Hexylamine

Endpoint summary

Description of key information

Short term toxicity to fish:

Study was conducted to assess the effect of test chemical n- hexylamine (CAS 111-26-2) on the mortality of fish Danio rerio. Test conducted according to OECD Guideline 203 (Fish, Acute Toxicity Test). The test substance was soluble in water, In house solubility was found to be 1100.77 mg/L. Therefore the stock solution prepared as 52.7ml /2 liter, with the concentration of 2g/100ml, and was kept for 2 hours stirring. After the completion of stirring, the sample was kept for settling and filtered it. After this as it is stock taken for experiment. From this stock solution further test concentrations were prepared for achieving test concentrations of 0.98 mg/L, 1.48 mg/L, 2.22mg/L, 3.33mg/L, 5 mg/L respectively and Zebra Fish Danio rerio were exposed to these concentration for 96 hours. Plastic aquaria containing 5 liters of potable water (passed through reverse osmosis system) were loaded with 8 fishes. A static procedure was used for the study and it was conducted in compliance with the OECD guideline 203. After 96 hours of exposure to test item to various nominal test concentrations, LC50 was determine to be >2.22mg/l and <3.33 mg/l as no effect were observed at 2.22 mg/l. Based on the LC50, it can be consider that the chemical was toxic and can be consider to be classified in aquatic chronic 2 category as per the CLP classification criteria.

Short term toxicity to aquatic invertebrates:

Aim of this study was to assess the short term toxicity of test chemical to aquatic invertebrate daphnia magna. Study was performed according to the OECD guideline 202 in a static system for the total exposure period of 48 hrs. The stock solution 100 mg/l was prepared by dissolving colourless liquid in reconstituted water. Test solutions of required concentration as were prepared by mixing the stock solution of the test sample with reconstituted test water. 0, 1, 2, 4, 8, 16 and 32 mg/l concentration were prepared. Effects on immobilization were observed for 48 hours. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. The median effective concentration (EC50) for the test substance in Daphnia magna was determined to be 11.8 mg/L on the basis of mobility inhibition effects in a 48 hour study. Based on the EC50 value, chemical was consider as toxic and classified in aquatic chronic 3 category as per the CLP classification criteria.

Toxicity to aquatic algae and cyanobacteria:

Study was to evaluate the short term toxicity effect of test chemical n- hexylamine (CAS 111-26-2) to aquatic algae Desmodesmus subspicatus. Study was performed according to the OECD guideline in a static system for the total exposure period of 72 hrs. The stock solution 100 mg/l was prepared by dissolving colourless liquid in OECD growth medium. Test solutions of required concentration were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. Different test concentrations were prepared 0, 1, 2, 4, 8 and 16 mg/l. Effect on the growth were measured for 72 hrs. The median effective concentration (ErC50) for the test substance, in Desmodesmus subspicatus was determined to be 11.9 mg/L on the basis of effects on growth rate inhibition in a 72 hour study. Thus based on the EC50 value, chemical consider as toxic and classified in aquatic chronic category 3 as per the CLP classification criteria.

Toxicity to microorganism:

In the first Tetratox assay is a short-term, static protocol using the common freshwater ciliate Tetrahymena pyriformis (strain GL-C). The 50% impairment growth concentration (IGC50) is the recorded endpoint.   Cultures are reared in 50 ml of a semi-defined medium in 250 ml Erlenmeyer flasks. In the TETRATOX assay, a range-finding assay followed by three replicate definitive tests is performed on each test material. Definitive test replicates consist of a minimum of five different concentrations of each test material with duplicate flasks of each concentration. . Duplicate controls, which have no test material but were inoculated with T. pyriformis, and a blank are used to provide a measure of the acceptability of the test by indicating the suitability of the medium and test conditions, and a basis for interpreting data from other treatments. Duplicate flasks are inoculated with an initial density of ≈2,500 cells/ml with log-growth-phase ciliates. Following ≈40 hours of incubation at 27 ± 1°C, population density is measured spectrophotometrically and 50% effect levels determined. The 50% inhibitory growth concentration in mg/l (IGC50) and the 95% fiducial interval are determined for each test compound. The IGC50 is calculated by probit analysis using the percent control-normalized absorbance as the dependent variable and the toxicant concentration in mg/l as the independent variable   The 50% Impairment(Inhibitory ) Growth Concentration IGC50 for hexylamine is estimated to be 1.6595mg/lt. It is reported to be bioreactive.

