Impact of - IDL-BNC @ IDRC - International Development Research ...

of chemicals, this price could increase dramatically to the point of becoming
unacceptable.
With the exception of a limited number of certain types of chemicals (pesticides,
food additives, some of the major air and drinking-water contaminants,
and some hazardous industrial chemicals), few products have been tested
appropriately for potential risks. The information available is, in most cases,
inadequate to estimate the levels that can be tolerated safely by humans.
The constant increase in the number and overall volume of chemicals on the
market increases the risk of exposure to humans and their environment
throughout the various phases of the lifespan of these substances: production,
storage, handling, transport, use, and disposal. Land-development activities,
such as quanying and dredging, also release naturally occurring chemicals
from the soil in quantities that exceed those released in normal geological
processes.
Sooner or later, many potentially toxic chemicals end up in the environment
as residue or wastes that pollute air, water, food, and soil and, thus, affect the
entire population. More and more chemicals are being added to animal feed
and more and more veterinary drugs are being administered to livestock.
Agricultural pesticides continue to increase, and their residues are found in
food together with their various metabolites.
About half a million people die every year of serious accidents resulting from
exposure to excessive doses of chemicals. The accidental leakage of methylisocyanate
at Bhopal killed over 2 000 people in a very short time, but it also
left more than 200 000 survivors severely incapacitated with painful and
irreversible lung damage.
Although, by definition and in practice, pesticides are poisons designed to kill
some forms of life, such as insects, nematodes, rodents, grasses, fungi, and so
on, most people recognize the advantages inherent in their use because of the
resulting benefits: controlling disease transmitted by vectors and increasing
agricultural productivity. To assure safe and beneficial use of pesticides, two
separate processes should take place before they are used in practice. The first
step is a scientific evaluation of any potential risk of a pesticide connected with
its intrinsic property to produce an adverse effect on humans and other biota.
The second process deals with management of the risk arising from using a
given pesticide, taking into account the balance of the risk against benefit, cost
of a product, and even local socioeconomic considerations.
Toxicologic and safety evaluation, of pesticides
Regardless of whether a pesticide molecule comes into contact with an organism
during its use as an agricultural chemical, household pesticide, or vectorcontrol
agent or is consumed as a residue in food or water, it must reach a
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