There is Compost and there is Compost. Determining the Quality of Compost: Deciding Factors
There is Compost and There is Compost: Key Requirements and Considerations for Quality of Commercially Available Compost Material
Question: Why does it matter?
Answer: Commercial grade composts can contain harmful chemicals and heavy metals, many of which can cause cancer, liver disease, and reduced immunity. These forever chemicals accumulate in the soil and the human body and must be kept out in order to call compost beneficial. Other contaminants such as plastics, glass and metals need to be kept out as well.
Background: Composting is a process whereby food scraps, yard waste, and other organic materials such as wood chips and sawdust are turned into soil by the application of water. While the concept is a good one, there are several problems with the process. Many materials collected for composting may contain dangerous chemicals, such as heavy metals, pesticides, and PFAS. Not only are these dangerous to human health, even in small quantities, but they accumulate in the soil and in the human body and become even more dangerous and toxic. Second, there are most likely bits of plastic or broken glass in commercially available compost, the result of cross-contamination at processing facilities or in the collection process. Finally, neither the USEPA nor the USDA test compost for contaminants. Some states (such as California) do, but most don’t. The Organic Materials Research Institute, and the US Composting Council, have a certification program, but only require testing every five years.
Opportunity: To improve the quality of the material coming into the composting facility, certain items have to be kept out and should be prohibited, such as food containers that contain PFAS. In addition, greater efforts should be made to make the public aware of the dangers of cross-contamination. We should also work toward a national standard and regular and frequent (batch) testing of commercial compost.
There are many challenges to compost, especially to commercial compost. Quality control is everything as the ingoing material determines the quality of the outgoing product.