Xylene

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:

experimental study

Adequacy of study:

key study

Study period:

1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non- GLP, guideline study, published in peer reviewed literature, acceptable with restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

Modified as adequate for testing volatile compounds.

GLP compliance:

not specified

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material:
Not applicable

Analytical monitoring:

yes

Details on sampling:

The concentration of the toxicant was determined at the beginning and end of the experiment.

Vehicle:

no

Details on test solutions:

Diluted solutions of aromatics were prepared from saturated aqueous solutions.

Test organisms (species):

Daphnia magna

Details on test organisms:

Data not reported

Test type:

other: Closed, static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Post exposure observation period:

None

Hardness:

Data not reported

Test temperature:

Data not reported

pH:

Data not reported

Dissolved oxygen:

Data not reported

Salinity:

Not applicable

Conductivity:

N/A

Nominal and measured concentrations:

Nominal and measured concentrations not stated. Authors state that mean measured concentrations fluctuated within 10%.

Details on test conditions:

The determination of 24 h IC50 (immobilisation concentartion for 50% of the organisms) on Daphnia was performed in closed bottle (150mL), completely filled with the test solution.

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

IC50

Effect conc.:

2.2 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Results refer to mean measured concentrations, whose fluctuations were within 10%.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

Data not reported

N/A

Validity criteria fulfilled:

not specified

Remarks:

insufficient data to confirm validity

Conclusions:

The reported IC50 for Daphnia magna was 2.2 mg/L.

Executive summary:

The reported IC50 for Daphnia magna was 2.2 mg/L. This study has been conducted according to OECD standard guidelines, analytical monitoring was performed and appropriate modifications for volatile compounds were made. Raw data were not included and therefore the validity of the test can not be confirmed.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP, guideline study, published in peer reviewed literature, acceptable with restrictions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

Modified as adequate for testing volatile compounds.

GLP compliance:

not specified

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material:
Not applicable

Analytical monitoring:

yes

Details on sampling:

The concentration of the toxicant was determined at the beginning and end of the experiment.

Vehicle:

no

Details on test solutions:

Diluted solutions of aromatics were prepared from saturated aqueous solutions.

Test organisms (species):

Daphnia magna

Details on test organisms:

Data not reported

Test type:

other: Closed, static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Post exposure observation period:

None

Hardness:

Data not reported

Test temperature:

Data not reported

pH:

Data not reported

Dissolved oxygen:

Data not reported

Salinity:

Not applicable

Conductivity:

N/A

Nominal and measured concentrations:

Nominal and measured concentrations not stated. Authors state that mean measured concentrations fluctuated within 10%.

Details on test conditions:

The determination of 24 hour IC50 (immobilisation concentartion for 50% of the organisms) on Daphnia was performed in closed bottle (150 mL), completely filled with the test solution.

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

IC50

Effect conc.:

4.7 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Results refer to mean measured concentrations, whose fluctuations were within 10%.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

Data not reported

N/A

Validity criteria fulfilled:

not specified

Remarks:

insufficient data to confirm validity

Conclusions:

The reported IC50 for Daphnia magna was 4.7mg/L.

Executive summary:

This has been chosen as the key study on the basis that it has been conducted according to OECD standard guidelines, analytical monitoring was performed and appropriate modifications for volatile compounds were made. Raw data was not included and therefore the validity of the test can not be confirmed.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2015

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

The Target Lipid Model (TLM) is a framework that relates toxicity to the physicochemical properties of a nonpolar organic constituent. It is a well documented and peer reviewed model that is widely used across the petrochemicals industry. This substance fits within the criteria of the model and there are no reservations about the validity of the model runs. It is expected that this data is reliable with restrictions.

Qualifier:

no guideline required

Principles of method if other than guideline:

The endpoint calculated is the LL50, EL50, and NOELR -
The narcosis TLM was developed to predict the toxicity of chemicals to aquatic organisms that act via narcosis. It is based on the hypothesis that target lipid is the site of toxic action within the organism, that octanol is the appropriate surrogate, and that target lipid has the same physical–chemical properties in all organisms.
The approach describes:
• The theory and how to predict the acute toxicity to these organisms;
• Development of an Acute to Chronic ratio [ACR] for only hydrocarbons and for 29 data points.

