Accumulation of Microcystin from Oscillatoria limnetica Lemmermann and Microcystis aeruginosa (Kützing) in Two Leafy Green Vegetable Crop Plants Lactuca sativa L. and Eruca sativa

Asmaa Bakr; Mashail Nasser Alzain; Nurah M Alzamel; Naglaa Loutfy

doi:10.3390/plants11131733

Accumulation of Microcystin from Oscillatoria limnetica Lemmermann and Microcystis aeruginosa (Kützing) in Two Leafy Green Vegetable Crop Plants Lactuca sativa L. and Eruca sativa

Plants (Basel). 2022 Jun 29;11(13):1733. doi: 10.3390/plants11131733.

Authors

Asmaa Bakr¹, Mashail Nasser Alzain², Nurah M Alzamel³, Naglaa Loutfy⁴

Affiliations

¹ Botany and Microbiology Department, Faculty of Science, Sohag University, Sohag 82524, Egypt.
² Department of Biology, College of Sciences, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia.
³ Department of Biology, College of Sciences and Humanities, Shaqra University, Shaqra 11961, Saudi Arabia.
⁴ Botany and Microbiology Department, Faculty of Science, South Valley University, Qena 83523, Egypt.

Abstract

The use of contaminated water to irrigate crop plants poses a risk to human health from the bioaccumulation potential of microcystins (MCs) in the edible tissues of vegetable plants. The main objective of this study is to determine the concentration of total microcystins (MC-LR and MC-RR) in leafy green plants (Lactuca sativa L. var. longifolia and Eruca sativa) that have previously been irrigated with polluted water. Integrated water samples were collected by cleaned plastic bottles at a depth of about 30 cm from one of the sources of water used to irrigate agricultural lands for crop plants. At the same time, samples from plants were also collected because this water from the lake farm is used for the irrigation of surrounding vegetable plants such as Lactuca sativa L. var. longifolia and Eruca sativa. The dominant species of cyanobacteria in water samples are Microcystis aeruginosa (Kützing) and Oscillatoria limnetica Lemmermann, which were detected with an average cell count 2,300,000 and 450,000 cells/mL, respectively. These two dominant species in water produced two MCs variants (MC-LR, -RR) that were quantified by high-performance liquid chromatography (HPLC). Dissolve and particulate MCs were detected in the irrigation waters by HPLC with concentrations of 45.04-600 μg/L. MCs in the water samples exceeded the WHO safety limit (1 μg/L) of MC in drinking water. In addition, the total concentration of Microcystin in Lactuca sativa L. var. longifolia and Eruca sativa were 1044 and 1089 ng/g tissues, respectively. The estimated daily intake (EDI) of microcystins by a person (60 kg) consuming 300 g of fresh plants exceeded the total daily intake guidelines (0.04 μg kg^-1 body weight) for human food consumption. According to the findings of this study, irrigation water and plants used for human consumption should be tested for the presence of MCs regularly through critical and regularly monitored programs to prevent the accumulation and transfer of such toxins through the food web.

Keywords: Eruca sativa; Lactuca sativa L.; Microcystis aeruginosa; Oscillatoria limnetica; accumulation; microcystins.

Grants and funding

PNURSP2022R103/Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.