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Dichlorvos

DESIGNATIONS

CAS No.: 62-73-7
Registry name: Dichlorvos
Chemical name: 2,2-Dichlorovinyl dimethyl phosphate
Synonyms, Trade names: 2,2-Dichloroethenyl dimethyl phosphate, O,O-dimethyl O-(2,2-dichlorovinyl) phosphate, DDVP, Nuvan, Vapona
Chemical name (German): Dichlorvos
Chemical name (French):
Dichlorvos
Appearance:
colourless to yellowy liquid

BASIC CHEMICAL AND PHYSICAL DATA

Empirical formula:

C4H7Cl2O4P

Rel. molecular mass:

220.98 g

Density:

1.314 g/cm3

Relative gas density:

7.63

Boiling point:

74C (at 1.32 hPa)

Vapour pressure:

1.6 Pa

Solvolysis/solubility:

in water: 10 g/l

miscible with most organic solvents

Conversion factors:

1 ppm = 9.19 mg/m3

1 mg/m3 = 0.11 ppm

ORIGIN AND USE

Usage:
Dichlorvos is an insecticide that mainly acts via the gas phase due to its relatively high vapour pressure. It may also be used as a contact insecticide. Dichlorvos is applied in form of aerosols or baits against flies and mosquitos.

Toxicity

Mammals:

Rat:

LD50 56-108 mg/kg, oral

acc. WHO, 1986

Rat:

LD50 75-210 mg/kg, dermal

acc. WHO, 1986

Rat:

LD50 56-80 mg/kg, oral

acc. WIRTH, 1981

Aquatic organisms:

Carp:

TLM > 40 mg/l (48 h)

acc. WHO, 1986

Goldfish:

TLM 10-40 mg/l (48 h)

acc. WHO, 1986

Water flea:

TLM 2.8 mg/l (3 h)

acc. WHO, 1986

Characteristic effects:

Humans/mammals: Intake takes place either by inhalation or via the gastro-intestinal tract. As is the case with phosphoric acid esters, dichlorvos is only slightly resorbed in the body. Above all, dichlorvos inhibits acetylcholinesterase and thus impairs the central nervous system. The symptoms are comparable to those of paraquat. According to WIRTH (1981), dichlorvos does not represent a genetic risk.

ENVIRONMENTAL STANDARDS

Medium/ acceptor

Sector

Country/ organ.

Status

Value

Cat.

Remarks

Source

Air:

Workp

D

L

1 mg/m3

MAK   DFG, 1989

Workp

SU

(L)

0.2 mg/m3

PDK Skin acc. KETTNER, 1979

Workp

USA

(L)

1 mg/m3

TWA   ACGIH, 1986

Foodstuffs:

 

WHO

G

0.004 mg/kg/d

ADI   acc. WHO, 1986

Assessment/comments

Dichlorvos is one of the organophosphoric insecticides for which the residue problems are similar to those of halogenated insecticides. Direct contact with dichlorvos is to be avoided on account of the fact that it inhibits the respiratory system.


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