What aspect of pesticide application can potentially lead to environmental contamination?

The answer encompasses all the options because each factor can independently contribute to environmental contamination in significant ways.

Pesticide drift occurs when pesticides are carried away from the intended area of application, often by wind. This unintended spread can lead to contamination of non-target plants, water sources, and soil, affecting ecosystems and potentially harming wildlife and humans in those areas.

Improper disposal of pesticide containers is another critical factor. If containers are not disposed of according to guidelines, they can leach chemicals into the environment. For instance, dumping unused pesticides in landfills or waterways can lead to soil and water pollution, posing risks to human health and biodiversity.

Over-application is also a significant concern. Applying more pesticide than necessary can result in excess chemicals remaining in the environment, which can migrate through soil and water systems. This can lead to long-lasting contamination, ultimately affecting various forms of life and disrupting chemical balances in ecosystems.

Thus, all these practices highlight how various aspects of pesticide application can lead to contamination, making the comprehensive answer fully justified.