German institute analyses reclaimed wastewater risk

The German Federal Institute for Risk Assessment (BfR) has recommended that fresh produce that is grown close to the ground and is intended to be eaten raw should not be irrigated with reclaimed wastewater due to the likelihood of causing illness.

Crops such as lettuce, carrots, strawberries and herbs grown in these conditions are at risk of carrying harmful viruses or parasites to humans, with the chance of causing both mild and severe sickness. The recommendation from the BfR, a scientific organisation that provides risk analysis of food, chemicals and product safety for Germany’s federal and state government bodies, comes based on emerging evidence that reclaimed wastewater has a chance of carrying viruses and protozoa if not properly treated.

“Reclaimed wastewater in agriculture poses a new challenge to food safety,” said BfR President Professor Dr Dr Andreas Hensel. “In order to reduce pathogens as much as possible, we need very good treatment and detection methods.”

The data do not currently support a conclusive risk assessment but the organisation is confident enough to make a strong recommendation against the practice of using the water to farm these particular plants, at least until treatment processes are available for the water.

Further research is apparently required to ascertain how to prevent the transfer of pathogens from wastewater to humans, which could happen at multiple points along the chain of production (specifically subsurface drip irrigation, drip irrigation, furrow irrigation, sprinkler system and hydroponic culture).

Three lengthy opinion pieces have now been produced by the BfR regarding reclaimed wastewater use in agriculture, outlining the case against using the water in certain agricultural sectors and okaying it in others. The first two pertain to viruses and protozoa and the third, published in 2020, relates to bacteria.

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