In September 2012 the Annals of Internal Medicine published a review of organic food studies. The conclusion? Organic food was not more nutritious than conventional food. But as a September 4, 2012, article at WebMD indicated, organic foods are desired because they are free of pesticides and antibiotics. Many believe organic food tastes better, and organic growing methods are better for the environment. So what is the environmental benefit of using organic methods?
Water is a convenient metric to use. In water footprint calculations, the gray water portion of the footprint is the water required to dilute pollutants back to clean water standards. A study documenting the pollution created by conventional cotton farming methods was recently published by C&A, a global market leader for organic cotton. Titled Grey Water Footprint Indicator of Water Pollution in the Production of Organic vs. Conventional Cotton in India, the C&A study shows that pollution created by conventional farming is 5.5 times greater than pollution created by organic growing methods.
In order to determine the maximum allowable pollutants in clean water, the Water Footprint Network advised C&A to use the stricter value for each contaminant from the following guidelines:
- EC (2008) – European environmental quality standards in the field of water policy.
- USEPA (2010b) ‐ US EPA national recommended water criteria for aquatic life.
- CCME (2007) ‐ Canadian water quality guidelines for the protection of aquatic life.
When fertilizers and pesticides are applied to crops, a percentage leaches out into local bodies of water. These percentages are typically 10%, 3%, and 1% for nitrogen, phosphorus, and pesticides respectively. The researchers interviewed 480 farmers across 40 villages in 4 districts from two India states.
The researchers found that conventional methods on average produced pollution that required 266.042 litres per kg of cotton (127,515 quarts or ~32,000 gallons per pound of cotton). organic methods on average produced pollution that required 53.257 liters per kg of cotton (25,526 quarts or ~6,400 gallons per pound of cotton). That’s an extra 25,500 gallons you need to dilute pollutants per pound of cotton.
Want to know what 32,000 gallons looks like? Well, if you were trying to carry it on a railroad, you’d need a car like this:
A standard 31,800 gallon tank car – roughly the amount of water needed to dilute runoff from growing a single pound of conventional cotton.
For fun, take a typical outfit (T-shirt, jeans, undies) and weigh them. Think how many railroad tanks of water were required to dilute the pesticides and extra fertilizers used to make that one outfit. Crazy!
One other factoid that’s important to cover. Folks will say, “But fields are so much more productive when you use pesticides and petrochemical fertilizers.” In the cotton study, the average yield for conventional farms was 500 kg per acre, or 1,100 lbs. The average yield for organic farms was 450 kgs, or 990 lbs. That’s 90%, and a thousand railcars less water required to dilute pollutants. Besides which, the charts in the report show that there were organic farms that were as productive as the most productive conventional farms, so it isn’t clear that organic farming necessarily results in lower yields.
The value of organic is clean water. Quality and taste are just added perks.
Meg is an engineer with a BS in Physics from George Mason University and a MS in Product Development (combined Systems Engineering and Masters in Business Administration curriculum) from Naval Postgraduate School.