A Phase 1 Environmental Site Assessment on a cattle ranch active from 1900 to 1935 identifies a facility formerly used for treating insect infestation of cattle. What compound would most likely be a potential environmental condition in the soil?

A Phase 1 Environmental Site Assessment on a cattle ranch active from 1900 to 1935 identifies a facility formerly used for treating insect infestation of cattle. What compound would most likely be a potential environmental condition in the soil?

• A. Arsenic
• B. Isopropyl n-phenylcarbamate (IPC)
• C. DDT
• D. Parathion

Answer: (A)

Understanding this scenario starts with how pesticide use has changed over time. In the early 1900s, inorganic arsenic compounds were commonly used to control external parasites on livestock and in related treatment facilities. Arsenic-based pesticides were widely applied and, unlike many later chemicals, persisted in soils for long periods. A cattle-insect-treatment facility active from 1900 to 1935 would thus be a strong candidate for soil containing arsenic residues. In contrast, DDT became popular after World War II (late 1940s onward), and parathion and IPC were developed and used more in the mid- to late-20th century. Those later-use pesticides are less likely to be associated with a site operating only up to 1935, making arsenic the best answer.

Understanding this scenario starts with how pesticide use has changed over time. In the early 1900s, inorganic arsenic compounds were commonly used to control external parasites on livestock and in related treatment facilities. Arsenic-based pesticides were widely applied and, unlike many later chemicals, persisted in soils for long periods. A cattle-insect-treatment facility active from 1900 to 1935 would thus be a strong candidate for soil containing arsenic residues. In contrast, DDT became popular after World War II (late 1940s onward), and parathion and IPC were developed and used more in the mid- to late-20th century. Those later-use pesticides are less likely to be associated with a site operating only up to 1935, making arsenic the best answer.