HEALTH AND ENVIRONMENTAL HAZARDS OF PESTICIDES

Romeo F. Quijano, M.D.
Professor, Univ. of the Phils. College of Medicine
President, HEAL Toxics
Pesticide Action Network Philippines


The health and environmental consequences of pesticide use are staggering, especially in Third World countries where there are less stringent regulatory controls and less effective implementation of whatever laws there are to protect public health and the environment. The use of synthetic pesticides and other chemicals results in contamination and adulteration of food, degradation and pollution of soil, water and air, and increased morbidity and mortality for the exposed population.

Production of Hazardous Pesticides

The health hazards associated with pesticide use have been known for years and the extent of harm they cause has increased, yet, chemical companies keep on pouring millions of tons of pesticides annually into the world’s biosphere. In 1995, the world pesticides market has expanded to US$30.265 billion, representing a 5% growth over the previous year and about five-fold increase over the past ten years. In 1997, despite increased environmental awareness worldwide, the major pesticide companies registered hefty profits, with sales increasing from 8% to as high as 40%. Much of these profits come from exports of pesticides already banned in their country of origin or pesticides considered “likely to cause problems under conditions of use in developing countries”. For example, more than 344 million pounds of hazardous pesticides were exported from US ports between 1992 and 1994, according to a report by the Foundation for Advancement in Science and Education. These exports included pesticides that were already banned in the U.S. and pesticides that were “severely restricted”. With the advent of “globalization”, more companies based in developed countries are being attracted to locate their active ingredient production facilities in the growing markets in the South, particularly, here in Asia. It is expected that the pesticide industry will continue to “pour” millions of tons of pesticides into this planet in the years to come.

Hazards to the Environment

Many of these pesticides being “poured” into this planet by the pesticide industry consist of pollutants that resist physical, biological, and chemical degradation. They are called “persistent organic pollutants”. They accumulate as they are taken up in the food chain and their concentrations are increased tremendously in certain tissues, like the liver. Their chemical characteristics enable them to move long distances through the atmosphere and are deposited even in areas very far away from the actual area of application. Thus, even the arctic seas are contaminated with these “persistent organic pollutants”. Examples of these “persistent organic pollutants” are DDT, endrin, lindane, endosulfan, and many other organochlorines.
Pesticides contaminate the environment in many ways. Widespread application of pesticides leads to drifting and contamination of land and waterways adjacent to target fields. Pesticide residues in soil contaminate crops subsequently grown on the same land. Pesticides in contaminated crops used as animal feeds eventually are found in meat and dairy products. Pesticides in the soil eventually also contaminate ground water, which is a source of drinking water. In the U.S., pesticides have been found to be pervasive contaminants in drinking water and 38% of food samples were found to contain pesticide residues.
A consequence of environmental contamination is the widespread killing of non-target organisms, including wildlife, cattle, birds, fish, bees, and pest’s natural enemies. This leads to loss of biodiversity and upsets the delicate balance in various ecosystems in various areas. This is made worse by the vicious cycle of pesticide-resistance. Eventually, pesticides become ineffective because of the inevitable emergence of resistant pests and crop losses ensue. This leads to the creation of new and more toxic pesticides which again eventually become ineffective because resistance will again emerge. The effect of this vicious cycle is the increasing number and amount of highly toxic pesticides in our environment leading in turn to greater loss of biodiversity and increased exposure risks to people.

Exposure and Poisoning

It has been estimated that about 25 million people are being poisoned by pesticides annually in developing countries. There is no segment of the population that is sheltered from exposure to pesticides. Exposure can occur during manufacture and formulation, transportation, storage, mixing, application and disposal. People everywhere affected through contamination of water, food, and air containing pesticide residues; by pesticides drifting from aerial spraying in plantation agriculture, from pesticides used in houses to ward off household pests, or from washing, bathing, or drinking water from irrigation ditches.
Most farmers in a Third World country are aware that pesticides are hazardous but there is lack of awareness of actual risks. The use of protective clothing is very low due to high temperature and humidity. Pesticide handlers are exposed heavily. Exposure of households in farming communities occur due to spray drifts. This exposure is further enhanced by the practice of washing the pesticide sprayers near or in irrigation canals. Farmers also use this water source for washing hands, feet, clothes, and for taking a bath. The manner of disposal of pesticide left-overs and containers also increase the risk of exposure to pesticides.
Pesticides enter the body through the skin, through breathing or through swallowing. Entry through the skin can happen through spills on clothing or directly on the skin, when pesticide spray settles on the skin or soaks clothing, when the applicator mixes pesticides with bare hands, or when touching pesticide-laden crops or clothing. Entry through breathing is most common in farmers who spray pesticides or for people nearby when spraying is done. People may not be aware that they are inhaling pesticides because some pesticides have no smell. Swallowing pesticides usually occur accidentally or on purpose, as in those committing suicide. Most people actually regularly ingest pesticides because most of the food they eat, and probably, also the water they drink, are already contaminated with pesticides.

