What is one of the key methods to mitigate the negative impacts of nitrates in water supplies?

Reducing nitrogen fertilizer usage is a key method to mitigate the negative impacts of nitrates in water supplies. Excessive application of nitrogen fertilizers in agricultural practices can lead to runoff, which increases the concentration of nitrates entering waterways. High levels of nitrates in drinking water can pose significant health risks, such as methemoglobinemia, also known as "blue baby syndrome," which affects infants.

By managing and reducing the use of nitrogen fertilizers, the amount of nitrates leached into the soil and subsequently into groundwater and surface water can be significantly lowered. This proactive approach not only protects public health but also enhances water quality, leading to a more sustainable environmental health practice.

Other options, such as planting more trees, while beneficial for overall ecosystem health, do not directly address the specific source of nitrate pollution. Implementing stricter building codes and encouraging more industrial development typically relate to land use and environmental impacts in different contexts, and do not focus on the specific issue of nitrate contamination in water supplies.