Is it safe to grow vegetables in plastic building waste? Is it safe to do it in the city where air quality might be poor? Those are the fundamental questions to ask yourself before you start urban gardening.
Safe gardening in the city
When you grow vegetables in the big city, it can hardly be avoided that the crops absorb unwanted substances from soil and air. However, the quantities are so small that it is not harmful to health. As associate professor Jakob Magid of the Department of Agricultural Science at the University of Copenhagen says: “When the general health risks of living in a big city are considered, the risk of eating city-grown vegetables is negligible … In an overall perspective, it is without a doubt beneficial that people grow their own vegetables. It provides fresh air, exercise and reestablishes the connection to how food is produced. These benefits must be weighed up against an extremely little risk.”
Absolutely no risk associated with rigid PVC waste in urban agriculture
To be on the safe side, we have asked a toxicologist about the safety of growing vegetables in discarded PVC building products,
Rigid PVC construction waste is normally divided into three waste categories: production waste, which is generated at manufacturing plants and often recycled locally; installation waste, which comes from the construction sites; and post-consumer waste. When it comes to the post-consumer products, there may be waste that contains a small percentage of heavy metals. To achieve long product life, for instance, lead compounds were added as stabilisers before 2015. These compounds, however, are so embedded in the PVC plastic that they are not released to the environment. Among other things, this has been shown by the Danish Environmental Protection Agency in a study, in which I personally participated, where drinking water was analysed after flowing through 30-40-year-old underground PVC pipes. Thus, there is absolutely no health risk associated with reusing PVC products containing heavy metals in urban agriculture.
Dr. Lars Blom, toxicologist
Source: The Danish Environmental Protection Agency: ”Field study of water supply pipes in plastic,” Environmental project no. 1049, 2005, https://www2.mst.dk/udgiv/publikationer/2005/87-7614-863-7/pdf/87-7614-864-5.pdf