1,2,4-trichlorobenzene

Biodegradation in water and sediment: simulation tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water and sediment: simulation testing, 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):

 

Removal in the sewage treatment plant (STP)

The concentration of 1,2,4-TCB in influents to an advanced wastewater treatment plant was measured at the average value of 0.46 µg/l. The effluent concentration in the same period was 0.01 µg/l in percolating filter effluent treated by lime clarification, ammonia stripping, activated charcoal, chlorination and reverse osmosis. (McCarty and Reinhard, 1980). This removal of 97.8% of 1,2,4-TCB is a special case which is not to be considered a worst case. The "water factory" was designed to improve the quality of biologically treated municipal wastewater before injection into the aquifer system.

 

The influent to a water factory was the effluent from a municipal STP (Orange county,). In 1976, the STP trickling effluent contained 1,2,4-TCB in the range <0.02 - 4.1µg/l (geometric mean 0.46 µg/l) and in 1978 after switching from trickling-filter to activated sludge treatment, the measured range in STP effluent was <0.02 - 0.5µg/l and the geometric mean 0.18 µg/l (McCarty and Reinhard, 1980).

 

Removal in surface water

The removal in seawater was studied in mesocosmos studies including the volatilisation (Wakeham et al., 1983). The tanks were 5.5 m high and 1.8 m in diameter and contained 13 m³ seawater. In the study, a mixture of volatile organic compounds was added. The dissipation was studied at conditions equal to spring (8-16°C), summer (20-22°C) and winter (3-7°C). The initial concentration 0.5µg/l was equivalent to the concentration measured in a moderately polluted bay. The concentrations were measured during 1-2 months.

 

The dissipation was relatively temperature independent with half-life of 2-3 weeks regardless of the season. Retardation of the biological activity by adding HgCl2 (2 mg/l) did not increase the summer dissipation time. Therefore, the dissipation was assumed to be primarily dissipation by volatilisation and not biodegradation. Thus, volatilisation dominates the dissipation of 1,2,4-TCB whereas biodegradation is of less importance according to the authors (Wakeham et al., 1983).

 

The half-lives in rivers in thewere estimated to be 2.1, 1.5 and 28 days based on monitoring data taken along the River Rhine (Zoeteman et al., 1980). These half-lives differ considerably and are likely to be very inaccurate since only a limited number of samples were taken.

 

Removal in sediment

Trichlorobenzenes are chemically stable in both aerobic and anaerobic environments. In studies on the degradation in anaerobic sediments, trichlorobenzenes were reductively dechlorinated to monochlorobenzenes via dichlorobenzenes.1,2,4-TCB was transformed via 1,4-dichlorobenzene (Bosma et al., 1988) and via 1,2- and 1,3- dichlorobenzenes (Peijnenburg et al., 1992). The study by Bosma et al. (1988) was performed as a column study using 25 cm high and 5.5 cm internal diameter wet packed with sediment from the River Rhine near Wageningen. The columns were percolated continuously at a flow rate of 1 cm/h in an upflow mode. It was concluded that the observed removal was a biological process because of the long lag-phase preceding the disappearance and that there was no elimination in anaerobic batch with autoclaved sediment. The study by Peijnenburg et al. (1992) was performed in a methanogenic sediment-water system maintained at 22ºC in a nitrogen atmosphere. The sediments were taken from a slow flowing river and a eutrophic pond. The anaerobic degradation rates were log k = -5.64 min-1 and log k = -5.62 min-1 (corresponding to the half-lives 212 days and 202 days), respectively. 1,2-, 1,3- and 1,4-dichlorobenzenes were formed in ratios of approximately 1.5:1:1.5 as confirmed by GC. Almost immediately after incubation began, monochlorobenzene could be detected.

