Nitrate pollution refers to the contamination of water sources, primarily from agricultural runoff, that contains high levels of nitrates. Nitrates are a type of chemical compound that are commonly found in fertilizers and manure, and can seep into groundwater or surface water through runoff, posing a threat to human health and the environment. High levels of nitrates in drinking water can lead to serious health issues, such as methemoglobinemia in infants, also known as "blue baby syndrome". Nitrate pollution can also contribute to the growth of harmful algae blooms in water bodies, leading to oxygen depletion and negative impacts on aquatic ecosystems. Researchers study nitrate pollution to understand its sources, impacts, and develop strategies to mitigate its effects on water quality and human health.