Question

You perform a study to determine how much a widely used insecticide called permethrin can biomagnify in aquatic food webs of wetlands next to agricultural fields during routine spraying. To do this, you radiolabel a batch of permethrin to trace it as it moves up the food chain. You determine that the permethrin concentration in the water of an adjacent wetland right after spraying is 0.13 micrograms per liter (μg/L). The permethrin concentration increases by 320 percent as it binds to algae and increases again by 170 percent in zooplankton as they consume the algae. Finally, the permethrin concentration increases by another 70 percent as small fish eat the algae. If you were to capture one of these fish and measure the concentration of permethrin in its tissues, what would the concentration be?

Group of answer choices

0.57 μg/L

2.506 μg/L

31.42 μg/L

7.71 μg/L

2.89 μg/L

Answer 1

The correct answer is

(b) 2.506 μg/L.

Calculation :-

1) The concentration of permethrin in water of an adjacent wetland just after spraying is 0.13 μg/L.

Now, the permethrin concentration increases by 320% in algae.

Increase amount of permethrin in algae =   

= 0.416 μg/L

Total amount of permethrin in algae

= 0.416 + 0.13

= 0.546 μg/L

2) The permethrin concentration Increases by 170% in zooplankton.

Increase in amount of permethrin in zooplankton

=

= 0.9282 μg/L

Total amount of permethrin in zooplankton

= 0.9282 + 0.546

= 1.4742 μg/L

3) Now, at last it is Increased by 70% in small fishes.

Increase in amount of permethrine in small fishes =

= 1.03194 μg/L

Total amount of permethrine in tissues of small fish

= 1.03194 + 1.4742

= 2.50612 μg/L

= 2.506 μg/L

Thus the correct answer is 2.506 μg/L.

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