mode of action.
The source substance ‘1,3-diisopropylbenzene' is a structural isomer of 1,4-diisopropylbenzene (target substance). The physico-chemical properties are highly equivalent based on the high structural similarity. As a conclusion, it is scientifically justified to address the endpoint Short-term toxicity to aquatic invertebrates with data on this isomer.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source substance: 1.3-diisopropylbenzene (or m-DIPB)
structural formula: C12H18
Smiles: CC(C)c1cccc(c1)C(C)C
Molecular weight: 162 g/mol
CAS 99-62-7
EC No 202-773-1
purity: not specified

target substance: 1.4-diisopropylbenzene (or p-DIPB)
structural formula: C12H18
Smiles: CC(C)c1ccc(cc1)C(C)C
Molecular weight: 162 g/mol
CAS 100-18-5
EC No 202-826-9
purity: not specified

No additional information is available on purity of the source and the target substances. Both substances are normally of high purity, containing only minor amounts of impurities that do not influence the read-across validity.

3. ANALOGUE APPROACH JUSTIFICATION
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".

4. DATA MATRIX
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".
Reason / purpose for cross-reference:
read-across source
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
> 0.91 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
>= 0.91 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
Survival was 100 % in the control and test substance exposures at 96 hours.

Summary of Analytical Measurements

Test Vessel Measured Concentrations (mg/L) Mean
0 hr. 48 hr. 96 hr
Control A ND ND ND ND
Control B ND ND ND ND
Test A 0.91 0.92 0.86 0.90
Test B 0.92 0.96 0.87 0.92

ND=None Detected

Validity criteria fulfilled:
yes
Conclusions:
The 96 hour LC50 was > 0.91 mg/L and the NOEC was ≥ 0.91 mg/L demonstrating no adverse effects at the limit of water solubility.
Executive summary:

A 96-hour acute toxicity study with Helisoma trivolvis (ramshorn snail) was conducted with m-diisopropylbenzene similar to ASTM Standard E 729-80 as part of a simultaneous toxicity study using seven species, one vertebrate and six invertebrates. The test was conducted using a recirculating elutriation system, using 1.0 g/20 L diluent water to provide a saturated solution. The flow rate was approximately 100 mL/minute passing through the elutriation column. Analytical verification of the exposure concentrations was conducted at 0, 48, and 96 hours. The mean measured concentrations were 0.90 and 0.92 mg/L for replicates A and B respectively. No mortality was observed in the control or test concentrations. The 96 hour LC50 was > 0.91 mg/L and the NOEC was ≥ 0.91 mg/L demonstrating no adverse effects at the limit of water solubility.


Based on the arguments presented in the Read Across statement attached in IUCLID Section 13, it is clear that the source and the target substances, which are structural isomers, show an identical toxicokinetic pattern. As such, the data presented here can be used to fulfil lthe information requirements for the target substance 1.4-diisopropylbenzene. 

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
In this justification, the read-across (bridging) concept is applied. Please refer to a full version of Read-across statement attached in the section 13 "Assessment reports".

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The underlying hypothesis for the read-across is that the target and the source substance have similar toxicological properties (including the same target organs) due to their structural similarity, resemblance to their chemical reactivity, and therefore a similar mode of action.
The source substance ‘1,3-diisopropylbenzene' is a structural isomer of 1,4-diisopropylbenzene (target substance). The physico-chemical properties are highly equivalent based on the high structural similarity. As a conclusion, it is scientifically justified to address the endpoint Short-term toxicity to aquatic invertebrates with data on this isomer.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source substance: 1.3-diisopropylbenzene (or m-DIPB)
structural formula: C12H18
Smiles: CC(C)c1cccc(c1)C(C)C
Molecular weight: 162 g/mol
CAS 99-62-7
EC No 202-773-1
purity: not specified

target substance: 1.4-diisopropylbenzene (or p-DIPB)
structural formula: C12H18
Smiles: CC(C)c1ccc(cc1)C(C)C
Molecular weight: 162 g/mol
CAS 100-18-5
EC No 202-826-9
purity: not specified

No additional information is available on purity of the source and the target substances. Both substances are normally of high purity, containing only minor amounts of impurities that do not influence the read-across validity.

