|Basic Concepts in Environment, Agriculture and Natural Resources Management: An Information Kit (IIRR, 1993, 151 p.)|
Pesticides: environmental and health effects
PESTICIDES: ENVIRONMENTAL AND HEALTH EFFECTS
Pesticides are any substance or mixture of substances used to prevent, destroy, repel or mitigate insects, rodents, nematodes, fungi, weeds and/or other organisms perceived to be troublesome (pest). Its use continues to be an essential and growing component of modern crop technologies. Also, there are several pesticides that are being used at the household level to repel or kill rats, mosquitoes and cockroaches.
However, pesticides pose health and environmental hazards, as has been documented. Worldwide statistics showed that there is a conservative estimate of two million cases of pesticide poisoning last year wherein four percent of this led to death. The problem of underreporting is noticeable because of the lack of knowledge and awareness on signs and symptoms of pesticide poisoning.
Unsafe, indiscriminate and irrational use of pesticides constitute the following:
· regular use of pesticides even when unnecessary;
· not wearing the appropriate protective clothing;
· improper storage, preparation, application and disposal of pesticides and used clothings; and,
· use of pesticides in cocktail or mixtures.
The effects of the indiscriminate use of pesticides can lead to ecological disruption. Among the effects are as follows:
· contamination of ground and surface waters; thus, killing aquatic life forms through runoff and seepage (environmental contamination);
· transmittal of pesticide residues through the food chain to the farm family and urban consumers (biological magnification);
· increase in the resistance of pest population to pesticides (resistance development); thereby, reducing efficacy and causing pest outbreak (pest succession);
· reduction in the population of beneficial insects (butterflies, spiders), parasites (earthworms) and predators; and,
· reduction in the population of microorganisms in the paddy soil and water that help sustain soil fertility while lowering chemical fertilizer use.
The effects of irrational and unsafe use of pesticides on health can lead to any of the following:
· acute poisoning (may occur from single exposure to the pesticide) which is manifested by skin and eye irritation, manifested as cough, colds and shortness of breath) respiratory tract irritation, systemic poisoning and, in some cases, death; and,
· chronic poisoning (results from months or years of continual exposure to pesticides) which can lead to nervous disorders (paralysis, numbness extremities, loss of consciousness), neurobehavioral effects (mental deterioration), anemia, sterility, birth defects and effects on the unborn (manifested as abortions, stillbirths). Chronic poisoning is also suspected to cause cancer of the lungs, brain, blood, digestive system and liver, as well as decreased body's immune system or defenses.
Because of the noted environmental and health effects of pesticides, there are several of them that have already been banned from the market. Among these are the famous DIRTY DOZEN which include Parathion, 2,4,5-T, Paraquat, DDT, Aldrin/Dieldrin/Endrin, Chlordimeform, Dibromochloropropane (DBCP), Chlordane/Heptachlor, HCH/Lindane, Ethylene dibromide, Camphechlor and Pentachlorophenyl (PCP). Organotins (Brestan and Aquatin) were also banned from the market recently.