Mercaptamine hydrochloride

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:

March 2018 - May 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

23 march 2006

Deviations:

yes

Remarks:

The breeding of the organisms is carried out according to method APAT IRSA CNR 8020 appendix 1 . It is believed that these modifications have not had an effect on the quality and integrity of the study and the data produced

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 46, 15 e 10 mg/l
- Sampling method: aliquot were taken
- Sample storage conditions before analysis: refrigerated storage 4±2°C

Vehicle:

no

Details on test solutions:

- Separation method : GC
- Conditions (column, mobile phase, etc.): solvent detection column (capillary column DB1, lenght: 60 m, int. diam. 0.53 mm)
- Detection method: FID
- Reproducibility in % (indicate method of evaluation; should be given for stated concentration levels): 20%
- Linearity range: 1-50 mg/l
- Extraction recovery (indicate if results are corrected or not for recoveries): not corrected
- Method of confirmation of identity of measured compound: standard (conc. 46 mg/l)

Test organisms (species):

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

Details on test organisms:

- Strain: PSEUDOKIRCHNERIELLA SUBCAPITATA (KORSHIKOV) F.HINDAK (1990)
- Source (laboratory, culture collection): Breeding of a certified Algaltox F kit
- Age of inoculum (at test initiation): 4/5 days
- Method of cultivation: APAT IRSA CNR 8020 appendix 1 .


ACCLIMATION

- Acclimation period: continuos breeding
- Culturing media and conditions (same as test or not): same as test excluding photoperiod (16 h light/ 8 h dark) and culturing media (see APAT IRSA CNR 8020 appendix 1)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

20-24°C ( tmin 21.4°C; tmax 22.1°C);

pH:

8.02÷8.43

Nominal and measured concentrations:

1.5, 4.6, 6.8, 10 (measured 7.3 mg/l), 15 (measured 13.3 mg/l), 22, 46 mg/L (measured 47.8 mg/l)

Details on test conditions:

TEST SYSTEM

- Test vessel: flask
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: glass, 50 ml, sample 20 ml
- Aeration: no
- Initial cells density: 104 cell/ml
- Control end cells density: 1.64 x 106 cell/ml
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6


GROWTH MEDIUM

- Standard medium used: OECD TG 201 medium


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: iso stock solution


OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: CONTINUOUS
- Light intensity and quality: 4400÷8800 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber )

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Annex 4 OECD 215 (excluding end concentrations)
- Range finding study: yes (1- 10- 100 mg/l)
- Test concentrations: 1.5 – 4.6 – 6.8 – 10 – 15 – 22 - 46 mg/l (definitive test)
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

zinc heptahydrate suplhate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

19.7 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Flocculation: no
- Aggregation of algal cells: no
- Any stimulation of growth found in any treatment: no

Reported statistics and error estimates:

The growth rates and the percentages of inhibition were calculated.
The curve dose /effect was done using tese values.
The value of the ErC50 was calculated from the curev dose / effect (calculation made using the Excel software and confirmed with the software R)

Validity criteria fulfilled:

yes

Conclusions:

In a 72h acute toxicty study, the cultures of Pseudokirchneriella subcapitata were exposed to Mercaptamine HCl at measure concentrations of 1.5, 4.6, 6.8, 10, 15, 22, 46 mg/L under static conditions in accordance to OECD guideline 201
The 72h EC50 (calculated form initial measured concentrations) was 19.8 mg/L
This study is classified as reliability 1 and satisfies the guideline requirements for an algal growth inhibition study

Key value for chemical safety assessment

EC50 for freshwater algae:

19.7 mg/L