Additional information

Summarized result for the toxicity of test chemical on the growth and mortality of aquatic life’s including fish, invertebrates, algae and microorganism were studied and are as mention below:

Short term toxicity to fish:

Based on the short term toxicity study available for the test chemical, studies were reviewed to determine the toxic nature of test chemical n- hexylamine (CAS 111-26-2) on the mortality of fish. The studies are as mentioned below:

In the first key experimental study was conducted to assess the effect of test chemical n- hexylamine (CAS 111-26-2) on the mortality of fish Danio rerio. Test conducted according to OECD Guideline 203 (Fish, Acute Toxicity Test). The test substance was soluble in water, In house solubility was found to be 1100.77 mg/L. Therefore the stock solution prepared as 52.7ml /2 liter, with the concentration of 2g/100ml, and was kept for 2 hours stirring. After the completion of stirring, the sample was kept for settling and filtered it. After this as it is stock taken for experiment. From this stock solution further test concentrations were prepared for achieving test concentrations of 0.98 mg/L, 1.48 mg/L, 2.22mg/L, 3.33mg/L, 5 mg/L respectively and Zebra Fish Danio rerio were exposed to these concentration for 96 hours. Plastic aquaria containing 5 liters of potable water (passed through reverse osmosis system) were loaded with 8 fishes. A static procedure was used for the study and it was conducted in compliance with the OECD guideline 203. After 96 hours of exposure to test item to various nominal test concentrations, LC50 was determine to be >2.22mg/l and <3.33 mg/l as no effect were observed at 2.22 mg/l. Based on the LC50, it can be consider that the chemical was toxic and can be consider to be classified in aquatic chronic 2 category as per the CLP classification criteria.

 

Another study from peer reviewed journal was also conducted. The objective of this study was to investigate the use of 96-h acute toxicity tests with juvenile fathead minnows and binary chemical mixtures to define the primary acute model of toxic action for diverse industrial organic chemicals. The 96-h acute toxicity tests with single chemicals and mixtures, and 26- to 34-d-old laboratory-cultured juvenile fathead minnows (Pimephalespromelas) were conducted. The experiments with mixtures were carried out under similar conditions as the experiments with single compounds. Exposures were conducted at 25°C in continuous flow-through systems with four or five toxicant concentrations and a control in duplicate for each LC50 determination. Toxicant concentrations in the test chambers were continuously renewed and measured daily. Methods of chemical analysis included high-pressure liquid chromatography (HPLC) and gas-liquid chromatography (GC). Toxicant concentrations were routinely corrected for spiked water recoveries. Percentage duplicate agreements were usually greater than 90%. The dilution water was taken directly from Lake Superior, and following sand filtration. It had a water hardness, alkalinity, and pH of approximately 45 mg/L as CaC03, 42mg/L as CaC03, and 7.8, respectively, for all tests. All toxicity tests were conducted without using solvent carriers. Mortalities were recorded daily and estimate of the concentration of toxicant most likely to cause 50 % mortality (LC50). The Lethal concentration causing 50% mortality value (LC50) of1 Pimephales promelas (Fathead Minnow) was determine to be 56.6 mg/L after 96 hours of exposure to test chemical. This lethal value indicates that the test substance n- hexylamine classified in aquatic category 3 as per the CLP criteria.

 

Above study was supported by the third study from peer reviewed journal. Aim of this study was to determine the effect of test chemical n- hexylamine on the mortality of fish Pimephales promelas for 96 hrs. Test conducted under the flow-through system. The Lethal concentration causing 50% mortality (LC50) of fathead minnow when exposed to test chemical for 96 hours under the test conditions is 56.23mg/l. It is reported to be bioactive. Thus based on the LC50 value, chemical consider to be toxic and classified as aquatic chronic 3 as per the CLP classification criteria.

 

Similarly in a 96 hour short team toxicity study, the effect of test chemical n- hexylamine was evaluated on Pimephales promelas (Fathead Minnow). The test substance was test in a concentration of 56.6 mg/l (53.8 to 59.6 mg/l). The results show 50% mortality of test organism’s population at given concentration. Therefore, chemical considered to be lethal at 56.6 mg/l (56600 mg/l) when tested on Pimephales promelas (Fathead Minnow) for 96 hrs. Thus considering the CLP Criteria for aquatic classification of the substance, it is concluded that the test chemical classified in aquatic chronic category 3.