Executive summary:

EU Risk Assessment (2003):

 

Removal in the sewage treatment plant (STP)

The concentration of 1,2,4-TCB in influents to an advanced wastewater treatment plant was measured at the average value of 0.46 µg/l. The effluent concentration in the same period was 0.01 µg/l in percolating filter effluent treated by lime clarification, ammonia stripping, activated charcoal, chlorination and reverse osmosis. (McCarty and Reinhard, 1980). This removal of 97.8% of 1,2,4-TCB is a special case which is not to be considered a worst case. The "water factory" was designed to improve the quality of biologically treated municipal wastewater before injection into the aquifer system.

 

The influent to a water factory was the effluent from a municipal STP (Orange county,). In 1976, the STP trickling effluent contained 1,2,4-TCB in the range <0.02 - 4.1µg/l (geometric mean 0.46 µg/l) and in 1978 after switching from trickling-filter to activated sludge treatment, the measured range in STP effluent was <0.02 - 0.5µg/l and the geometric mean 0.18 µg/l (McCarty and Reinhard, 1980).

 

Removal in surface water

The removal in seawater was studied in mesocosmos studies including the volatilisation (Wakeham et al., 1983). The tanks were 5.5 m high and 1.8 m in diameter and contained 13 m³ seawater. In the study, a mixture of volatile organic compounds was added. The dissipation was studied at conditions equal to spring (8-16°C), summer (20-22°C) and winter (3-7°C). The initial concentration 0.5µg/l was equivalent to the concentration measured in a moderately polluted bay. The concentrations were measured during 1-2 months.

 

The dissipation was relatively temperature independent with half-life of 2-3 weeks regardless of the season. Retardation of the biological activity by adding HgCl2 (2 mg/l) did not increase the summer dissipation time. Therefore, the dissipation was assumed to be primarily dissipation by volatilisation and not biodegradation. Thus, volatilisation dominates the dissipation of 1,2,4-TCB whereas biodegradation is of less importance according to the authors (Wakeham et al., 1983).

 

The half-lives in rivers in thewere estimated to be 2.1, 1.5 and 28 days based on monitoring data taken along the River Rhine (Zoeteman et al., 1980). These half-lives differ considerably and are likely to be very inaccurate since only a limited number of samples were taken.

 

Removal in sediment

Trichlorobenzenes are chemically stable in both aerobic and anaerobic environments. In studies on the degradation in anaerobic sediments, trichlorobenzenes were reductively dechlorinated to monochlorobenzenes via dichlorobenzenes.1,2,4-TCB was transformed via 1,4-dichlorobenzene (Bosma et al., 1988) and via 1,2- and 1,3- dichlorobenzenes (Peijnenburg et al., 1992). The study by Bosma et al. (1988) was performed as a column study using 25 cm high and 5.5 cm internal diameter wet packed with sediment from the River Rhine near Wageningen. The columns were percolated continuously at a flow rate of 1 cm/h in an upflow mode. It was concluded that the observed removal was a biological process because of the long lag-phase preceding the disappearance and that there was no elimination in anaerobic batch with autoclaved sediment. The study by Peijnenburg et al. (1992) was performed in a methanogenic sediment-water system maintained at 22ºC in a nitrogen atmosphere. The sediments were taken from a slow flowing river and a eutrophic pond. The anaerobic degradation rates were log k = -5.64 min-1 and log k = -5.62 min-1 (corresponding to the half-lives 212 days and 202 days), respectively. 1,2-, 1,3- and 1,4-dichlorobenzenes were formed in ratios of approximately 1.5:1:1.5 as confirmed by GC. Almost immediately after incubation began, monochlorobenzene could be detected.

Reference 2

Endpoint:

biodegradation in water and sediment: simulation testing, 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:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: Acinetobacter and Pseudomonas from industrial waste water treatment plants

Conclusions:

Interpretation of results: other: oxidative dehalogenation

Executive summary:

Springer (1988)

1,2,4-Trichlorobenzene (TCB) could be oxidatively dehalogenated with a quantitative release of inorganic chloride from organic bound chlorine.

