1,2,4-trichlorobenzene

Bioaccumulation: terrestrial

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

bioaccumulation: terrestrial

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 / BUA report.

Principles of method if other than guideline:

EU Risk Assessment

GLP compliance:

not specified

EU Risk Assessment (2003):

 

The accumulation in earthworms was studied by Beyer (1996) in a standard soil (69.7% sand, 20% clay, 10% peat and 0.3% CaCO3) where clitellate, i.e. sexually mature, Lumbricus terrestris were exposed to 10 ppm 1,2,4-TCB during 8 and 26 weeks. The BCF was 0.09 in the 8-week experiment and 0.06 in the 26-week experiment (Beyer, 1996). Because of 1,2,4 -TCB¿s high adsorption capacity and the high-soil organic matter content in the study, BCF would be expected to be lower than under most field conditions. Taking these results into consideration results from other organochlorines including hexachlorobenzene indicate according to Beyer (1996) that BCF of 1,2,4-TCB for earthworms may be around 1 in soil with normal ranges of organic matter. Beyer (1996) shows that BCFearthworm for chlorobenzenes increases with the degree of chlorination and that the BCF of hexachlorobenzene for Lumbricus terrestris was 0.27. He compares this result in a study with an OECD standard soil with 10% organic matter with a study where a BCF for Lumbricus terrestris was 2 to 3 in a soil with 2.6% organic matter (Lord et al., 1980).

 

In comparison byemploying the equilibrium method, the bioconcentration factor for earthworm, according to the TGD (equations 62 and 63)and taking the soil-water partition coefficient into account, is estimated to be:BCFearthworm =Kearthworm-porewater . ((RHOsoil.10-3)/Ksoil-water) = 0.25.0.16.Kow.(1.700/42.2) =18; i.e an order of magnitude higher than the BCF based on experimental data,which however is regarded more reliable, because of the existence of comparable results in several studies with other chlorinated benzenes.

Executive summary:

EU Risk Assessment, 2003:

The accumulation in earthworms was studied by Beyer (1996) in a standard soil (69.7% sand, 20% clay, 10% peat and 0.3% CaCO3) where clitellate, i.e. sexually mature, Lumbricus terrestris were exposed to 10 ppm 1,2,4-TCB during 8 and 26 weeks. The BCF was 0.09 in the 8-week experiment and 0.06 in the 26-week experiment (Beyer, 1996). Because of 1,2,4 -TCB¿s high adsorption capacity and the high-soil organic matter content in the study, BCF would be expected to be lower than under most field conditions. Taking these results into consideration results from other organochlorines including hexachlorobenzene indicate according to Beyer (1996) that BCF of 1,2,4-TCB for earthworms may be around 1 in soil with normal ranges of organic matter. Beyer (1996) shows that BCFearthworm for chlorobenzenes increases with the degree of chlorination and that the BCF of hexachlorobenzene for Lumbricus terrestris was 0.27. He compares this result in a study with an OECD standard soil with 10% organic matter with a study where a BCF for Lumbricus terrestris was 2 to 3 in a soil with 2.6% organic matter (Lord et al., 1980).
In comparison byemploying the equilibrium method, the bioconcentration factor for earthworm, according to the TGD (equations 62 and 63)and taking the soil-water partition coefficient into account, is estimated to be:BCFearthworm =Kearthworm-porewater . ((RHOsoil.10-3)/Ksoil-water) = 0.25.0.16.Kow.(1.700/42.2) =18; i.e an order of magnitude higher than the BCF based on experimental data,which however is regarded more reliable, because of the existence of comparable results in several studies with other chlorinated benzenes.

Reference 2

Endpoint:

bioaccumulation: terrestrial

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented publication which meets basic scientific principles. For bioaccumulation in plants there is no current guideline on methods aavailable to compare with.

Principles of method if other than guideline:

In an Outdoor experiment simulating field conditions radiolabeled [14C]1,2,4-trochlorobenze was added to lysimeters of 60 x 60 x 70 cm filled with soil.

