Metals, Industrial Waste, Pesticides entering a Food Chain

Metals, industrial waste and pesticides can enter food chains, causing damage to organisms at all trophic levels. Their entry points usually are through the air, water or soil. They can be particularly harmful to top predators due to a process called biomagnification.
Biomagnification refers to the increasing concentration of toxic substances in organisms as we move up the food chain. These substances are not easily broken down or excreted and tend to accumulate in living organisms.
Metals like lead, mercury, cadmium and arsenic can be released into the environment through industrial waste. Once they enter the food chain, these metals do not degrade and accumulate in the bodies of organisms.
Mercury contamination in water can result in mercury accumulating in fish. When these fish are consumed by humans or other predators, the mercury can cause severe health problems.
Industrial waste often ends up in rivers and oceans where it is taken up by algae and small fish. From there, it makes its way up the food chain, accumulating in larger fish, marine mammals, and finally humans.
Pesticides and herbicides are commonly used in agriculture. They can contaminate the soil or be washed into nearby water bodies, where they get absorbed by plants and animals.
Most pesticides are non-biodegradable. They can build up in the bodies of organisms, leading to problems such as reproductive failure, immune system disturbance and disruption of normal growth patterns.
The use of DDT (dichlorodiphenyltrichloroethane) is a famous case study of pesticide biomagnification. Even though it has been banned in most countries due to its harmful effects, DDT is still found in the environment due to its long persistence time.
Measures can be taken to reduce the risk of these substances entering the food chain, such as treating industrial waste to remove toxic substances before they are released into the environment, properly disposing of pesticides and minimising their use, or phasing out the use of particularly harmful substances altogether.