Uses and Environmental Pollution of Biocides - Pesticides: Evaluation of Environmental Pollution - page 16

rather than capital-intensive. Environmental Effects Monitoring (EEM) reduces reliance on
high-end analytical chemistry with its large capital costs and lengthy training. EEM can
involve many other types of biological measures such as fish health, fecundity, immune
suppression, etc. Many of these tests are simple and are of low cost (Ongley 1996).
Based on the limited literature on pesticide use and impacts in Africa, Calamari and
Naeve (1994) conclude that:
The concentrations found in various aquatic compartments, with few exceptions are
lower than in other parts of the world, in particular in developed countries which have
a longer history of high pesticide consumption and intense use. Generally, the coastal
waters, sediments and biota are less contaminated than inland water environmental
compartments, with the exception of a few hot spots.
One of the mandates of the Basel Convention is to help countries eliminate their stock-
piles of obsolete pesticides. Stockpiles have accumulated largely because some products
that were banned for health or environmental reasons were never properly discarded.
These pesticides contain some of the most dangerous insecticides produced—members of
the POPs group. These dangerous chemicals threaten communities through the potential
contamination of food, water, soil, and air. Poor communities are the most vulnerable to
environmental degradation of this sort.
1.3.3 Pesticides Residues in Food
Pesticide use may lead to traces of residues in food. When a crop is treated with a pesti-
cide, a very small amount of the pesticide, or indeed what it changes to in the plant (its
“metabolites” or “degradation products”), can remain in the crop until after it is harvested
(residues). Occasionally, residues may also result from environmental or other “indirect”
sources. Many of the broad-spectrum pesticides do not biodegrade readily and remain
in the environment for many years, where they contaminate air, water, soil, and other
resources. Residues of old pesticides, such as DDT (banned in the developed countries
for many years), are an example of such environmental contaminants. Chlorinated pesti-
cides accumulate in animals and humans and biomagnify in the food chain at different
levels. Food consumption has been identified as the major pathway of human exposure,
accounting for >90% compared to other ways of exposure such as inhalation and dermal
contact. The major food sources of POPs have been reported to be fat-containing animal
products, fish, and shellfish (Fries 1995). Therefore, dietary intake studies have been car-
ried out extensively in most developed countries.
The monitoring program is the prime means of ensuring that pesticides are used in accor-
dance with Good Agricultural Practice . The program is essential to the elimination of abuses
in the use of pesticides, such as use of excessive dose rates, failure to respect the minimum
periods specified between last application and harvest (i.e., preharvest intervals), and use
for purposes for which they are not authorized (i.e., illegal uses). When used in accordance
with Good Agricultural Practice , unacceptable levels of pesticide residues should not occur
in treated produce (IDAFRD 2001). Monitoring programs for EU countries are conducted
on a regular basis to evaluate the health risks of pesticides. In 2004, 47% of fruit, vegetables,
and cereals consumed in Europe contained pesticide residues according to the annual DG
SANCO report (European Commission 2006).
Pesticide residue levels in treated crops are regulated through the establishment of max-
imum residue levels (MRLs). EPA sets MRLs, or tolerances, for pesticides that can be used