Agricultural soil treated continuously with synthetic pesticides often experiences long-term ecological damage. Which of the following chemical characteristics best explains why organochlorine pesticides such as DDT present a severe long-term threat to soil ecosystems and higher trophic levels?
- They resist microbial degradation due to stable carbon-chlorine bonds and bioaccumulate in the fatty tissues of organisms.Answer
- BThey rapidly break down into carbon(IV) oxide in the soil, directly contributing to stratospheric ozone layer depletion.
- CThey function as water-soluble addition polymers that undergo immediate microbial breakdown into harmless soil minerals.
- DThey react rapidly with soil moisture to liberate gaseous allotropes of elemental chlorine into the atmosphere.
Answer
Organochlorine pesticides like DDT resist microbial degradation due to stable carbon-chlorine bonds and bioaccumulate in the fatty tissues of organisms across the food chain.
Organochlorine pesticides such as DDT possess strong carbon-chlorine () bonds that resist chemical and microbial degradation in soil. Furthermore, their high fat-solubility (lipophilicity) causes them to accumulate in the fatty tissues of living organisms, leading to biomagnification across successive levels of the food chain.
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Pesticide Persistence and Bioaccumulation in Environmental Chemistry
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