| Study after study has identified riverbanks that need revegetating, waterways that need to be cleaned, pollutants that have to be eradicated. |
| An electronic cleaner produces negative ions that are attracted to the pollutants. |
| These attach themselves to airborne pollutants such as exhaust fumes, giving them an electrical charge. |
| The main cause is excess nitrogen run-off from farm fertilizers, sewage and industrial pollutants. |
| Finally, pollutants can change the nutrient balance of a waterbody, making it over-rich, a process known as eutrophication. |
| Dust and construction materials, such as wood, wallboard, and insulation, contain nutrients that allow biological pollutants to grow. |