Reference 3

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

Type of information:

experimental study

Adequacy of study:

other information

Study period:

1980

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Principles of method if other than guideline:

The methodology is based on an evaluation of uptake into cells and subsequent respiration of radiolabeled organic substrates in short-term experiments. The data can be used to calculate turnover times or kinetic parameters.
The amount of radiolabel taken up into cells was determined by incubating a water sample with a radiolabeled substrate and subsequently filtering the sample, thus retaining microorganisms and any intracellular radiolabeled compound on the filter. The radioactivity on the filters was subsequently counted on a Packard Tri-Carb scintillation counter.

GLP compliance:

no

Radiolabelling:

yes

Inoculum or test system:

natural water

Duration of test (contact time):

>= 6 - <= 10 h

Kinetic assessment of trichlorobenzene by Estuary microbial community:

Date	Temperature [°C]	Turnover rate [h^-1]	Maximum metabolic velocity [ng*liter^-1* h^-1]
8/10/80	30	0.0006	9.1
11/7/80	14		<0.1 (below detection limit)

Executive summary:

Pfaender (1982)

The methodology is based on an evaluation of uptake into cells and subsequent respiration of radiolabeled organic substrates in short-term experiments. The data can be used to calculate turnover times or kinetic parameters.
The amount of radiolabel taken up into cells was determined by incubating a water sample with a radiolabeled substrate and subsequently filtering the sample, thus retaining microorganisms and any intracellular radiolabeled compound on the filter. The radioactivity on the filters was subsequently counted on a Packard Tri-Carb scintillation counter.

 

Kinetic assessment of trichlorobenzene by Estuary microbial community:

Date	Temperature [°C]	Turnover rate [h^-1]	Maximum metabolic velocity [ng*liter^-1* h^-1]
8/10/80	30	0.0006	9.1
11/7/80	14		<0.1 (below detection limit)

Reference 4

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

Type of information:

experimental study

Adequacy of study:

other information

Study period:

1980-1981

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Principles of method if other than guideline:

Biodegradation rates were assessed by heterotrophic uptake kinetics (Pfaender and Bartholomew, 1982, Appl. Environ. Microbiol. 44:159-164). This protocol measures both the uptake of radiolabeled substrate into microbial cells and subsequent respiration to 14CO2. After incubation, the 14CO2 produced from respiration was trapped from the headspace above acidified samples, and substrate uptake into cells was determined by filtering the water sample through membrane filters.

GLP compliance:

no

Radiolabelling:

yes

Inoculum or test system:

natural water

Duration of test (contact time):

>= 4 - <= 10 h

summary of kinetic parameters for 1,2,4-trichlorobenzene

Date	Site	Temperature [°C]	Vmax^a) [ng * l^-1* h^-1]	Km^b)
11-7-80	Upstream	12	7.5	6.5
	Estuarine	14	<1	-
	Marine	17	<1	-
5-26-81	Upstream	24	<1	-
	Estuarine	28	7.9	7.0
	Marine	24	2.3	4.5

a) susbstrate uptake into cells. A V_max< 1 ng * l^-1* h^-1represents a metabolic rate less than that detectable by this technique.

b) CO²production from respiration

Executive summary:

Bartholomew (1983)

Biodegradation rates were assessed by heterotrophic uptake kinetics (Pfaender and Bartholomew, 1982, Appl. Environ. Microbiol. 44:159-164). This protocol measures both the uptake of radiolabeled substrate into microbial cells and subsequent respiration to 14CO₂. After incubation, the 14CO₂ produced from respiration was trapped from the headspace above acidified samples, and substrate uptake into cells was determined by filtering the water sample through membrane filters.