 

Similarly Test for acute toxicity was carried out on embryos of Danio rerio. The effects of basicity were investigated adjusting pH´s of 8.0 to 12.0 using a 0.1 n NaOH – solution after 48 h for lethal and sub lethal effects. The lethal concentration (LC50) for embryos of Danio rerio zebrafish was considered to be 42.31mg/l (32.18-46.45 mg/l) when exposed to test chemical for 48 hours. Thus according to lethal concentration the test substance consider to be toxic to fish and thus classified in aquatic chronic category 3.

 

Thus based on the above studies from experimental study report, peer reviewed journal and secondary sources, it was concluded that the chemical n- hexylamine (CAS 111-26-2) was toxic and classified in aquatic chronic category 2.

 

Short term toxicity to aquatic invertebrates:

Various short term studies available for the test chemical n- hexylamine were reviewed to determine the toxic nature of test chemical on the mobility of aquatic invertebrates. The studies are as mentioned below:

In the first key experimental study toxicity were measured. Aim of this study was to assess the short term toxicity of test chemical to aquatic invertebrate daphnia magna. Study was performed according to the OECD guideline 202 in a static system for the total exposure period of 48 hrs. The stock solution 100 mg/l was prepared by dissolving colourless liquid in reconstituted water. Test solutions of required concentration as were prepared by mixing the stock solution of the test sample with reconstituted test water. 0, 1, 2, 4, 8, 16 and 32 mg/l concentration were prepared. Effects on immobilization were observed for 48 hours. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. The median effective concentration (EC50) for the test substance in Daphnia magna was determined to be 11.8 mg/L on the basis of mobility inhibition effects in a 48 hour study. Based on the EC50 value, chemical was consider as toxic and classified in aquatic chronic 3 category as per the CLP classification criteria.

 

Similar study was also conducted which supports the classification of chemical. In a 24 hrs short term toxicity study the effect of test chemical was evaluated on Daphnia magna. The substance was test in a concentration of 20 mg/l (11-42 mg/l). The results show 50% immobility of test organism population at given concentration. Therefore, chemical considered to be toxic at 20 mg/l when tested on Daphnia magna for 24 hrs. Based on the result, chemical was considered to be classified in aquatic chronic category 3 as per CLP classification criteria.

 

Thus based on the above results, chemical n- hexylamine consider to be toxic and classified as aquatic chronic category 3 as per the CLP classification criteria.

 

Toxicity to aquatic algae and cyanobacteria:

Various short term studies available for the test chemical n- hexylamine (CAS 111-26-2) were reviewed to determine the toxic nature of test chemical on the growth of algae. The studies are as mentioned below:

 

Objective of this first experimental study was to evaluate the short term toxicity effect of test chemical n- hexylamine (CAS 111-26-2) to aquatic algae Desmodesmus subspicatus. Study was performed according to the OECD guideline in a static system for the total exposure period of 72 hrs. The stock solution 100 mg/l was prepared by dissolving colourless liquid in OECD growth medium. Test solutions of required concentration were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. Different test concentrations were prepared 0, 1, 2, 4, 8 and 16 mg/l. Effect on the growth were measured for 72 hrs. The median effective concentration (ErC50) for the test substance, in Desmodesmus subspicatus was determined to be 11.9 mg/L on the basis of effects on growth rate inhibition in a 72 hour study. Thus based on the EC50 value, chemical consider as toxic and classified in aquatic chronic category 3 as per the CLP classification criteria.

 

