" sodium nitrate. This active compound, which is mined exclusively in South America, is employed primarily by organic farmers growing winter vegetables in dry soil. They use it as a soluble fertilizer to enhance the soil with nitrogen. In addition to the environmental costs of mining and shipping the compound, sodium nitrate contributes to groundwater pollution by furthering freshwater eutrophication (intensification of phosphorous and nitrogen) and salinization. "

― James McWilliams , Just Food: Where Locavores Get It Wrong and How We Can Truly Eat Responsibly