3-mercaptopropionic acid

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1999-10-18 to 1999-12-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Hessisches Ministerium fuer Umwelt, Energie, Jugend, Familie und Gesundheit

Analytical monitoring:

yes

Details on sampling:

samples were drawn from the test solutions, filled into 2 L-glass bottles with glass stoppers and freezed at approx. -20°C until measurement

Vehicle:

no

Details on test solutions:

test was performed in tap water from the municipal drinking water supply (this water fulfills the requirements for the dilution water indicated in the OECD Guideline 203). pH was not adjusted.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: zebra fish (Brachydanio rerio)
- Source: Tagis-Aquarium, D-63303 Dreieich, Germany
- Length at study initiation: approx. 3 cm
- Feeding during test: no

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

approx. 21°C; see results tables

pH:

pH was not adjusted; see results tables

Dissolved oxygen:

test solutions were aerated during the incubation period to verify an oxygen content of >60% of the saturation value during the study; see results tables

Nominal and measured concentrations:

nominal (mg/L): 1000, 800, 400, 200, 100, and 0 (= control);
the single measured test item concentrations are not reported (the biological effects based on measured concentrations are reported; see below)

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, fill volume: glass, ca. 5 L, approx. 3 L
- Aeration: yes
- Renewal rate of test solution (frequency): daily
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): no vehicle used


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water


OTHER TEST CONDITIONS
- Photoperiod: light : dark cycle : 16h : 8 h


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2.0 (but not for the highest test concentration)

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

15 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: measured: 24 h old test medium (before semi-static renewal)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

98 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: measured: 24 h old test medium (before semi-static renewal)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

174 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: measured: 24 h old test medium (before semi-static renewal); LC100 directly taken from the concentration being measured

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

110 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

270 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

400 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: LC100 directly taken from the nominal concentration being tested

Results with reference substance (positive control):

No reference substance was used.

Reported statistics and error estimates:

The LC50 value was calculated using a validated computer program on the basis of EXCEL 5.0, the LC50 value was determined as well as the LD100 and the NOEC together with the 95% confidence limits.

Sublethal observations / clinical signs:

Mortality data in the time course of the test (7 fish per test concentration):

Conc. of test substance (mg/L)	Mortality (%) after
	24 h	48 h	72 h	96 h
Control(0)	0	0	0	0
1000	100	100	100	100
800	100	100	100	100
400	100	100	100	100
200	14	14	14	14
100	0	0	0	0

 

pH value, O₂ content and temperature during the time course of the test:

Conc. of test substance (mg/L)	Incub. Time (h)	pH value		O2 content (mg O2/L)		Temperature (deg C)
		t0	t24	t0	t24	t0	t24
Control (0)	0	8.07	-	8.4	-	19.5	-
	24	8.09	7.90	8.3	8.5	19.9	21.7
	48	8.19	8.61	8.5	8.4	20.0	22.0
	72	7.98	8.46	8.4	8.1	20.2	22.1
	96	-	8.48	-	8.1	-	23.0
1000	0	3.97	-	8.3	-	19.8	-
	24	-	3.90	-	8.2	-	20.8
800	0	4.17	-	8.3	-	19.8	-
	24	-	4.09	-	8.2	-	20.8
400	0	5.31	-	8.4	-	19.7	-
	24	-	7.35	-	7.6	-	22.6
200	0	6.51	-	8.3	-	19.7	-
	24	6.46	8.26	8.4	7.7	19.9	22.6
	48	6.63	8.36	8.4	7.9	20.0	22.0
	72	6.65	8.29	8.4	8.1	20.2	22.1
	96	-	8.46	-	8.2	-	23.0
100	0	7.07	-	8.4	-	19.6	-
	24	6.77	8.47	8.3	7.8	19.9	22.3
	48	7.08	8.45	8.5	7.9	20.0	22.0
	72	7.12	8.44	8.4	8.1	20.2	22.1
	96	-	8.50	-	8.2	-	23.0

t0 = values after fresh preparation of the test solutions;
temperatures < 21 deg C represent a deviation of the
protocol and the SOP (23 +/- 2 deg C are recommended) - this
deviation does not diminish the integrity of the study.
t24 - values after 24 h of incubation with the fish

Calculated values based on measured concentrations (after 96 h):
LC0 = 23 mg/L (statistically calculated value; geometric
mean of the measured concentrations between t0 and t96 h
were used)
LC50 = 88 mg/L (statistically calculated value; geometric
mean of the measured concentrations between t0 and t96 h
were used)
LC100 = 245 mg/L (directly taken from the concentration
being measured)

Calculated values based on nominal concentrations (after 96 h):
LC0 = 110 mg/L (statistically calculated value)
LC50 = 270 mg/L (statistically calculated value)
LC100 = 400 mg/L (directly taken from the concentration
being tested)

Results of the TOC measurements:
Amount of test substance: 103 mg/L
Measured TOC at t0 = 35.3 mg/L
Measured TOC after 96 h = 36.0 mg/L
TOC analyses indicated that the organic matter of the test
substance remained constant in the aqueous phase. 

