3(or 4)-methylbenzene-1,2-diamine

Biodegradation in soil

Administrative data

Endpoint:

biodegradation in soil

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented and scientifically sound study.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Measuring the amount of 14CO2 produced form the aerobic biodegradation of 2,4-TDA in soils.

GLP compliance:

no

Test type:

laboratory

Test material

Test material information

Constituent 1

Reference substance name:

4-methyl-m-phenylenediamine

EC Number:

202-453-1

EC Name:

4-methyl-m-phenylenediamine

Cas Number:

95-80-7

Molecular formula:

C7H10N2

IUPAC Name:

4-methylbenzene-1,3-diamine

Details on test material:

2,4-TDA recrystallised by M. Kimak of Air Products and Chemicals.
Purity 99.9%

Uniformly 14C ring labeled 2,4-diaminotoluene dihydrochloride (custom synthesised by Dupont New England Nuclear (Boston, MA) with a specific activity of 1.9mCi/mmole and a radiochemical purity of 99% as deteremined by TLC)

Radiolabelling:

yes

Study design

Oxygen conditions:

aerobic

Soil classification:

other: Washington Silt Loam

Soil properties

Soil no.:

#1

Soil type:

silt loam

% Clay:

19

% Silt:

60

% Sand:

21

pH:

5

CEC:

13.6 meq/100 g soil d.w.

Details on soil characteristics:

Surface soil obtained from a farm field in Pennsylvania.

Soil type: Washington silt loam
21% sand
60% silt
19% clay
Cation exchange capacity: 13.6 meq/100g
Ca: 7.59 meq/100g
Mg: 1.26 meq/100g
K: 0.68 meq/100g
pH: 5
Combustible content: 5.7 %
Field capacity at 1/3 Bar: 23.05%
TOC: 1.3%

Duration of test (contact time)

Soil No.:

#1

Duration:

365 d

Parameter followed for biodegradation estimation:

CO2 evolution

radiochem. meas.

Experimental conditions

Soil No.:

#1

Temp.:

25°C

Details on experimental conditions:

Test substance added to the soil at 5 microg/g and at approx. 4-5*10(6) disintegrations per minute of 14C per flask (1.8 - 2.3 microCi per flask)

To 50g of air-dried, 2 mm sieved silt loam was added water to provide 75% of 1/3 bar moisture tension in the soil. The test substance was added to the soil at the 5 microg/g level and at approximately 4-5*10(6) disintegrations per minute of 14C per flask (1.8 - 2.3 microCi per flask). The flasks were incubated in darkness in a microbial incubator at 25°C for up to one year. Sodium hydroxide solution was used to trap the carbon dioxide formed and liquid scintillation counting was performed using a Beckman Model LS 3801 instrument.

Results and discussion

% Degradation

Soil No.:

#1

% Degr.:

ca. 0

Parameter:

radiochem. meas.

Sampling time:

73 d

Transformation products:

not specified

Evaporation of parent compound:

not specified

Volatile metabolites:

not specified

Residues:

not specified

Details on results:

% Biodegradation

Time (days), % biodegradation

3d, 1.9%
7d, 4.0%
14d, 7.9%
28d, 10.8%
56d, 14.8%
210d, 36.8%
365d, 34.2%

Any other information on results incl. tables

The 14C labeled 2,4-TDA started to biodegrade immediately with the aerobic soil. The biodegradation slowed later perhaps due to the increasing binding of the 2,4-TDA with humic acids in the soil.

This study also demonstrated the strong binding of 2,4-TDA to soil.

2,4-TDA apparently undergoes aerobic biodegradation in soil.

NB. Apparently some of the 14CO2 was lost during the latter period of incubation, so that the % biodegradation figures given above for 210d and 365d were calculated from the loss of C-14 from the soil plus the water extracts of the soil. Therefore, the last two results (210d and 365d) should be considered as not relevant.