2-chloro-2-methylbutane

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Study period:

2017-01-23

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:

1. SOFTWARE
ECOSAR v 1.00

2. MODEL
ECOSAR v.1.00, EPI Suite v4.10 developed by US EPA (©2000-2011)
Neutral Organics

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CAS No. 594-36-5, further input logKow =2.52, water solubility=329 mg/L, MP= -73.5°C.
4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: Green Algae, 96 h, EC50, Neutral Organics
- Unambiguous algorithm: Log 96-h EC50 (mmol/L) = -0.6271 log Kow + 0.5687. LC50 in millimoles per liter, to convert multiply by molecular weight.
- Defined domain of applicability: The green algae 96-h EC50 values used to develop this SAR were measured and the octanol water partition coefficients (Kow) were calculated using the computer program, KOWWIN (Version 1.67). To fall within the apllicability domain, the substance must be a solvent, non-reactive, non-ionizable neutral organic compound eg. alkyl halides. Furthermore the substance must have a logKow of maximal 6.4 and a maximum molecular weight of 1000. Limitations: If the log Kow value is greater than 6.4, or if the compound is solid and the EC50 exceeds the water solubility by 10X, no effects at saturation are predicted.

- Appropriate measures of goodness-of-fit and robustness and predictivity: Coefficient of Determination (R2) = 0.5956, N = 51 + 11-
- Mechanistic interpretation: The green algae 96-h EC50 values used to develop this SAR were measured and the octanol water partition coefficients (Kow) were calculated using the computer program, KOWWIN (Version 1.67). The (Q)SAR model is for neutral organics.

5. APPLICABILITY DOMAIN
- Descriptor domain: The substance has a logKow below 6.4, the molecular weight is 106.60 (below 1000) and belongs to the group of alkyl halides.
- Structural and mechanistic domains: Neutral organics
- Similarity with analogues in the training set: Alkyl halides are covered in the trainings set.
- Other considerations (as appropriate): The experimental logKow of 2.52, MP of -73.5 °C and water solubility of 329 mg/L has been used in the QSAR model.

6. ADEQUACY OF THE RESULT
ECOSAR v.1.00 is a well-accepted (Q)SAR model for prediction of aquatic ecotox. The substance falls in the application domain of this model. The data will be used in a weight-of-evidene approach.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: ECOSAR Program v.1.00 in EPI Suite v.4.10

Principles of method if other than guideline:

(Q)SAR estimation by ECOSAR v.1.00, EPI Suite v.4.10, developed by US EPA (©2000-2011).

Test material

Test material information

Constituent 1

Reference substance name:

2-chloro-2-methylbutane

EC Number:

209-836-2

EC Name:

2-chloro-2-methylbutane

Cas Number:

594-36-5

Molecular formula:

C5H11Cl

IUPAC Name:

2-chloro-2-methylbutane

Specific details on test material used for the study:

SMILES : C(CC)(CL)(C)C
CAS Num: 000594-36-5
MOL FOR: C5 H11 CL1
MOL WT : 106.60
Log Kow: 2.52 (User entered)
Melt Pt: -73.50 deg C
Wat Sol: 329 mg/L (measured)

Study design

Water media type:

freshwater

Total exposure duration:

96 h

Results and discussion

Effect concentrations

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

10.379 mg/L

Conc. based on:

test mat.

Remarks on result:

other: (Q)SAR estimation

Details on results:

If the log Kow of the chemical is greater than 6.4, or if the compound is solid and the EC50 exceeds the water solubility by 10X, no effects at saturation are predicted for these endpoints.
Maximum LogKow: 6.4 (Green Algae EC50)

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

The QSAR model fulfil the validity criteria.

Conclusions:

A LC50 of 10.379 mg/L for green algae (96 h) was predicted using the QSAR prediction programm ECOSAR v.1.00.