Equation purposed by Hakason for evaluation of potential ecological risk given as under:
RIi = (Ti*Ci)/Si
Where
Ti is the Background value of elements
Ci is the actual concentration of an element
Si is the biological coefficient of element
I want to know about Si (background values of elements like Cr, Fe, Mn, and Zn) in water and Ti ( biological coefficient of Fe, Cr, Mn, and Zn).