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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Description of key information

Two Daphnia magna acute toxicity tests were conducted with 1-nitropropane according to the OECD 202 daphid acute toxicity guideline.  The most recent test (2009) was conducted under GLP while the older test was a non-GLP study.  In addition, a QSAR value for daphnids was generated using the USEPA ECOSAR v1.00 model as part of EPISuite v4. 
The key study for aquatic invertebrate toxicity is the most recent daphnid acute toxicity test. This test was conducted under GLP, using flow-through conditions to maintain test concentrations due to the volatile potential for the chemical. Analytical verification of test solutions was conducted and demonstrated that test concentrations were on target and remained stable for the duration of the exposure. The results are calculated based on mean measured concentrations. The 48-hour EC50 was 380 mg 1-nitropropane/L.
The supporting study determined a similar value with a 24-hour EC50 of 258 mg 1-nitropropane/L.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
380 mg/L

Additional information

Two aquatic invertebrate acute toxicity tests were conducted withDaphnia magnaexposed to 1-nitropropane according to the OECD 202 daphnid acute toxicity guideline. The most recent test (2009) was conducted under GLP while the older test was a non-GLP study. In addition, a QSAR value for freshwater invertebrates was generated using the USEPA ECOSAR v1.00 model as part of EPISuite v4.

 

The key study for aquatic invertebrate acute toxicity is the most recent test. This test was conducted under GLP, using sealed-vessels with zero-headspace to minimize loss of test material due to the volatile potential for the chemical. Analytical verification of test solutions was conducted and demonstrated that test concentrations were on target and remained stable for the duration of the exposure. The results are calculated based on arithmetic mean measured concentrations. The 48-hour EC50 was 380 mg/L.

 

The report for the earlier study did not provide adequate detail on test conditions or test methods to be considered a key study. This study was also only conducted for 24 hours rather than the current requirement of 48 hours. However, at the time this study was conducted, the OECD 202 guideline requirement was a 24-hour exposure. The report was inconclusive as to whether the exposures were conducted in sealed test vessels and or whether exposure concentrations were maintained over the 24-hour exposure period. Three exposures were conducted and a mean 24-hour EC50 value of 258 mg/L was reported. The reported results from this test were somewhat consistent with the results for the recent test (24-hour EC50 values of 258 and 696 mg/L, respectively). The 24-hour EC50 values are within approximately a factor of two, indicating a consistent response.

 

The ECOSAR LC50 value was 281 mg/L, which is similar to the experimentally derived EC50 values.

 

These results indicate that 1-nitropropane is not dangerous to freshwater aquatic invertebrates.