Environmental quality has recently become a major concern of many Americans. Agriculture is a major industry causing considerable pollution and does so especially through runoff. The runoff carries with it phosphates, nitrates, pesticides, and other materials which become toxic in concentrated quantities. Agriculture also is a source of pollution through animal wastes and by-products of food processing. Through sedimentation from agricultural lands and leaching, residual chemicals are carried to the nation's major streams, rivers, and underground water bodies.