3. ANALOGUE APPROACH JUSTIFICATION
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".

4. DATA MATRIX
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".
Reason / purpose for cross-reference:
read-across source
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
> 0.91 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
Survival was 100 % in both of the control replicates and 90 % in both of the test substance exposures at 96 hours.

Summary of Analytical Measurements

Test Vessel Measured Concentrations (mg/L) Mean
0 hr. 48 hr. 96 hr
Control A ND ND ND ND
Control B ND ND ND ND
Test A 0.91 0.92 0.86 0.90
Test B 0.92 0.96 0.87 0.92

ND=None Detected

Validity criteria fulfilled:
yes
Conclusions:
The 96 hour LC50 was > 0.91 mg/L demonstrating a lack of significant adverse effects at the limit of water solubility.
Executive summary:

A 96-hour acute toxicity study with Asellus intermedius (pillbug) was conducted with m-diisopropylbenzene similar to ASTM Standard E 729-80 as part of a simultaneous toxicity study using seven species, one vertebrate and six invertebrates. The test was conducted using a recirculating elutriation system, using 1.0 g/20 L diluent water to provide a saturated solution. The flow rate was approximately 100 mL/minute passing through the elutriation column. Analytical verification of the exposure concentrations was conducted at 0, 48, and 96 hours. The mean measured concentrations were 0.90 and 0.92 mg/L for replicates A and B respectively. No mortality was observed in the control and 10 % mortality was observed in both replicates of the test concentrations. The 96 hour LC50 was > 0.91 mg/L demonstrating a lack of significant adverse effects at the limit of water solubility.


Based on the arguments presented in the Read Across statement attached in IUCLID Section 13, it is clear that the source and the target substances, which are structural isomers, show an identical toxicokinetic pattern. As such, the data presented here can be used to fulfil lthe information requirements for the target substance 1.4-diisopropylbenzene. 

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
In this justification, the read-across (bridging) concept is applied. Please refer to a full version of Read-across statement attached in the section 13 "Assessment reports".

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The underlying hypothesis for the read-across is that the target and the source substance have similar toxicological properties (including the same target organs) due to their structural similarity, resemblance to their chemical reactivity, and therefore a similar mode of action.
The source substance ‘1,3-diisopropylbenzene' is a structural isomer of 1,4-diisopropylbenzene (target substance). The physico-chemical properties are highly equivalent based on the high structural similarity. As a conclusion, it is scientifically justified to address the endpoint Short-term toxicity to aquatic invertebrates with data on this isomer.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source substance: 1.3-diisopropylbenzene (or m-DIPB)
structural formula: C12H18
Smiles: CC(C)c1cccc(c1)C(C)C
Molecular weight: 162 g/mol
CAS 99-62-7
EC No 202-773-1
purity: not specified

target substance: 1.4-diisopropylbenzene (or p-DIPB)
structural formula: C12H18
Smiles: CC(C)c1ccc(cc1)C(C)C
Molecular weight: 162 g/mol
CAS 100-18-5
EC No 202-826-9
purity: not specified

No additional information is available on purity of the source and the target substances. Both substances are normally of high purity, containing only minor amounts of impurities that do not influence the read-across validity.

3. ANALOGUE APPROACH JUSTIFICATION
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".

4. DATA MATRIX
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".
Reason / purpose for cross-reference:
read-across source
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
> 0.91 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
Survival was 100 % in the control and 80 % and 90 % in replicates A and B respectively of the test substance exposures at 96 hours.

