According to World Health Organization (WHO), pesticide poisoning counts for the death of approximately 220,000 people worldwide. That is quite an alarming. Pesticides were invented to eradicate the insects, herbs or weeds which infect or compete for food with the crops and trees. Most of the pesticides being used are chemical in nature. The history of pesticide usage goes back to Mesopotamian civilizations in 2000 BC where they used elemental sulfur dusting to protect crops. From the 15th century to 20th century, farmers were using different pesticides but the 1950s was the revolutionary era in pesticide industry. The discovery of DDT, an organochlorine, replaced arsenic based pesticides. Since then, we have a wide range of pesticides, which protect the crops and fruit trees and increase the yield by many folds. The other side of the picture came into view when DDT was found to restrict the reproduction of fish eating birds in 1960s.It was the first time when the potential threat of pesticides to biodiversity was considered. Now we are aware of all the hazards of pesticides posed on environment, humans and animals.
On short term basis, we are definitely getting a lot of profit, but in long term its risks outweigh the benefits. The negative effects of pesticides include exposure to humans, food contamination, environmental pollution, water contamination, threat to biodiversity, resistance development in pests and killings of non-target species. Damage to nature’s any resource is ultimately a loss and dangerous for human existence.
More than 90% of pesticides sprayed go off target and pollute the environment. The particles of pesticides remain suspended in air and carried to other areas by wind, the process termed as Pesticide Drift. It affects all the living things in the areas which were not even sprayed with pesticides. Natural and artificial water reservoirs are being contaminated through runoff from pesticide treated plants and land. Runoff, leaching and spilling are the major routes water contamination. Pesticides pollute surface water and as well as ground water. Even rain water samples were found to be contaminated with pesticides. In a multi-state study in USA on water samples from less than 2% wells, all the samples were found to have elevated concentrations than the standard “Maximum Contaminant Level”. More than 50% U.S. population use ground water as drinking water and they all are at a major risk of diseases like cancer. United States Environmental Protection Agency (EPA) has already selected five herbicides to be banned. These banned herbicides happen to be found in every sample collected across the country. Pesticides disturb the natural aquatic systems.
The chemical pesticides are posing continuous threats to human health which were not initially known. Now we have a huge amount of evidences to support our case. No population in the world is safe from pesticide exposure and developing countries are facing a lot of it. These countries are categorized as high risk groups. The people who are in direct exposure to pesticides include pesticide factory workers, sprayers and other farm workers. The formulation and production processes are completely risk free. And then workers who handle them are also at higher risks. All the people who get exposed to pesticides may show acute or delayed symptoms. Acute effects include abdominal discomfort, vomiting, headaches and dizziness. In China, approximately 500 deaths occur due to poisoning by pesticides.
Cancer is among the lead long term effects of pesticide exposure. Leukemia, lung, liver, breast, brain, lymphoma and skin cancers have been associated with pesticides. Exposure of pregnant women to pesticides increases the risk of cancers in babies. Presence of pesticides in household is also associated with leukemia in children. Even low levels of pesticide exposure increase the risk of developing Parkinson’s disease by 70%. Long term exposure can also result in dementia. It is also linked with birth defects and fetal deaths. A few pesticides are reported to cause infertility in males which included low sperm count, germinal epithelium damage and even genetic changes in the sperms. More commonly, dermatitis cases are reported every year in people who come into direct contact with pesticides. Crops, vegetables and fruits grown using pesticides contain chemical residues. This also can result in dangerous effects.
Pursuing this further, pesticides accumulate in plant’s body, called as bioaccumulation. This happens because plants do not have any mechanism to remove it. Pesticides are absorbed through roots and travel to other parts of plant through vascular system. And because most of the pesticides are synthetic in nature, the plants cannot break it down. When animals and humans eat that plant, the pesticide residues transfer to that organism’s body and lead to harmful effects. Apart from risks to humans, many other species are being poisoned. The friendly insects which are beneficial for crops are near to extinction. Bees, butterflies and other bugs which help in plants pollination process are being killed by these pesticides. Approximately 8% pollination of plants worldwide relies on these pollinators. In several states of United States, bees are very difficult to find due to excessive use of pesticides. In China, situation is so worse that people hire workers to pollinate plants manually with their hands. This not only has contributed to crop loss but has also disturbed the nature’s ecosystem.
Additionally, all the pests are developing mechanisms to protect themselves from pesticides. This is called pesticide resistance. Insects and herbs make genetic changes in themselves or produce certain chemicals or proteins which help them to sustain toxic environment. Different insects and herbs species are getting stronger day by day against pesticides. The resistance against a specific pesticide is heritable to next generation. Many pests are now resistant to multiple pesticides and there are also some pests who are resistant to all pesticides. So the farmers tend to use stronger pesticides that pose more risk to environment. So spraying on those pests is the total economic loss and just a contribution to contamination. These pesticides are not able to harm pests, but affect other organisms that have not developed pesticide resistance. The pesticides are also linked with the reduced fertility of soil.
And lastly, pesticides are most commonly used poisons for suicide. Mostly in rural and agriculture areas, pesticides are present in household. The reason of more than 60% suicides in China, Sri Lanka and Malaysia was reported to be pesticide ingestion. Global suicide statistical data indicates pesticides as the most common method of suicide worldwide. If the pesticides get banned, it will definitely decrease the suicide rate in the world.
Pesticides are becoming more and more lethal especially for humans. We can completely cut off the usage of pesticides. Today we have many advanced techniques and methods in farming which do not require the use of pesticides. The adoption of organic farming methods which include biological control of pests, use of hormones to interfere with insect’s developmental stages, genetics control of pests and somehow the Integrated Pest Management (IPM) can lower the use of pesticides.