Determination of 3-MPA in test medium:

Sampling Time (h)*	Concentration of test substance (mg/L)
	Nominal	Measured
0	400	345
0	200	96
0	100	20
0	0	nd
t24(96h)	400**	174
t24(96h)	200	86
t24(96h)	100	13

nd = no peaks detected
* = The samples were drawn from the water tanks into 2-L
carboys made of brown glass and deep frozen at approx. - 18
deg C until analyses.
** = Incubated without fish, because by 24 h all fish had
died.   

All validity criteria for the test guideline were met.

Validity criteria fulfilled:

yes

Conclusions:

LC50 (calculated value): 270 mg/L

Executive summary:

3-Mercaptopropionic acid was tested for acute toxicity towards fish according to OECD-Test Guideline 203. In order to investigate the influence of the test substance towards fish the animals were exposed to different concentrations of the test substance semistatically. Daily the test solutions were prepared freshly and exarnined for dead animals. Under the conditions used for the test, toxic effects of the test substance towards fish were observed at concentrations beginning at 200 mg/L prepared in drinking water. The following LC-values were obtained after 96h:

o LCO (calculated value): 110 mg/L

o LC50 (calculated value): 270 mg/L

o LC100 (observed): 400 mg/L (directly taken from the nominal concentration being tested)

Within TOC-analyses performed with a test solution freshly prepared in tap water, and after 96h (this is the time schedule for a fish toxicity test), it could be shown, that the organic matter of the test substance remained constant in the aqueous phase. Upon chemical analyses of test solutions performed with freshly prepared test solutions and after 48h of incubation in a daphnia toxicity test (Study-No. IF-99/21946-00) it could be demonstrated, that the test substance was partially oxidized, and thus there are two components, the original test substance and the oxidation product, present in the test solution. It cannot be distinguished between a toxic effect of the original test substance and the oxidation product because they are both present in the test solution representing also a dynamic process. For this reason, the results of this test are based on the nominal concentrations tested. As an alternative calculation using the measured concentration of the original test substance 3-mercaptopropionic acid after 24h of incubation, respectively (semi-static test), the following LC-values were obtained after 96h:

LC0 (calculated value): 15 mg/L

o LC50 (calculated value): 98 mg/L

o LC100 (observed): 174 mg/L (directly taken from the concentration being measured)

These values don't represent the real environmental conditions because the test substance is rapidly oxidized by the oxygen content in the aqueous phase.

Description of key information

LC50 (96 h) = 270 mg/L (Brachydanio rerio)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Remarks:

(nominal)

Effect concentration:

270 mg/L

Additional information

3-Mercaptopropionic acid was tested for acute toxicity towards fish according to OECD-Test Guideline 203. In order to investigate the influence of the test substance towards fish the animals were exposed to different concentrations of the test substance semistatically. Daily the test solutions were prepared freshly and exarnined for dead animals. Under the conditions used for the test, toxic effects of the test substance towards fish were observed at concentrations beginning at 200 mg/L prepared in drinking water. The following LC-values were obtained after 96h:

o LCO (calculated value): 110 mg/L

o LC50 (calculated value): 270 mg/L

o LC100 (observed): 400 mg/L (directly taken from the nominal concentration being tested)

Within TOC-analyses performed with a test solution freshly prepared in tap water, and after 96h (this is the time schedule for a fish toxicity test), it could be shown, that the organic matter of the test substance remained constant in the aqueous phase. Upon chemical analyses of test solutions performed with freshly prepared test solutions and after 48h of incubation in a daphnia toxicity test (Study-No. IF-99/21946-00) it could be demonstrated, that the test substance was partially oxidized, and thus there are two components, the original test substance and the oxidation product, present in the test solution. It cannot be distinguished between a toxic effect of the original test substance and the oxidation product because they are both present in the test solution representing also a dynamic process. For this reason, the results of this test are based on the nominal concentrations tested. As an alternative calculation using the measured concentration of the original test substance 3-mercaptopropionic acid after 24h of incubation, respectively (semi-static test), the following LC-values were obtained after 96h:

LC0 (calculated value): 15 mg/L

o LC50 (calculated value): 98 mg/L

o LC100 (observed): 174 mg/L (directly taken from the concentration being measured)

These values don't represent the real environmental conditions because the test substance is rapidly oxidized by the oxygen content in the aqueous phase.