Pesticides And The Environment
Despite growing research on safer alternatives, agriculture today involves the use of large amounts of toxic chemicals including chemical fertilizers and pesticides. While they are intended to kill one or more pests, or fertilise the soil for instance, the effects are often far-reaching. Several of these pesticides are persistent. These not only remain in the environment, but seep into our soil and water rendering it poisonous and travel for millions of miles finding themselves where they were never even used! Remember, studies show that less than 0.1% of pesticides applied for pest control reach their target pests. This means more than 99.9% end up in the environment, affecting not only public health but contaminating our resources and disturbing the eco-system balance in our farms as well as the general atmosphere.
With the use of pesticides, we are contaminating and poisoning natural resources on which our very survival depends. Pesticide drift (pesticides carried to other areas by wind) poses a threat to human life as well as wildlife.
Let us begin with farm eco-systems themselves. Pesticide use often adversely impacts beneficial insects and predators which can control pests. Such use often becomes a treadmill for the farmers, when such natural control factors are destroyed. Meanwhile, the target pest itself is likely to develop resistance at the genetic level to the pesticide because that is Nature's principle.
Toxic chemicals sprayed on agricultural fields have also been responsible for killing of unintended organisms of the higher order too – in India, reports of peacocks getting killed are repeatedly seen due to pesticides used in agriculture. Many other bird species have also been impacted and it is well known that millions of birds are killed each year due to pesticides. Reductions of bird populations have been correlated to pesticide use in various studies. Even in India, several species of birds are reported to be on the verge of extinction including due to overuse of pesticides.
Pesticides are also known to contaminate our water resources, both as surface run off and leaching into the groundwater aquifers. Aquatic life is known to have been impacted in many instances with such pesticide contamination, including through accidental spills/intentional disposal. Studies on fish showed physiological and behavioural changes due to exposure to pesticides.
It is also well documented that pesticides do impact soil biodiversity. Earthworms, termed as farmers' friends, are adversely impacted. It has been found that pesticide presence in soil in turn hinders healthy plant processes like nitrogen-fixation! Pesticides are also known to have other harmful impacts on plant growth and development.
Pesticides have been implicated in poisoning and killing of bees which has a complex eco-system effect thereafter.
While pesticides are known to have cause acute poisoning and deaths of animals that have strayed into pesticide-sprayed agricultural fields, an indirect effect can be of eliminating certain food sources on which such wild animals depend. In India, reports have emerged of animals in national parks and sanctuaries also being impacted adversely due to the use of pesticides in farming (tea estates and the like, near Kaziranga National Park, for instance).
The information on dangers is mounting, but so is the science on safer alternatives. Ultimately, what we do to the environment, in fact, we do to ourselves and all the species with whom we share this planet!