Summary of Analytical Measurements

Test Vessel Measured Concentrations (mg/L) Mean
0 hr. 48 hr. 96 hr
Control A ND ND ND ND
Control B ND ND ND ND
Test A 0.91 0.92 0.86 0.90
Test B 0.92 0.96 0.87 0.92

ND=None Detected

Validity criteria fulfilled:
yes
Conclusions:
The 96 hour LC50 was > 0.91 mg/L demonstrating a lack of significant adverse effects at the limit of water solubility.
Executive summary:

A 96-hour acute toxicity study with Gammarus fasciatus (sideswimmer) was conducted with m-diisopropylbenzene similar to ASTM Standard E 729-80 as part of a simultaneous toxicity study using seven species, one vertebrate and six invertebrates. The test was conducted using a recirculating elutriation system, using 1.0 g/20 L diluent water to provide a saturated solution. The flow rate was approximately 100 mL/minute passing through the elutriation column. Analytical verification of the exposure concentrations was conducted at 0, 48, and 96 hours. The mean measured concentrations were 0.90 and 0.92 mg/L for replicates A and B respectively. No mortality was observed in the control. 10 % and 20 % mortality was observed in replicates A and B respectively of the test concentrations. The 96 hour LC50 was > 0.91 mg/L demonstrating a lack of significant adverse effects at the limit of water solubility.


Based on the arguments presented in the Read Across statement attached in IUCLID Section 13, it is clear that the source and the target substances, which are structural isomers, show an identical toxicokinetic pattern. As such, the data presented here can be used to fulfil lthe information requirements for the target substance 1.4-diisopropylbenzene. 

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
In this justification, the read-across (bridging) concept is applied. Please refer to a full version of Read-across statement attached in the section 13 "Assessment reports".

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The underlying hypothesis for the read-across is that the target and the source substance have similar toxicological properties (including the same target organs) due to their structural similarity, resemblance to their chemical reactivity, and therefore a similar mode of action.
The source substance ‘1,3-diisopropylbenzene' is a structural isomer of 1,4-diisopropylbenzene (target substance). The physico-chemical properties are highly equivalent based on the high structural similarity. As a conclusion, it is scientifically justified to address the endpoint Short-term toxicity to aquatic invertebrates with data on this isomer.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source substance: 1.3-diisopropylbenzene (or m-DIPB)
structural formula: C12H18
Smiles: CC(C)c1cccc(c1)C(C)C
Molecular weight: 162 g/mol
CAS 99-62-7
EC No 202-773-1
purity: not specified

target substance: 1.4-diisopropylbenzene (or p-DIPB)
structural formula: C12H18
Smiles: CC(C)c1ccc(cc1)C(C)C
Molecular weight: 162 g/mol
CAS 100-18-5
EC No 202-826-9
purity: not specified

No additional information is available on purity of the source and the target substances. Both substances are normally of high purity, containing only minor amounts of impurities that do not influence the read-across validity.

3. ANALOGUE APPROACH JUSTIFICATION
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".

4. DATA MATRIX
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".
Reason / purpose for cross-reference:
read-across source
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
> 0.91 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
>= 0.91 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
Survival was 100 % in the control and test substance exposures at 96 hours.

Summary of Analytical Measurements

Test Vessel Measured Concentrations (mg/L) Mean
0 hr. 48 hr. 96 hr
Control A ND ND ND ND
Control B ND ND ND ND
Test A 0.91 0.92 0.86 0.90
Test B 0.92 0.96 0.87 0.92

ND=None Detected

Validity criteria fulfilled:
yes
Conclusions:
The 96 hour LC50 was > 0.91 mg/L and the NOEC was ≥ 0.91 mg/L demonstrating no adverse effects at the limit of water solubility.
Executive summary:

A 96-hour acute toxicity study with Lumbriculus variegatus (segmented worm) was conducted with m-diisopropylbenzene similar to ASTM standard E729-80 as part of a simultaneous toxicity study using seven species, one vertebrate and six invertebrates. The test was conducted using a recirculating elutriation system, using 1.0 g/20 L diluent water to provide a saturated solution. The flow rate was approximately 100 mL/minute passing through the elutriation column. Analytical verification of the exposure concentrations was conducted at 0, 48, and 96 hours. The mean measured concentrations were 0.90 and 0.92 mg/L for replicates A and B respectively. No mortality was observed in the control or test concentrations. The 96 hour LC50 was > 0.91 mg/L and the NOEC was ≥ 0.91 mg/L demonstrating no adverse effects at the limit of water solubility.