Acute Toxicity

Most pesticides are acutely toxic and can cause death, disability, organ dysfunction, incapacitating symptoms, and various other illnesses. Immediate effects may include dizziness, headache, nausea and vomiting, abdominal pain, difficulty of breathing, palpitations, weakness, and many other symptoms which, very often, may not be readily recognized as pesticide poisoning. Depending on the degree and circumstances of the exposure, the health effects may be mild, moderate or severe.
In pesticide applicators, dizziness, headache, abdominal pain, and difficulty of breathing are a common occurrence. People predisposed to asthma are in greater risk of developing acute respiratory symptoms after exposure to pesticides. Difficulty of breathing mayoccur even with very little exposure in predisposed individuals. Weakness and tingling sensation in the extremities are also common symptoms observed in occupationally exposed individuals. These symptoms occur usually upon exposure to the organophosphate and carbamate pesticides.
Skin irritation, allergic reaction, and other skin ailments occur when there is direct contact with the pesticide. Fungicides and certain herbicides like paraquat are the more likely culprits although most other pesticides can cause ailments.
Eye irritation and blurring of vision more commonly occur with organophosphates and carbamates. These are usually transient in nature but in certain instances, like with the triphenyltin compounds or paraquat, permanent damage to the eye leading to blindness may occur.
Certain conditions may aggravate the condition of pesticide poisoning. Malnutrition, for example, can increase the susceptibility to pesticide poisoning to as much as 2,000 times. Alcohol intake can mask the early symptoms of acute poisoning and may lead to a more severe type of poisoning. Smoking cigarettes while exposed to pesticides may also aggravate pesticide poisoning. Simultaneous exposure to different types of pesticides and other poisons also increase the likelihood of adverse health effects.

Chronic Health Effects

It is not only the acute or immediate effects that make pesticides dangerous. The adverse effects of pesticides may manifest only after months or years of exposure. These chronic or long-term effects may occur even with low levels of exposure. The weight of scientific evidence show that even low levels of exposure to pesticides can cause serious immune and metabolic disorders, neurologic effects, reproductive anomalies, cancer and other chronic diseases in animals and in humans. Death rates of people are higher in areas with high pesticide usage compared to those living in areas with low pesticide usage. The higher number of deaths is not only caused by a higher rate of acute pesticide poisoning but also by a higher rate of chronic debilitating diseases.
Recent studies have shown that certain pesticides can disrupt the human endocrine system, which includes the glands that control the release of hormones in our bodies. There are also pesticides that can actually “mimic” hormones found in the human body. Such pesticides are commonly found in several countries of the South. In the Philippines, for example, countrywide surveys reveal that pesticide residues of these “hormone mimickers”, some of which are already “banned” in developed countries, are found in a wide range of vegetables and fruits. One such pesticide found in food is endosulfan. This pesticide belongs to a chemical group called “organochlorines”. Such chemicals can “mimic” the hormones in our bodies and have been associated with higher incidences of breast cancer, testicular and prostate cancer, reduction in male fertility, and defects in male sex organs.
Another pesticide belonging to this category is DDT. Residues of this pesticide long banned in developed countries have been found also in a number of vegetables and food products, not only in the Philippines, but also in other countries. In India, let me cite a survey conducted by the Punjab Agricultural University revealing the presence of DDT and HCH residues in wheat and maize flour and rice. Most of the samples contain DDT residues above the legal limit. Another study conducted by the National Institute of Nutrition, Hyderabad, for the Consumer Education and Research Center, Ahmedabad, showed that organochlorines were found in different proportions in the food samples tested consisting of food grains, milk and milk products and packaged food commodities such as jam and coffee. Four of the pesticides tested were present beyond the so-called “Maximum Residue Limit” or MRL.

Women and Pesticides

Women and children are particularly vulnerable to pesticide exposure. Most of the peasant women in the Philippines, for example, work on farms that use pesticides heavily such as rice, corn, sugar, vegetables, and fruit farms. Their important role in the food production process has been glossed over or neglected. In rice growing areas, women spend 8-10 hours soaking in pesticide-laden fields, weeding, transplanting, picking snails, and harvesting. Women bathe and wash clothes in pesticide contaminated irrigation channels. In post-harvest activities, women get in direct contact with agricultural products contaminated with chemical residues. The multiple roles of women often result in overfatigue and weakened health making them more susceptible to pesticide poisoning. A woman’s body contains more fatty tissue than a man’s body, thus she “stores” more pesticides in her body, especially in breasts. When a woman gets pregnant, she passes the pesticides to the fetus. When the baby is born, the mother will again pass the pesticides to her baby by breastfeeding her contaminated milk.
Pesticides are known to cause infertility, spontaneous abortion, stillbirths, and birth defects. Certain genital cancers may be caused by pesticides, and low sperm counts in men have been associated with pesticide exposure. In Third World countries, the adverse effects of pesticides tend to occur more frequently and are likely to be more severe because of aggravating conditions like poverty, ignorance, malnutrition, and other social, economic and political factors that are driven by the characteristics of global power relations.
Adverse health effects do not only happen to people who work with pesticides. Practically everybody has some contact with small amounts of pesticides through contaminated food, water, and air. Pesticide residues are found in samples of vegetables, fruits, rice and other kinds of food. Water samples, including those from sources of drinking water, have been found to be contaminated also by different kinds of pesticides. The use of pesticides in households and yards have also been found to be associated with serious adverse health effects. Even the use of the innocently looking household pest strip, advertised as innocuous by pesticide companies, have been associated with increased incidence of childhood leukemia.

