Hexylamine

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experimental test result performed using standard test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Principles of method if other than guideline:

Short term toxicity of test chemical to aquatic algae was performed according to the 201 OECD guideline in a static system.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

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.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: 86.81 SAG
- Source (laboratory, culture collection): Institute of botany of the ASCR
- Initial biomass concentration: 5x10(3) cells /ml
- Method of cultivation: No data available

ACCLIMATION - No data available
- Acclimation period:
- Culturing media and conditions (same as test or not):
- Any deformed or abnormal cells observed:

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

±1 hour

Test temperature:

23±2°C

pH:

Test at highest concentration: 8.8 (change to 7.7 during tests)
Control: 8.0 (changed to 7.5 during test)

Nominal and measured concentrations:

0, 1, 2, 4, 8 and 16 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 ml Glass vessel
- Type (delete if not applicable): closed (with air permeable stopper)
- Sample volume: 15 ml
- Initial cells density: 5x10(3) cells/ml
- No. of vessels per concentration (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: Continuous
- Light intensity and quality: 6000-8000 lx

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: microscope with counting chamber Cyrus I or electronic particle counter.
- Other: ErC50 was calculated using non-linear regression by the software Prism 4.0

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (K2Cr2O7)

Key result

Duration:

72 h

Dose descriptor:

other: ErC50

Effect conc.:

11.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95 % CI was 6.9 - 20.4 mg/l

Results with reference substance (positive control):

Results with reference substance valid
- EC50: 0.77 mg/L

Reported statistics and error estimates:

EC50 was calculated using non linear regression by the software Prism 4.0

Validity criteria fulfilled:

yes

Conclusions:

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.

Executive summary:

Objective of this study was to evaluate the short term toxicity effect of test chemical 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.

 

Description of key information

Study was conducted 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.

Key value for chemical safety assessment

EC50 for freshwater algae:

11.9 mg/L

Additional information

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.