Metam-sodium

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Data is from peer reviewed journal

Justification for type of information:

Data is from peer reviewed journal

Qualifier:

according to guideline

Guideline:

other: as mention below

Principles of method if other than guideline:

The aim of this study was to ascertain whether Metam-sodium was developmentally toxic to embryos zebrafish during gastrulation and early segmentation periods and also detect the effects on the mortality, hatching pattern and notochord defect.

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material : Metam-sodium
- Molecular formula : C2H4NNaS2
- Molecular weight : 129.1826 g/mol
- Smiles notation : C(=S)(NC)[S-].[Na+]
- InChl : 1S/C2H5NS2.Na/c1-3-2(4)5;/h1H3,(H2,3,4,5);/q;+1/p-1
- Substance type: Organic
- Physical state: Solid
- Other: Chemical purchased from Chem Service, Inc. (West Chester, PA).

Analytical monitoring:

not specified

Vehicle:

no

Details on test solutions:

Details on test solutions
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A sodium metam stock solution of 0.29 M was prepared (37.46 mg/l) in water at pH 9 and was stored at 4° C until further dilution.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

Details on test organisms
TEST ORGANISM
- Common name: Danio rerio Zebrafish
- Strain: AB strain zebrafish
(Danio rerio)
- Age at study initiation (mean and range, SD): Embryo(s)
- Method of breeding: Embryos were collected from group spawns. Adult AB strain zebrafish (Danio rerio) were raised and kept at standard laboratory conditions of 28° C on a 14 h light/10 h dark photoperiod. Fish water consisted of reverse osmosis water supplemented with a commercially available salt solution (0.6% Instant Ocean).

Test type:

static

Water media type:

saltwater

Total exposure duration:

48 h

Post exposure observation period:

After 44 hrs and 48 hrs

Test temperature:

28 ° C

pH:

7.4

Details on test conditions:

Details on test conditions
TEST SYSTEM
- Test vessel: 20 ml glass vials
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 20 ml of glass vials sealed with Teflon-lined lids to prevent loss by volatilization.
- No. of organisms per vessel: 20 embryos
- No. of vessels per concentration (replicates): 3

- Photoperiod: 14 h light/10 h dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable: Hatching pattern and mortality and defect in the notochord formation (deformation).

Reference substance (positive control):

not specified

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

0.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Other details not known

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.038 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Notochord defect

Remarks on result:

other: Other details not known

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.036 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Reduction in hatching

Remarks on result:

other: Other details not known

Details on results:

- Behavioural abnormalities: After the exposure of chemical for 48 hrs, effect on the Reduction in hatching, Notochord defect and mortality were observed. The animals appear to have delayed and weakened spontaneous motion

Reported statistics and error estimates:

For LC50 and EC50 statistical analysis was performed using a p-value of 0.05 for significance. This was tabulated with SigmaStat Version 2.03 for Windows software.

Validity criteria fulfilled:

not specified

Conclusions:

Based on the effect on the mortality the LC50 was determine at 0.25 mg/l. But defect in Notochord and hatching pattern of embryos zebrafish, the EC50 was determine at 0.038 mg/l and 0.036 mg/l by the chemical exposure Metam-sodium for 48 hrs.

Executive summary:

The aim of this study was to ascertain whetherMetam-sodiumwas developmentally toxic to embryos zebrafish during gastrulation and early segmentation periods and also detect the effects on the mortality, hatching pattern and notochord defect.

 

A sodium metam stock solution of 0.29 M (37.46 mg/l) was prepared in water at pH 9 was stored at 4° C until further dilution. Adult AB strain zebrafish (Danio rerio) were raised and kept at standard laboratory conditions of 28° C on a 14 h light/10 h dark photoperiod. Fish water consisted of reverse osmosis water supplemented with a commercially available salt solution (0.6% Instant Ocean). 20 embryos were added in 20 ml of glass vials sealed with Teflon-lined lids to prevent loss by volatilization. After the exposure period, effect were observed and test performed in three replicates.

 

Based on the effect on themortality the LC50 was determine at 0.25 mg/l. But defect in Notochord and hatching pattern of embryos zebrafish, the EC50 was determine at 0.038 mg/l and 0.036 mg/l by the chemical exposureMetam-sodium for 48 hrs. As the effect were observed at the very low concentration thus chemical was consider as toxic and can be consider to be classified as aquatic acute category 1 as well as chronic 1 as per the CLP classification criteria.

