Benzene

Toxicity to terrestrial plants

Administrative data

Endpoint:

toxicity to terrestrial plants: long-term

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

The target lipid model (TLM) is a framework that relates toxicity to the physicochemical properties of a nonpolar organic constituent. The TLM, and HC5, have been applied to soils and sediment using equilibrium partitioning (EqP) model. This framework utilizes organic carbon partition coefficients (Koc) to convert aquatic based effect levels (CW) to bulk soil- and sediment-based effect levels. The combined TLM-EqP framework was validated previously for soil and sediment acute and chronic toxicity endpoints. The registered substance is within the scope of the TLM and EqP frameworks.

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Refinement and validation of TLM-derived HC5 values. Independent review.

Author:

McGrath JA, Di Toro DM, Fanelli CJ

Year:

2015

Bibliographic source:

HDR, Mahwah, NJ

Reference 2

Reference Type:

publication

Title:

Extension and validation of the target lipid model for deriving predicted no-effect concentrations for soils and sediments

Author:

Redman AD, Parkerton TF, Paumen ML, McGrath JA, den Haan K, DiToro DM

Year:

2014

Bibliographic source:

Environmental Toxicology and Chemistry, 33: 12, pp. 2679-2687.

Materials and methods

Test guideline

Qualifier:

no guideline required

Principles of method if other than guideline:

The target lipid model (McGrath et el., 2015) and equilibrium partitioning model (Redman et al., 2014) as described in the cited references were used to determine soil effect levels of the registered substance. A detailed explanation of the calculation method is provided in the 'Attached justification'.
For detailed model description and justification of QSAR prediction: see fields 'Justification for type of information' and 'Attached justification'.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Benzene

EC Number:

200-753-7

EC Name:

Benzene

Cas Number:

71-43-2

Molecular formula:

C6H6

IUPAC Name:

benzene

Test material form:

not specified

Details on test material:

Common name: Benzene
No other data provided

Specific details on test material used for the study:

NA

Test organisms

1

Species:

Avena sativa

Plant group:

Monocotyledonae (monocots)

2

Species:

Brassica rapa

Plant group:

Dicotyledonae (dicots)

Results and discussion

Effect concentrations

Effect concentrations 1

Species:

Avena sativa

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

133.825 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

seedling emergence

Effect concentrations 2

Species:

Avena sativa

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

25.637 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Effect concentrations 3

Species:

Brassica rapa

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

86.405 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

seedling emergence

Effect concentrations 4

Species:

Brassica rapa

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

16.553 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The TLM-EqP predicted effect values for Benzene were 86.405 and 16.553 mg/kg soil dw for short-term (14-day LC50) and long-term effects (21-day EC10) to Brassica rapa, respectively. The TLM-EqP predicted effect values for Benzene were 133.825 and 25.637 mg/kg soil dw for short-term (14-day LC50) and long-term effects (21-day EC10) to Avena sativa, respectively.

Executive summary:

The registered substance is highly volatile which complicates environmental testing. Therefore, a modeling framework is needed to account for the bioavailability of the substance to perform read-across and data gap filling. The TLM-EqP modeling has been validated as a suitable method for predicting effect values in terrestrial plants. The TLM-EqP predicted effect values for Benzene were 86.405 and 16.553 mg/kg soil dw for short-term (14-day LC50) and long-term effects (21-day EC10) to Brassica rapa, respectively. The TLM-EqP predicted effect values for Benzene were 133.825 and 25.637 mg/kg soil dw for short-term (14-day LC50) and long-term effects (21-day EC10) to Avena sativa, respectively.