1,2,4-trichlorobenzene

Biodegradation in soil

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in soil, other

Type of information:

other: EU Risk Assessment

Adequacy of study:

other information

Reliability:

other: EU Risk Assessment

Rationale for reliability incl. deficiencies:

other: No reliability is given as this is a summary entry for the EU RAR.

GLP compliance:

not specified

EU Risk Assessment (2003):

 

1,2,4-TCB can be degraded in soil, although very slowly (Marinucci and Bartha, 1979; Wilson et al., 1981). The aerobic mineralisation was studied using 14C-labelled 1,2,4-TCB and a mineralisation rate measured as CO2 development/day (Marinucci and Bartha, 1979).

 

In a study using a sandy loam (pH 6.5) added 1,2,4-TCB at a concentration of 50µg/g soil, the degradation in soil was observed to be slow. The incubation was performed at 20°C for 3 to 12 weeks. 1,2,4-TCB was subject to mineralisation as soil poisoned with 1% HgCl2 or NaN3 reduced the CO2 evolution consistently. Anaerobic conditions either continuously or alternated weekly with aerobic incubation periods markedly depressed the mineralisation. The mineralisation rate was 0.181µg/day/20 g soil equivalent to 9µg/d/kg. The turnover rate (% 1,2,4-TCB converted to CO2/day = 0.075%) was maximal at 10µg/g soil and sharply declined at higher concentrations (Marinucci and Bartha, 1979). Haider et al. (1974) used 10µg/g (in 100 g soil) and observed a mineralisation rate about twice as high.

Executive summary:

EU Risk Assessmen, 2003:

1,2,4-TCB can be degraded in soil, although very slowly (Marinucci and Bartha, 1979; Wilson et al., 1981). The aerobic mineralisation was studied using 14C-labelled 1,2,4-TCB and a mineralisation rate measured as CO2 development/day (Marinucci and Bartha, 1979).

 

In a study using a sandy loam (pH 6.5) added 1,2,4-TCB at a concentration of 50µg/g soil, the degradation in soil was observed to be slow. The incubation was performed at 20°C for 3 to 12 weeks. 1,2,4-TCB was subject to mineralisation as soil poisoned with 1% HgCl2 or NaN3 reduced the CO2 evolution consistently. Anaerobic conditions either continuously or alternated weekly with aerobic incubation periods markedly depressed the mineralisation. The mineralisation rate was 0.181µg/day/20 g soil equivalent to 9µg/d/kg. The turnover rate (% 1,2,4-TCB converted to CO2/day = 0.075%) was maximal at 10µg/g soil and sharply declined at higher concentrations (Marinucci and Bartha, 1979). Haider et al. (1974) used 10µg/g (in 100 g soil) and observed a mineralisation rate about twice as high.

Reference 2

Endpoint:

biodegradation in soil, other

Type of information:

other: BUA report

Adequacy of study:

other information

Reliability:

other: BUA report

Rationale for reliability incl. deficiencies:

other: No reliability is given as this is a summary entry for the BUA report.

Principles of method if other than guideline:

BUA report

GLP compliance:

not specified

BUA report (1987):

 

In a degradation study in soil 1,2,4-trichlorobenzene was converted to 2,4,5- and 2,4,6-chlorophenol (Ballschmiter et al., 1977). Other studies support these findings. Marinucci and Bartha (1979) showed a degradation of 9 µg/kg/day. Adapted microorganisms are able to degrade 1,2,4-trichlorobenzene with high efficiency (Haberer and Normann, 1987).

Executive summary:

BUA report (1987):

In a degradation study in soil 1,2,4-trichlorobenzene was converted to 2,4,5- and 2,4,6-chlorophenol (Ballschmiter et al., 1977). Other studies support these findings. Marinucci and Bartha (1979) showed a degradation of 9 µg/kg/day. Adapted microorganisms are able to degrade 1,2,4-trichlorobenzene with high efficiency (Haberer and Normann, 1987).

Reference 3

Endpoint:

biodegradation in soil, other

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Original reference is not available.

GLP compliance:

not specified

Type:

(pseudo-)first order (= half-life)

Executive summary:

Wang, 1994:

The half-life of 1,2,4-trichlorobenzene in a sewage sludge-amended soil in microcosm experiments is:

	half-life (d)	* R	period (d)	loss (%)
first step	22.5	0.981	0-75	83.2
second step	49500	1.0	75-259	2.26
general	23.3	0.955		85.5

The half-life of 1,2,4-trichlorobenzene in a standard spiked soil in microcosm experiments is:

	half-life (d)	* R	period (d)	loss (%)
first step	12.5	0.972	0-75	64.5
second step	194	0.942	75-259	19.8
general	19.4	0.867		84.3

* R = regression coefficients

Reference 4

Endpoint:

biodegradation in soil, other

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Original reference is not available.

GLP compliance:

not specified

Type:

(pseudo-)first order (= half-life)

Executive summary:

Mackay, 1992:

The suggested half-life in soil is:
mean half-life (hours): 5500 ( ca. 8 months)
range (hours): 3000 - 10000

Reference 5

Endpoint:

biodegradation in soil, other

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Original reference is not available.

GLP compliance:

not specified

Type:

(pseudo-)first order (= half-life)

Executive summary:

Howard, 1991:

Half-lives in soil:
high: 4320 h (6 m)
low :  672 h ( 4 w)

Scientific judgement based upon unacclimated aerobic soil grab data (low t1/2: Haider, K. et al. (1981), high t1/2: Marinucci, A.C. and Bartha, R. (1979)

Reference 6

Endpoint:

biodegradation in soil, other

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Original reference is not available.

