Phenol, dodecyl-, branched, sulfurized

Short-term toxicity to aquatic invertebrates

Description of key information

There are three main (key& supporting) studies which are selected for assessment and read-across to the Registration material for freshwater. They all gave the same result and the LL50 is assumed to also be appropriate to use for extrapolation to the registration substance.  Test results reported in the study as “lethal concentrations” are reported in this summary as “lethal loading rate”, because test results are based on WAF loading rates.
However, the registration material does not contain oil as a component, hence the results of the tested samples (their LC50s/LL50s) are adjusted to account for the % of active ingredient present in order to create LL50 values for the registration material. 
Freshwater results: Nominal concentrations including oil: 96-h LL50 (reported as “LC50” in the report) >1,000 mg/L. There is information that the sample tested was CAS 68855-45-8 and contains around 25% oil. Therefore the end results for the Registration material are considered to be an LC/LL50 value greater than or equal to 75% of the result given, i.e. 750mg/l. 
Saltwater results: The 96-hour LC50 from the best of the marine studies was > 40 mg/L, the highest treatment level tested. However, the toxicity noted in this study is much higher than in the freshwater studies and there are questions as to whether there may be other factors involved which would reduce reliability.  However, it would appear to be the best result we currently have for the marine compartment. The % oil in this sample would normally be around 40%, hence we adopt a value of 24mg/l for the registration material (bearing in mind that this may be overly precautionary). 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

750 mg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

24 mg/L

Additional information

There are no available data for this endpoint for CAS: 96152-43-1, therefore a number of studies from supporting, structurally similar substances have been used for read-across purposes to address this endpoint.

There are three main (key/supporting) studies which have been used and which form a weight of evidence:

1) In the key study (Ward 1993/CAS 68855 -45 -8), a structurally similar material was tested to determine the acute toxicity of the water accommodated fraction (WAF) of 100, 300, and 1,000 mg/L mixtures of the test material and water to the daphnid,Daphnia magna during a study conducted at T.R. Wilbury Laboratories, Inc. The test was performed from 6th to 8th August, 1991 and was conducted according to the OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test). The reliability rating for this study is 1, however this is being used as read across to a supporting substance as there was no available data to fulfil this endpoint for the test material and so the reliability rating will be reduced to 2, according to the criteria of Klimisch, 1997. This study is being used as read across from Phenol, tetrapropenyl-, sulfurized, carbonates, calcium salts).

2) A second equally reliable study performed at the same time on another material in the Category by the same facility (Ward 1993) again tested the acute toxicity of the water accommodated fraction (WAF) of 100, 300, and 1,000 mg/L mixtures of the test material and water to the daphnid, Daphnia magna was investigated during a study conducted at T.R. Wilbury Laboratories, Inc. The test, which was designed to determine the toxicity of the test substance, was conducted according to the OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test). The reliability rating for this study is 1, however this is being used as read across to a supporting substance as there was no available data to fulfil this endpoint for the test material and so the reliability rating will be reduced to 2, according to the criteria of Klimisch, 1997. This study is being used as read across from Phenol, tetrapropenyl-, sulfurized, carbonates, calcium salts).

3) In the other main (supporting) study (Ward, 1997), the acute toxicity of the water accommodated fraction (WAF) of five mixtures of the test material and water to the daphnid,Daphnia magna, was investigated during a study conducted at T.R. Wilbury Laboratories, Inc. The test, which was designed to determine the toxicity of the test substance, was performed from November 13 to 15, 1996 and was conducted according to the OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test). The reliability rating for this study is 1, however this is being used as read across to a supporting substance as there was no available data to fulfil this endpoint for the test material and so the reliability rating will be reduced to 2, according to the criteria of Klimisch, 1997. This study is being used as read across from Phenol, tetrapropenyl-, sulfurized, calcium salts CAS No. 68855-45-8. The 24 and 48-h EL50s (stated “EC50s” in report) >1,000 mg/L loading rate. The 24 and 48-h NOELR (stated as “NOECs” in report) = 1000 mg/L based on WAF loading rates.

Additional key & supporting studies exist for these category materials, though performed under marine conditions:

4) The Exxon, 1993 study was considered a key study for the marine environment as it was conducted under marine conditions but only supporting for freshwater evaluation. However for chemical safety assessment purposes, the LC50 from this study will satisfactory fulfil the marine key study endpoint. The study was conducted according to US EPA guideline, comparable to OECD guideline, however there were no details on dose concentration analysis and so a reliability rating of 2 was assigned.

This study is being used as read across from Phenol, tetrapropenyl-, sulfurized, carbonates, calcium salts).

Result: The 96-hour LC50 was > 40 mg/L, the highest treatment level tested.

The toxicity noted in this study is much higher than in the freshwater studies and there are questions as to whether there may be other factors involved which would explain this. However, it would appear to be the best result we currently have for the marine compartment.

5) The Douglas M.T. and Sewell I.G., 1988 study (HRC report number: CMA 2(1)/88923) is a supporting study as it was considered to be unreliable. Due to the test substance forming a very poor dispersion in the water column and adhering to the mesh screens around the propeller shield the study was not considered to be reliable and has been assigned a reliability rating of 3, according to the criteria of Klimisch, 1997. This study is being used as read across from Phenol, tetrapropenyl-, sulfurized, carbonates, calcium salts). The values obtained are not considered robust enough for use in assessment.

6) The Douglas M.T. and Sewell I.G., 1988 study (HRC report number: CMA 2(1)/88925) is a supporting study as it was considered to be unreliable.

During the conduction of the study, the test solution is considered to have been improperly prepared in that test material was added to solution in amount that was far in excess of water solubility. Furthermore, the test substance formed a very poor dispersion in the water column and adhered to the mesh screens around the propeller shield and a small number of globules of the test substance were observed circulating in the water. As such the study has been assigned a reliability rating of 3, according to the criteria of Klimisch, 1997. The values obtained are not considered robust enough for use in assessment.