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Long-term toxicity to aquatic invertebrates

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Reference
Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2019
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
Remarks:
This summary has a reliability of 2 because the results are estimated using a computer model that is appropriate for use with this hydrocarbon substance.
Justification for type of information:
QSAR prediction: see Petrorisk Assessment Report.
Qualifier:
no guideline required
Principles of method if other than guideline:
The aquatic toxicity was estimated by a QSAR, the Petrotox computer model (PETROTOX-UDM_ver3.01-2006-01438-01-E). This model combines a partitioning model used to calculate the aqueous concentration of hydrocarbon components with the Target Lipid Model used to calculate acute and chronic toxicity of non-polar narcotic chemicals. Petrotox computes toxicity based on the summation of the aqueous-phase concentrations of hydrocarbon block(s) that represent a hydrocarbon substance and membrane-water partition coefficients (KMW) that describe the partitioning of the hydrocarbons between the water and organism.
GLP compliance:
no
Remarks:
The data were calculated by a computer model
Analytical monitoring:
not required
Vehicle:
no
Test organisms (species):
Daphnia magna
Test type:
other: QSAR modeled data
Water media type:
freshwater
Limit test:
no
Total exposure duration:
21 d
Duration:
21 d
Dose descriptor:
NOELR
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
reproduction
Validity criteria fulfilled:
yes
Conclusions:
The Hydrocarbons, C14-C16, n-alkanes, isoalkanes, <2% aromatics, estimated freshwater invertebrate 21-day NOELR (No Observed Effect Loading Rate) value is >1000 mg/l based on reproduction.
Executive summary:

The aquatic toxicity was estimated using the Petrotox computer model (PETROTOX-UDM_ver3.01-2006-01438-01-E), which combines a partitioning model used to calculate the aqueous concentration of hydrocarbon components as a function of substance loading with the Target Lipid Model used to calculate acute and chronic toxicity of non-polar narcotic chemicals. Petrotox computes toxicity based on the summation of the aqueous-phase concentrations of hydrocarbon block(s) that represent a hydrocarbon substance and membrane-water partitioning coefficients (KMW) that describe the partitioning of the hydrocarbons between the water and organism. The Hydrocarbons, C14-C16, n-alkanes, isoalkanes, <2% aromatics, estimated freshwater invertebrate 21-day NOELR (No Observed Effect Loading Rate) value is >1000 mg/l based on reproduction.

Description of key information

The GTL Gasoil (C8-C26) measured freshwater invertebrate 21-day NOELR (No Observed Effect Loading Rate) is 32 mg/L for effects on survival and reproduction of Daphnia magna, based on WAF (nominal) loading rate.

The Hydrocarbons, C14-C16, n-alkanes, isoalkanes, <2% aromatics, estimated Daphnia magna 21-day NOELR (No Observed Effect Loading Rate) value is >1000 mg/l based on reproduction.

The value is estimated using the Petrotox computer model (PETROTOX-UDM_ver3.01-2006-01438-01-E).

Key value for chemical safety assessment

Additional information

A Daphnia reproduction study has been conducted with the freshwater species Daphnia magna for the related substance GTL Gasoil (Goodband, 2011). The test was conducted in accordance with OECD 211 (1998) and in compliance with GLP and best practise was followed regarding the preparation of the WAFs.

Daphnia magna were exposed to water accommodated fractions (WAFs) of GTL Gasoil over a range of nominal loading rates of 10, 32 and 100 mg/l for a period of 21 days under semi-static test conditions. The test was conducted using sealed test vessels to minimise any potential for volatile losses.

The 21-day LOELR based on parental mortality was determined to be 100 mg/L load rate WAF, as significant mortalities (P≥ 0.05) were seen in the parental generation and all parental daphnids were eliminated prior to the production of young at this treatment level.

The 21-day NOELR, based on parental mortalities, was determined to be 32 mg/L loading rate WAF as no significant mortalities (P≥ 0.05) were observed in the parental generation and no significant differences were seen between the control and the 32mg/L loading rate WAF test group in terms of numbers of live young produced per adult by day 21.  

There was no significant effect on time to first brood at any treatment level.

The registered substance is a complex hydrocarbon UVCB whose constituents have variable physicochemical properties. Therefore, a modelling framework is needed to account for the bioavailability of the constituents in the mixture, which was then used to predict the toxicity of the substance as a whole. The target lipid model (TLM) and HC5, have been applied and modelled data are considered fit for purpose.

Detailed information covering the calculation model, compositional data used as input, validity, applicability and adequacy of the result are attached in section 13.2 of IUCLID.

The Hydrocarbons, C14-C16, n-alkanes, isoalkanes, <2% aromatics, estimated Daphnia magna 21-day NOELR (No Observed Effect Loading Rate) value is >1000 mg/l based on reproduction.

The value is estimated using the Petrotox computer model (PETROTOX-UDM_ver3.01-2006-01438-01-E).