Description of key information

The aim of this study was to ascertain whetherMetam-sodium was developmentally toxic to embryos zebrafish during gastrulation and early segmentation periods and also detect the effects on the mortality, hatching pattern and notochord defect. A sodium metam stock solution of 0.29 M (37.46 mg/l) was prepared in water at pH 9 was stored at 4° C until further dilution. Adult AB strain zebrafish (Danio rerio) were raised and kept at standard laboratory conditions of 28° C on a 14 h light/10 h dark photoperiod. Fish water consisted of reverse osmosis water supplemented with a commercially available salt solution (0.6% Instant Ocean). 20 embryos were added in 20 ml of glass vials sealed with Teflon-lined lids to prevent loss by volatilization. After the exposure period, effect were observed and test performed in three replicates. Based on the effect on the mortality the LC50 was determine at 0.25 mg/l. But defect in Notochord and hatching pattern of embryos zebrafish, the EC50 was determine at 0.038 mg/l and 0.036 mg/l by the chemical exposureMetam-sodium for 48 hrs. As the effect were observed at the very low concentration thus chemical was consider as toxic and can be consider to be classified as aquatic acute category 1 as well as chronic 1 as per the CLP classification criteria.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.25 mg/L

Additional information

Based on the various experimental data for the target chemical Metam-sodium (137-42-8) study have been reviewed to determine toxic nature of on the growth and other activity of fish. The studies are as mentioned below: 

 

In the first key experimental study for the Metam-sodium (137-42-8) from peer reviewed journal (toxicological sciences 2004), study was to ascertain whether Metam-sodium was developmentally toxic to embryos zebrafish during gastrulation and early segmentation periods and also detect the effects on the mortality, hatching pattern and notochord defect. A sodium metam stock solution of 0.29 M (37.46 mg/l) was prepared in water at pH 9 was stored at 4° C until further dilution. Adult AB strain zebrafish (Danio rerio) were raised and kept at standard laboratory conditions of 28° C on a 14 h light/10 h dark photoperiod. Fish water consisted of reverse osmosis water supplemented with a commercially available salt solution (0.6% Instant Ocean). 20 embryos were added in 20 ml of glass vials sealed with Teflon-lined lids to prevent loss by volatilization. After the exposure period, effect were observed and test performed in three replicates. Based on the effect on the mortality the LC50 was determine at 0.25 mg/l. But defect in Notochord and hatching pattern of embryos zebrafish, the EC50 was determine at 0.038 mg/l and 0.036 mg/l by the chemical exposure Metam-sodium for 48 hrs. As the effect were observed at the very low concentration thus chemical was consider as toxic and can be consider to be classified as aquatic acute category 1 as well as chronic 1 as per the CLP classification criteria.

 

 

Similarly in the second experimental study from the same source for Metam-sodium (137-42-8), toxicity was measured. Study was to ascertain whether Metam-sodium was developmentally toxic to embryos zebrafish and show any effect on the hatching pattern and mortality. A sodium metam stock solution of 0.29 M (37.46 mg/l) was prepared in water at pH 9 was stored at 4° C until further dilution. Adult AB strain zebrafish (Danio rerio) were raised and kept at standard laboratory conditions of 28° C on a 14 h light /10 h dark photoperiod. Fish water consisted of reverse osmosis water supplemented with a commercially available salt solution (0.6% Instant Ocean). 20 embryos were added in 20 ml of glass vials sealed with Teflon-lined lids to prevent loss by volatilization. After the exposure period, effect were observed. Based on the effect on the hatching pattern and mortality of embryos zebrafish, the LOEL (Lowest-observable-effect-level) was determine at 0.02 mg/l by the chemical exposure Metam-sodium. As the effect were observed at the very low concentration thus chemical was consider as toxic and can be consider to be classified as aquatic acute category 1 as well as chronic 1 as per the CLP classification criteria.

 

Above studies was supported by another handbooks and authoritative database for the Metam-sodium (137-42-8) from (HSDB, IUCLID dataset, Pesticides properties and AGROTOX, 2018). Aim of this study was to determine the nature of chemical Metam-sodium on the growth of aquatic fishes Lepomis macrochirus. Study was conducted under the static system for 96 hrs of exposure. After exposure abnormal swimming behaviour, apathy was observed. Based on the mortality of test organisms by the chemical Metam-sodium for 96 hrs, the LC50 was observed at 0.175 mg/l and NOEC was determine at 0.215 mg/l. Thus based on the LC50, chemical was consider as toxic and classified as aquatic acute 1 as well as chronic 1 category as per the CLP classification criteria.

 

Similarly in the fourth supporting study for the chemical the Metam-sodium (137-42-8) from authoritative database 2018 supports the classification of chemical. Aim of this study was to determine the nature of chemical Metam-sodium on the growth of aquatic fishes. Study was conducted under the static system for 96 hrs of exposure. Based on the mortality of test organisms by the chemical Metam-sodium for 96 hrs, the LC50 was observed at 35 mg/l. Thus based on the LC50, chemical was consider as toxic and classified as aquatic chronic 3 category as per the CLP classification criteria.

 

As the above studies conducted on different fishes and condition and exposure time was also different, thus toxicity was observed in the range of 0.175 to 35 mg/l. But as the experimental full studies conducted according to the standard conditions thus on that basis, chemical was consider as toxic and can be consider to be classified as aquatic acute category 1 as well as chronic 1 as per the CLP classification criteria.