Butyl 3-mercaptopropionate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

This selected scenario covers the category approach for which the read-across hypothesis is based on structural similarity. For the REACH information requirement under consideration, the property investigated in studies conducted with different source substances is used to predict the property that would be observed in a study with the target substance if it were to be conducted. Similar properties are observed for the different source substances; this may include absence of effects for every member of the category.
There are expected to be differences in strength of the effects forming a regular pattern. The prediction will be based on a worst-case approach or trend analysis as appropriate for the respective endpoint. The read-across is a category approach based on the hypothesis that the substances in this category share structural similarities with common functional groups. This approach serves to use existing data on aquatic toxicity for substances in this category.
The hypothesis corresponds to Scenario 4 of the RAAF. The substances MMP, BuMP, EHMP, iOMP, iC13MP, ODMP, GDMP, TMPMP, PETMP, and Di-PETMP are esters of a common acid, 3-mercaptopropionic acid (3-MPA). The key functionality and main driver for ecotoxicity of the substances within this category is the presence of free SH-groups. It can be predicted with high confidence that the substances within this category will lead to the same type of effects.
For details, please refer to the category document attached to Iuclid section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.65 mg/L

Nominal / measured:

estimated

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Conclusions:

The predicted 96-h LC50 of BuMP for freshwater fish is 0.65 mg/L

Description of key information

The 96-h LC50 of BuMP for freshwater fish is estimated by read across to be 0.65 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

0.65 mg/L

Additional information

No experimental data is available for BuMP. However, short-term toxicity studies in fish were conducted with MPA, MMP, EHMP, iOMP, GDMP, TMPMP, PETMP and di-PETMP. A justification for read-across is attached to Iuclid section 13.

 

3-MPA

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 examined 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 nominal LC-values were obtained after 96 h:

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)

 

MMP

The acute toxicity of the test item 3-mercaptopropanoic acid methyl ester (MMP) to rainbow trout (Oncorhynchus mykiss) was investigated in a 96-hour flow-through test according OECD TG 203, (1992). In this flow-through test, the concentrations of the test item in the test media were maintained by dosing concentrated test item solutions (=application solutions) into test water by using automatic dispenser units. The solvent N,N-Dimethylformamide (DMF) was used as vehicle for the dosage of the test item with limited water solubility. This solvent was chosen for its solubility properties and its relative non-toxicity to fish.

The 96 h LC50 based on nominal concentrations was determined to be 1.7 mg/L.

 

EHMP

The test substance was tested under semi-static conditions for toxicity towards fish according to OECD-Test Guideline 203. For this purpose the animals were exposed to different concentrations of the test substance. Under the conditions used for this study the LC50-value after 96h was calculated to be 1.03 mg of test substance per litre.

 

iOMP

A study was performed to assess the acute toxicity of the test material to rainbow trout (Oncorhynchus mykiss) in accordance with OECD TG 203.

Following a preliminary range-finding test, fish were exposed, in groups of seven, to an aqueous solution of the test material over a range of nominal test concentrations of 0.068, 0.12, 0.22, 0.38 and 0.68 mg/l for a period of 96 hours at a temperature of approximately 14°C under semi-static test conditions. The test material solutions were prepared by stirring an excess (50 mg/l) of test material in dechlorinated tap water using a propeller stirrer at approximately 1500 rpm at a temperature of approximately 14°C for 24 hours. After the stirring period any undissolved test material was removed by filtration (0.2 um Sartorius Sartopore filter, first approximate 1 litre discarded in order to precondition the filter) to produce a saturated solution of the test material. This saturated solution was then further diluted as necessary, to provide the remaining test groups.

The number of mortalities and any sub-lethal effects of exposure in each test and control vessel were determined 3 and 6 hours after the start of exposure and then daily throughout the test until termination after 96 hours.

The 96 h LC50 based on nominal concentration was determined to be 0.16 mg/L.

 

GDMP

The short-term toxicity of GDMP to zebra fish (Brachydanio rerio) was assessed in a study according to OECD TG 203. The fish were exposed to five test concentrations of 0.26, 0.36, 0.51, 0.71 and 1.0 mg/L (nominal) of the test item under semi-static conditions (renewal every 24 h).

The cumulative mortality was 0% at the end of the test. The cumulative mortality in teh 0.26, 0.36, 0.51, 0.71 and 1.0 mg/L groups was 4.8, 38, 90, 100 and 100%, respectively. No abnormal sublethal responses were observed in the control. Behavioural abnormalities including spasmodic swimming, reduced activity, overturn and loss of equilibrium were observed at all concentrations levels.

Under the conditions of this test, the 96 h LC50 to Danio rerio was 0.0594 mg/L (mean, meas.). The 96 h LC50 based on nominal concentrations was determined to be 0.42 mg/L.

