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Endosulfan

DESIGNATIONS

CAS No.: 115-29-7
Registry names: Endosulfan
Chemical name: 6,7,8,9,10,10-Hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxide
Synonyms, Trade names: Beosit, Thiodan, Thiofor, Malix
Chemical name (German): Endosulfan, 6,7,8,9,10,10-Hexachlor-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxid
Chemical name (French): Endosulfane
Appearance: yellow to brownish-yellow crystalline solid; odour like SO2
Note: Technical endosulfan is a mixture of endosulfan isomers (80% a -isomer / 20% b -isomer)

BASIC CHEMICAL AND PHYSICAL DATA

Empirical formula:

C9H6Cl6O3S

Rel. molecular mass:

406.95 g

Density:

1.745 g/cm3

Relative gas density:

14.1

Boiling point:

106°C at 0.9 hPa (partial decomposition)

Melting point:

technical 70-100°C

a -isomer 108-109°C

b -isomer 206-208°C

Vapour pressure:

< 1 x 10-3 Pa

Solvolysis/solubility:

 in water 1.4 mg/l;
in benzene 33 g/l;
in xylene 45 g/l;
in chloroform 50 g/l;
in tetrachloromethane 29 g/l;
in methanol 11 g/l.

ORIGIN AND USE

Usage:
Endosulfan is an insecticide.

Origin/derivation:
Endosulfan is produced from hexachlorocyclopentadiene, by Diels-Alder reaction with butenediol, followed by cyclisation with thionyl chloride.

Production figures:
KOCH (1989) estimates the annual production in the Federal Republic of Germany as approx. 2,500 t.

Toxicity

Mammals:

Rat:

LD50 30-110 µg/kg, oral

acc. PERKOW, 1992
 

LC50 10-30 µg/m3, inhalation (4 h)

acc. PERKOW, 1992
 

LD50 730 µg/kg, dermal

acc. PERKOW, 1992

Mouse:

LD50 6.9-13.5 mg/kg, oral

acc. KOCH, 1989

Aquatic organisms:

Fish

LC50 1.2-1.5 mg/l (96h)

acc. PERKOW, 1992

Characteristic effects:

Humans/mammals: Resorption following oral intake is a slow process which is however promoted by fats. Rapid metabolic degradation takes place in the organism with the formation of endosulfandiol. Non-metabolised endosulfan is excreted with urine as are the degradation products. According to KOCH (1989), bioaccumulation is not to be expected. Liver and kidney damage have only been found to date in animal experiments. There are no data available on mutagenic or carcinogenic potentials.

ENVIRONMENTAL BEHAVIOUR

Endosulfan is stable under normal conditions. Hydrolysis takes place in an acetic or alkaline aqueous medium with the formation of less toxic diol and sulphur dioxide. The chemical structure of endosulfan is such that it is more reactive than DDT or lindane.

The environmental behaviour is determined by the poor solubility in water and the volatility of the substance. It is not accumulated in biotic and abiotic media because of its reactivity. Rapid degradation takes place.

Attention should be paid to the high toxicity in aquatic organisms (water hazard class 3).

ENVIRONMENTAL STANDARDS

Medium/ acceptor

Sector

Country/ organ.

Status

Value

Cat.

Remarks

Source

Water:

Drinkw

D

L

0.1 mg/l

    

acc. KOCH, 1989

Drinkw

D

L

0.5 mg/l

   As sum total for pesticides acc. KOCH, 1989

Drinkw

DDR

L

5 mg/l

     acc. KOCH, 1989
 

SU

  

1-3 ng/l

   Fish breeding waters acc. KOCH, 1989

Air:

Workp

SU

(L)

0.1 mg/m3

PDK

   acc. SORBE, 1989

Workp

USA

(L)

0.1 mg/m3

TWA

   ACGIH, 1989

Assessment/comments

The use of endosulfan in the vicinity of surface waters should be the subject of extremely critical assessment on account of its high toxicity in aquatic organisms.

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