The effect of pesticides in aquaponic systems
Bozidar Raskovic (University of Belgrade) received a grant from the EU Aquaponics Hub to spend three weeks at the University of South Bohemia in České Budějovice (CZ) in order to study the effects on biofilter bacteria of an organic pesticide containing azadirachtin, which comes from the neem tree (Azadirachta indica), and a synthetic pesticide containing chlorpyrifos. Contrary to expectations, the measured levels of ammonia, nitrite and nitrate showed that the organic pesticide containing azadirachtin was more detrimental to bacteria than the synthetic pesticide. The slow down in nitrification leads to higher concentrations of ammonia and nitrites, which are potentially dangerous for fish. Both organic and synthetic pesticides should be used with caution in aquaponic systems.