tris (4-nonylphenol, branch) phosphorous acid ester

Short-term toxicity to aquatic invertebrates

Description of key information

TNPP is not acutely toxic to daphnia at loading levels at or slightly above its highest estimated water solubility (0.05 mg/L). These results were confirmed in subsequent long-term daphnia testing which showed no effects at a loading rate of 0.1 mg/L (double the highest estimated water solubility limit).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.3 mg/L

Additional information

There were no acute aquatic effects to daphnia form TNPP at levels at or slightly above TNPP's water solubility level.

The key study was run at loading levels well above the water solubility limit of TNPP and the test solution (water accommodated fraction) was stirred for 78 hours prior to testing in order to adequately mix and "age" the test solution and to allow for the formation of hydrolysis products. Detectable levels of nonylphenol (NP) were observed in the highest test concentration, which lead the authors to conclude that hydrolysis of the TNPP had indeed occurred as they assumed the test substance was 100% pure. However, given that the TNPP loading level of 100 mg/L is 2000 times higher than the highest estimated solubility limit (50 µg/L) and the fact that the actual test substance is more likely to be >99% pure rather than 100% pure, it is possible that the measured NP in the test solution was due to its presence as a minor impurity in the test material.

Regardless, the study supports the conclusion that TNPP is not toxic to daphnia at loading levels at or slightly above its highest estimated water solubility (0.05 mg/L). These results were confirmed in subsequent long-term daphnia testing at a loading rate of 0.1 mg/L (double the highest estimated water solubility limit).