Tetrabutylammonium bromide

Biodegradation in soil

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in soil

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Qualifier:

according to guideline

Guideline:

other: Modeling database

Principles of method if other than guideline:

Fugacity Model by EPI Suite estimation database

GLP compliance:

no

Test type:

other: Estimated

Radiolabelling:

not specified

Oxygen conditions:

other: Estimation

Soil classification:

not specified

Details on experimental conditions:

Level III Fugacity model
EPI Suite contains a Level III fugacity model. In general, fugacity models predict the partitioning of an organic compound in an evaluative environment. A Level III model assumes steady-state but not equilibrium conditions. The Level III model in EPI Suite predicts partitioning between air, soil, sediment and water using a combination of default parameters and various input parameters that may be user defined or estimated by other programs within EPI Suite.

The model environment consists of 4 main compartments: air, water sediment and soil. There are also sub-compartments such as an aerosol phase, suspended solids, and biota phase, within specific main compartments. A fixed temperature of 25ᵒC is assumed. Mass transport between the compartments via volatilization, diffusion, deposition and runoff are modeled. level III models is a steady state, non-equilibrium model. Steady state conditions mean that the change in concentration of a chemical in each compartment (i) with respect to time eventually approaches zero. The model does not assume that a common equilibrium (fugacity) exists between the phases, so if a chemical is emitted into one compartment it can partition to the other compartments. Loss of chemical occurs through two processes: reaction and advection. Reaction is the biotic or abiotic degradation of the chemical that is calculated using the user specified or model calculated half-lives of the chemical in each of the 4 main compartments. Advection processes are considered for the air, water and sediment compartments. Advection is the removal of chemical from a compartment through losses other than degradation (reaction). The rate of advection in a given compartment is determined by a flow rate (m3/hour), calculated by dividing the volume of the compartment by an advection time.

Soil No.:

#1

% Recovery:

77.3

Remarks on result:

other: other details not available

Key result

Soil No.:

#1

% Degr.:

50

Parameter:

other: Half life

Sampling time:

17.33 d

Remarks on result:

other: other details not available

Key result

Soil No.:

#1

DT50:

17.33 d

Type:

other: estimated data

Remarks on result:

other: 17.33 d = 416 h; other details not available

Transformation products:

not specified

Conclusions:

Biodegradation half-life of test chemical in soil was estimated to be 17.33 days (416 hrs).

Executive summary:

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (2018). If released into the environment, 81% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 17.33 days (416 hrs). Based on half-life value, it is concluded that the test chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

Description of key information

Biodegradation in Soil and sediment:

The substance does not have widespread professional, and consumer uses in plant protection product which was further confirmed by the registrant as well as its downstream users. Thus, the studies focusing on Soil and Sediment compartments by following OECD 307 and 308 can be excluded in absence of widespread use. The same information is also updated in Chemical safety report (CSR).

 

Furthermore, based on the results of OECD 302B which clearly indicates that test substance is inherently biodegradable in water with degradation percentage of 80.74% in 28 days of exposure duration, by following all the validity criteria as per the selected test guidelines. Since substance is highly soluble in water, also considering the results based on OECD 302 B along with actual uses of the substance, we consider the most suitable method for the simulation study would be with aerobic mineralisaiton by surface water following OECD 309 test guidelines.

 

The above-mentioned OECD 309 study is currently ongoing and results along with robust study summary will be soon updated within the dossier.

EPI data:

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (2017). If released into the environment, 81% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 17.33 days (416 hrs). Based on half-life value, it is concluded that the test chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

Key value for chemical safety assessment

Half-life in soil:

17.33 d

at the temperature of:

25 °C

Additional information

Biodegradation in Soil and sediment:

The substance does not have widespread professional, and consumer uses in plant protection product which was further confirmed by the registrant as well as its downstream users. Thus, the studies focusing on Soil and Sediment compartments by following OECD 307 and 308 can be excluded in absence of widespread use. The same information is also updated in Chemical safety report (CSR).

 

Furthermore, based on the results of OECD 302B which clearly indicates that test substance is inherently biodegradable in water with degradation percentage of 80.74% in 28 days of exposure duration, by following all the validity criteria as per the selected test guidelines. Since substance is highly soluble in water, also considering the results based on OECD 302 B along with actual uses of the substance, we consider the most suitable method for the simulation study would be with aerobic mineralisaiton by surface water following OECD 309 test guidelines.

 

The above-mentioned OECD 309 study is currently ongoing and results along with robust study summary will be soon updated within the dossier.

EPI data:

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (2017). If released into the environment, 81% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 17.33 days (416 hrs). Based on half-life value, it is concluded that the test chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.