Environmental Engineering Reference
In-Depth Information
15.6 Toxic Hazards of Pesticide Exposure in Man (General)
Exposure to pesticides, either directly or indirectly, may induce acute or chronic health
impairment to humans.
15.6.1 Acute Intoxication
Almost half of the world's 6.5 billion people live in rural areas, mostly in farm households.
Of the roughly 2 billion workers in the world, in 1990, 1.1 billion (over half) were farmers,
the largest occupationally exposed group. Of these, 95% lived and worked in developing
countries (WRI 1994).
Toxic outbreaks or collective poisonings have resulted from misuse of almost every type
of pesticide: OCPs such as DDT, lindane, and chlordane; chlorinated camphenes such as
toxaphene; cyclodienes such as aldrin and dieldrin; OP and carbamate cholinesterase inhib-
itors; organomercury fungicides; inorganics; and others (Ferrer and Cabral 1993). Acute poi-
soning incidents can occur in any country. In recent years, they have become less common
in developed countries than in developing countries. But unfortunately, reliable statistics
on individual poisonings by pesticides are difficult to obtain (Hodgson and Levi 1996).
Acute human pesticide poisoning represents a significant cause of morbidity and mortal-
ity in underdeveloped and developing countries. The World Health Organization (WHO)
estimated that there are approximately 3 million cases of APP annually, with 220,000 deaths.
On the basis of a survey of self-reported minor poisoning carried out in the Asian regions, it
is estimated that there could be as many as 25 million agricultural workers in the develop-
ing world suffering an episode of poisoning each year (Jeyaratnam 1990). About 95% of fatal
pesticide poisoning occurs in less developed countries (Ellenhorns et al. 1997). OP and CM
pesticides are believed to cause tens of thousands of deaths and many more clinical poi-
sonings every year. The principal mechanism of their action, namely the inhibition of cho-
linesterase group of enzymes, is also responsible for numerous and differing toxic effects
that are mediated by other mechanisms, such as inflammation, immunotoxicity, myopathy,
genetic toxicity, oncogenicity, and developmental and reproductive toxicity (Ballantyne and
Marrs 1992). Moreover, reported use of certain OP and CM pesticides was associated with
increased non-Hodgkin's lymphoma (NHL) incidences (Dreiher and Kordysh 2006).
Many researchers tried to correlate various enzymes with the harmful effects of pes-
ticides, especially in the case of glutamate oxaloacetate transaminase (GOT), glutamate
pyruvate transaminase (GPT), and alkaline phosphatase (ALP) (Misra et al. 1985; Kamal
et al. 1990; Azmi et al. 2006).
15.6.2 Chronic Effects
Recently, public concern over potential adverse health effects has focused on a number
of chronic end points—carcinogenesis, developmental and reproductive effects, immuno-
logical effects, neurotoxicity, cytogenetic damage, and endocrine disruption. Next is a brief
survey of the most reported chronic effects of pesticides in humans.
i. Carcinogenesis : Through linear risk extrapolation of animal data and maximum
exposure levels of 550 million people, it is reported that there are 37,000 cancer
cases yearly associated with pesticide use in developing countries (WHO 1990).
Search WWH ::




Custom Search