The behavior of arsenic accumulation in onion (Allium cepa) structures by irrigation water: Effect of phosphates and arsenic on the total bioactive compounds and antioxidant capacity

Abstract The presence of arsenic (As) in irrigation water is a threat to agricultural crops as well as human health. The presence of arsenic and phosphorous in irrigation water influences the behavior of bioaccumulation, biotransfer, and total bioactive compounds in the distinct parts of the onion structure. The present work evaluates the behavior of the bioaccumulation and biotransfer of As in the structures of onion (Alliun cepa) through a composite central design and response surface method. The factors employed include the concentration of arsenic (V) and phosphate (V) in the nutritive solution. Additionally, this study analyzes the behavior of the effect that the induced stress has on the total bioactive compounds (phenols and flavonoids) and antioxidant capacity (ABTS and DPPH) in the onion roots. The results showed that the physiological properties, bioaccumulation factors, As transference, as well as the total bioactive compounds in the onion structure, are affected by the competition of As and phosphates (P(V)) in the irrigation water. For concentrations of As and phosphorous of 450 mg L− 1 and 0.30 mg L− 1 respectively in irrigation water, there are negative effects on the equatorial diameter of the bulb, length, weight of leaf, and weight of bulb. Besides, the transference and bioaccumulation factors range from 2.36 to 22.22 and from 2.15 to 7.81 respectively, suggesting that the plant has a translocated ability of As from root to aerial organs and it is possible to accumulate As. Besides, it is found that under the mean conditions of As and phosphorous in irrigation water, a greater production occurs in total phenolic compounds and antioxidant capacity (ABTS and DPPH) as a response to the stress generated by As.