The logkow used for calculation:
m- xylene= 3.20

Specific details on test material used for the study:

N/A

Details on sampling:

N/A

Test organisms (species):

Daphnia magna

Details on test organisms:

N/A

Remarks on exposure duration:

N/A

Post exposure observation period:

N/A

Hardness:

N/A

Test temperature:

N/A

pH:

N/A

Dissolved oxygen:

N/A

Salinity:

N/A

Conductivity:

N/A

Nominal and measured concentrations:

N/A

Details on test conditions:

N/A

Key result

Duration:

48 h

Dose descriptor:

LL50

Effect conc.:

8.73 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Details on results:

N/A

Results with reference substance (positive control):

N/A

Reported statistics and error estimates:

N/A

N/A

Conclusions:

The estimated LL50 of Oncorhynchus mykiss for this substance is 8.730 mg/L. The target substance is a hydrocarbon acting via baseline toxicity, and falls within the parametric, structural and mechanistic domain of the model.

Executive summary:

The short-term aquatic toxicity to this substance was estimated using the Target Lipid Model based on methologies described by McGrath et al. (2004, 2015). The estimated LL50 of Oncorhynchus mykiss for this substance is 8.730 mg/L.

Reference 4

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP, guideline study, published in peer reviewed literature, acceptable with restrictions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

appropriate modifications for volatile compounds

GLP compliance:

not specified

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material:
Not applicable

Analytical monitoring:

yes

Details on sampling:

The concentration of the toxicant was determined at the beginning and end of the experiment.

Vehicle:

no

Details on test solutions:

Data not reported

Test organisms (species):

Daphnia magna

Details on test organisms:

Data not reported

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Post exposure observation period:

None

Hardness:

Data not reported

Test temperature:

Data not reported

pH:

Data not reported

Dissolved oxygen:

Data not reported

Salinity:

Not applicable

Conductivity:

N/A

Nominal and measured concentrations:

Nominal and measured concentrations not stated. Authors state that mean measured concentrations fluctuated within 10%.

Details on test conditions:

The determination of 24 hour IC50 (immobilisation concentartion for 50% of the organisms) on Daphnia was performed in closed bottle (150 mL), completely filled with the test solution.

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

IC50

Effect conc.:

1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: results refer to mean measured concentrations, whose fluctuations were within 10%.

Details on results:

Data not reported

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

Data not reported

N/A

Validity criteria fulfilled:

not specified

Remarks:

Insufficient data to confirm validity

Conclusions:

The reported IC50 for Daphnia magna for o-xylene was 1 mg/L.

Executive summary:

This has been chosen as the key study on the basis that it has been conducted according to OECD standard guidelines, analytrical monitoring was performed and appropriate modifications for volatile compounds were made. Raw data was not included and therefore the validity of the test can not be confirmed.

Reference 5

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2015

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

The Target Lipid Model (TLM) is a framework that relates toxicity to the physicochemical properties of a nonpolar organic constituent. It is a well documented and peer reviewed model that is widely used across the petrochemicals industry. This substance fits within the criteria of the model and there are no reservations about the validity of the model runs. It is expected that this data is reliable with restrictions.

Qualifier:

no guideline required

Principles of method if other than guideline:

The endpoint calculated is the LL50, EL50, and NOELR -
The narcosis TLM was developed to predict the toxicity of chemicals to aquatic organisms that act via narcosis. It is based on the hypothesis that target lipid is the site of toxic action within the organism, that octanol is the appropriate surrogate, and that target lipid has the same physical–chemical properties in all organisms.
The approach describes:
• The theory and how to predict the acute toxicity to these organisms;
• Development of an Acute to Chronic ratio [ACR] for only hydrocarbons and for 29 data points.

