The PLI value greater than one indicates the metal pollution in the sediments. Is anyone experienced the extremely high values (suppose 100 or 1000) in the marine sediments samples?
I have published a paper that reported extreme metal pollution load indices of up to 31. However this was NOT in marine sediments. It was in peri-urban freshwater dams that received a lot of urban run-off and effluent discharges. I suppose it is possible to have values of up to 100 after a prolonged period of pollution. This is because metals generally adsorb onto sediments, therefore keep accumulating over time. You also need to be sure that the metal levels you are detecting in sediments are not due to the geochemistry of the bottom surface (as opposed to pollution).
Here is a link to our publication.
Article Heavy metal contamination of water and fish in peri-urban da...
You gave a quite logical answer. Metal concentrations in a particular area are highly dependable on the geochemistry and background levels of metals. Beyond this, high pollution may be influenced by accidental contamination. Actually, I want to know about extremely PLI values reported for marine sediments. Thanks for your answer.