Ethylene

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

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.

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):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

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:

96 h

Dose descriptor:

LL50

Effect conc.:

115 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Result from QSAR

Details on results:

N/A

Reported statistics and error estimates:

N/A

Sublethal observations / clinical signs:

N/A

Conclusions:

The estimated LL50 for this substance is 115 mg/L.

Executive summary:

The short-term aquatic toxicity to this substance was estimated using the Target Lipid Model based on methodologies described by Mcgrath et al. (2004). The estimated LL50 for this substance is 115 mg/L.

Description of key information

In the absence of measured data for fish, ECOSAR and TLM QSAR modelling was used to estimate the LL50 value. The estimated 96 -hour LL50 estimated from TLM QSAR is 115 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

115 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:

The Target Lipid Model (Mcgrath et al., 2004) calculated an LL50 of 115.27 mg/L.

ECOWIN v1 ECOSAR supporting study form Nabholz and Mayo-Bean (2009) calculated a 96-hour LC50 of 126 mg/L.