2-nitrotoluene

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

bioaccumulation in aquatic species: fish

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

Specific details on test material used for the study:

- Analytical purity: not specified

BUA report (1989):

The log Kow values for the isomeric nitrotoluenes indicate weak bioaccumulation.

 

The 1986 MITI List attributes little or no bioaccumulation to nitrotoluenes (MITI, 1986).

 

Dutch authors (Canton et al., 1985) give the following bioconcentration factor for o-nitrotoluene in the guppy (Poecilia reticulata), based on the fresh weight (no further experimental details are given): BCF = 20 (log BCF = 1.3).

 

Another study (Deneer, et al., 1987) on the accumulation of o-nitrotoluene in the guppy (Poecilia reticulata) gave the following bioconcentration factor, based on fat content, in a 3-day test with an o-nitrotoluene concentration of 6.6. mg/l: BCF = 190.6 (log BCF = 2.28).

Executive summary:

BUA report (1989):

The log Kow values for the isomeric nitrotoluenes indicate weak bioaccumulation.

The 1986 MITI List attributes little or no bioaccumulation to nitrotoluenes (MITI, 1986).

Dutch authors (Canton et al., 1985) give the following bioconcentration factor for o-nitrotoluene in the guppy (Poecilia reticulata), based on the fresh weight (no further experimental details are given): BCF = 20 (log BCF = 1.3).

Another study (Deneer, et al., 1987) on the accumulation of o-nitrotoluene in the guppy (Poecilia reticulata) gave the following bioconcentration factor, based on fat content, in a 3-day test with an o-nitrotoluene concentration of 6.6. mg/l: BCF = 190.6 (log BCF = 2.28).

Reference 2

Endpoint:

bioaccumulation in aquatic species: fish

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.

Principles of method if other than guideline:

EU Risk Assessment

GLP compliance:

not specified

Specific details on test material used for the study:

- Analytical purity: not specified

EU Risk Assessment (2008):

 

Fish (experimentally)

Cyprinus carpio was exposed during 42 days to 0.1 mg/l of 2-nitrotoluene resulting in a BCF ranging from 12.5 to 29.9. A similar range (BCF from 6.6 to 29.7) was measured after an exposure of 0.01 mg/l for 42 days (MITI, 1992). A similar value, a BCF ca. 20 was cited, for 2 -nitrotoluene in guppies (Poecilia reticulata), by BUA (1989). Data provided by Canton et al. (1985) give a BCF of 20 for 2 -nitrotoluene in the guppy, based on fresh weight (this datum is considered as additional information since no further experimental details are given).

 

Deneer et al., (1987b) carried out another study on the accumulation of 2 -nitrotoluene in the guppy (P. reticulata) giving a log BCF of 2.28 (BCF: 190.5), based on fat content, in a 3-day test, using concentration of 6.6 mg 2 -nitrotoluene/l. For this bioconcentration test, female guppies (5 to 8 months old) were used. The wet weight varied from 60 to 450 mg at the end of the experiment; mean fat content was 8 ± 2%. This is also in agreement with the information from Hendriks et al., (2001), considering the average percentage of lipid content in P. reticulata around 10%. Under these considerations, a BCF of 19 could be estimated for the whole fish. It was previously established, in preliminary experiments, that the type of short term assay used to determine BCF would not lead to erroneous results, since the concentrations found in fish and water showed that the steady state value for fish C(fish)/C(water) was reached after approximately 6 h. This fact was confirmed by the authors, who indicated no apparent differences between BCFs determined on subsequent days.

 

In another experiment (Wang et al., 1999), 2 -nitrotoluene was selected as a model compound for a laboratory continuous-flow-experiment where the uptake of the compound by the goldfish (Carasius auratus) and a triolein SemiPermeable Membrane Device (SPMD) was followed. 40 goldfish and the SPMDs were placed in an exposure chamber. A concentrated mixture of 9 nitroaromatics was added at a constant rate (1 ml/min) into the main water flow to the chamber by a peristaltic pump. The experiment was conducted for 20 days with a concentration of 1.63 mg/l of 2-nitrotoluene in the exposure chamber. Measured, BCF was determined as 4.4 and 312.6 for fish and SPMDs, respectively. Information extracted from these figures is very relevant since it gives an indication of the importance of the rapid elimination metabolism in fish. The higher BCF value estimated from SPMDs would indicate higher accumulation rates in those organisms with a lower elimination metabolism. The dialysis recovery for the nitroaromatic compound from goldfish in recovery studies were from 57% to 71%, and the deviation of the averaged recovery did not exceed 16%. It can be assumed that the final values can be slightly underestimated. Based on the Kow and the uptake rate constant, Wang et al. (1999) estimated the time to reach 90% steady-state concentration, in SPMD and in goldfish, in 4.08 and 6.64 days, respectively, and the elimination rate in 0.57 (hours^-1) and 0.35 (hours^-1) for SPMDs and goldfish, respectively.

