Mercaptamine hydrochloride

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

February 2018 - May 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

yes

Remarks:

Stock solution, used for ISO water preparation, are 5 times more concentrated than OECD 202 annex III.

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 10, 4 , 1 mg/L
- Sampling method: aliquots were taken
- Sample storage conditions before analysis: 4±2°C for all determination except pH determinations (directly carried).

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Starting from the 100 mg/L SOLUTION in ISO test water, following test solutions in ISO test water were prepared: 1, 1.6, 2.5, 4, 6.3, 10 mg/L.
100 mg/L SOLUTION in ISO test water was prepared new for each test
- Eluate: NO
- Controls: ISO TEST SOLUTION without test substance
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): NO

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: Daphnia magna Straus 1820
- Source: Breeding of a certified Daphtokit
- Age of parental stock: 30 days
- Feeding during test: NO

ACCLIMATION
- Acclimation period: continuos breeding
- Acclimation conditions (same as test or not): same as test excluding light intensity (1000 ± 20% lux) and breeding water (mineral wayer similar for chemical composition to ISO test water)
- Type and amount of food: green algae (Pseudokirchneriella subcapitata) and brewer's yeast; 300000 cells/ml
- Feeding frequency: every day
- Health during acclimation (any mortality observed): no mortality observed

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

240 g/L of CaCO3

Test temperature:

20±1°C (taverage 20°C; tmin 19.9°C; tmax 20.1°C)

pH:

8.00÷8.70

Dissolved oxygen:

8.60-8.74 mg/L

Nominal and measured concentrations:

1 (measured 1.39), 1.6, 2.5, 4 (measured 5.47), 6.3, 10 (measured 9.76) mg/L.
Standard: Mercaptamine hydrochloride 50 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: beaker
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 100 ml glass beaker filled with 50 ml of sample
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: iso stock solutions
- Culture medium different from test medium: Culture medium is a mineral water with little differences in chemical composition than test medium
- Intervals of water quality measurement: every new batch of culture medium is controlled; test medium is controlled at every use

OTHER TEST CONDITIONS
- Photoperiod: 16h luce e 8h buio
- Light intensity:300±20% lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : number of immobilized daphnids observed at 24 and 48h

VEHICLE CONTROL PERFORMED: no vehicle

RANGE-FINDING STUDY
- Test concentrations: 1, 10 and 100 mg/l
- Results used to determine the conditions for the definitive study: yes; provisional 48hEC50 turned out to be between 1 and 10 mg/l

Reference substance (positive control):

yes

Remarks:

Potassium Chloride

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.75 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: NO
- Observations on body length and weight: NO
- Other biological observations:NO
- Mortality of control:NO
- Other adverse effects control:NO
- Abnormal responses:NO
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values:NO

Reported statistics and error estimates:

Statistical processing of test results was performed using a probit test contained in the EPA software indicated in the US EPA “Methods for measuring the acute toxicity of effluents and receiving waters to freshwater and marine organisms” – Fifth edition - october 2002.
The same software returns the value of 95% confidence limits

	CONTROL	1mg/L	1.6mg/L	2.5mg/L	4mg/L	6.3mg/L	10mg/L
1	0	0	1	2	5	5	5
2	0	0	1	2	3	5	5
3	0	0	0	2	4	5	5
4	0	0	0	2	4	5	5
IMMOBILIZATION (TOTAL)	0	0	2	8	16	20	20
TOTAL EXPOSED	20	20	20	20	20	20	20
% OF IMMOBILIZED	0	0	10	40	80	100	100

Validity criteria fulfilled:

yes

Conclusions:

The 48h acute toxicity of Mercaptamine HCl to Daphnia magna was studied under static conditions. Daphnids were exposed to ISO test water control and test chemical at measure concentration of 1, 1.6, 2.5, 4, 6.3, 10 mg/L of test substance for 48h.
Immobilization sublethal effects were observed daily.
The 48h EC50 was 2.75 mg/L (LC95%: 2.38-3.18 mg/l).
No sublethal effects were observed.
Based on the results, Mercaptamine HCl would be consider as NO toxic to invertebrates.
This study is classified as reliability 1 and satisfies the guideline requirements for an acute toxicity with freshwater invertebrates.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

2.75 mg/L