GLP compliance:

not specified

Radiolabelling:

yes

Test organisms (species):

other: cress plants

Total exposure / uptake duration:

79 d

Nominal and measured concentrations:

nominal concentration: 2,02 mg/kg dry soil in a 10-cm depth

Residue Concentration, Total¹⁴C Content and Bioaccumulation Factors of Radioactive 1,2,4-Trochlorobenzene in Cress Plants after Treatment of Soil with¹⁴C-Labeled Chlorinated Benzenes under Outdoor Conditions

time of exposure [days]	concentration of ^14C [µg/g] (µg calculated as parent compounds per g dry plant matter)	Total ^14C [ng/plant] (calculated as parent compounds)	bioaccumulation factor (concentration of ^14C, calculated as parent compounds, in dry plant matter, divided by concentration of ^14C in dry soil)
11	2.3	4.69	11
32	0.27	7,77	3.3
78	0.07	10.6	1.5

 

When considering the time course of residues in the plants, it is obvious that the concentration of radioactive substances in dry plant matter, as well asbioaccumulation factors, decreased with time. This effect isdue to growth dilution, since the absolute amounts of radioactive substances in plants increased with time.

Executive summary:

Topp, 1989 (barley plants):

Residue Concentration, Total14C Content and Bioaccumulation Factors of Radioactive 1,2,4-Trochlorobenzene in Cress Plants after Treatment of Soil with14C-Labeled Chlorinated Benzenes under Outdoor Conditions.

time of exposure [days]	concentration of 14C [µg/g] (µg calculated as parent compounds per g dry plant matter)	Total ^14C [ng/plant] (calculated as parent compounds)	bioaccumulation factor (concentration of 14C, calculated as parent compounds, in dry plant matter, divided by concentration of 14C in dry soil)
11	2.3	4.69	11
32	0.27	7.77	3.3
78	0.07	10.6	1.5

When considering the time course of residues in the plants, it is obvious that the concentration of radioactive substances in dry plant matter, as well asbioaccumulation factors, decreased with time. This effect isdue to growth dilution, since the absolute amounts of radioactive substances in plants increased with time.

Reference 3

Endpoint:

bioaccumulation: terrestrial

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented publication which meets basic scientific principles. For bioaccumulation in plants there is no current guideline on methods available to compare with.

Principles of method if other than guideline:

In an Outdoor experiment simulating field conditions radiolabeled [14C]1,2,4-trochlorobenze was added to lysimeters of 60 x 60 x 70 cm filled with soil.

GLP compliance:

not specified

Radiolabelling:

yes

Test organisms (species):

other: barley plants

Total exposure / uptake duration:

125 d

Nominal and measured concentrations:

nominal concentration: 2,02 mg/kg dry soil in a 10-cm depth

Residue Concentration, Total¹⁴C Content and Bioaccumulation Factors of Radioactive 1,2,4-Trochlorobenzene in Barley Plants after Treatment of Soil with¹⁴C-Labeled Chlorinated Benzenes under Outdoor Conditions

time of exposure [days]	concentration of ^14C [µg/g] (µg calculated as parent compounds per g dry plant matter)	Total ^14C [ng/plant] (calculated as parent compounds)	bioaccumulation factor (concentration of ^14C, calculated as parent compounds, in dry plant matter, divided by concentration of ^14C in dry soil)
11	9.3	188	36
32	2.0	363	16
70	0.35	926	5.8
124	0.23	747	4.3

 

When considering the time course of residues in the plants, it is obvious that the concentration of radioactive substances in dry plant matter, as well as bioaccumulation factors, decreased with time. This effect isdue to growth dilution, since the absolute amounts of radioactive substances in plants increased with time except for the days between 70 and 125. In this period, plant growing declines, and the loss of radioactive compounds by evapotranspiration probably exceeds further uptake from soil.

Executive summary:

Topp, 1989 (barley plants):

Residue Concentration, Total¹⁴C Content and Bioaccumulation Factors of Radioactive 1,2,4-Trochlorobenzene in Barley Plants after Treatment of Soil with¹⁴C-Labeled Chlorinated Benzenes under Outdoor Conditions

time of exposure [days]	concentration of ^14C [µg/g] (µg calculated as parent compounds per g dry plant matter)	Total ^14C [ng/plant] (calculated as parent compounds)	bioaccumulation factor (concentration of ^14C, calculated as parent compounds, in dry plant matter, divided by concentration of ^14C in dry soil)
11	9.3	188	36
32	2.0	363	16
70	0.35	926	5.8
124	0.23	747	4.3

 

When considering the time course of residues in the plants, it is obvious that the concentration of radioactive substances in dry plant matter, as well asbioaccumulation factors, decreased with time. This effect isdue to growth dilution, since the absolute amounts of radioactive substances in plants increased with time except for the days between 70 and 125. In this period, plant growing declines, and the loss of radioactive compounds by evapotranspiration probably exceeds further uptake from soil.