 

Canton et al. (1985) determined experimentally a BCF of 20 for 2-nitrotoluene on fish (P. reticulata).

 

Fish (calculated):

The log Kow (2.3) for 2-nitrotoluene indicates a weak bioaccumulation potential. According to the TGD, BCF data for fathead minnows (P. promelas) for substances with log Kow < 6 can be estimated following the equation:

 

Log BCF = 0.85 * log Kow  - 0,70 = 0.85 * 2.3 - 0.70 BCF = 17.99

 

Additionally, Canton et al. (1985) calculated a theoretically value of BCF = 39, according to the view of octanol/water partition coefficient, in aquatic species using the formula log BCF = 0.76 * log Pow  - 0.23. This value was not considered for the assessment, since experimental data and a calculated value according to TGD are available.

 

Sabljic (1987) predicted the bioconcentration factor of 2-nitrotoluene from the molecular connectivity model log BCF = 1.58 (BCF = 38), calculated by the computer program GRAPH III. Molecular connectivity is a method of describing molecular structure based solely on bonding and branching patterns rather than physical or chemical characteristics.

 

Summary:

In summary, the bioconcentration factor (BCF) for 2-nitrotoluene has been experimentally determined to be between 4.4 (based on fat content) and 29.9. BCF values of 17.99 and 39 have been calculated based on different models using the log octanol/water partition coefficient (log Kow) of 2.30. These BCF values suggest that 2-nitrotoluene can be considered as non accumulative (BCF<100) and will not bioaccumulate significantly in fish.

 

Bioconcentration data are only available for freshwater fish. A BCF of 20 has been chosen as an average value for further calculations. This value suggests that 2-nitrotoluene can be considered as a substance with low accumulative potential (BCF<100), and will not bioaccumulate significantly in fish, due to the rapid elimination metabolism in these organisms (elimination rate of 0.35 hours-1; half life of ca.2 hours).

 

secondary poisoning

According to the low bioaccumulation potential and the rapid elimination of this compound in fish and mammals, no secondary poisoning potential is expected from this substance.

Executive summary:

EU Risk Assessment, 2008

Summary:

In summary, the bioconcentration factor (BCF) for 2-nitrotoluene has been experimentally determined to be between 4.4 (based on fat content) and 29.9. BCF values of 17.99 and 39 have been calculated based on different models using the log octanol/water partition coefficient (log Kow) of 2.30. These BCF values suggest that 2-nitrotoluene can be considered as non accumulative (BCF<100) and will not bioaccumulate significantly in fish.

 

Bioconcentration data are only available for freshwater fish. A BCF of 20 has been chosen as an average value for further calculations. This value suggests that 2-nitrotoluene can be considered as a substance with low accumulative potential (BCF<100), and will not bioaccumulate significantly in fish, due to the rapid elimination metabolism in these organisms (elimination rate of 0.35 hours-1; half life of ca.2 hours).

Secondary poisoning:

According to the low bioaccumulation potential and the rapid elimination of this compound in fish and mammals, no secondary poisoning potential is expected from this substance.

Reference 3

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

(Q)SAR

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

results derived from a (Q)SAR model, with limited documentation / justification

Principles of method if other than guideline:

Method: other: calculated with BCFWIN v. 1.66

GLP compliance:

no

Type:

BCF

Value:

11.78

The log Kow of 2.30 was used for estimation

Executive summary:

QSAR calculation (Bayer Industry Services, 2006)

The BCF value was calculated with the software EPI Suite (BCFWIN v. 1.66) using the log Kow of 2.30 for estimation. The QSAR calculation resulted in a BCF value of 11.78.

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".

EU Risk Assessment, 2008

Summary:

In summary, the bioconcentration factor (BCF) for 2-nitrotoluene has been experimentally determined to be between 4.4 (based on fat content) and 29.9. BCF values of 17.99 and 39 have been calculated based on different models using the log octanol/water partition coefficient (log Kow) of 2.30. These BCF values suggest that 2-nitrotoluene can be considered as non accumulative (BCF<100) and will not bioaccumulate significantly in fish.

BUA report (1989)

The log Kow values for the isomeric nitrotoluenes indicate weak bioaccumulation.

The 1986 MITI List attributes little or no bioaccumulation to nitrotoluenes (MITI, 1986).

Dutch authors (Canton et al., 1985) give the following bioconcentration factor for o-nitrotoluene in the guppy (Poecilia reticulata), based on the fresh weight (no further experimental details are given): BCF = 20 (log BCF = 1.3).

Another study (Deneer, et al., 1987) on the accumulation of o-nitrotoluene in the guppy (Poecilia reticulata) gave the following bioconcentration factor, based on fat content, in a 3-day test with an o-nitrotoluene concentration of 6.6. mg/l: BCF = 190.6 (log BCF = 2.28).

QSAR calculation (Bayer Industry Services, 2006)

The BCF value was calculated with the software EPI Suite (BCFWIN v. 1.66) using the log Kow of 2.30 for estimation. The QSAR calculation resulted in a BCF value of 11.78.