Based on the arguments presented in the Read Across statement attached in IUCLID Section 13, it is clear that the source and the target substances, which are structural isomers, show an identical toxicokinetic pattern. As such, the data presented here can be used to fulfil lthe information requirements for the target substance 1.4-diisopropylbenzene. 

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
In this justification, the read-across (bridging) concept is applied. Please refer to a full version of Read-across statement attached in the section 13 "Assessment reports".

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The underlying hypothesis for the read-across is that the target and the source substance have similar toxicological properties (including the same target organs) due to their structural similarity, resemblance to their chemical reactivity, and therefore a similar mode of action.
The source substance ‘1,3-diisopropylbenzene' is a structural isomer of 1,4-diisopropylbenzene (target substance). The physico-chemical properties are highly equivalent based on the high structural similarity. As a conclusion, it is scientifically justified to address the endpoint Short-term toxicity to aquatic invertebrates with data on this isomer.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source substance: 1.3-diisopropylbenzene (or m-DIPB)
structural formula: C12H18
Smiles: CC(C)c1cccc(c1)C(C)C
Molecular weight: 162 g/mol
CAS 99-62-7
EC No 202-773-1
purity: not specified

target substance: 1.4-diisopropylbenzene (or p-DIPB)
structural formula: C12H18
Smiles: CC(C)c1ccc(cc1)C(C)C
Molecular weight: 162 g/mol
CAS 100-18-5
EC No 202-826-9
purity: not specified

No additional information is available on purity of the source and the target substances. Both substances are normally of high purity, containing only minor amounts of impurities that do not influence the read-across validity.

3. ANALOGUE APPROACH JUSTIFICATION
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".

4. DATA MATRIX
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".
Reason / purpose for cross-reference:
read-across source
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
> 0.91 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
>= 0.91 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
Survival was 100 % in the control and test substance exposures at 96 hours.

Summary of Analytical Measurements

Test Vessel Measured Concentrations (mg/L) Mean
0 hr. 48 hr. 96 hr
Control A ND ND ND ND
Control B ND ND ND ND
Test A 0.91 0.92 0.86 0.90
Test B 0.92 0.96 0.87 0.92

ND=None Detected

Validity criteria fulfilled:
yes
Conclusions:
The 96 hour LC50 was > 0.91 mg/L and the NOEC was ≥ 0.91 mg/L demonstrating no adverse effects at the limit of water solubility.
Executive summary:

A 96-hour acute toxicity study with Dugesia tigrina (flatworm) was conducted with m-diisopropylbenzene similar to ASTM standard E 729-80 as part of a simultaneous toxicity study using seven species, one vertebrate and six invertebrates. The test was conducted using a recirculating elutriation system, using 1.0 g/20 L diluent water to provide a saturated solution. The flow rate was approximately 100 mL/minute passing through the elutriation column. Analytical verification of the exposure concentrations was conducted at 0, 48, and 96 hours. The mean measured concentrations were 0.90 and 0.92 mg/L for replicates A and B respectively. No mortality was observed in the control or test concentrations. The 96 hour LC50 was > 0.91 mg/L and the NOEC was ≥ 0.91 mg/L demonstrating no adverse effects at the limit of water solubility.


Based on the arguments presented in the Read Across statement attached in IUCLID Section 13, it is clear that the source and the target substances, which are structural isomers, show an identical toxicokinetic pattern. As such, the data presented here can be used to fulfil lthe information requirements for the target substance 1.4-diisopropylbenzene. 

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
In this justification, the read-across (bridging) concept is applied. Please refer to a full version of Read-across statement attached in the section 13 "Assessment reports".

