The unknown danger in your organic garden fertilizer

By: Alexis Potoff

Summary. PFAs are Per- and polyfluoroalkyl substances that are manmade. There is evidence that this chemical, which can be found in a wide range of places, can have adverse effects on human health and can accumulate in the body over time. Some of the places PFAs can be found are in biosolids, cleaning products, and food that was contaminated either by packaging, the facility it was produced in, or by being grown in contaminated soil or water. The focus of this blog post is on biosolids, or treated sewage sludge, and its common use as garden fertilizer. Many fertilizers are made with this sludge and sold at various retailers like Lowe’s, Menards, and The Home Depot. Such fertilizers are commonly marketed as organic. While the EPA does require that biosolids be tested for certain heavy metals and pathogens, they do not have a limit on the amount of PFAs that are allowed to remain in the soil. This means that a range of the different soils that a person can purchase at their local gardening store may contain these harmful chemicals. The Sierra Club tested some of these soils in commercial labs to check their contents: “Each product contained 14 to 20 of the 33 tested PFAS chemicals, with total concentrations ranging from 38 to 233 parts per billion (ppb)” (sierraclub.org). They go on to elaborate that this amount of PFAs is considered highly polluted meaning that there is a high probability of contamination by using them. The best thing that people can do is to check their different types of soil for biosolids before purchasing and potentially choose another option to avoid the continued build up of PFAs.​

Why we should care?  This topic is important for us to consider so that we can be cognizant of our impacts on the environment. We cannot stop the spread of PFAs but we are capable of lessening their impact at home.

Photo Credit: https://www.pennington.com/all-products/fertilizer/resources/what-is-organic-fertilizer

Example Article.  

https://www.sierraclub.org/sludge-garden-toxic-pfas-home-fertilizers-made-sewage-sludge

I found this particular article interesting because I work at a gardening store and do a considerable amount of gardening myself, so I have a lot of involvement with different soils. I had no idea that many of the soils titled as “organic” could potentially contain biosolids and PFAs which can harm the environment. It is almost ironic considering that an activity such as gardening that seems to be a positive impact could be negative depending on the soil a person uses. In the future I will keep my eye out for which soils I purchase and recommend to customers. 

Science in Action.

Dr. Youn Jeong Choi is an Analytical Chemist at Purdue University.

Dr. Youn Jeong Choi currently appears to focus her research on different types of PFAs and their impacts involving different materials. Conveniently, this is almost directly involved with the topic of this article. While her research is not entirely focused on soils, it is helpful to have more information on other impacts of PFAs. Some of her other research involves aerobic biodegradation, aqueous film forming foam, resins, and uptake by the Northern Leopard frog. This is relevant to the topic of PFAs in the environment because it directly discusses the way this chemical can have an impact in multiple different ways.