2-methylpentane-1,5-diamine

Endpoint summary

Additional information

Reliable acute data for the three trophic levels (algae, invertebrates and fish) are available together with data on microorganism toxicity. Additionally a reliable study on Daphnia magna reproduction (RL category 1) was performed and the alga data may also assessed for chronic effects (EC₁₀ reported). Due to the caustic properties of the members of the amine heads category adjustment of pH to physiological values is a prerequisite for meaningful results considered however in only a subset of available studies. Comparison of non-adjusted toxicity data for both, fish and microorganisms for the three category members corresponds to what would be expected from physico-chemical data (DCH being less caustic than HMD, no experimental data for MPMD).

An algae studyperformed according to internationally accepted guidelines and GLP included also chemical analysis. Stability of the test item (HMD) throughout the test period of 72 hours at high light intensity and comparably high temperature confirmed the stability of the test substance. Therefore, stability may also be assumed in regard to acute tests on fish and invertebrates. Algae proved to be of very low sensitivity in regard to the amine heads category if pH is adjusted to physiological values (EC₁₀ 72 h, growth rate: 118 mg/L).

Acute fish toxicity is even lower as long as pH is adjusted to the physiological range. Two reliable studies report 96-hours LC₅₀-values of >215 mg/L and 1825 mg/L, respectively for amine heads category member HMD.

Invertebrates represent the most sensitive trophic level. The acute EC₅₀(48 h) was calculated as 31.5 mg/L. This value is the geometric mean of two equally reliable 48 h tests on Daphnia magna yielding EC₅₀-values of 19.8 mg/L and 50 mg/L, respectively.

Additionally reliable chronic data are available for daphnia. The semi-static test (change of test medium 3 times per week) with analytical verification of test item concentration resulted in a NOEC reproduction (21 d) of 4.16 mg/L and an EC₅₀(21 d) for adult mortality of 6 mg/L (time weighted mean measured concentrations). This corroborates that invertebrates represent by far the most sensitive trophic level.

No data are available for chronic fish toxicity. In acute tests fish however proved to be least sensitive compared to algae and invertebrates and given the ready biodegradability of all three members of the category chronic toxicity is rendered very unlikely.

Considering microorganism toxicity in regard to sewage treatment plants, a 20-h EC₁₀ of 12.5 g/L was determined from a growth inhibition test on Pseudomonas putitada when pH was adjusted to environmentally acceptable levels. This renders the amine heads category essentially non-toxic to sewage treatment plant microorganisms.