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The underlying hypothesis for the read-across is that the target and the source substance have similar toxicological properties (including the same target organs) due to their structural similarity, resemblance to their chemical reactivity, and therefore a similar mode of action.
The source substance ‘1,3-diisopropylbenzene' is a structural isomer of 1,4-diisopropylbenzene (target substance). The physico-chemical properties are highly equivalent based on the high structural similarity. As a conclusion, it is scientifically justified to address the endpoint Short-term toxicity to aquatic invertebrates with data on this isomer.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source substance: 1.3-diisopropylbenzene (or m-DIPB)
structural formula: C12H18
Smiles: CC(C)c1cccc(c1)C(C)C
Molecular weight: 162 g/mol
CAS 99-62-7
EC No 202-773-1
purity: not specified

target substance: 1.4-diisopropylbenzene (or p-DIPB)
structural formula: C12H18
Smiles: CC(C)c1ccc(cc1)C(C)C
Molecular weight: 162 g/mol
CAS 100-18-5
EC No 202-826-9
purity: not specified

No additional information is available on purity of the source and the target substances. Both substances are normally of high purity, containing only minor amounts of impurities that do not influence the read-across validity.

3. ANALOGUE APPROACH JUSTIFICATION
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".

4. DATA MATRIX
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".
Reason / purpose for cross-reference:
read-across source
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 0.93 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
>= 0.93 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
No lack of mobility was observed in the control or the tested concentrations over the 48 hour exposure.

Summary of Analytical Measurements

Test Vessel Measured Conc. mg/L Mean
0 hr. 48 hr.
Control A ND ND ND
Control B ND ND ND
Test A 0.91 0.92 0.92
Test B 0.92 0.96 0.94

ND=None Detected

Validity criteria fulfilled:
yes
Conclusions:
The 48 hour LC50 was > 0.93 mg/L and the NOEC was ≥ 0.93 mg/L demonstrating no adverse effects at the limit of water solubility.
Executive summary:

A 48-hour acute toxicity study with Daphnia magna with m-diisopropylbenzene was conducted as part of a simultaneous toxicity study using seven species, one vertebrate and six invertebrates. The test was conducted using a recirculating elutriation system, using 1. 0 g/20 L diluent water to provide a saturated solution. The flow rate was approximately 100 mL/minute passing through the elutriation column. Analytical verification of the exposure concentrations was conducted at 0, and 48 hours. The mean measured concentrations were 0.92 and 0.94 mg/L for replicates A and B respectively. No lack of mobility was observed in the control or test concentrations. The 48 hour LC50 was > 0.93 mg/L and the NOEC was ≥ 0.93 mg/L demonstrating no adverse effects at the limit of water solubility.


Based on the arguments presented in the Read Across statement attached in IUCLID Section 13, it is clear that the source and the target substances, which are structural isomers, show an identical toxicokinetic pattern. As such, the data presented here can be used to fulfil lthe information requirements for the target substance 1.4-diisopropylbenzene. 

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
In this justification, the read-across (bridging) concept is applied. Please refer to a full version of Read-across statement attached in the section 13 "Assessment reports".

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The underlying hypothesis for the read-across is that the target and the source substance have similar toxicological properties (including the same target organs) due to their structural similarity, resemblance to their chemical reactivity, and therefore a similar mode of action.
The source substance ‘Mixture of 1,3-diisopropylbenzene and 1,4-diisopropylbenzene' is a mixture of structural isomers, 1,3- diisopropylbenzene and 1,4-diisopropylbenzene (target substance). The physico-chemical properties are highly equivalent based on the high structural similarity. As a conclusion, it is scientifically justified to address the endpoint Short-term toxicity to aquatic invertebrates with data on this mixture of isomers.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source substance: Mixture of 1,3-diisopropylbenzene and 1,4-diisopropylbenzene (Diisopropylbenzene), CAS no. 25321-09-9
structural formula: C12H18
Smiles: CC(C)C1=CC=CC=C1C(C)C
Molecular weight: 162 g/mol
CAS 25321-09-9
EC No 246-835-6
purity: not specified

target substance: 1.4-diisopropylbenzene (or p-DIPB)
structural formula: C12H18
Smiles: CC(C)c1ccc(cc1)C(C)C
Molecular weight: 162 g/mol
CAS 100-18-5
EC No 202-826-9
purity: not specified

No additional information is available on purity of the source and the target substances. Both substances are normally of high purity, containing only minor amounts of impurities that do not influence the read-across validity.

