Question

The insecticide DDT has a half-life in the human body of approximately 7 years. [In 7 years its concentration decreases to half its initial concentration). Although DDT is no longer used in the United States, 25 years ago that average farmer had a body DDT concentration of 22ppm [parts per million by weight). Estimate what the farm workers present concentration is?

Answer 1

Using the half-life formula, the estimated present concentration of DDT in a farmer's body, who had a concentration of 22ppm 25 years ago, is approximately 1.826ppm.

Step-by-step explanation:

The insecticide DDT has a half-life of approximately 7 years in the human body. This means that after 7 years, the concentration of DDT decreases to half its initial value. To estimate the present concentration of DDT in a farmer's body, who had a concentration of 22ppm 25 years ago, we use the half-life formula:

C(t) = C_0 * (1/2)^(t/T_half)

Where:

• C(t) is the concentration at time t
• C_0 is the initial concentration
• T_half is the half-life of the substance

By plugging in the values:

C(25) = 22ppm * (1/2)^(25/7) ≈ 22ppm * (1/2)^(3.57142857)

After calculation, the approximate present concentration is:

C(25) ≈ 22ppm * (1/2)^3.57142857 ≈ 22ppm * 0.083 ≈ 1.826ppm

Therefore, the estimated present concentration of DDT in the farmer's body is approximately 1.826ppm.

Answer 2

explanation below

Step-by-step explanation:

Dichlorodiphenyltrichloroethane, also known as DDT is a chemical compound that is found in insecticides. In 1972, the United States Environmental Protection Agency issued an order for the cancellation of requests for the chemical compound because it affects wildlife and pose risks to humans as well.

From the question here, it was noted that the initial concentration was 22ppm 25years ago and so if it takes 7years to decay by half, the actual concentration in present day farmers could be calculated as follows;

25years ago - 22ppm

18years ago - 11ppm

11years ago – 5.5 ppm

4 years ago - 2.75ppm

Since 7yrs = 0.5

Then 4yrs will be [ [4/7] x 0.5] = 0.2857

Then if 0.5 = 2,

Then 0.2857 = [ [ 0.2857/0.5] x 2] = 1.1428

So present year concentration would then be [2.75ppm/1.1428] = 2.406ppm