The occurrence of lithium in the environment of the Jordan Valley and its transfer into the food chain.

Lithium is found in trace amounts in all soils. It is also found in plants and in nearly all the organs of the human body. Low Li intake can cause behavioral defects. Thus, this study was conducted to investigate the concentration and distribution of water-soluble Li in soils of the Jordan Valley and its concentration in citrus trees and some important food crops in view of the significant implications of Li for human health. The concentration of soluble Li was measured in 180 soil samples collected at two depths (0-20 and 20-40 cm) whereas its content was determined in fully expanded leaves collected from citrus and different vegetable crops. Concentrations of soluble Li in soils vary from 0.95 to 1.04 mg l(-1) in topsoil and from 1.06 to 2.68 mg l(-1) in subsoil, while Li concentration in leaves ranged from 2 to 27 mg kg(-1) DM. Lithium concentrations in leaves of crops of the same family or different families vary with location in the valley; i.e., they decreased from north to south. It is concluded that soluble Li in soils and the plant family did not solely affect Li transfer in the food chain. In addition, soil EC, Ca, Mg, and Cl, which increased from north to south, might adversely affect plant Li uptake. The current study also showed that consuming 250-300 g FW of spinach day(-1) per person is recommended to provide consumers with their daily Li requirement necessary for significant health and societal benefits.