Hydrocarbons, ethylene-manuf.-by-product distn. residues

Ecotoxicological Summary

Additional information

Experimental data provided for Category H was WAF. Deriving PNEC’s for UVCB substances based on WAF information is inappropriate. PNECs were therefore derived using the Petrotox/HC5 method for aquatic and STP. PNEC aqua was derived using the PETROTOX v.3.05 model. . A carbon number of C12 was used with a split of 70% aliphatic and 30% aromatic. A boiling point input range of 179-233°C was used as the input parameter to derive the PNEC aqua for aliphatics and a boiling point of 222-275°C was used as the input parameter to derive the PNEC aqua for aromatics. These are consistent with the boiling point range of C12 aliphatic and aromatic compounds in the Petrotox CONCAWE library.

 

Based on this information the aqua PNEC derived was 0.001mg/l and soil and sediment PNEC’s were derived based on this using the equilibrium partitioning method.

 

 The HC5 model states that it is expect that substances with a Log Kow higher than 5 will not pose a toxicity hazard to other WWTP microbes due to solubility and organism constraints, therefore only an aromatic STP PNEC was derived.

Conclusion on classification

Tested streams

Some ecotoxicology studies are available for streams within the High Benzene Naphthas as detailed below:   These were all proprietary studies. The most sensitive endpoint was a 96 hr LL50 of 1.1 mg/l. This was a GLP compliant study which followed a standard guideline. It is considered reliable and suitable for use as a key study.

Ecotoxicity Labelling for the High Benzene Napthas Category 

Data on the acute aquatic toxicity of 2 members of this category (CAS Numbers:  68513-69-9; 68921-67-5) was obtained from proprietary sources. No data was identified in the published literature. The data from these streams has been read across to the other category members.

The studies were conducted to standard guidelines and according to GLP and so are considered fully reliable for use as key/supporting studies. Authors report the LC50 based on nominal loading rates (WAF) and mean measured concentrations. As the test substance is a hydrocarbon stream with various components reporting a measured concentration could be misleading as the measured concentration does not relate to a concentration of the raw stream. Instead we have used the results reported as WAF, which better represent the potential toxicity of the test substance. Similar sensitivity was found in all three trophic levels (fish 96 hr LL50 range 1.1 -5.6 mg/l; Invertebrates 48hr EL50 1.2 -2.3; Algae 72 hr ErL50 range 2.2-2.3 mg/l)

WAF data can be used for comparison with the criteria for environmental classification under both the DSD and CLP Regulations. However, its use must be considered carefully. Based on the available data (96 hr LL50 1.1 mg/l WAF) streams in this category should have the classification R 51/53 under the DSD and Chronic 2 under the CLP regulations.

The measured partition coefficients of three streams in this category have log Kow ranges from 2.2 to >6.5. Therefore, the classifications cannot be removed.

Conclusion.

Based on the available experimental data (96 hr LL50 1.1mg/l WAF) streams in this category should have the classification R51/53 under the DSD and Chronic 2 under the CLP regulations.

However, the classification of streams in this category may be impacted by other constituents. Components which may impact the classification (i.e. those that are R50/53) should be identified by the registrants and the impact of their environmental classification included in the assessment. The classification of each stream can be determined following the equations given in the notes below. 

Note: 

Under the DSD

R50/53 applies if sum of components with R50/53 is >25%.

R51/53 applies if sum of components with R51/53 is >25% or if sum of components with R50/53 is >2.5%.

R52/53 applies if sum of components with R52/53 is >25% or if sum of components with R51/53 is >2.5% or if sum of components with R50/53 is >0.25%.

Under the CLP Regulations

Acute 1 applies if sum of components with acute 1 is >25%.

Chronic 1 applies if sum of components with chronic 1 is >25%.

Chronic 2 applies if sum of components with chronic 1 multiplied by 10 plus the sum of components with chronic 2 is >25%.

Chronic 3 applies if sum of components with chronic 1 multiplied by 100 plus the sum of components with chronic 2 multiplied by 10 plus the sum of components with chronic 3 is >25%.

Chronic 4 applies is sum of components with chronic 1, 2, 3 and 4 is >25%.