6-[(p-tosyl)amino]hexanoic acid, compound with 2,2',2''-nitrilotriethanol (1:1)

Short-term toxicity to aquatic invertebrates

Description of key information

The LC50 of a formulated product containing the registered substance was found to be 1626.1 mg/l. The formulated product contains 44.7% of the registered substance. Assuming a linear dose-response relationship, 44.7% of 1626.1 mg/l = 726.87 mg/l. Therefore the LC50 for the registered substance is proposed to be 726.87 mg/l. The registered substance is not considered to be toxic to aquatic invertebrates based on the findings of this study.

Key value for chemical safety assessment

Marine water invertebrates

Marine water invertebrates

Effect concentration:

726.87 mg/L

Additional information

The acute toxicity of the a formulated product containing the registered substance to aquatic invertebrates was determined in accordance with the draft ISO Testing Method 14669:1999 (E). Nominal test concentrations of the test material were prepared over the range 112.5 mg/l to 2000 mg/l. The marine invertebrate Acartia tonsa was exposed to the test concentrations in order to determine the concentration which killed 50% of the copepods over 48 hours (LC₅₀). The lowest concentration of test material producing 100% mortality could not be determined from this study. All concentrations of test material produced some mortality in this study. There was some evidence of a dose response in this study. All parameters measured in this study lay within the acceptable tolerance limits. The test material is not considered toxic to Acartia tonsa within the conditions of this study. The formulated product contains 44.7% of the registered substance. Assuming a linear dose-response relationship, 44.7% of 1626.1 mg/l = 726.87 mg/l. Therefore the LC₅₀ for the registered substance is proposed to be 726.87 mg/l. The registered substance is not considered to be toxic to aquatic invertebrates based on the findings of this study. In addition, an equivalent study was conducted on a formulated product containg a structurally similar substance to the registered substance (N-methyl salt). The 48 hour LC₅₀ of the read-across material was found to be 646 mg/l. The formulated product contains 44.7% of the registered substance. Assuming a linear dose-response relationship, 44.7% of 646 mg/l = 288.76 mg/l. Therefore the LC50 for the registered substance is proposed to be 288.76 mg/l. The N-Methyl salt is not considered to be toxic to aquatic invertebrates. Read-across between the registered substance and the test material (a formulated product containing N-methyl salt, which is structurally similar to the registered substance) is considered justified owing to the structural similarity of the two substances. Both are salts of a carboxylic acid and triethanolamine. The acid components are structural isomers and differ only in the position of a single methyl group in the N-methyl salt. This is not expected to change the bioavailability of the substances, and both substances have shown similarity in the results of other physical endpoints such as water solubility.

The 48 hour LC₅₀ of triethanolamine was found to be 1951.4 mg/l. Triethanolamine is not considered to be toxic to aquatic invertebrates.