3. ANALOGUE APPROACH JUSTIFICATION
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".

4. DATA MATRIX
Please refer to the full version of the read-across statement attached in the section 13 "Assessment reports".
Reason / purpose for cross-reference:
read-across source
Duration:
24 h
Dose descriptor:
NOEC
Effect conc.:
0.246 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
0.725 mg/L
95% CI:
>= 0.624 - <= 0.843
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks:
Concentration of inhibition of hemiparallel swimming
Duration:
48 h
Dose descriptor:
EC0
Effect conc.:
0.246 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
0.392 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 0.246-0.754 mg/L
Details on results:
Since the measured concentrations of some test substances exceeded ± 20 % of the set values, the measured values (geometric mean) were used to calculate the influence concentrations.
Therefore, the measured values (geometric mean values) were used to calculate the concentrations.
Reported statistics and error estimates:
Data Analysis: Probit method, binomial or Moving average for LC50

Effect Data:
EC50 (24hr) = 0.725 mg/L (mc) (95 % C.I.= 0.624-0.843 mg/L)
EC0 (24hr) = 0.246 mg/L (mc)
EC50 (48hr) = 0.392 mg/L (mc) (95 % C.I.= 0.246-0.754 mg/L)
EC0 (48hr) = 0.246 mg/L (mc)
mc: based on measured concentrations

Mortality or Immobility: No test organisms were immobilized at control, solvent control, 0.200 and 0.360 mg/L.
One individual was immobilized at 0.630 mg/L after 24 hours.
All individuals were immobilized at 1.10 mg/L after 48th hour and 2.00 mg/L on and after 24th hour.




























































Table 2      The Numbers of Immobile Daphnia (Percent Immobility)



Nominal Concentration (mg/L;



Measured Concentration



Cumulative Numbers of Immobilized Daphnia (Percent Immobility)



24 Hours



48 Hours



Control



 



0 ( 0)



2 (10)



Solvent Control



 



0 ( 0)



0 ( 0)



0.200



0.134



0 ( 0)



0 ( 0)



0.360



0.246



0 ( 0)



0 ( 0)



0.630



0. 419



1(5)



12 ( 60)



1.10



0. 754



10 ( 50)



20 (100)



2. 00



1.36



20 (100)



20 (100)



*: Mean measured concentration (Geometric Mean)



- Calculation of toxicity values: To calculate toxicity, the mean measured concentrations was used.

Water chemistry (pH and DO) and temperature in test:
Water chemistry and temperature were measured for control and each concentration at the start and 24th hour.
pH: 8.2 - 8.6
DO: 8.4 - 8.8 mg/L
Water Temperature: 19.9 - 20.0 °C

Measured Concentrations :
The test concentrations were measured at the start and 24th hour(before exchange of test solution).
For some of them, the deviation from the nominal were not less than +/- 20 %.
 



















































































Table1 Measured Concentrations of the Test Substance in Test Water


(Semi-Static Conditions)



Nominal Concentration (mg/L)



Measured concentration (mg/L)



Geometric Mean



0 Hour new



Percent of Nominal



24 Hours old



Percent of Nominal



During 24 Hours (mg/L)



Control



< 0. 002



 



< 0. 002



 



 



Solvent Control



< 0. 002



 



< 0. 002



 



 



0.200



0.159



80



0.113



57



0.134



0. 360



0. 279



78



0.217



60



0. 246



0.630



0. 469



74



0. 374



59



0. 419



1.10



0. 863



78



0. 658



60



0. 754



2. 00



1.52



76



1.21



61



1.36



new: freshly prepared test solutions



old: test solutions after 24 Hours exposure (Geometric mean)



