Substance Identity
CAS Number 78-79-5
Chemical Name 1,3-Butadiene, 2-methyl-
Type of substance Organic
SMILES C(C=C)(=C)C
Moiety of concern organic
Categorization Results

Meets Government of Canada Categorization Criteria? Yes
Meets Human Health Categorization Criteria? Yes
Meets Environmental Criteria for Categorization? No
Persistent (P)? No
Rational for P Category
Bioaccumulative (B)? No
Rational for B Experiment
Inherently Toxic to Aquatic Organisms (iT)? No
Rational for iT Experiment
DSL Quantity range (tonnes/year) >1000T

Ecological data supporting decisions

Underlying data regarding persistence

Media of concern leading to Categorization Air
Experimental Biodegradation half-life (days) Not Available
Predicted Ultimate degradation half-life (days) 15
MITI probability of biodegradation 0.6729
TOPKAT probability of biodegradation 0.004
Experimental Ozone Reaction half-life (days) 0.801282051282051
Reference (ozone reaction) ATKINSON,R.; KINETICS AND MECHANISMS OF THE GAS-PHASE REACTIONS OF THE HYDROXYL RADICAL WITH ORGANIC COMPOUNDS.; JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA. MONOGRAPH NO. 1.; 1989
EPI Predicted Ozone reaction half-life (days) 0.8186
Experimental Atmospheric Oxidation half-life (days) 0.105885588558856
Reference (oxidation) ATKINSON,R.; KINETICS AND MECHANISMS OF THE GAS-PHASE REACTIONS OF THE HYDROXYL RADICAL WITH ORGANIC COMPOUNDS.; JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA. MONOGRAPH NO. 1.; 1989
EPI Predicted Atmospheric Oxidation half-life (days) 0.1017

Underlying data regarding Bioaccumulation

Empirical Log Kow 2.42
Reference (Log Kow) CLOGP (1986)
Log Kow predicted by KowWin 2.58
Log BAF T2MTL predicted by Gobas 0.798941949577408
Log BCF 5% T2LTL predicted by Gobas 0.770247490097667
Log BCF Max predicted by OASIS 2.06810889317883
Log BCF predicted by BCFWIN 1.163
Experimental BCF (log) 1.04252799691936
Reason for pivotal value Average Vertebrate BCF
Test species BCF/BAF (Latin) Cyprinus carpio
Test species BCF/BAF (Common) Common carp
Mean water concentration (ug/l) 50
Mean water concentration (comment) Below water solubility by a factor of 5
Water concentration: Measured/Nominal/Uncertain Measured
RadioLabel No
Exposure duration (days) 42
Exposure duration (comment) Sufficient exposure duration for 80% steady state; "Reported steady state"
Exposure type Flow-through
Mean temperature (deg. Celcius) 22
Exposure route Water (but fed)
Exposure media Fresh Water
Mean measured lipid content (%) 4.8
Tissue analysed Whole body
Calculation method Cb/Cw
Comment (BAF/BCF) Average BCF; Apparent measured water concentrations; Reported "Steady state"
Reference (BAF/BCF) Chemicals Evaluation and Research Institute. 1992. Biodegradation and Bioconcentration of Existing Chemical Substances under the Chemical Substances Control Law. http://qsar.cerij.or.jp/cgi-bin/DEGACC/index.cgi?e

Underlying data regarding inherent toxicity to aquatic organisms

Pivotal value for iT (mg/l) 42.54
Experimental result iT (mg/l) 42.54
Exposure duration iT (hours) 96
Robust Study Summary iT
78795-AT-LC50-F-Lebret.doc
78795-AT-LC50-F-Lepmac.doc
78795-AT-LC50-F-Pimpro.doc
78795-AT-LC50-F-Caraur.doc
Toxicity to fathead minnow (LC50 in mg/l) as predicted by Topkat v6.1 59.3
Toxicity to fish (LC50 in mg/l) as predicted by Ecosar v0.99g 14.39
Toxicity to fish (LC50 in mg/l) as predicted by Oasis Forecast M v1.10 29.1578
Toxicity to fish (LC50 in mg/l) as predicted by Aster 26.658725
Toxicity to fish (LC50 in mg/l) as predicted by PNN 11.87688
Toxicity to daphnia (EC50 in mg/l) as predicted by Topkat v6.1 3.2
Toxicity to fish, daphnia, algae or mysid shrimp (EC50 or LC50 in mg/l) as predicted by Ecosar v0.99g 2.743
Chronic toxicity to daphnia or algae (EC50 in mg/l) as predicted by Ecosar v0.99g 1.061
Toxicity to fish (LC50 in mg/l) as predicted by Neutral Organics QSAR in Ecosar v0.99g 1.44E+001

Human Health data supporting decisions
Underlying data regarding potential for exposure

LPE/IPE/GPE Greatest Potential for Exposure (HC Simple Exposure Tool)

Underlying data regarding Previous Assessments

Underlying data regarding Simple Hazard Assessment

AgencyAssessment
EC Genotoxicity - Category 3
IARC Carcinogenicity - Group 2B
NTP Carcinogenicity - Reasonably anticipated to be a human carcinogen
EC Carcinogenicity - Category 2

Underlying data regarding Complex Hazard Assessment