Uses and Environmental Pollution of Biocides - Pesticides: Evaluation of Environmental Pollution - page 14

1.3.1 Human Health
Global use of pesticides creates substantial health impacts in all parts of the world,
although the exact toll is difficult to pinpoint, given both the various chemicals and the
types of exposure. In short, not all pesticides are equally risky, and not all people are
equally at risk. There are two broad categories of health effects caused by pesticides: short-
term effects (acute effects), which appear immediately or very soon after exposure, and
long-term effects (chronic effects), which may manifest themselves many years later and
whose origins are often difficult to trace.
The four routes of exposure are skin (dermal), lungs (inhalation), mouth (oral), and
eyes. Suspected chronic effects from exposure to certain pesticides include birth defects,
toxicity to a fetus, benign or malignant tumors, genetic changes, blood disorders, nerve
disorders, endocrine disruption, and reproduction effects. The symptoms of pesticide
poisoning can range from a mild skin irritation to coma or even death. Different classes
or families of chemicals cause different types of symptoms. Individuals also vary in their
sensitivity to different levels of these chemicals (Lorenz 2009). For instance, mild organo-
phosphate poisoning manifests in the form of malaise, vomiting, nausea, diarrhea, loose
stools, sweating, abdominal pain, and salivation. Moderate poisoning includes dyspnea,
decreased muscular strength, bronchospasm, miosis, muscle fasciculation, tremor, motor
incoordination, bradycardia, and hypotension/hypertension. Severe manifestation
could result in coma, respiratory paralysis, extreme hypersecretion, cyanosis, sustained
hypotension, extreme muscle weakness, muscular paralysis, and convulsion (Iowa State
University 1995). Pesticides can cause a range of adverse effects on human health, includ-
ing injury to the nervous system, lung damage, reproductive dysfunction, dysfunction
of the endocrine and immune systems, and possibly cancer. Breast cancer is major pub-
lic health concern. A number of studies have pinpointed the causal link between body
burden of some organochlorine pesticides and the higher risk of breast cancer in some
developing countries (Tawfic Ahmed et al. 2001).
Exposure to pesticides is mainly divided into three categories: occupational exposure
(spray operators and farm), accidental exposure, and pesticide residues in food. Workers
with occupational exposures to pesticides on average have significantly greater exposure
than the rest of the population (Ongley 1996). Although attempts to reduce pesticide use
through organic agricultural practices and the use of other technologies to control pests
continue, exposures to pesticides occupationally, through home and garden use, through
termite control or indirectly through spray drifts, and through residues in household
dust, food, and water are common (Fenner-Crisp 2001). Even in developed countries,
despite the strict regulations and the use of safer pesticides, occupational exposures may
be significant.
The majority of pesticide poisonings and deaths occur in the developing world and
account for a staggering 99% of the related deaths, although these countries use only 25%
of global pesticide production (FAO Newsroom 2004).
Reasons for this include the following: developing countries have a higher proportion
of the population involved in agriculture, their safe-health standards can be inadequate
or nonexistent, they have poorer pesticide handling practices, they commonly use unsafe
equipment, and their knowledge of health risks and safe use is limited. Also, harmful
pesticides are easily accessible (Ongley 1996). The World Health Organization and the
United Nations Environment Programme estimate that each year, 3 million workers in
agriculture in the developing world experience severe poisoning from pesticides, about
18,000 of whom die (Miller 2004). It is believed that in developing countries, the incidence