Polyethylene polyamine, pentaethylenehexamine fraction

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

Study period:

20-03-1990 to 25-03-1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Study is complete, performed under GLP and valid. however no analysis was performed and thus the usability for riskassessment purposes is limited when assessing the bioavailable fraction.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

The test was carried out with the unicellular green algae; Selenastrum capricornutum ATCC 22662. This strain was maintained on mineral salts agar slants in the light at room temperature.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

between 22 and 24 °C

pH:

7.1-8.8

Nominal and measured concentrations:

nominal: 0, 0.125, 0.250, 0.500, 1.000, 2.000 mg/L

Details on test conditions:

The culturing apparatus is a cabinet in which the temperature is maintained between 22° and 24°C, and continuous uniform illumination is provided in the spectral range of 400 to 700 nm. The light intensity is in the range of 6000 to 10000 lux which is obtained by using seven 30 W fluorescent lamps (colour temperature of approximately 4300 K), at a distance of 0.35 m from the algal culture. The culture flasks were rotated continuously at 100 rpm to prevent sedimentation of the algae.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: both growth rate and biomass

Details on results:

The ErC50 and EbC50 (0-72 h) of pentaethylenehexamine are 1. 7 and 0.7 mg/litre respectively. The NOEC determined of pentaethylenehexamime is 0.250 mg/litre.

Results with reference substance (positive control):

in line with guideline

Reported statistics and error estimates:

The EC50 values were computed from the best fitted line (least square method) through the points given by the probit of the percentage inhibition and the logarithm of the concentration of the test substance. The EC50 value calculated with the area under the growth curve is termed EbC50 (0-72 h) whereas the EC value calculated with the specific growth rate is termed ErC50 Confidence limits were computed based on Fieller's theorem. All computations were performed with the software package SAS.

The extinction of the controls increased by a factor of 48 within 72 hours which met the validity criteria. From the extinctions of potassium dichromate an ErC50 and EbC50 (0 -72 h) were determined of 1.6 and 1.2 mg/litre, respectively.

These values of the reference compound are in accordance with data of an international inter-laboratory test showing

that the test organisms have not changed significantly and that the slight modification of the mineral salts medium does not influence the result. The pH in the algal culture should not deviate more than 1.5 unit during the test. The pH measurements show a limited pH increase. Because pentaethylenehexamine is not readily biodegradable the biodegradation of the test compound within 3 days is impossible. The temperature was 23°C.

Validity criteria fulfilled:

yes

Conclusions:

The ErC50 and EbC50 (0-72 h) of PEHA are 1.7 and 0.7 mg/litre respectively. The NOEC determined of PEHA is 0.25 mg/litre. The study was performed under GLP and meets all validity criteria. Only nominal test concentrations are presented which limits the use of this data when performing a riskassessment when looking at the bio-available fraction

Executive summary:

The toxicity of pentaethylenehexamine (PEHA) to exponentially growing S. capricornutumhas been assessed over an exposure period of 72 hours. The algal inhibition test was performed according to the EEC/OECD (201) test guidelines One minor deviation from the protocol of the algal inhibition test was introduced.

- The KH2PO4 and NaCO3 concentrations in the test medium were increased to 160 and 100 mg/litre, respectively, to maintain a constant pH.

- Preliminary experiments to determine the concentration range are performed but not reported according to the guidelines.

In the definitive test the algae were exposed to the following nominal concentrations of 0.125, 0.250, 0.500, 1.00 and 2.00 mg/litre. The EbC50 (0 -72 h) and ErC50 of PEHA for S. capricornutumare 1.7 and 0.7 mg/litre, respectively. The NOEC determined of tetraethylenepentamine is 0.25 mg/litre. All tets concentrations are based on nominal. All validity criteria are met and thus the study is valid.

However the usability of the presented data islimited due to the absence of actual measured concentrations and therefore no information on the bioavailable fraction.

Description of key information

EC50 (72 h): 1.7 mg/L (nominal)

NOEC (72 h): 0.25 mg/L (nominal)

Key value for chemical safety assessment

EC50 for freshwater algae:

1.7 mg/L

EC10 or NOEC for freshwater algae:

0.25 mg/L

Additional information

The acute toxicity of the substance to aquatic algae was tested in a study set up according to OECD guideline 201 and GLP. The freshwater algae Pseudokirchneriella subcapitata was exposed to nominal substance concentrations of 0.125, 0.250, 0.500, 1.000 and 2.000 mg/L. Analytical dose verification was not performed since the substance was expected to be stable under the tested conditions.

Based on the algal growth rate an EC50 (72 h) of 1.7 mg/L (nominal) was determined. The NOEC (72 h) was 0.25 mg/L for algal growth and biomass respectively.