Metam-sodium

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Justification for type of information:

Data is from secondary source

Qualifier:

according to guideline

Guideline:

other: Zahn-Wellens method

Principles of method if other than guideline:

Biodegradation study was conducted for 20 days for evaluating the percentage biodegradability of test substance Metam-sodium. The study was performed according to Zahn-Wellens method.

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material : Metam-sodium
- Common name: Sodium methyldithiocarbamate
- 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

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Duration of test (contact time):

20 d

Initial conc.:

200 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

DOC removal

Remarks:

or COD

Parameter:

% degradation (DOC removal)

Remarks:

or COD

Value:

1

Sampling time:

1 d

Remarks on result:

other: Other details not known

Parameter:

% degradation (DOC removal)

Remarks:

or COD

Value:

8

Sampling time:

6 d

Remarks on result:

other: Other details not known

Parameter:

% degradation (DOC removal)

Remarks:

or COD

Value:

84

Sampling time:

19 d

Remarks on result:

other: Other details not known

Parameter:

% degradation (DOC removal)

Remarks:

or COD

Value:

77

Sampling time:

20 d

Remarks on result:

other: Other details not known

Details on results:

Test substance undergoes 1, 8, 84 and 77% degradation by DOC removal or COD parameter in 20 days.

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

The percentage degradation of test substance Metam-sodium was determined to be 1, 8, 84 and 77% by DOC removal or COD parameter in 20 days. Thus, based on percentage degradation, Metam-sodium is considered to be readily biodegradable in water.

Executive summary:

Biodegradation study was conducted for 20 days for evaluating the percentage biodegradability of test substance Metam-sodium (CAS no. 132-87-6). The study was performed according to Zahn-Wellens method under aerobic conditions. Activated sludge (not adapted) was used as a test inoculum for the study. Initial test substance conc. used in the study was 200 mg/l based on TOC removal, respectively.The initial TOC concentration after 3 hours was -21%.The percentage degradation of test substance Metam-sodium was determined to be 1, 8, 84 and 77% by DOC removal or COD parameter parameter in 20 days. Thus, based on percentage degradation, Metam-sodium is considered to be readily biodegradable in water.

Description of key information

Biodegradation study was conducted for 20 days for evaluating the percentage biodegradability of test substance Metam-sodium (CAS no. 132-87-6) (IUCLID dataset, 2000). The study was performed according toZahn-Wellens method under aerobic conditions. Activated sludge (not adapted) was used as a test inoculum for the study. Initial test substance conc. used in the study was 200 mg/l based on TOC removal, respectively.The initial TOC concentration after 3 hours was -21%.The percentage degradation of test substance Metam-sodium was determined to be 1, 8, 84 and 77% by DOC removal or COD parameter parameter in 20 days. Thus, based on percentage degradation, Metam-sodiumis considered to be readily biodegradable in water.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Experimental study for the target compound Metam-sodium (CAS No. 137-42-8) and various supporting studies for its structurally and functionally similar read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study from secondary source (IUCLID dataset, 2000), biodegradation experiment was conducted for 20 days for evaluating the percentage biodegradability of test substance Metam-sodium (CAS no. 132-87-6). The study was performed according to Zahn-Wellens method under aerobic conditions. Activated sludge (not adapted) was used as a test inoculum for the study. Initial test substance conc. used in the study was 200 mg/l based on TOC removal, respectively.The initial TOC concentration after 3 hours was -21%.The percentage degradation of test substance Metam-sodium was determined to be 1, 8, 84 and 77% by DOC removal or COD parameter parameter in 20 days. Thus, based on percentage degradation, Metam-sodium is considered to be readily biodegradable in water.

 

In a supporting study from authoritative database (HSDB and PubChem, 2017) for the read across chemical 1,2-Ethanediylbiscarbamodithioic acid disodium salt (CAS no. 142-59-6), biodegradation experiment was conducted for evaluating the percentage biodegradability of read across substance 1,2-Ethanediylbiscarbamodithioic acid disodium salt (CAS no. 142-59-6). The study was performedunder aerobic conditions using activated sludge as a test inoculum. Test chemical conc. used for the study were 9.8, 10.2, 9.6 and 9.8 mg/l, respectively. Test chemical was fed over four consecutive days to a bench scale activated sludge unit at a conc. of 3 liters synthetic sewage per day. The percentage degradation of test substance1,2-Ethanediylbiscarbamodithioic acid disodium salt was determined to be 96% after a 1 day period. Thus, based on percentage degradation, 1,2-Ethanediylbiscarbamodithioic acid disodium salt is considered to be readily biodegradable in nature.

 

For the read across chemical ammonium N-methyldithiocarbamate (CAS no. 39680-90-5), biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of read across substance ammonium N-methyldithiocarbamate (CAS no. 39680-90-5). Activated sludge was used as a test inoculums for the study. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of test substance ammonium N-methyldithiocarbamate was determined to be 2-13, 41 and 73-87% by BOD, O2 consumption, TOC removal, Test material analysis and HPLC parameter in 28 days. Thus, based on percentage degradation (73-87%), ammonium N-methyldithiocarbamate is considered to be readily biodegradable in nature.

 

On the basis of above results for target chemical Metam-sodium (from secondary source IUCLID dataset, 2000) and for its read across substance (from authoritative database HSDB and PubChem, 2017), it can be concluded that the test substance Metam-sodium can be expected to be readily biodegradable in nature.