Microcystin exposure of the Belgian population: feasibility of unifying fragmented exposure data

Microcystin (MC) congeners are hepatotoxins produced by aquatic cyanobacteria. Uncovering
potential exposure routes in Belgium requires assessing the impact of these toxins on the
population. Various approaches evaluate exposure separately for different intoxication routes
(environmental and food consumption). However, the aggregated exposure from various
stressors is not commonly done. With access to various collection sites and a national
consumption database, a holistic approach to microcystins exposure should be feasible.
Eight MCs were quantified in different matrices representing multiple intoxication pathways
using UHPLC-MS/MS. Overall, 79 samples from algal blooms, 75 drinking water samples, 35
algal-based food supplements, and 103 fruits and vegetables from supermarkets were analyzed.
MCs were found in the bloom samples (86.08%) and algal food supplements (22.86%) but not in
drinking water, fruit and vegetables. Daily estimated exposure was calculated for the food
supplements, and the ratio of bloom samples above the proposed guidance values for recreational
waters (24 μg/L) was determined.
Aggregated exposure assessment needs additional data: consumption data for algal supplements,
dietary exposure from foods, proper modelling to episodic environmental exposures. Specific
exposure scenarios resulting from collaborative research show the feasibility of unifying the
exposure prediction for a part of the Belgian population.