The impact of season on the dynamics of trace elements and heavy metals in shallot farming system and their human health Risk evaluation

Abstract This study aims to study the effect of seasonal variations against soil physio chemical properties and to determine their effect on the absorption of trace elements and heavy metals from the soil to all parts of the shallot plants. In addition, in this study an assessment of human health risks was carried out through the consumption of shallot bulbs planted in different seasons. Analysis of heavy metal and trace element contents were carried out using the Neutron Activation Analysis (NAA) method. From the research result, it was known that seasonal differences affect soil physio chemical properties and the distribution and mobility of heavy metals and trace elements in the soil and their translocation in plants. In the rainy season, the BCF value of heavy metals in the order of Br > Na > K > Sr > Zn > Mg > Mn > Cr > Se > La > Co > Fe > As > Sc > Sm > Hf > V > Al > Rb > Ba > Th > U > Ti, while in the dry season, the order was Br > Na > K > Zn > Sr > Mg > Cr > Mn > Co > La > Sm > Sc > Fe > As > Hf > Se > V > Rb > Al > Th > Ba > U > Ti. The concentration of Mn, Sm, La, Cr, Fe, and Zn in shallots parts was in the order of roots > leaves > bulbs, while the concentration of Mg, K, Br, Na, Se, and Ba elements in the order of leaves > roots > bulbs. The risk identification and the human health risk assessment conducted to the potentially known toxic elements of U, V, Al, Mn, As, Cr, Fe, Zn, Co, Th, Ba and Sr gave target hazard quotient (THQ) and hazard index (HI) that were lower than 1 for all of them in either rainy or dry season.