Dear Mr. Kundula,

your question is another one of those resembling the well-known equation with several unknowns. I would like to get some information about the grain size, the profile you sampled, the section of the river and type..... Without answers to these questions and more it is almost impossible to provide you with a tailormade answer. On the other hand which element do you want information about.

Even if this bunch of questions is answered one can only constrain rather than answer this question but one or the other may come closer to your expectations

H.G.Dill

Thank you sir for your immediate and thought provoking response.

We are working on surface sediment samples collected from Krishna and Godavari river delta regions. Our sediment samples are mostly composed of silt and clay size particles. Natural background values for Major, Trace and REE elements are required for these two river sediments to estimate the pollution status of certain toxic elements like Co, Cu, Pb, Zn, Ni, Cr, As etc., present in our samples.

Dear Mr. Kundula,

in your case I would use for background values the books written bei Wedepohl (Folder collection) and Turekian. They have published background values of marine and terrestrial sediments. I can only give you an idea of the magnitude of background values that you might expect for your elements under consideration: Co 20 ppm, Cu 50 ppm, Pb 20 ppm, Zn: 100 to 200 ppm, As: 15 ppm, Cr: 90 ppm. In some reducing environments such as the prodelta muds these values may be elevated in red muds they may be lower.

This is to give you a rough idea.

I wish you much succes

H.G.Dill

Thank you sir for you valuable suggestions and references that you have quoted here regarding background values. Your recommendations will surely help us to achieve good results.

with regards

K. Bhaskara Rao

It is a pleasure for me to have been of assistance for your studies.

H.G.Dill

Its my pleasure to have a great personality like you sir.