What effects do organochlorine pesticides cause in wildlife?

• A. Eggshell thinning in raptors and estrogenic effects in birds leading to infertility
• B. Increased egg production in most species
• C. Enhanced migratory behavior
• D. No significant wildlife effects

Answer: (A)

Organochlorine pesticides are persistent, lipophilic contaminants that act as endocrine disruptors in wildlife. In birds, the best-documented effects are eggshell thinning and estrogenic disruption of reproduction. DDT and its metabolite DDE, for example, interfere with calcium deposition in the shell gland, producing thinner eggshells that crack easily and lower hatchability. At the same time, some organochlorines exhibit estrogen-like activity, which can alter hormone balance and lead to infertility or feminization in birds. These combined reproductive harms were famously seen in raptors after widespread use of DDT, making eggshell thinning with associated infertility the hallmark wildlife outcome. The other options describe effects that are not supported by how organochlorines affect wildlife reproduction.