Summary of kinetic parameters for 1,2,4-trichlorobenzene

Date	Site	Temperature [°C]	Vmax^a) [ng * l^-1* h^-1]	Km^b)
11-7-80	Upstream	12	7.5	6.5
	Estuarine	14	<1	-
	Marine	17	<1	-
5-26-81	Upstream	24	<1	-
	Estuarine	28	7.9	7.0
	Marine	24	2.3	4.5

a) susbstrate uptake into cells. A V_max< 1 ng * l^-1* h^-1represents a metabolic rate less than that detectable by this technique.

b) CO²production from respiration

Reference 5

Endpoint:

biodegradation in water and sediment: simulation testing, 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

Oxygen conditions:

anaerobic

Inoculum or test system:

other: enrichment cultures originated from percolation columns filled with Rhine River sediments

Conclusions:

Interpretation of results: other: reductive dechlorination

Executive summary:

Holliger (1992)

1,2,4-Trichlorobenzene was reductively dechlorinated by enrichment cultures in the presence of lactate, glucose, ethanol, or isopropanol as the electron donor. 1,3-Dichlorobenzene and 1,4-dichlorobenzene were the dechlorination products found. Electrochemical reduction predicts 1,2,4-trichlorobenzene as the major intermediate of hexachlorobenzene degradation.

Reference 6

Endpoint:

biodegradation in water: sewage treatment simulation testing

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:

The microbial degradation of 1,2,4-trichlorobenzene to CO2 in activated sludge was determined. The procedure simulates processes in nature whereby intermittently low concentrations of chemicals occure. The effect of the sludge on the 1,2,4-trichlorobenzen is measured by the distribution of the test chemical between sludge and water and its conversion and degradation to CO2.

GLP compliance:

not specified

Radiolabelling:

yes

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

% Degr.:

< 0.1

Parameter:

CO2 evolution

Executive summary:

Freitag (1985)

The microbial degradation of 1,2,4-trichlorobenzene to CO₂ in activated sludge was determined. The effect of the sludge on the 1,2,4-trichlorobenzen is measured by the distribution of the test chemical between sludge and water and its conversion and degradation to CO₂. A degradation <0.1% was obtained.

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".

 

Holliger (1992)

1,2,4-Trichlorobenzene was reductively dechlorinated by enrichment cultures in the presence of lactate, glucose, ethanol, or isopropanol as the electron donor. 1,3-Dichlorobenzene and 1,4-dichlorobenzene were the dechlorination products found. Electrochemical reduction predicts 1,2,4-trichlorobenzene as the major intermediate of hexachlorobenzene degradation.

 

Springer (1988)

1,2,4-Trichlorobenzene (TCB) could be oxidatively dehalogenated with a quantitative release of inorganic chloride from organic bound chlorine.

 

Freitag (1985)

The microbial degradation of 1,2,4-trichlorobenzene to CO2 in activated sludge was determined. The effect of the sludge on the 1,2,4-trichlorobenzen is measured by the distribution of the test chemical between sludge and water and its conversion and degradation to CO2. A degradation <0.1% was obtained.

 

Bartholomew (1983)

Biodegradation rates were assessed by heterotrophic uptake kinetics (Pfaender and Bartholomew, 1982, Appl. Environ. Microbiol. 44:159-164). This protocol measures both the uptake of radiolabeled substrate into microbial cells and subsequent respiration to 14CO₂. After incubation, the 14CO₂ produced from respiration was trapped from the headspace above acidified samples, and substrate uptake into cells was determined by filtering the water sample through membrane filters.

Summary of kinetic parameters for 1,2,4-trichlorobenzene

Date	Site	Temperature [°C]	Vmax^a) [ng * l^-1* h^-1]	Km^b)
11-7-80	Upstream	12	7.5	6.5
	Estuarine	14	<1	-
	Marine	17	<1	-
5-26-81	Upstream	24	<1	-
	Estuarine	28	7.9	7.0
	Marine	24	2.3	4.5

a) susbstrate uptake into cells. A V_max< 1 ng * l^-1* h^-1represents a metabolic rate less than that detectable by this technique.

b) CO²production from respiration

 

Pfaender (1982)

The methodology is based on an evaluation of uptake into cells and subsequent respiration of radiolabeled organic substrates in short-term experiments. The data can be used to calculate turnover times or kinetic parameters.
The amount of radiolabel taken up into cells was determined by incubating a water sample with a radiolabeled substrate and subsequently filtering the sample, thus retaining microorganisms and any intracellular radiolabeled compound on the filter. The radioactivity on the filters was subsequently counted on a Packard Tri-Carb scintillation counter.

