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Contamination Prevention on the Farm

Posted by Josh Kaufman on 1/18/2017 to Ag - GAP

As the population has increased, so has the importance of agriculture. According to the EPA, there are more than 330 million acres of farmland in the United States. The need for additional crops and livestock to feed the masses has spurred technological advances that allow farmers to produce more high-quality products at a faster rate. The innovations in machinery, as well as growing and harvesting techniques, have made mass food production possible, but it also has created additional sources of contamination that must be addressed.

With agriculture, a major concern is nonpoint source (NPS) pollution, which comes from a variety of sources and is caused by runoff from rainfall or snowmelt that carry natural or man-made contaminants across the land and into bodies of water. Studies by the National Water Quality Assessment have identified agriculture as the leading source of NPS pollution in rivers and streams, the second largest source in wetlands, and the third largest source in lakes.

Contamination prevention on the farm must be a priority, which is why many Good Agricultural Practices listed on a GAP audit deal with addressing and preventing runoff. According to the CDC, people who consume fruit or vegetables exposed to contaminated water can become infected with bacteria like E. coli and salmonella, viruses like hepatitis A, parasites, and toxins. The good news is that many pollution-causing activities are reasonably simple to prevent if a proper conservation plan is in place. In this article, you’ll learn about some of the main sources of NPS pollution on the farm and the ways you can prevent them.


Chemical applications like pesticides and herbicides eliminate threats to crops, but they are powerful agents that must be handled and utilized properly. Only people who are certified through regulatory agencies should apply chemicals, and they should always follow application instructions exactly as printed on the label. It’s important to look at weather forecasts before applying chemicals. Spraying should not take place if winds are greater than 10 miles per hour or if heavy rain is expected within 24 hours because those conditions cause unwanted spread of chemicals. When not using chemicals, store them in a locked building on impermeable shelves over an impermeable floor with either no drains or drains that lead to an acceptable holding tank. This will keep any leaks or spills contained.


Livestock manure promotes crop growth, but it does contain pathogens so there are steps that should be taken to prevent contamination. To avoid runoff, manure should not be applied on frozen, snow-covered, or flood-prone ground. The EPA suggests utilizing cover crops, which include certain grasses, grains, or clovers. Cover crops keep nutrients out of water by recycling excess nitrogen and reducing soil erosion. It’s also beneficial to plant buffer trees, shrubs, and grass around fields — especially those near bodies of water — to absorb and filter out nutrients before they reach the water. Like chemicals, fertilizer should be stored in a roofed storage facility that is isolated away from fields, orchards, and handling facilities. There should be barriers to prevent leaching, runoff, or windspread.


Irrigating crops with contaminated water puts consumers, as well as surrounding clean water sources, at risk. With this in mind, take steps to ensure your irrigation water is pure. Irrigation water should come from a treated source or a properly constructed, capped well that is in good condition and easily accessible. Water should be regularly tested for harmful organisms and high sediment levels. Water treatments or settling ponds can remedy situations if your tests reveal concerns. Other best practices include installing anti-backflow or check valve devices on all plumbing systems and ensuring no cross connections exist between water supplies.

Portable Sanitation Equipment

Portable sanitation equipment makes it easy for workers to maintain high levels of sanitation when in the fields or orchards. For this reason, having easy access to units is a GAP best practice. However, this is only effective if the equipment is clean, fully stocked, and in good condition. Contamination can occur if toilets leak chemical waste or sinks leak gray water. If you own the units, make sure you clean and restock them regularly and check them for damage. If the units are rented, ensure the units you receive are delivered in good condition and are serviced regularly enough to prevent any potential risks to crops.


If your crops are located anywhere close to where livestock are kept, take steps to protect them from animal pathogens. One of our recent articles examined this topic in great detail. To read it, click here.

Learn More

To learn more about GAP compliance and best practices, download a FREE copy of GAP Compliance Made Easy at AgSinksTB.com. You can also request FREE Toilet & Handwashing Compliance Signs to post on your portable sanitation equipment.

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