Hi Ali

Problem with organic matter is that lowers the amount of bio-available metal 

There are many models to describe this behaviour and you need to consider other physical parameters and aspects as well, such as pH etc

However, the concentration of metal for remediation experiment is sometimes so high that , there  in no worry about contribution of organic matter, since ther would be plenty of metal available.

For more details, have a look at one of my publications

https://www.researchgate.net/publication/273324320_Consideration_of_the_bioavailability_of_metalmetalloid_species_in_freshwaters_experiences_regarding_the_implementation_of_biotic_ligand_model-based_approaches_in_risk_assessment_frameworks

Article Consideration of the bioavailability of metal/metalloid spec...

thank you a lot. but my question was not on organic matter, although it is one of the key for metal reemedial, but Organic contaminat such us phenenthrene, pyrene,,,,,PAHs