Properties and Uses of Chlorpyrifos in the United States - Reviews of Environmental Contamination and Toxicology - page 14

Table 1 Physicochemical properties of chlorpyrifos
Parameter Values for Chlorpyrifos Source

Chemical Name O,O-diethyl o-(3,5,6-trichloro-2-pyridyl

phosphorothioate

USEPA ( 2011b )

Chemical Abstracts Service
(CAS) Registry Number

2921-88-2

Empirical formula C 9 H 11 Cl 3 NO 3 PS

USEPA Pesticide Code (PC #) 59101

Smiles notation S = P(OC1 = NC(=C(C = C1Cl)Cl)Cl)(OCC)

OCC

Molecular mass 350.6 g mol −1 Mackay et al.

(2014 )

Vapor pressure (25 °C) 1.73 × 10 −5 torr

Water solubility (20 °C) 0.73 mg L −1

Henry's Law Constant 1.10 × 10 −5 atm m −3 mol −1

Log K OW 5.0

Table 2 Environmental fate properties of chlorpyrifos
Parameter Values Source

Hydrolysis (t½) pH 5: 73 d USEPA ( 2011b )

pH 7: 72 d
pH 9: 16 d

Aqueous photolysis (t½) 29.6 d

Aerobic soil metabolism (t½) 2-1,576 d, N = 68 (next highest value

is 335 d)

See SI Table A-1

Aerobic aquatic metabolism (t½) 22-51 d, N = 3 See SI Table A-5

Anaerobic soil metabolism (t½) 15 and 58 d USEPA ( 2011b )

Anaerobic aquatic metabolism (t½) 39 and 51 d

Soil adsorption coefficient K OC 973-31,000 mL g −1 , N = 33 See SI Table A-4

Terrestrial field dissipation (t½) 2-120 d, N = 58 See SI Table A-3