Rainwater

Pollution and composition

Aside from contamination of rainwater by sulfuric and nitric oxides, which produces acid rain, various pollutants from industry and household wastes can end up in rainwater, causing detrimental effects on aquatic and human life. Pollutants from solid waste, leaking vehicles and machinery, fertilizers and other potentially hazardous substances enter water sources directly through dumping or as surface runoff following heavy rain. One classification of pollutants of particular note is perfluoroalkyl substances, synthetic chemical compounds used in a wide variety of consumer products. Rain has the potential to dissolve and transport different compounds, including the aforementioned toxic substances, with certain ions such as calcium and bicarbonate appearing frequently, in more acidic rainwater. However, the composition of rainwater at any given time and place is highly variable based on the ongoing manufacturing, farming, and waste-producing activities.