Rhett Kaines: because pestisides and fertilizer can canaminate things like water which animals drink and can kill your fish
Erica Bottaro: Most runoff contains pesticides and other chemicals that are used on the plants. These chemicals get mixed into the water supply and other parts of the environment and can poison anything that ingests it.
Buster Exline: Agriculture runoff usually includes pesticides and fertilizers. The fertilizers mainly consist of phosphorus and nitrogen which conribute to algal blooms if they reach a body of water. Once there are too many algal blooms and they begin to die, all the oxygen is sucked out of the water by decomposers who use it to process and decompose the algae. Without oxygen, the marine life (and animals, including humans, who depend on it) cannot survive. The Mississippi River which flows into the Gulf of Mexico is a prime example of this - the river flushes so much agriculture runoff from the Corn Belt (agriculture area! s that run North to South along the Mississippi River) that there is a massive area of oxygen-less water where no marine life can live (besides maybe a few jelly fish). Industry that is dependent upon fishing goes under as well as the food chains for all animals dependent on the now oxygenless waters. Pesticides, on the other hand, are chemicals that are toxic to insects so that the plants are not eaten. Do you think that humans can handle excessive amounts of toxins in surface waters? I think not. Also, pesticides, like DDT, have been outlawed in most countries (including the United States) because they were shown to cause cancer. Pesticides that are currently used could very well be considered carcinogens in the near future but are currently determined "safe"; just as DDT was. Oganic polyculture is the only sustainable way for our future; others feel GMO food is the answer. However, only time will tell....Show more
Scot Rotruck: The fertilizer in the runoff can lead! to extreme growth of algae which then die and tie up all the ! oxygen in the water as it decays, creating "dead zones", especially in the Gulf of Mexico near the mouth of the Mississippi River.Other plants can grow out of control and clog the waterways.Pesticides that don't "degrade" can get into the food chain and damage wildlife and even people.We about lost the Bald Eagle when DDT in ag runoff got in the fish they ate and their eggshells were too thin to allow the chick to hatch.Another runoff is the very fine soil called silt which can get into the gills of fish and other marine life and kill it.The problem is that we force farmers to over-fertilize, use pesticides and grow crops on marginal land to keep food prices low. And don't forget how much runoff comes from the roof and parking lots of all the buildings and roads we've built, and the pollution from the cars we drive....Show more
Nedra Oltz: As some of the other answers have pointed out, there is a substantial amount of runoff from non-agricultural sources, too. Those ! sources of runoff can also pollute the soil and water. In some cases they find their way into basements and gardens.For example, in a many U.S. cities and towns the sewers are old clay pipes 100 to 150 years old, and they carry storm water, too. The clay breaks or the sections come apart over the years. It is not just the publicly owned sewers that are a problem. The pipes on private property can create just as much disease and property destruction. This is not something that environmental groups want to bother about. They would rather work on keeping areas near where they live pristine....Show more
Clinton Migliori: What the other posters said is true, only they ignored the fact that not all herbicides, insecticides, nutrients (fertilizer) and silt are the result of agriculture. Water is like a magnet and will pick up just about anything you can think of. This includes herbicides, insecticides and fertilizers the average homeowner uses in their backyard or! garden. On a per acre basis, homeowners apply 10-50 times more on a p! er acre basis than do farmers. Why? Cost. For a competitive homeowner, an extra $10 may make his yard greener than his neighbor. $10 doesn't sound like much, but if a farmer were to apply the same amount of fertilizer, it would cost him $100 per acre "extra". If he's a large operator with 1000 acres of corn, that's $100,000. So of course a farmer isn't going to over apply products like his urban brethren does.And don't forget about other sources...businesses that apply fertilizer instead of salt to icy parking lots, sewage treatment plants that dump additional nutrients into streams even though they meet all state regulations, mega amounts of herbicides applied to railroad or utility right of ways, soil erosion from construction areas and so on. Oh, don't forget nutrients such as nitrogen that leeches from decomposing organic matter in wooded areas. Better blame that one on Mother Nature. My job includes working with schoolkids on environmental issues and when aske! d, you wouldn't believe how many kids parents dump used motor oil into the storm sewer drain, the ditch behind the house, on the ground behind the garage, in a sinkhole (which usually leads directly to a groundwater source) and so on. And any time it rains on a parking lot or road, where do you think the motor oil, transmission oil and antifreeze drips go? Into the nearest stream. I really like what happened several years ago in the Springfield, Missouri area. A local stream was contaminated with E coli and fingers were immediately pointed at local dairy farmers. After doing some DNA testing, the E coli bacteria was found to be of human origin, not animal. Some very vocal environmental advocates quickly shut up after realizing they were the ones pooping in their own water. In no way am I trying to justify over-applying or miss-applying the products listed above by anyone. The point I'm making is that protecting the environment isn't just a farmer's responsibi! lity, it's everyones responsibility....Show more
Rebeca Mckin: A ! lot of the answers submitted deal with pesticides but a significant source of water pollution is sedimentary runoff. Since farmers till the soil you have more chance of sediments making their way to creeks and streams. This can cloud water, lower oxygen content and raise temperatures. Any slight changes can have a drastic affect on fish populations.
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