 

Kinetic assessment of trichlorobenzene by Estuary microbial community:

Date	Temperature [°C]	Turnover rate [h^-1]	Maximum metabolic velocity [ng*liter^-1* h^-1]
8/10/80	30	0.0006	9.1
11/7/80	14		<0.1 (below detection limit)

 

EU Risk Assessment (2003):

Removal in the sewage treatment plant (STP)

The concentration of 1,2,4-TCB in influents to an advanced wastewater treatment plant was measured at the average value of 0.46 µg/l. The effluent concentration in the same period was 0.01 µg/l in percolating filter effluent treated by lime clarification, ammonia stripping, activated charcoal, chlorination and reverse osmosis. (McCarty and Reinhard, 1980). This removal of 97.8% of 1,2,4-TCB is a special case which is not to be considered a worst case. The "water factory" was designed to improve the quality of biologically treated municipal wastewater before injection into the aquifer system.

 

The influent to a water factory was the effluent from a municipal STP (Orange county,). In 1976, the STP trickling effluent contained 1,2,4-TCB in the range <0.02 - 4.1µg/l (geometric mean 0.46 µg/l) and in 1978 after switching from trickling-filter to activated sludge treatment, the measured range in STP effluent was <0.02 - 0.5µg/l and the geometric mean 0.18 µg/l (McCarty and Reinhard, 1980).

 

Removal in surface water

The removal in seawater was studied in mesocosmos studies including the volatilisation (Wakeham et al., 1983). The tanks were 5.5 m high and 1.8 m in diameter and contained 13 m³ seawater. In the study, a mixture of volatile organic compounds was added. The dissipation was studied at conditions equal to spring (8-16°C), summer (20-22°C) and winter (3-7°C). The initial concentration 0.5µg/l was equivalent to the concentration measured in a moderately polluted bay. The concentrations were measured during 1-2 months.

 

The dissipation was relatively temperature independent with half-life of 2-3 weeks regardless of the season. Retardation of the biological activity by adding HgCl2 (2 mg/l) did not increase the summer dissipation time. Therefore, the dissipation was assumed to be primarily dissipation by volatilisation and not biodegradation. Thus, volatilisation dominates the dissipation of 1,2,4-TCB whereas biodegradation is of less importance according to the authors (Wakeham et al., 1983).

 

The half-lives in rivers in thewere estimated to be 2.1, 1.5 and 28 days based on monitoring data taken along the River Rhine (Zoeteman et al., 1980). These half-lives differ considerably and are likely to be very inaccurate since only a limited number of samples were taken.

 

Removal in sediment

Trichlorobenzenes are chemically stable in both aerobic and anaerobic environments. In studies on the degradation in anaerobic sediments, trichlorobenzenes were reductively dechlorinated to monochlorobenzenes via dichlorobenzenes.1,2,4-TCB was transformed via 1,4-dichlorobenzene (Bosma et al., 1988) and via 1,2- and 1,3- dichlorobenzenes (Peijnenburg et al., 1992). The study by Bosma et al. (1988) was performed as a column study using 25 cm high and 5.5 cm internal diameter wet packed with sediment from the River Rhine near Wageningen. The columns were percolated continuously at a flow rate of 1 cm/h in an upflow mode. It was concluded that the observed removal was a biological process because of the long lag-phase preceding the disappearance and that there was no elimination in anaerobic batch with autoclaved sediment. The study by Peijnenburg et al. (1992) was performed in a methanogenic sediment-water system maintained at 22ºC in a nitrogen atmosphere. The sediments were taken from a slow flowing river and a eutrophic pond. The anaerobic degradation rates were log k = -5.64 min-1 and log k = -5.62 min-1 (corresponding to the half-lives 212 days and 202 days), respectively. 1,2-, 1,3- and 1,4-dichlorobenzenes were formed in ratios of approximately 1.5:1:1.5 as confirmed by GC. Almost immediately after incubation began, monochlorobenzene could be detected.