 

Validity criteria fulfilled:
yes
Remarks:
According to the OECD guideline validity criteria, no more than 10 % Daphnids were immobilized and dissolved oxygen concentration was greater than 3 mg/L in control and test vessels.
Conclusions:
Short term toxicity to aquatic invertebrates test shows 48h EC50 = 0.392 mg/L (95 % confidence limit: 0.246 - 0.754 mg/L) and NOEC 48h = 0.246 mg/L
Executive summary:

The short term toxicity to aquatic invertebrates study was performed according to OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test), Part I. Daphnia magna were exposed to test item (mixture of diisopropylbenzene isomers) concentrations for 48 h in semi closed system. The test was conducted using solvent (mixture of a dispersant of HCO40 and DMF) and the estimated values were higher than water solubility, however, analytical monitoring was done. In this test, it could not be separated the true toxicity of the test substance from the physical effect of non-dissolving substance. It was determined that EC50 (48h) value of 0.392 mg/L (95 % confidence limit: 0.624 - 0.754 mg/L, measured concentration) and NOEC(48h) value of 0.246 mg/L.


Based on the arguments presented in the Read Across statement attached in IUCLID Section 13, it is clear that the source substance, which consists only of the target substance and its structural isomer, shows an identical toxicokinetic pattern. As such, the data presented here could be used to fulfil lthe information requirements for the target substance 1.4-diisopropylbenzene.

Description of key information

- MOE, 2000d: Short-term toxicity to D. magna, diisopropylbenzene (mixed isomers), semi closed system: EC50 (48h) = 0.392 mg/L (95 % confidence limit: 0.246 - 0.754 mg/L) and NOEC(48h) = 0.246 mg/L.


- Ewell, 1986: Short-term toxicity of m-diisopropylbenzene to Asellus intermedius (pillpug); Dugesia tigrina (flatworm), Gammarus fasciatus (sideswimmer); Helisoma trivolvis (snail), Lubriculus variegatus (segmented worm) and Pimephales promelas (fathead minnow); LC50 (96 h) > 0.90 and 0.92 mg/L, respectively (for pillbug, flatworm, sideswimmer, snail, segmented worm, and fathead minnow). EC50 > 0.92 and 0.94 mg/L, respectively (for water flea); NOEC = 0.90 and 0.92 mg/L (for flatworm, snail, segmented worm, and fathead minnow; The NOEC was not determined for the sideswimmers and pillbugs) and NOEC = 0.92 and 0.94 mg/L (for water fleas). 


 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Dose descriptor:
EC50
Effect concentration:
0.392 mg/L

Additional information

A 48 hour acute study with Daphnia magna (MOE, 2000d) was conducted with the mixed isomers (meta- and para-diisopropylbenzene) under semi-static conditions. The test solutions were prepared using a solvent carrier with nominal concentrations ranging from 0.2 to 2.0 mg/L which all exceeded the water solubility of the substance. The test resulted in a EC50 of 0.392 mg/L and a NOEC of 0.246 mg/L based upon mean measured concentrations.


Another 48 hour Daphnia magna acute study was conducted with m-diisopropylbenzene as part of a 7 species study (Ewell, 1986). The study was conducted as a limit test using a recirculating column elution apparatus providing a constant saturated solution. No immobility to Daphnia magna (NOEC) was observed in this test at the mean measured concentration of 0.93 mg/L. Five other invertebrate species were also included in the 7 species studies and exposed for 96 hours. The LC50s for those 5 other invertebrate species were > 0.91 mg/L, the mean measured concentration of the saturated solution over 96 -hours. The results of these studies suggest no acute effects to invertebrate organisms at the limit of water solubility.


 


Based on the arguments presented in the Read Across statement attached in IUCLID Section 13, it is clear that the source substance, which either consists of the target substance and its structural isomer or is its structural isomer show identical toxicokinetic patterns. As such, the data presented here could be used to fulfill the information requirements for the target substance 1.4-diisopropylbenzene.