Hexylamine

Endpoint summary

Additional information

Fish:

A study was conducted on the golden orfe (Leuciscus idus) to assess the acute toxicity of n-hexylamine. The substance was tested in a static 96 h- procedure. The nominal concentrations were 10, 21.5, 46.4 and 100 mg/L. 10 fish were used per aquarium and per concentration. The LC50 (96 h) was determined to be 14.7 mg/L. No mortality and no symptoms were observed in an additional test solution (100 mg/L), which was pH-adjusted, resulting in an LC50 (96 h) of >100 mg/L based on the pH-adjusted test solution.

In a publication (Geiger et al. 1986) another 96 hours static toxicity test on fish is described which was conducted on fathead minnows (Pimephales promelas). The nominal test concentrations were 0, 13.2, 20.3, 31.3, 48.1, 74 mg/L (measured 12.3, 18.9, 29, 43.9, 66.4 mg/L). Deaths occurred from the 48.1 mg/L group onwards. Behavioural abnormalities were loss of schooling behavior, hypoactivity and loss of equilibrium, also observed in the 48.1 and 74 mg/L groups. Based on these results the LC50 (96 h) as well as the EC50 (96 h) values were determined to be 56.6 mg/L.

Daphnia:

In a study on Daphnia magna, the short-term toxicity of the test substance was assessed. For preparation of a stock solution, the test substance was weighed into the test medium (ISO medium) and the mixture was ultrasonicated for 5 min and stirred for 22 hours. Afterwards the solution was diluted to the nominal test substance concentrations 0, 3.125, 6.25, 12.5, 25, 50 and 100 mg/L. The total test duration was 48 hours, after 24 hours the test substances were renewed. 20 daphnia per vessel and a total of 20 per concentration and 30 for the negative control were tested. Based on mobility, the EC50 (48 h) of hexylamine was determined to be 13.2 mg/L (measured: 8.6 mg/L). In comparison, potassium dichromate was used as positive control and resulted in an EC50 (48 h) of 1.14 mg/L.

Algae:

In a weight-of-evidence-approach an ErC50 value of 1.98 mg/L (geometric mean) was calculated based on the ErC50 value of 0.23 mg/L for octylamine (CAS 111-86 -4) and the ErC50 value of 17 mg/L for butylamine (CAS 109-73-9).

The estimated ErC50 (72 h) value 1.98 (mg/L, geometric mean) was confirmed by two OECD-Toolbox-estimates yielding EC50-values of 6.3 mg/L and 4.71 mg/L.

In an additional weight-of-evidence-approach an ErC10 value of 0.5 mg/L (geometric mean) was calculated based on the ErC10 value of 0.07 mg/L for octylamine (CAS 111-86 -4) and the ErC10 value of 3.7 mg/L for butylamine (CAS 109-73-9).

The EC10-value of 0.5 mg/L was confirmed using a trend analysis (Excel function VARIATION) based on data from primary amines with varying chain length. EC10- or TCC (~EC3)-values from the following primary amines were considered:

Methylamine, CAS-# 74-89-5;

Ethylamine, CAS-# 75-04-7;

Butylamine, CAS-# 109-73-9;

Octylamine, CAS-# 111-86-4.

An EC10/NOEC value of 0.34 mg/L was calculated using the Excel function VARIATION.

Microorganisms:

N-hexylamin was tested for its toxicity to Pseudomonas putida using a static procedure. The nominal test concentrations were 15.625, 31.25, 62.5, 125, 250, 500 and 1000 mg/L. The test duration was 17 hours. Based on growth inhibition, the EC50 was determined to be 306 mg/L, the EC10 was determined to be 167 mg/L.

In a second test, the substance was tested on activated sludge from an industrial wastewater treatment plant. The exposure duration was 10 min. Only one concentration (997 mg/L, nominal) was tested. Based on respiration inhibition, no effects were observed and the EC20 was determined to be greater than 997 mg/L. Determination of an EC50 value was not possible on the basis of these test results. Therefore the study was considered as not assignable.