How can bodies of water be polluted by natural causes, such as the result of the water cycle?
Water from rain or storms may can cause harm to bodies of water. During the water cycle, water vapor cools causing it to condense on foreign particles (acids from emissions/vocanic ash/pollen/dust, etc.) When clouds become saturated precipitation occurs. During this stage of the water the cycle, gravity may pull pollutants to the ground. Accumulated precipitation also contributes to contaminants on the ground being picked up by flowing water. Sewage, hazardous wastes, pesticides, fertilizers, agricultural wastes and construction debris can be transported into clean bodies of water causing pollution/unsafe aquatic conditions.