Hi, Ali, your task is realy very difficult! There are a lot of factors you have to considered. Many of them are dependent from soil composition, pH, presence of organic complexes etc. Under certain conditions heavy metals convert state whcih do not directly uptale by roots.

I would suggest youb to use hydroponic culture for this kind of experiments. And you need to have specail electrode for determination of the real concentration of the heavy metals.  http://www.nico2000.net/analytical/cadmium.htm

Thank you sir for reply. Currently i am using the following procedure-

dissolving 100mg of heavy metal in 50ml of Double distilled water and then mixing with 300g of soil. Then i fill this soil in pot and keeping it for 48h for stabilization of heavy metal.

Thanks! The main question what was the "real" concentration of heavy metals in the soil, ea. the concentration of the cation which avlable for uptake by roots. Soil bacteria you want to study can only modified soil pH (for example), thus, alter "real" concnetration of the heavy metals by inducing chelation etc. . 

Dear Ali,

Dr. Pasternak gives you good suggestion regarding the conditions you have to keep in mind during addition of heavy metals in soil and their availability to plants. As soil pH alters the availability (or real concentration) of metals in soil you have to check how much metal content is available after the stabilization (in your case 48 h). This you can check by analyse the metal content in liquid form (dissolving the known content of metal in water or diluted acid) and other in the soil (where you have mixed known amount of metal. This gives you indication about the efficiency of the metal recovery from soil and also the content of available metal. 

one more thing.... why you are dissolving the metal in water? In my opinion water alone does not acts as dissolving agent. Studies reported that low pH favors dissolution of metals effectively. several companies also provide metal solutions in acidic solution (such as 10% HNO3 solution and others). Search on the web gives you more information regarding dissolution of metals salts in different solutions.

Hope this will help you. All the best.

Dear Ali,

You can contaminate soil easily by heavy metal. You should make standard solution of respective heavy metal then mix with soil and keep for stabilization for one week.

Ali Asger Bhojiya

I am working on a similar topic and facing same challenges. I am trying to artificially contaminate my soil with Cd and Cr.

How did you go about yours ?

kindly reply