Similar experimental study was also conducted. The study was designed to assess the effect of the test chemical n- hexylamine (CAS 111-26-2) on the growth of green alga Chlorella vulgaris. The study was conducted in accordance with “OECD guideline 201 – Alga, growth inhibition test”. The test solution was prepared in aseptic condition. The test item was prepared by adding 25mg of test item in 250ml of BBM to get the final concentration of 100mg/L. This stock solution was stirred for 20 minutes to get a homogenous solution for the experiment. The remaining test solutions were prepared by dilution from the above stock solution. The concentrations were chosen according to the available data of the test item. To have a better growth and visibility of cells, the initial cell density of the culture was kept 1 X 10000 cells/ml. Care was taken to have a homogeneous solution for the experiment. The fresh water green alga Chlorella vulgaris, was used as the test system (organism). Sterile, unicellular, suspension cultures of algae were obtained from National Environmental Engineering Research Institute (NEERI), and maintained at Unique Ecotox Research Laboratory. The culture was examined under the microscope to confirm that it was unicellular, healthy and not contaminated. According to the test validity criteria the following criteria are met in this test: As per OECD 201, the biomass in the control cultures should have increased exponentially by a factor of at least 16 within the 72 hr test period. This corresponds to a specific growth rate of 0.92 per day. Thus, the observed specific growth rate in the control cultures during the experiment was 1.54 per day. Secondly the mean coefficient of variation for section by section specific growth rates (days 0-1, 1-2 & 2-3, for 72 hr tests) in the control cultures must not exceed 35%. Thus, the observed mean coefficient of variation in the control cultures during the experiment was 14.71%. The coefficient of variation of average specific growth rates during the whole test period in replicate control cultures must not exceed 10%. Thus, the observed coefficient of variation of average specific growth rates during the experiment in control cultures was 1.638%. Hence, the test is considered valid as per OECD guideline, 201. After 72 hours of exposure to test chemical to various nominal test concentrations, EC50 was determine to be 23.349 mg/l graphically and through probit analysis. Thus on the basis of EC50 value, chemical n- hexylamine (CAS 111-26-2) consider to be toxic and classified as aquatic chronic 3 as per the CLP classification criteria.

Thus on the basis of EC50 value, chemical n- hexylamine (CAS 111-26-2) consider to be toxic and classified as aquatic chronic 3 as per the CLP classification criteria.

 

Toxicity to microorganism:

Various short term studies available for the test chemical n- hexylamine (CAS 111-26-2) were reviewed to determine the toxic nature of test chemical on the growth of microorganism. The studies are as mentioned below:

 

In the first Tetratox assay is a short-term, static protocol using the common freshwater ciliate Tetrahymena pyriformis (strain GL-C). The 50% impairment growth concentration (IGC50) is the recorded endpoint.   Cultures are reared in 50 ml of a semi-defined medium in 250 ml Erlenmeyer flasks. In the TETRATOX assay, a range-finding assay followed by three replicate definitive tests is performed on each test material. Definitive test replicates consist of a minimum of five different concentrations of each test material with duplicate flasks of each concentration. . Duplicate controls, which have no test material but were inoculated with T. pyriformis, and a blank are used to provide a measure of the acceptability of the test by indicating the suitability of the medium and test conditions, and a basis for interpreting data from other treatments. Duplicate flasks are inoculated with an initial density of ≈2,500 cells/ml with log-growth-phase ciliates. Following ≈40 hours of incubation at 27 ± 1°C, population density is measured spectrophotometrically and 50% effect levels determined. The 50% inhibitory growth concentration in mg/l (IGC50) and the 95% fiducial interval are determined for each test compound. The IGC50 is calculated by probit analysis using the percent control-normalized absorbance as the dependent variable and the toxicant concentration in mg/l as the independent variable   The 50% Impairment(Inhibitory ) Growth Concentration IGC50 for hexylamine is estimated to be 1.6595mg/lt. It is reported to be bioreactive.

 

Above study was also supported by the second study. The comparatively quick and low cost bioassay with Photobacterium phosphoreum, strain NRRL-B-11177 (Microtox3), occasionally also referred to as Vibrio fischerii, strain NRRL-B-11177 was used to assess the toxicity of hexylamine to aquatic bacteria. The luminescent bacterial bioassay requires only a short period of time, i.e. minutes. In terms of testing a broad range of different chemicals with many different modes of action, a somewhat longer assay time, i.e. 30 min, is preferred, mainly to ascertain that potential diffusion problems are eliminated at source. Normally the pT values for a particular chemical rarely vary much with exposure time. The most commonly used operating conditions are 15°C for the EC50tests with exposure times of 5 to 30 min. The pH of the test system can vary in the range of 5< pH <9 without great effect on the luminescence. The Effective Concentration causing 50% mortality of luminescent bacteria Photobacteria phosphereum was found to be 14 mg/l after 30 minutes exposure to hexylamine.

 

The solvation parameter model to construct models for estimating the non-specific toxicity of neutral organic compounds to the photo bacterium Vibrio fischeri, the bacterium Pseudomonas putida, the protozoan Tetrahymena pyriformis, the green alga Scendesmus quadricaudaand the brine shrimp Artemia salina. The solvation parameter model is based on a cavity model of solvation. Transfer of a solute from the donor to the acceptor phase requires creation of a cavity in the acceptor phase for the solute, an energetically unfavorable process that is opposed by solvent–solvent interactions. According to the study the excess toxicity (IGC50) for hexylamine is 0.63