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". 

Topp, 1989 (barley plants):

Residue Concentration, Total14C Content and Bioaccumulation Factors of Radioactive 1,2,4-Trochlorobenzene in Barley Plants after Treatment of Soil with14C-Labeled Chlorinated Benzenes under Outdoor Conditions

time of exposure [days]	concentration of 14C [µg/g] (µg calculated as parent compounds per g dry plant matter)	Total 14C [ng/plant] (calculated as parent compounds)	bioaccumulation factor (concentration of 14C, calculated as parent compounds, in dry plant matter, divided by concentration of 14C in dry soil)
11	9.3	188	36
32	2.0	363	16
70	0.35	926	5.8
124	0.23	747	4.3

 

When considering the time course of residues in the plants, it is obvious that the concentration of radioactive substances in dry plant matter, as well asbioaccumulation factors, decreased with time. This effect is due to growth dilution, since the absolute amounts of radioactive substances in plants increased with time except for the days between 70 and 125. In this period, plant growing declines, and the loss of radioactive compounds by evapotranspiration probably exceeds further uptake from soil.

 

Topp, 1989 (barley plants):

Residue Concentration, Total14C Content and Bioaccumulation Factors of Radioactive 1,2,4-Trochlorobenzene in Cress Plants after Treatment of Soil with14C-Labeled Chlorinated Benzenes under Outdoor Conditions.

time of exposure [days]	concentration of 14C [µg/g] (µg calculated as parent compounds per g dry plant matter)	Total ^14C [ng/plant] (calculated as parent compounds)	bioaccumulation factor (concentration of 14C, calculated as parent compounds, in dry plant matter, divided by concentration of 14C in dry soil)
11	2.3	4.69	11
32	0.27	7.77	3.3
78	0.07	10.6	1.5

When considering the time course of residues in the plants, it is obvious that the concentration of radioactive substances in dry plant matter, as well asbioaccumulation factors, decreased with time. This effect isdue to growth dilution, since the absolute amounts of radioactive substances in plants increased with time.

 

EU Risk Assessment, 2003:
The accumulation in earthworms was studied by Beyer (1996) in a standard soil (69.7% sand, 20% clay, 10% peat and 0.3% CaCO3) where clitellate, i.e. sexually mature, Lumbricus terrestris were exposed to 10 ppm 1,2,4-TCB during 8 and 26 weeks. The BCF was 0.09 in the 8-week experiment and 0.06 in the 26-week experiment (Beyer, 1996). Because of 1,2,4 -TCB's high adsorption capacity and the high-soil organic matter content in the study, BCF would be expected to be lower than under most field conditions. Taking these results into consideration, results from other organochlorines including hexachlorobenzene indicate according to Beyer (1996) that BCF of 1,2,4-TCB for earthworms may be around 1 in soil with normal ranges of organic matter. Beyer (1996) shows that BCF earthworm for chlorobenzenes increases with the degree of chlorination and that the BCF of hexachlorobenzene for Lumbricus terrestris was 0.27. He compares this result in a study with an OECD standard soil with 10% organic matter with a study where a BCF for Lumbricus terrestris was 2 to 3 in a soil with 2.6% organic matter (Lord et al., 1980).
In comparison by employing the equilibrium method, the bioconcentration factor for earthworm, according to the TGD (equations 62 and 63) and taking the soil-water partition coefficient into account, is estimated to be: BCF earthworm = K earthworm-porewater . ((RHOsoil.10-3)/Ksoil-water) = 0.25.0.16.Kow.(1.700/42.2) =18; i.e an order of magnitude higher than the BCF based on experimental data, which however is regarded more reliable, because of the existence of comparable results in several studies with other chlorinated benzenes.