The logkow used for calculation:
o-xylene= 3.12

Specific details on test material used for the study:

N/A

Details on sampling:

N/A

Details on test solutions:

N/A

Test organisms (species):

Daphnia magna

Details on test organisms:

N/A

Post exposure observation period:

N/A

Hardness:

N/A

Test temperature:

N/A

pH:

N/A

Dissolved oxygen:

N/A

Salinity:

N/A

Conductivity:

N/A

Nominal and measured concentrations:

N/A

Details on test conditions:

N/A

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

10.389 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Details on results:

N/A

Results with reference substance (positive control):

N/A

Reported statistics and error estimates:

N/A

N/A

Conclusions:

The estimated LC50 of Oncorhynchus mykiss for this substance is 10.389 mg/L. The target substance is a hydrocarbon acting via baseline toxicity, and falls within the parametric, structural and mechanistic domain of the model.

Executive summary:

The short-term aquatic toxicity to this substance was estimated using the Target Lipid Model based on methologies described by McGrath et al. (2004, 2015). The estimated LC50 of Oncorhynchus mykiss for this substance is 10.389 mg/L.

Reference 6

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP, guideline study, published in peer reviewed literature, acceptable with restrictions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

Modified as adequate for testing volatile compounds.

GLP compliance:

not specified

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material:
Not applicable

Analytical monitoring:

yes

Details on sampling:

The concentration of the toxicant was determined at the beginning and end of the experiment.

Vehicle:

no

Details on test solutions:

Diluted solutions of aromatics were prepared from saturated aqueous solutions.

Test organisms (species):

Daphnia magna

Details on test organisms:

Data not reported

Test type:

other: Closed, static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Post exposure observation period:

None

Hardness:

Data not reported

Test temperature:

Data not reported

pH:

Data not reported

Dissolved oxygen:

Data not reported

Salinity:

Not applicable

Conductivity:

N/A

Nominal and measured concentrations:

Nominal and measured concentrations not stated. Authors state that mean measured concentrations fluctuated within 10%.

Details on test conditions:

The determination of 24 hour IC50 (immobilisation concentartion for 50% of the organisms) on Daphnia was performed in closed bottle (150 mL), completely filled with the test solution.

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

IC50

Effect conc.:

3.6 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Results refer to mean measured concentrations, whose fluctuations were within 10%.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

Data not reported

N/A

Validity criteria fulfilled:

not specified

Remarks:

insufficient data to confirm validity

Conclusions:

The reported 24 hour IC50 for Daphnia magna for p-xylene was 3.6 mg/L.

Executive summary:

This has been chosen as the key study on the basis that it has been conducted according to OECD standard guidelines, analytrical monitoring was performed and appropriate modifications for volatile compounds were made. Raw data was not included and therefore the validity of the test can not be confirmed.

Reference 7

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2015

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

The Target Lipid Model (TLM) is a framework that relates toxicity to the physicochemical properties of a nonpolar organic constituent. It is a well documented and peer reviewed model that is widely used across the petrochemicals industry. This substance fits within the criteria of the model and there are no reservations about the validity of the model runs. It is expected that this data is reliable with restrictions.

Qualifier:

no guideline required

Principles of method if other than guideline:

The endpoint calculated is the LL50, EL50, and NOELR -
The narcosis TLM was developed to predict the toxicity of chemicals to aquatic organisms that act via narcosis. It is based on the hypothesis that target lipid is the site of toxic action within the organism, that octanol is the appropriate surrogate, and that target lipid has the same physical–chemical properties in all organisms.
The approach describes:
• The theory and how to predict the acute toxicity to these organisms;
• Development of an Acute to Chronic ratio [ACR] for only hydrocarbons and for 29 data points.

