Water Issues

There are many aspects that affect agriculture that most people do not think of. Water is a significant resource for agriculture. The farming industries use enormous amounts of water. the protection of water may be one of the most significant environmental issues that is affecting agriculture. “Roughly 50% of all Americans and 95% of rural residents depend upon groundwater as their primary source of drinking water. That makes groundwater an extremely valuable resource which is often neglected and taken for granted.” (Focusing)

A growing concern of the public is contamination of groundwater through pesticide usage. The public worry about farmers' use of pesticides and how much is getting into the groundwater thus becoming a dangerous to the health of the public. Groundwater comes from precipitation seeping down into the earth. The amount of water that ends up as groundwater changes depending on the climate and soil conditions. Groundwater is continuously moving towards streams, lakes or wells. Some groundwater may travel only a few feet until it emerges at a point of discharge a few hours later. Some groundwater may percolate down to depths of 6,000 feet or more, travel hundreds of miles underground to a point of discharge, and emerge hundreds or thousands of years later.

Ground water is generally slow moving and this is a significant factor in making groundwater contamination such a great problem. Animal Feedlots have the potential for groundwater pollution hazard, from intense agricultural activities such as nitrate pollution from feedlots. This is why the public is so worried about farms.  Although feedlots cover a relatively small area, they produce a huge volume of animal waste. Normally, the ground is able to absorb animal wastes without much threat to groundwater, but the intense concentration of these wastes in and around animal feedlots is too great for the earth to absorb without the risk of groundwater pollution. Also liquid runoff from these areas has also been responsible for the pollution of some surface water. Pesticides and fertilizers have long been assumed of being groundwater contaminates, but the proof is slow in coming. Although some of the chemicals in these products are toxic, most of them become adhered to subsurface rock. Thus, the potential pollutant is retained and does not enter groundwater in a dissolved state.

Also, the use of field tiles in heavily fertilized areas has proven to be a good way of interrupt the potential contaminates before they can pollute groundwater. Clay tiles are placed two or three feet below the surface to help drain the farmland. Then the runoff is directed to surface rivers and streams. Unfortunately, that while the groundwater are save from contamination, surface waters are not. After periods of heavy rain, the nitrate levels in lakes, rivers, and streams surrounding farmlands are often above recommended levels.

Another cause of groundwater contamination is the disposal of waste materials directly onto the land, in holding ponds and lagoons, and in sanitary landfills. In land disposal, potential pollutants such as manure, sludge, and industrial wastes may be heaped in mounds or spread directly over the ground. Any soluble products in the waste may be dissolved by precipitation and infiltrate into the subsurface soil and rock, eventually polluting the groundwater. Holding ponds and lagoons are shallow excavations anywhere from a few square feet to many acres in area. They are commonly used to hold oilfield seepage, municipal sewage, and a variety of other wastes, including industrial chemicals which generally contain a variety of toxic compounds. When the holding ponds or lagoons are unlined, the pollution hazard is especially great. But even some common liners such as clay, plastic, asphalt, and concrete have been found unreliable in certain cases. Sanitary landfills are made by placing wastes in excavations and covering them daily with a layer of soil. They are called "sanitary" to indicate that garbage is not left in the open air to produce odors and to attract vermin and insects. But even though a landfill is covered, precipitation will still seep through it and "leech" contaminants as it moves along, ultimately resulting in groundwater contamination. 

Focusing on Ag Issues - Issues - Environmental Examples. (n.d.). Career Account Web Pages. Retrieved     April 23, 2011, from http://web.ics.purdue.edu/~peters/HTML/issues/environmental-examples.html