 

TMPMP

The purpose of this study was to evaluate the acute toxicity of the test item TMPMP to fish according to OECD TG 203. For this purpose, juvenile Rainbow Trout were exposed in a semi-static test to various concentrations under defined conditions for 96 hours. The recorded effects were the mortality and sublethal effects on the fish.

This study encompassed 7 treatment groups (6 dose rates of the test item and a control) each containing 7 individuals. The acute toxicity to unfed juvenile Rainbow Trout was determined in an aerated, semi-static, 96-hour test. The test fish were observed at test start and after approximately 2, 24, 48, 72 and 96 hours test duration for sublethal effects and mortality. Dead fish were removed at least once daily and discarded.

In the control and at the concentrations up to 0.0728 mg test item/L, all fish survived until the end of the experiment and no signs of intoxication occurred. At 0.335 to 9.92 mg test item/L, all fish died until the end of the test.

96-hour LC50: 0.156 mg test item/L (mean meas.)

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

Therefore, the 96 h LC50 is given as nominal concentration: 0.624 mg/L, nominal (WAF)

 

PETMP

A study according to OECD TG 203 was performed to assess the acute toxicity of the test material to rainbow trout (Oncorhynchus mykiss).

Following a preliminary range-finding test, fish were exposed, in groups of seven, to an aqueous solution of the test material over a range of concentrations of 0.10, 0.18, 0.32, 0.56 and 1.0 mg/l for a period of 96 hours at a temperature of approximately 14°C under semi-static test conditions. The number of mortalities and any sub-lethal effects of exposure in each test and control vesse! were determined 3 and 6 hours after the start of exposure and then daily throughout the test until termination after 96 hours.
The 96-Hour LC50 based on nominal test concentrations was 0.42 mg/l with 95% confidence limits of 0.32 - 0.56 mg/l.

Analysis of the nominal 0.10 and 0.18 mg/l test concentrations showed measured concentrations in the untreated and centrifuged samples to be less than the limit of quantitation (LOQ) of the analytical method throughout the test.
Analysis of the freshly prepared 0.32, 0.56 and 1.0 mg/l test concentrations at 0, 24, 48 and 72 hours showed measured test concentrations to range from less than the LOQ to 0.580 mg/l for the untreated samples and less than the LOQ to 0.507 mg/l for the centrifuged samples. A decline in measured concentration was observed in the old media at 24, 48, 72 and 96 hours with measured concentrations in the range of less than the LOQ to 0.465 mg/l for the untreated samples and less than the LOQ to 0.308 mg/l for the centrifuged samples. The decline in measured concentrations observed over the test period was in line with the preliminary stability analyses conducted.

However, effect levels based on mean measured concentrations don't represent the real environmental conditions because the test substance is rapidly oxidized by the oxygen content in the aqueous phase. Therefore, nominal values are used for hazard assessment.

 

Di-PETMP

The acute toxicity of the test item Di-PETMP to rare minnow (Gobiocypris rarus) was determined by a semi-static test according to OECD TG 203 . Based on the result of the preliminary test, a
limit test was performed with a nominal concentration of 10mg/L of the test item (Solubility of Di-PETMP in water: </= 3.7 mg/L). A blank control was carried out at the same time. The test duration was 96h and the frequency of renewal in the limit test was every 24h.
Seven test organisms were used for test concentration and control, respectively. No replicate was used. During the test, the mortality and abnormal behavior of the test
organism were recorded at 3h, 24h, 48h, 72h, 96h and the 96h-LCs, was determined.
Water quality parameters of test solution including temperature, dissolved oxygen and pH value were measured during the test duration. The test concentrations of test solutions were analyzed by LC-MS/MS.

There were no mortalities or abnormalities observed in fish of the control group and the treatment group during the test.
Concentration analysis result of samples showed that, for newly prepared saturated test solution with nominal concentration of 10mg/L, the averaged analyzed concentration were 92.81 µg/L, 94.85 µg/L, 104.36 mg/L, 129.44 µg/L at time point of 0h, 24h, 48h and 72h (new solution ), respectively; After 24 hour of exposure, the analyzed concentrations at time point of 24h, 48h, 72h and 96h (old solution ) were all less than the limit of quantification (LOQ,50m g/L). During the test, the analyzed concentrations of Di-PETMP were not maintained in the initial concentration of 80%-120% in the exposure system because of the inevitable oxidation effect.

However, effect levels based on mean measured concentrations don't represent the real environmental conditions because the test substance is rapidly oxidized by the oxygen content in the aqueous phase. Therefore, nominal values are used for hazard assessment.

Based on a trend analysis, the 96 h LC50 for BuMP is estiumated to be 0.65 mg/L.