The logkow used for calculation:
p-xylene= 3.09

Specific details on test material used for the study:

N/A

Details on sampling:

N/A

Details on test solutions:

N/A

Test organisms (species):

Daphnia magna

Details on test organisms:

N/A

Post exposure observation period:

N/A

Hardness:

N/A

Test temperature:

N/A

pH:

N/A

Dissolved oxygen:

N/A

Salinity:

N/A

Conductivity:

N/A

Nominal and measured concentrations:

N/A

Details on test conditions:

N/A

Key result

Duration:

48 h

Dose descriptor:

LL50

Effect conc.:

11.076 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Details on results:

N/A

Results with reference substance (positive control):

N/A

Reported statistics and error estimates:

N/A

N/A

Conclusions:

The estimated LL50 of Oncorhynchus mykiss for for this substance is 11.076 mg/L.The target substance is a hydrocarbon acting via baseline toxicity, and falls within the parametric, structural and mechanistic domain of the model.

Executive summary:

The short-term aquatic toxicity to this substance was estimated using the Target Lipid Model based on methologies described by McGrath et al. (2004, 2015). The estimated LL50 of Oncorhynchus mykiss for this substance is 11.076 mg/L.

Reference 8

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2015

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

The Target Lipid Model (TLM) is a framework that relates toxicity to the physicochemical properties of a nonpolar organic constituent. It is a well documented and peer reviewed model that is widely used across the petrochemicals industry. This substance fits within the criteria of the model and there are no reservations about the validity of the model runs. It is expected that this data is reliable with restrictions.

Qualifier:

no guideline required

Principles of method if other than guideline:

The endpoint calculated is the LL50, EL50, and NOELR -
The narcosis TLM was developed to predict the toxicity of chemicals to aquatic organisms that act via narcosis. It is based on the hypothesis that target lipid is the site of toxic action within the organism, that octanol is the appropriate surrogate, and that target lipid has the same physical–chemical properties in all organisms.
The approach describes:
• The theory and how to predict the acute toxicity to these organisms;
• Development of an Acute to Chronic ratio [ACR] for only hydrocarbons and for 29 data points.

The logkow used for calculation:
xylene = 3.16

Specific details on test material used for the study:

N/A

Details on sampling:

N/A

Details on test solutions:

N/A

Test organisms (species):

Daphnia magna

Details on test organisms:

N/A

Post exposure observation period:

N/A

Hardness:

N/A

Test temperature:

N/A

pH:

N/A

Dissolved oxygen:

N/A

Salinity:

N/A

Conductivity:

N/A

Nominal and measured concentrations:

N/A

Key result

Duration:

48 h

Dose descriptor:

LL50

Effect conc.:

9.519 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other:

Details on results:

N/A

Results with reference substance (positive control):

N/A

Reported statistics and error estimates:

N/A

N/A

Conclusions:

The estimated LL50 of Oncorhynchus mykiss for this substance is 9.519 mg/L. The target substance is a hydrocarbon acting via baseline toxicity, and falls within the parametric, structural and mechanistic domain of the model.

Executive summary:

The short-term aquatic toxicity to this substance was estimated using the Target Lipid Model based on methologies described by McGrath et al. (2004, 2015). The estimated LL50 of Oncorhynchus mykiss for this substance is 9.519 mg/L.

Description of key information

The lowest result is a 24 hour EC50 of 1 mg/L for o-xylene (Galassi 1988). The estimated LL50 values from TLM QSAR were 8.730 - 11.076 mg/L.

The experimental value was used for chemical safety assessment.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

1 mg/L

Additional information

Data are available on the acute toxicity of each of the xylene isomers and ethylbenzene to aquatic invertebrates. The study by Galassi et al (1988) follows OECD 202 and uses Daphnia magna, whilst Holcombe et al (1987) used a flow through system to expose different species (including Daphnia magna) simultaneously. Niederlehner et al (1998) used Ceriodaphnia dubia as the test organism. All studies included analytical confirmation of the exposure concentrations.

 

The 24 hour EC50 results reported in the key studies from Galassi at al (1988) for the xylene isomers and ethylbenzene are very similar, with a range of 1 - 4.7 mg/L. The lowest result will be used in the risk assessment.

 

A TLM modeling framework was used to support values derived experimentally and are presented as supporting studies.

The estimated LL50 values from TLM QSAR were 8.730 - 11.076 mg/L