The presence of heavy metals in sediments can result in a decrease in the quality of waters, which is a long time can a negative impact on aquatic organisms and public health.

Dear Dr. Newman,

there are various reference values from the Clark value which gives you the mean values of metal concentration on a global basis through the guidelines of the WHO which sets levels for contaminated soil and water to the local guidelines which often issued in terms of habitat and working sites. It is comprehensible that the level of contamination between housing areas and mining sites needs to be different.

On the other hand what is the unit you measured your Cr contents, in ppm , ppb....or anything else?

Moreover, the type of chemical compounds plays a decisive role. If you measure the concentration of Ba in sediments and you get the same values it depends on the solubility product of the chemical compound. While BaSO4 at the same rate is absolutely non-toxic, BaCO3 can be highly toxic and as such the technical term contaminated has different meanings, a purely geochemical one and a medical one. Both Ba compounds are chemical compounds which may be encountered as barite and witherite, respectivley, in sedimentary and other host rocks. It is first and foremost the availability of the heavy metals in the host sediment and their potential to enter the food chain or get inhaled and incorporated into the lungs by respiration. The third component it gamma radiation which is restricted to U and Th and their decay products.

It is not that easy to answer your question in the way you have raised it.

I wish you much success

H.G.Dill

You can do ANOVA so as to make conclusions

I think these papers could help you;

They're available on the ResearchGate Server for download.

Heavy metals are poorly soluble in water, so predominantly to suspended particles that then settle as sediment. Heavy metals can thus enter the food chain in the aquatic environment, and become available for accumulation in biota.