Risk analysis of irrigating lettuce, carrots and strawberry with microcystine-contaminated water

General introduction

The increased prominence of cyanobacteria blooms in canals and open surface basins cause sources of irrigation water to be polluted with cyanotoxins (microcystins).  CYANTIR, a 2-year FOD-project with UGent as coordinator and partners ILVO, Sciensano, Inagro and ULG, aims to investigate whether irrigation with microcystin polluted water is risky to human health in terms of residual concentrations of microcystins that could accumulate on or in the edible parts of plants and therefore could be transferred to humans via consumption. The project chose lettuce, carrots and strawberries as model crops for a leafy vegetable, a root vegetable and a soft fruit, respectively. 

Research approach

This project has ended. The researchers have in three wel-controlled greenhouse trials exposed three types of freshly consumed crops (lettuce, carrot and strawberry) during their last growth month to irrigation water loaded with 100µg/L microcystin congener LR (MC-LR). A commercially pure MC-LR was used for these irrigation trials. Also, for the different crops, at least 2 different irrigation methods were used. The level of MC-LR present on and in the crop at harvest was determined with an LC-MS/MS method by Sciensano. The project studied primarily the edible parts of the plant for cumulative microcystin (MC) exposure, but other plant parts were also examined. 

Relevance/Valorisation

The data obtained provide a first insight into the various factors that may influence the degree of microcystin accumulation in the plant. Although accumulation of MC-LR was demonstrated in all crops, concentrations in the edible parts of the plant remained low. The observed values for MC-LR were below 10 µg/kg for lettuce, carrots and strawberries. Based on these preliminary data, the conclusion is that there is no immediate concern for Belgian public health from MC-LR contamination through irrigation of the food crops studied. However, caution remains necessary.  Additional experiments are needed to make a reliable risk assessment. 

Funding provider(s)
FOD Volksgezondheid, Veiligheid van de voedselketen en Leefmilieu