GLP compliance:

not specified

Type:

(pseudo-)first order (= half-life)

Executive summary:

Howard, 1989:

1,2,4-Trichlorobenzene will be expected to adsorb to the organic matter in soil. It will not hydrolyze but it may biodegrade, slowly in the soil.

Reference 7

Endpoint:

biodegradation in soil, other

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Principles of method if other than guideline:

- 14C-labeled 1,2,4-trichlorobenzene was added to a soil-water-suspension
- after 5 days the test was finished and samples were taken by different chemical treatments (e.g. volatile organic compounds and CO2 in the headspace, determination of test substance and 14CO2 in aqueous phase)

GLP compliance:

not specified

Radiolabelling:

yes

Soil no.:

#1

Soil type:

other: loamy neutral soil

Soil No.:

#1

Duration:

5 d

Transformation products:

not measured

Evaporation of parent compound:

no

Volatile metabolites:

no

Residues:

no

degradation to^14CO2 [%]	volatile organic compounds [%]	activity in water [%]	extractable activity from soil (extraction by methanol) [%]	not extractable activity (combustion of soil) [%]	balance [%]
5.7	0.6	16.7	111.0	5.6	139.6

Executive summary:

Korte, 1986:

14C-labeled 1,2,4-trichlorobenzene was added to a soil-water-suspension. After 5 days the test was finished and samples were taken by different chemical treatments (e.g. volatile organic compounds and CO2 in the headspace, determination of test substance and 14CO2 in aqueous phase). Following values were determined:

degradation to14CO2 [%]	volatile organic compounds [%]	activity in water [%]	extractable activity from soil (extraction by methanol) [%]	not extractable activity (combustion of soil) [%]	balance [%]
5.7	0.6	16.7	111.0	5.6	139.6

Description of key information

For transported isolated intermediates according to REACh, Article 18, this endpoint is not a data requirement. However, data is available for this endpoint and is thus reported under the guidance of "all available data".

 

Korte, 1986:

14C-labeled 1,2,4-trichlorobenzene was added to a soil-water-suspension. After 5 days the test was finished and samples were taken by different chemical treatments (e.g. volatile organic compounds and CO2 in the headspace, determination of test substance and 14CO2 in aqueous phase). Following values were determined:

degradation to14CO2 [%]	volatile organic compounds [%]	activity in water [%]	extractable activity from soil (extraction by methanol) [%]	not extractable activity (combustion of soil) [%]	balance [%]
5.7	0.6	16.7	111.0	5.6	139.6

 

Howard, 1989:
1,2,4-Trichlorobenzene will be expected to adsorb to the organic matter in soil. It will not hydrolyze but it may biodegrade, slowly in the soil.

 

Howard, 1991:
The Half-lives in soil is:
high: 4320 h (6 m)
low : 672 h ( 4 w)

Scientific judgement based upon unacclimated aerobic soil grab data (low t1/2: Haider, K. et al. (1981), high t1/2: Marinucci, A.C. and Bartha, R. (1979)

Mackay, 1992:
The suggested half-life in soil is:
mean half-life (hours): 5500 ( ca. 8 months)
range (hours): 3000 – 10000

 

Wang, 1994:

The half-life of 1,2,4-trichlorobenzene in a sewage sludge-amended soil in microcosm experiments is:

	half-life (d)	* R	period (d)	loss (%)
first step	22.5	0.981	0-75	83.2
second step	49500	1.0	75-259	2.26
general	23.3	0.955		85.5

The half-life of 1,2,4-trichlorobenzene in a standard spiked soil in microcosm experiments is:

	half-life (d)	* R	period (d)	loss (%)
first step	12.5	0.972	0-75	64.5
second step	194	0.942	75-259	19.8
general	19.4	0.867		84.3

* R = regression coefficients

 

EU Risk Assessment, 2003:
1,2,4-TCB can be degraded in soil, although very slowly (Marinucci and Bartha, 1979; Wilson et al., 1981). The aerobic mineralisation was studied using 14C-labelled 1,2,4-TCB and a mineralisation rate measured as CO2 development/day (Marinucci and Bartha, 1979).
In a study using a sandy loam (pH 6.5) added 1,2,4-TCB at a concentration of 50µg/g soil, the degradation in soil was observed to be slow. The incubation was performed at 20°C for 3 to 12 weeks. 1,2,4-TCB was subject to mineralisation as soil poisoned with 1% HgCl2 or NaN3 reduced the CO2 evolution consistently. Anaerobic conditions either continuously or alternated weekly with aerobic incubation periods markedly depressed the mineralisation. The mineralisation rate was 0.181µg/day/20 g soil equivalent to 9µg/d/kg. The turnover rate (% 1,2,4-TCB converted to CO2/day = 0.075%) was maximal at 10µg/g soil and sharply declined at higher concentrations (Marinucci and Bartha, 1979). Haider et al. (1974) used 10µg/g (in 100 g soil) and observed a mineralisation rate about twice as high.

 

BUA report (1987):
In a degradation study in soil 1,2,4-trichlorobenzene was converted to 2,4,5- and 2,4,6-chlorophenol (Ballschmiter et al., 1977). Other studies support these findings. Marinucci and Bartha (1979) showed a degradation of 9 µg/kg/day. Adapted microorganisms are able to degrade 1,2,4-trichlorobenzene with high efficiency (Haberer and Normann, 1987).