What is the primary risk of using improperly formulated pesticides?

The primary risk associated with using improperly formulated pesticides is groundwater contamination. When pesticides are not formulated correctly, they may not break down as intended, leading to the potential for harmful chemicals to leach into the soil and subsequently contaminate the groundwater supply. This poses significant risks not only to the environment but also to human health, as contaminated groundwater can affect drinking water sources.

Other answers, while related to the broader impact of pesticide use, do not specifically address the immediate and severe consequences tied to improper formulation. Loss of crop yield can occur due to ineffective pest control, but it does not directly relate to the formulation quality. Similarly, increased water retention and soil erosion are environmental factors that may be influenced by agricultural practices but are not the primary concern directly stemming from the misformulation of pesticides. Groundwater contamination stands out as a critical issue due to its lasting and potentially dangerous effects on both ecosystems and public health.