Hydrocarbons, C11-C12, isoalkanes, <2% aromatics

Endpoint summary

Description of key information

There is data available for this substance. Additionally, key and weight-of-evidence data is available for structural analogues. The data is read across to this substance based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

The substances are poorly soluble and made of constituents with various water solubility. As a consequence, the exposures were performed with Water Accommodated Fractions (WAFs). Therefore, the results are based on nominal loadings.

The toxicity level was never reached in any fish, while some of the experimental studies for aquatic invertebrate, algal or microorganism acute studys showed a toxicity effect. Therefore, this substance is considered to display no acute aquatic toxicity for fish based on an analogue read across approach.

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Additional information

Key and weight-of-evidence information is summarised below:

Short-term toxicity to fish

Hyd C8-C10, cyclics, <2% arom 96-h LL50 (mortality) for Oncorhynchus mykiss of 3.6 mg/L

Hyd C10-C12, isoalkanes, <2% arom LL50 value for Oncorhynchus mykiss >1000 mg/L. No mortality was observed in either the control or treatment systems.

Hyd C10-C13, nic, <2% arom 96-h LL50 (mortality) for Oncorhynchus mykiss >1000 mg/L. No mortality was observed in either the control or treatment systems.

Hyd C13-C16, n-alkanes, <2% arom 96-h LL50 (mortality) for fathead minnow (Pimephales promelas) >76800 mg/L

Long-term toxicity to fish

The application of Hyd C10-C13, ni, <2% arom to fathead minnow eggs and larvae was considered to have no significant effect on the hatching, survival or growth. It was considered unnecessary and unrealistic to test at loading rates in excess of 100 mg/L.

Short-term toxicity to aquatic invertebrates

Hyd C10-C12, isoalkanes, <2% arom 48-hour LL50 is reported as >1000 mg/L. There was no mortality at the 1000 mg/L loading level after 48 hours. Therefore, the 48-hour LL0 for mortality is reported as 1000 mg/L. There was also no mortality in the control.

Hyd C10-C12, isoalkanes, <2% arom the 96-hour LL50 is reported as >1000 mg/L. There was no mortality at the 320 and 1000 mg/L loading levels after 96 hours. However, effects on swimming and feeding behavior were observed in the 320 and 1000 mg/L loading levels.

Hyd, C10-C13, ni, <2% aromatics EL50 values of greater than 100 mg/L Daphnia magna. The No Observed Effect Loading Rate was 100 mg/L loading rate WAF.

 

Long-term toxicity to aquatic invertebrates

Hyd C10-C12, isoalkanes, <2% arom exposure of Daphnia magna during the 21-day study at a loading rate of 1 mg/L produced significantly fewer (<0.05) live offspring per adult than the adult daphnids in the control media.

Hyd C10-C12, isoalkanes, <2% arom showed no effects on survival, reproduction, or length of Daphnia magna at nominal and measured concentrations of 0.026 and 0.025 mg/L, respectively.

Hyd C11-C12, isoalkanes, <2% arom showed no effects on survival, reproduction, or length of Daphnia magna at nominal concentrations of 1 and 0.1 mg/L, respectively.

Hyd C11-C12, isoalkanes, <2% arom showed no effects on survival, reproduction, or length of Daphnia magna at nominal and measured concentrations of 0.020 and 0.011mg/L, respectively.

Hyd C11-C12, isoalkanes, <2% arom exposure of Daphnia magna during the 21-day study at a loading rate of 1 mg/L produced significantly fewer (<0.05) live offspring per adult than the adult daphnids in the control media.

Toxicity to algae and cyanobacteria

Growth of Pseudokirchneriella subcapitata cultures, as measured by biomass and growth rate, exposed to a water accommodated fraction of Hyd C10-C12, isoalkanes, <2% arom was not inhibited over 72 hours. The growth of algae in the the test systems was greater than the controls, which performed normally. Therefore, the 72-hr EL50 values for the two endpoints are reported as >1000 mg/L

Growth of Pseudokirchneriella subcapitata cultures, as measured by biomass and growth rate, exposed to a water accommodated fraction of Hyd C10-C13, nic, <2% arom was not inhibited over 72 hours. The growth of algae in the the test systems was greater than the controls, which performed normally. Therefore, the 72-hr EL50 values for the two endpoints are reported as >1000 mg/L.

Exposure of Pseudokirchneriella subcapitata to Hyd C10-C13, ni, <2% arom gave EL50 values of greater than 100 mg/L loading rate WAF. The No Observed Effect Loading Rate was 100 mg/L loading rate WAF.

Exposure of Pseudokirchneriella subcapitata to Hyd C10-C13, ni, <2% arom gave EL50 values of greater than 100 mg/L loading rate WAF. The No Observed Effect Loading Rate was 100 mg/L loading rate WAF.

Toxicity to microorganisms

The aquatic toxicity was estimated using the PETROTOX computer model (v4.0), 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 nonpolar 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.