258
C. R. Krishna Murti and T. S. S. Dikshith
light, humidity, and diverse microbial activity. The food habits of people living
in the tropic and sUbtropic regions are also quite different from those in temperate
regions. When considering the impact of toxic chemicals on human health, it
becomes imperative to take into account the climatic, socioeconomic, ethnic,
and health backgrounds (e.g., nutritional status, coexistent parasitic diseases)
of the people exposed to the chemicals.
The per-hectare use of pesticides in India is at present about 330 g as
opposed to 1490 g in Japan. The use of pesticides in India is certain to register
an upward trend in order to meet the increasing food needs of a growing population and to contain vector-borne human and cattle diseases. The use of pesticides has thus become an essential part of the Indian strategy of crop protection,
particularly under an intensive agriculture program envisaging high-yielding and
short-duration varieities of cereals and pulses. The toxicological implications of
the extensive use of pesticides in agriculture are consequently of great relevance
to problems of health planning.
Pesticides came into wide use in agriculture and public health around 1944.
The benefits, manifested as enhanced farm productivity and inexpensive control
of insect-borne diseases, were so overwhelming that the problem of their toxicity
was ignored until 1960.
Pesticides, microorganisms, soil, water, and air interact with one another
in a closed network system. Various factors are involved (Venkataraman and
Rajya Lakshmi, 1971) in the bioactivationldetoxification of pesticides in the
above network. The problem of contamination of grain, pesticides, dairy products, vegetables, and fruits and of the living environment can be visualized from
Fig. 10.1. DDT levels in some food products are listed in Table 10.1. Elucidation
of the factors controlling the interaction of pesticides with environmental factors
has posed a challenge to scientists. The symptoms of poisoning due to accidental
or occupational exposure to pesticides have been recognized in India. Episodes
of poisoning in 1955 in Cochin and Kerala (Karunakaran, 1958), in the Sitapur-Hardoi area, and in Uttar Pradesh in 1977 and the "Handigodu syndrome"
of Kamataka (Report of National Institute of Nutrition, Hyderabad, 1977) have
been documented.
Pesticidal chemicals in use today cover hundreds of organic molecules.
Among these, the "insecticides" are regarded as the ones which cause the maximum health hazards. The persistent types, such as DDT, BHC, endosulfan,
aldrin, dieldrin, endrin, heptachlor, toxaphene, and chlordane, are all varieties
of organochlorine insecticides. Being readily soluble in lipids, they accumulate
in fat deposits of man and animals. In addition, they are not metabolized fast
enough to facilitate their rapid elimination from the body.
Two other important types of insecticides are the organophosphorus compounds [exemplified by parathion, malathion, diazinon, dichlorvos, methyl demeton, phosphamidon, fenitrothion (Sumithion), dimethoate, and quinalphos]
C. R. Krishna Murti and T. S. S. Dikshith
light, humidity, and diverse microbial activity. The food habits of people living
in the tropic and sUbtropic regions are also quite different from those in temperate
regions. When considering the impact of toxic chemicals on human health, it
becomes imperative to take into account the climatic, socioeconomic, ethnic,
and health backgrounds (e.g., nutritional status, coexistent parasitic diseases)
of the people exposed to the chemicals.
The per-hectare use of pesticides in India is at present about 330 g as
opposed to 1490 g in Japan. The use of pesticides in India is certain to register
an upward trend in order to meet the increasing food needs of a growing population and to contain vector-borne human and cattle diseases. The use of pesticides has thus become an essential part of the Indian strategy of crop protection,
particularly under an intensive agriculture program envisaging high-yielding and
short-duration varieities of cereals and pulses. The toxicological implications of
the extensive use of pesticides in agriculture are consequently of great relevance
to problems of health planning.
Pesticides came into wide use in agriculture and public health around 1944.
The benefits, manifested as enhanced farm productivity and inexpensive control
of insect-borne diseases, were so overwhelming that the problem of their toxicity
was ignored until 1960.
Pesticides, microorganisms, soil, water, and air interact with one another
in a closed network system. Various factors are involved (Venkataraman and
Rajya Lakshmi, 1971) in the bioactivationldetoxification of pesticides in the
above network. The problem of contamination of grain, pesticides, dairy products, vegetables, and fruits and of the living environment can be visualized from
Fig. 10.1. DDT levels in some food products are listed in Table 10.1. Elucidation
of the factors controlling the interaction of pesticides with environmental factors
has posed a challenge to scientists. The symptoms of poisoning due to accidental
or occupational exposure to pesticides have been recognized in India. Episodes
of poisoning in 1955 in Cochin and Kerala (Karunakaran, 1958), in the Sitapur-Hardoi area, and in Uttar Pradesh in 1977 and the "Handigodu syndrome"
of Kamataka (Report of National Institute of Nutrition, Hyderabad, 1977) have
been documented.
Pesticidal chemicals in use today cover hundreds of organic molecules.
Among these, the "insecticides" are regarded as the ones which cause the maximum health hazards. The persistent types, such as DDT, BHC, endosulfan,
aldrin, dieldrin, endrin, heptachlor, toxaphene, and chlordane, are all varieties
of organochlorine insecticides. Being readily soluble in lipids, they accumulate
in fat deposits of man and animals. In addition, they are not metabolized fast
enough to facilitate their rapid elimination from the body.
Two other important types of insecticides are the organophosphorus compounds [exemplified by parathion, malathion, diazinon, dichlorvos, methyl demeton, phosphamidon, fenitrothion (Sumithion), dimethoate, and quinalphos]