JEE Advanced levelSingle correct optionDifficulty 3 of 3ev152
In a food chain the DDT concentrations (in ppm) are: water 0.00005, plankton 0.04, small fish 0.5, large fish 2.0, fish-eating bird 25. Which step has the largest magnification factor, and what is the overall factor from water to bird?
Awater to plankton; 2.5×104
Blarge fish to bird; 5.0×103
Cwater to plankton; 5.0×105
Dplankton to small fish; 5.0×105
Answer: C
Factors per step: water to plankton 0.04/0.00005=800, plankton to small fish 12.5, small fish to large fish 4, large fish to bird 12.5. The largest is the first step (800). Overall, 25/0.00005=5.0×105.