Pesticide Residues in Milk and Milk Products - Pesticides: Evaluation of Environmental Pollution - page 577

TABLE 18.1
Physicochemical Properties of Some Pesticide Residues

Water
Solubility
mg/L at 25°C

Type of
Compound log P Excretion in Mammals

Organochlorine Residue
Lindane 8.5 3.5 It is fairly readily metabolized by animals to

pentachlorocyclohexane, 1,2,4-trichlorobenzene, and isomeric
trichlorophenols and excreted as glucuronic acid derivatives.

Dieldrin 0.186 4.32-5.4 Some accumulation of dieldrin occurs in animal tissue, particularly

fat; dieldrin is very slowly metabolized to water-soluble products
that are excreted from the body.

DDT 0.005 6.19 It is metabolized (very slowly) to a range of saturated and

unsaturated products by progressive dechlorination.

Heptachlor 0.056 5.44 Residues accumulate in fatty tissues and are excreted in milk.

Endosulfan 0.32-0.33 4.74 a In animals, heptachlor metabolizes to the epoxide, which can be

found in most body organs, but it particularly accumulates in
body fat.
Rapidly metabolized and excreted by mammals.

Organophosphorus residues
Fenitrothion

14 b 3.43 Rapid mammalian metabolism and excretion. The most important

metabolites are dimethylfenitrooxon and 3-methyl-4-nitrophenol.

Fenthion 4.2 4.84 Elimination of residues in mammals by excretion of hydrolysis

products. Major metabolites are fenthion sulfoxide and sulfone
and their oxygen analogs. Further degradation of these
metabolites to the corresponding phenols can occur.

2,4-D 620 2.62 Rapidly eliminated from mammals (as parent compound), often

within 24 h. Maximum organ concentration is reached in
approximately 12 h.

Atrazine 33 2.3 In mammals, rapid and complete metabolism of ingested residues

is primarily by oxidative dealkylation of the amino groups.

Carbamate residues
Aldicarb

4930 b 1.36 Aldicarb is toxic to mammals, but sublethal doses are metabolized

rapidly with over 90% excreted in 3-4 days.

Carbaryl 120 1.59 In mammals, carbaryl does not accumulate and is rapidly

metabolized to nontoxic substances, particularly 1-napthol, and
excreted.

Propoxur 0.14 1.9 In mammals, metabolism, principally to 2-hydroxyphenyl-N-

methylcarbamate and 2-isopropoxyphenol, and excretion in the
urine are rapid.

Pyrethroids
Cypermethrin

0.004 6.6 In rats, it is virtually eliminated from the body within 8 days with

extensive metabolism occurring.

Deltamethrin 0.006 6.1 b In insects and mammals, elimination is by hydrolysis,

hydroxylation, and elimination as glucoside conjugate.

Permethrin <0.2 µg 4.6 In rats, it is virtually eliminated from the body within 8 days with

extensive metabolism occurring.

Source: From Tomlin, C. 2000. The Pesticide Manual: A World Compendium , 15th edn. British Crop Protection

Council.

a 22°C.
b 20°C.