Ethylene

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to fish, other

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2009

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: QSAR calculation, reliable with restrictions

Justification for type of information:

QSAR prediction

Principles of method if other than guideline:

The Ecosar class program has been developed primarily for the evaluation of neutral organic compounds and organic classes with excess toxicity. The QSARs in the Ecosar program are developed for chemical classes based on measured test data that have been submitted by industry or they are developed by other sources for chemicals with similar structures, e.g., phenols. Using the measured aquatic toxicity values and estimated Kow values, regression equations can be developed for a class of chemicals. Toxicity values for new chemicals may then be calculated by inserting the Kow into the regression equation and correcting the resultant value for the molecular weight of the compound.

GLP compliance:

not specified

Remarks:

Not applicable

Specific details on test material used for the study:

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

Analytical monitoring:

not required

Details on sampling:

Not applicable

Details on test solutions:

Not applicable

Test organisms (species):

other: fish

Details on test organisms:

Not applicable

Test type:

other: Not applicable

Water media type:

freshwater

Total exposure duration:

30 d

Post exposure observation period:

Not applicable

Hardness:

Not applicable

Test temperature:

Not applicable

pH:

Not applicable

Dissolved oxygen:

Not applicable

Salinity:

Not applicable

Conductivity:

N/A

Nominal and measured concentrations:

Not applicable

Details on test conditions:

Not applicable

Key result

Duration:

30 d

Dose descriptor:

other: ChV

Effect conc.:

12.385 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

calculated using the neutral organic QSAR. Data entered: log kow = 1.13, Melting point = -169.15°C, water solubility = 131 mg/l

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

Not applicable

N/A

Validity criteria fulfilled:

not applicable

Remarks:

QSAR

Conclusions:

The predicted 30d ChV for ethylene was 12.385 mg/L.

Executive summary:

The predicted 30d ChV for ethylene was 12.385mg/l. Measured data are not available for ethylene for this endpoint. Due to the practical difficulties associated with the ecotoxicity testing of gases (i.e. maintaining exposure concentrations) the use of QSAR toxicity estimates is an appropriate alternative. The ECOSAR model is a reliable and appropriate QSAR model to apply to ethylene as it is based on a related chemical dataset that calculates the toxicity of neutral organic hydrocarbons whose mode of action is non-polar narcosis. The endpoint calculated here, 30 day ChV of 12.385 mg/L, is therefore a reasonable estimate of its baseline toxicity.

Reference 2

Endpoint:

long-term toxicity to fish, other

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 target lipid model 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.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Key result

Duration:

32 d

Dose descriptor:

NOELR

Effect conc.:

22.083 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

ChV (chronic value, QSAR)

Conclusions:

The estimated NOELR for this substance is 22.083 mg/L.

Executive summary:

The long-term aquatic toxicity to this substance was estimated using the Target Lipid Model based on methodologies described by Mcgrath et al. (2015). The estimated NOELR for this substance is 22.083 mg/L.

Description of key information

In the absence of measured data for fish, ECOSAR and TLM QSAR modelling was used to estimate the EC10 and NOELR. The estimated 21 -day ChV from ECOSAR QSAR is 12.39 mg/L and NOELR estimated from TLM QSAR is 22.083 mg/L.

The lowest value was used for the chemical safety assessment.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

12.39 mg/L

Additional information

Ethylene is a gas at standard temperature and pressure and is expected to partition primarily to air, therefore aquatic toxicity tests may not be relevant. In addition, it is technically difficult to maintain aqueous concentrations of gases for toxicity testing.

Measured data are not available for ethylene for this endpoint. Due to the practical difficulties associated with the ecotoxicity testing of gases (i.e. maintaining exposure concentrations) the use of QSAR toxicity estimates is an appropriate alternative. Two QSAR models have been used to estimate the short term toxicity to fish:

ECOWIN v1 ECOSAR (Nabholz and Mayo-Bean 2009) calculated a 21 day ChV of 12.39 mg/L.

The Target Lipid Model (Mcgrath et al., 2004) calculated an NOELR of 22.083 mg/L.