Question

How can pesticides enter food chain and harm human beings? "I want a long answer for my project"

Answer 1

Pesticides refer to any substance or mixture of substances intended for preventing, destroying, repelling, or lessening the damage of any pest. A pest is any living organism that could harm crops and people or other animals, or is in an undesirable location. Pesticides may be chemical, biological, or antimicrobial. They are released into the environment primarily through the spraying of insecticides on fruits and vegetables and other crops, such as corn, wheat, rice, and cotton, and by the use of herbicides on grass.


Pesticides are found in the environment, in streams, rivers, lakes, groundwater, and the soil, including fields (where chlorophenols, particularly in the form of weed killers, build up over the years) and chemically treated lawns.

Pesticides have entered the food chain: chemicals from pesticides get into groundwater or streams, then into the grass and other vegetation, then into herbivorous animals and then carnivorous and omnivorous animals such as humans. Those animals at the top of the food chain, such as humans or scavengers, fare worse than those below them, as the buildup of toxins is much greater at the top. In the aquatic food chain, chemicals from pesticides enter agricultural runoff or wastewater, then are taken up by algae and plankton, then small organisms, then larger fish, and finally humans. Fish containing mercury or other chemicals can be lethal to people.

See now these harmful chemicals can enter the food chain in several trophic level. The major is being in the first trophic level. I hope you understand what is food chain and trophic levels. If not then please comment for additional information.

So these chemicals enter the roots of the plants by the soil. Once this enter the plant they get accumulated in the plants and fruits. Those plants and fruits are consumed directly by us or by the herbivorous animals and then by carnivores …!!! Well you know food chain. So ultimately it undergo bio-magnification and reaches the human body in maximum concentration.

I can think of a couple of examples:

1. rBST

"Recombinant bovine growth hormone, also known as rBGH or rBST, is injected into cows to make them produce more milk. This practice, which is known to cause harm to cows and may pose harm to humans, is banned in Canada, Japan, Australia, and all 25 countries of the European Union."

2. Mercury

"The reports, produced by the Biodiversity Research Institute and an international coalition of environmental campaign groups called the Zero Mercury Working Group, say that mercury contamination of seafood is not only on the rise across the globe, but that "smaller traces of the toxic metal may be enough to cause restricted brain development or other health problems for humans who eat them."