What could be a consequence of pesticide runoff?

Contamination of water sources is a significant consequence of pesticide runoff. When pesticides are applied to agricultural fields, heavy rains or irrigation can wash these chemicals off the surfaces and into nearby streams, rivers, and lakes. This runoff can lead to the introduction of harmful substances into aquatic ecosystems, posing risks not only to aquatic life but also to drinking water supplies for human populations. The presence of pesticides in water sources can lead to a variety of health issues and can disrupt the balance of aquatic ecosystems, harming fish and other organisms that rely on clean water for survival.

In contrast, the other options highlight scenarios that do not directly correlate with the effects of pesticide runoff. For instance, increased crop growth typically requires careful management of pesticides to avoid adverse effects rather than runoff, which could actually harm crops. Similarly, there is usually a visible impact on the environment due to pesticide runoff, as it often results in pollution and ecosystem disruption rather than a neutral outcome. Enhanced soil nutrition is also unlikely, as runoff can erode soil quality and lead to loss of beneficial microorganisms and nutrients rather than enhancing them.