Pesticides and Cancer

One of the more serious long term effects of pesticides on people’s health is cancer. Several pesticides are already known to cause cancer in humans. Others may not have direct evidence of causation but have shown to be associated with increased cancer incidence. Many others have been shown to cause cancer in animals but evidence of causation in humans is non-conclusive or lacking. Many more have not been shown to cause cancer, mainly because they have not been studied well. Many pesticides exhibit similarities in chemical structure and actions as other chemicals previously shown to cause cancer. Many other indirect evidences, for example, steroid-like effects, production of by-products indicating cellular damage, and disruption of intercellular communication point to the carcinogenic effects of pesticides. Indication of genetic damage, like mutations and chromosomal aberrations, as well as embryotoxicity and immunotoxicity, are also commonly associated with exposure to pesticides. Practically all pesticides are potentially cancer producing or at least cancer promoting. Even the so-called “Green Label” pesticides are potentially cancer-producing.

Pesticides and Childhood Cancer

One of the more recent concerns about pesticides is the association of childhood cancer with exposure to pesticides at home. A study published in the American Journal of Public Health has found elevated rates of cancer in children exposed to pesticides in their homes and yards. The study found a four-fold increase in the risk of soft-tissue sarcoma, a very invasive type of cancer in children whose yards were treated with pesticides. The investigators also found a link between the use of pest strips containing dichlorvos and increased incidence of childhood leukemia. Pest strips present an exceptional health risk because they emit a continuous vapor of the pesticide into the household air that the residents breathe continuously. The study also found evidence of an association between home pest extermination and lymphomas.
It is extremely difficult to prove without doubt that a certain chemical causes cancer in humans. Most available data are from animal studies. Since it takes several years for cancer to develop, the evidence of causation or association between the use of a pesticide and cancer in humans takes extremely long time to accumulate and gathering it involves a tremendous amount of resources. It is therefore important that the “precautionary principle” be applied in the evaluation, regulation and control of pesticides.

Key elements Affecting Exposure of People to Pesticides: Pesticide Industry and Pesticide Regulation

The use of pesticides, particularly in Third World agriculture, was heightened during the so-called “Green Revolution” pushed by multilateral institutions and agricultural research agencies with close links to transnational companies. Monocropping and use of “high yielding varieties” which required high inputs of chemicals practically wiped-out traditional self-reliant ways and made most farming communities in the Third World dependent on pesticides and global capital. Over time, even with no serious pest attacks, farmers increasingly applied pesticides. Sales pressures from pesticide companies pushed pesticide consumption to grow by leaps and bounds. Farmers usually obtained their knowledge about pesticide use from sales agents or government technicians highly influenced by pesticide companies. Persistent and uncontrolled advertising and promotions created an extremely unbalanced and biased information flow.
Despite international codes pertaining to pesticide regulation and control, the real situation in a Third World country is that pesticide regulation is largely ineffective. Inadequacies in enforcement capabilities resulting from socio-economic difficulties have encouraged pesticide companies to build new or move existing production facilities to Third World countries thereby facilitating exports of highly toxic and banned pesticides. This is further compounded by non-harmonized regulatory actions among Third World countries. The strained and very limited human and financial resources, the weak institutional infrastructures, the susceptibility to foreign pressures and the lack of political will severely compromise the formulation, implementation, monitoring and enforcement of pesticide laws and policies.
The overwhelming profit motivation sets aside concerns for public health and safety. Of the approximately 3,000 toxic chemicals put out yearly by chemical companies, less than ten percent undergo thorough toxicologic evaluation. Regulatory bodies rely mainly on data provided by the pesticide companies which are treated as “confidential” and not accessible to the public. Companies conceal or distort facts exaggerate benefits, and make no mention of adverse effects. Product labels and advertisements hardly carry information that would warn consumers of the health risks. Worse, many so-called “independent” sources of information such as universities, WHO and FAO, are also influenced, if not outrightly dictated upon by the interests of huge transnational chemical companies. These huge companies, in fact, have common interests with ruling power elites and employ state mechanisms to protect their interests and suppress critics. This and the other factors mentioned above, objectively increase exposure to pesticides in the Third World resulting in widespread adverse health effects.

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©heal toxics, 2003
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