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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

Two non-GLP studies according to or similar to OECD guidelines 203 are available for the 2-nitropropane.
The key study determined a 96-hour LC50 for 2-nitropropane of >612.5 mg 2-nitropropane/L in the fathead minnow (Pimephales promelas). The supporting study determined a 48-hour LC50 for 2-nitropropane of 620 mg 2-nitropropane in the zebra fish (Brachydanio rerio (new name: Danio rerio)).

Key value for chemical safety assessment

LC50 for freshwater fish:
612.5 mg/L

Additional information

Both studies lacked in specific detail but provided enough information to be considered acceptable with reservations. Neither study was conducted under good laboratory practice (GLP) principles. Both studies indicated that they had been conducted according to the OECD 203 Acute Fish toxicity guideline. Specifics on actual test conditions were lacking in both studies but implication is that the test conditions were according to the specified guideline requirements. Both reports indicated analytical confirmation of exposure concentrations were conducted and provided the analytical methodology but neither reported the results from these analyses. The exposure in the key study was not done under sealed vessel conditions so potential for volatilization of the test material existed. The exposure period for this test was 96 hours. The supporting study with zebra fish was conducted using covered vessels to minimize volatilization of the test material.  The exposure period for this test was reported as 96 hours yet only 48 hour endpoints were presented. No explanation as to why 96 hour values were given. It is possible that since the test material was volatile and the exposure was static, thus not allowing for aeration of the test solutions, that dissolved oxygen dropped below minimum saturation (60%) during the last 48 hours of the test. With the fish loading and covering of vessels limiting air exchange this is a possibility. This may have left the data from 72 and 96 hours unusable. This is speculation but is a reasonable outcome based on experience.

 

Based on this information, the fathead minnow acute test is considered the key study for the short-term toxicity to fish endpoint. The LC50 >612.5 mg/L would result in a classification of Not Dangerous for this material based on fish toxicity.