Benzyldimethyl(octadecyl)ammonium chloride

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

From June 10, 1996 to June 21, 1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

KL2 due to RA

Justification for type of information:

Refer to the section 13 of IUCLID dataset for details on the read across justification. The algae study with the read across substance is considered sufficient to fulfil the information requirements as further explained in the provided endpoint summary.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

yes

Remarks:

analysis in test vessels was not conducted due to loss of substance causing the concentration to fall below detection limit. This does mean the actual exposure concentration changed with time due to adhesion of the substance to algae.

GLP compliance:

yes

Analytical monitoring:

yes

Details on test solutions:

A test substance stock suspension was prepared by weighing out the test substance using a analytical balance [AE 163, Mettler-Toledo AC, Greifensee, Switzerland Standard Operation Procedure K4 (4.13). For the definitive test 0.1009g test substance was mixed in a limited amount of mineral salts medium and mixed for 5 min. The pH was adjusted to pH=7.3 using 1 M sodium hydroxide. Finally, the solution was filled up to 100 mL in a volumetric flask with mineral salts medium.

For the definitive test an amount of culture medium was prepared by diluting the stock mineral salts in a 3-L vessel. This medium was sterilized by filter sterilization (0.2 pm). The inoculum was added from an exponentially growing culture. Various amounts of of the stock solution of the test substance were added to the test vessels (100 mL Erlenmeyers) in order to obtain the following nominal concentrations (triplicate): 0.005, 0.015, 0.045, 0.136 and 0.407 mg/L. The test vessels were filled with inoculated medium upto a total volume of 40 mL using a sterilized dispenser. In addition, six replicate of the control were included. The extinction in each Erlenmeyer was measured after 0, 24, 48, 72 and 96h. Algal medium was used as a blank in the spectrophotometer.

Test organisms (species):

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

Details on test organisms:

Preparation of the inoculum:
The initial stock culture was inoculated with Selenastrum capricornutum from a sloped agar tube and checked for purity by microscopic means.
This algal stock culture (40 mL) of Senostrum capricornutum was regularly transferred to fresh mineral medium to act as inoculum for the test.

The extinction of an exponentially growing stock culture was measured. The cell density was determined using the calibration curve described above From this algal culture a dilution was prepared to obtain an initial cell denslty of 10,000 cells/mL in the medium of the definitive test.

The quality of the algae was checked by performing a growth inhibition test with a reference compound (potassium dichromate) simultaneously with the definitive test.

Test type:

static

Water media type:

freshwater

Total exposure duration:

96 h

Post exposure observation period:

Five random samples were microscopically examined for bacterial contamination after the test. No contamination was observed.

Test temperature:

21.6 to 23.0°C

pH:

8.5 to 10.0

Salinity:

The deionized water used to make algae medium had a conductivity of less than 5 P S.cm and a TOC content of less than 2 mg/L. This water was produced from tap water in a water purification system (Spectrum-Elgastat, Breukelen, The Netherlands). For full media composition, refer to the report.

Nominal and measured concentrations:

0.005, 0.015, 0.045, 0.136 and 0.407 mg/L (nominal)
A 1.0 mg/L-concentration was measured before and after test to determine stability over test period (no algae).

Details on test conditions:

The culturing apparatus was a temperaturecontrolled illuminated orbital incubator (Gallenkamp INR 401, Breda, The Netherlands). Standard Operation Procedure K 1 1 (4.8) in which the temperature was maintained at ca. 25°C and a continuous uniform illumination was provided in the spectral range of 400 to 700 nm by using 30 W fluorescent lamps of the type ‘universal white’ (colour temperature of approximately 4000 K), at a distance of 0.35 m from the algal cultures. The culture flasks were rotated continuously at 100 rev/min to prevent sedimentation of the algae.
The test was performed in 100 mL Erlenmeyers containing 40 mL of mineral salts medium. The test flasks were closed with cotton-wool stoppers.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

0.01 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

biomass

Remarks on result:

other: 0.02 - 0.03; 95% confidence limits

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

0.03 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: 0.06 - 0.07; 95% confidence limits

Key result

Duration:

96 h

Dose descriptor:

LOEC

Effect conc.:

0.003 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

96 h

Dose descriptor:

EC10

Effect conc.:

0.011 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

96 h

Dose descriptor:

EC10

Effect conc.:

0.002 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

biomass

Details on results:

- Exponential growth in control: Yes
- Flocculation: No
- Adherence to test vessels: No
- Any stimulation of growth found in any treatment: No

Results with reference substance (positive control):

The definitive test is valid as shown by the EbC50 and Erc50 values of the reference compound, potassium dichromate (0.95 and 1.8 mg/L, respectively), the increase of the extinction of the control over 72 h by a factor of 64 and by a maximum deviation of the pH of 1.5 unit.

