A pesticide which is a chlorinated hydrocarbon is sprayed on a food crop. The food chain is: Food crop - Rat -Snake - Hawk. In this food chain, the highest concentration of the pesticide would accumulate in which one of the following?

Chlorinated hydrocarbons (organochlorines) are persistent, lipophilic pesticides that accumulate in body fat and blood lipids and resist degradation, so they persist for years in organisms [2]. Such non-degradable chemicals become progressively concentrated at successive trophic levels — a process called biological magnification — so organisms higher in a food chain carry larger burdens than those below them [1]. Birds of prey feeding on contaminated vertebrates are known to bioaccumulate and suffer toxic effects because organochlorines biomagnify in terrestrial food webs, producing especially high residues in raptors [3]. In the chain Food crop → Rat → Snake → Hawk, the hawk is the apex predator and therefore will have the highest pesticide concentration.

Sources

1. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 29: Environment Issues and Health Effects > Testing Of Pesticide Toxicity > p. 415
2. [1] Science , class X (NCERT 2025 ed.) > Chapter 13: Our Environment > 13.1.1 Food Chains and Webs > p. 212
3. [3] https://downloads.regulations.gov/EPA-HQ-OW-2009-0819-8483/attachment_10.pdf