Question

Increase in concentration of chemical substance along the trophic level of food chain is called :

• A. Bioconcentration
• B. Bioremediation
• C. Biomagnification
• D. Biotransformation

Hint:

Remember: "Bioaccumulation" is over time within a single organism, whereas "Biomagnification" is the progressive increase in concentration *across* trophic levels in a food chain.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Environmental pollutants, especially lipophilic and non-biodegradable chemicals like heavy metals, mercury, and organochlorine pesticides (e.g., DDT), can enter aquatic food webs.
The progressive accumulation of these substances through food chains affects top predators, including carnivorous fishes and humans.

Step 2: Detailed Explanation:
Biomagnification (also known as bioamplification) is the biogeochemical process whereby the tissue concentration of a persistent, bioaccumulative, and toxic substance increases systematically at each successive step in a food chain.
Because lower-trophic-level organisms (like zooplankton) consume large volumes of contaminated primary producers (phytoplankton), they accumulate the chemical in their fatty tissues.
When these zooplankton are consumed by small forage fishes, and those forage fishes are in turn consumed by larger predatory fishes, the chemical concentration increases exponentially at each trophic level.
Consequently, top predators have the highest concentration of the toxin in their bodies.
Let us clarify the related terms:
1. Bioconcentration: The direct absorption of a chemical by an aquatic organism from the surrounding water phase through its gills or skin, without taking food intake into account.
2. Bioremediation: The utilization of living organisms (like bacteria, algae, or plants) to break down, neutralize, or remove environmental pollutants from soil or water.
3. Biotransformation: The chemical alteration of a compound (such as a drug or toxin) by an organism's metabolic processes, typically converting it into a more water-soluble form to facilitate excretion.

Step 4: Final Answer:
Thus, the increase in concentration of a chemical substance along the trophic level of a food chain is called Biomagnification.