Crops of fruits and vegetables are important for a healthy diet, but the fertilizers and pesticides used to protect them can pollute local water sources. Fertilizers contain nitrates, and some pesticides contain carbamates; both of these chemicals can be toxic. Each time it rains, the chemicals from farms run into nearby lakes and rivers. Science can provide evidence of water pollution and maybe stop the use of these chemicals near sources of water. But how will this affect the farmers or food resources in the area?