Reported statistics and error estimates:

All computations were performed using the Akzo programme ‘Algal’ (version 3.3) made in SAS (4.7).

Table 1. Summary of results absorbance

Nominal concentration mg/L (mean)	0h	96h
Control	0.006	1.031
0.005	0.006	0.971
0.015	0.006	0.631
0.045	0.007	0.308
0.136	0.007	0.020
0.407	0.006	0.009

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the EbC50, and ErC50 (0-96h) of the test substance were 0.02 mg/L (i.e., approximately equivalent to 0.01 mg a.i./L) and 0.06 mg/L (i.e., approximately equivalent to 0.03 mg a.i./L), respectively. The LOEC determined from the results for the test substance was 0.0025 mg a.i./L and the NOEC derived from the results for test substance was <0.0025 mg a.i./L (nominal).

Executive summary:

A study was conducted to determine the toxicity to aquatic algae of the read across substance, C12-16 ADBAC (active: 50.2%), according to OECD Guideline 201, in compliance with GLP. Selenastrum capricornutum were exposed for 96 h to nominal concentrations of 0, 0.005, 0.015, 0.045, 0.136 and 0.407 mg/L of test substance. Analytical dose verification was performed. Chemical analysis of duplicate samples taken at the beginning (96% recovery) and at the end (98% recovery) of the test indicated that the exposure concentrations were substantially achieved. Growth rate and biomass were recorded throughout the experiment. Under the study conditions, the EbC50 and ErC50 (0-96 h) were 0.02 mg/L (equivalent to 0.01 mg a.i./L) and 0.06 mg/L (equivalent to 0.03 mg a.i./L), respectively. The ErC10, EbC10, LOAEC and NOEC values were determined at 0.0114 mg a.i./L, 0.002 mg a.i./L, 0.0025 mg a.i./L and < 0.0025 mg a.i./L (nominal) respectively (Kroon, 1996). Based on the results of the read across study, similar the 96 h EbC50, ErC50 and NOEC values can also be considered for the test substance, C18 ADBAC, for toxicity to aquatic algae.

Description of key information

Based on the results of the read across study, the 96 h EbC50, ErC50, EbC10 and ErC10 values of the test substance, C18 ADBAC, for toxicity to aquatic algae is considered to be 0.01 mg a.i./L, 0.03 mg a.i./L, 0.002 mg a.i./L and 0.0114 mg a.i./L (nominal) respectively.

Key value for chemical safety assessment

EC50 for freshwater algae:

0.03 mg/L

EC10 or NOEC for freshwater algae:

0.011 mg/L

Additional information

A study was conducted to determine the toxicity to aquatic algae of the read across substance, C12-16 ADBAC (active: 50.2%), according to OECD Guideline 201, in compliance with GLP. Selenastrum capricornutum were exposed for 96 h to nominal concentrations of 0, 0.005, 0.015, 0.045, 0.136 and 0.407 mg/L of test substance. Analytical dose verification was performed. Chemical analysis of duplicate samples taken at the beginning (96% recovery) and at the end (98% recovery) of the test indicated that the exposure concentrations were substantially achieved. Growth rate and biomass were recorded throughout the experiment. Under the study conditions, the EbC50 and ErC50 (0-96 h) were 0.02 mg/L (equivalent to 0.01 mg a.i./L) and 0.06 mg/L (equivalent to 0.03 mg a.i./L), respectively.The ErC10, EbC10, LOAEC and NOEC values were determined at 0.0114 mg a.i./L, 0.002 mg a.i./L, 0.0025 mg a.i./L and < 0.0025 mg a.i./L (nominal) respectively (Kroon, 1996). Based on the results of the read across study, similar the 96 h EbC50, ErC50 and NOEC values can also be considered for the test substance, C18 ADBAC, for toxicity to aquatic algae.