Occurrence of β-N-Methylamino-L-Alanine (BMAA) Toxin in irrigation Water and Field Vegetable Plants and Assessing Its Potential Risk to Human Health

This study investigates the presence of the neurotoxin β-N-methylamino-L-alanine (BMAA) and its cyanobacterial producers in irrigation water as wells its potential accumulation in nine commonly consumed vegetables from Egyptian farmlands. The HPLC–MS/MS analysis revealed that phytoplankton samples contained higher concentrations of free BMAA (0.6–11.4 μg L⁻¹) than protein-bound form (0.01–3.3 μg L⁻¹), in association with the abundance of dominant cyanobacteria in irrigation water sites. Extracellular dissolved BMAA was also detected in cell-free irrigation water, but with very low concentrations (0.1–0.2 μg L⁻¹). Meanwhile, BMAA was also detected in a protein-bound form (0.05–7.7 µg g⁻¹ fresh weight) in most vegetable plants, with highest levels obtained in zucchini fruits followed by watercress levels, tomato fruits, green pepper fruits, radish leaves, and pea fruits. The BMAA concentrations accumulated in these vegetables correlated with BMAA concentrations detected in relevant irrigation water sites.

Hence, the presence of BMAA in vegetables could pose a risk to human through eating contaminated edible pant parts. The study recommends ongoing monitoring of BMAA and other cyanotoxins in irrigation waters and edible plants in order to safeguard the public from exposure to such serious toxins.