Once you get a geochemical set of data, you may use the following indices. But, bear in mind they 1) are all indicative and may not always represent the composition.

1) Enrichment factor( Ergin et al. 1991)

2) contamination factor classification (Pekey et al., 2004)

3) Pollution Load Index (PLI) (Tomlinson et al., 1980)

4) Index of Geo accumulation proposed by Muller (1979)

Check with ERL limits

Since you are interested in last 100 years, look at radionuclides 210Pb, 137Cs, 7Be... for dating as well as to see if any mixing takes place. The estuarine areas are prone to intense sediment mixing and removal from tidal forcing, so may not be ideal sites for studying the chronology of human impacts.

Always analyse refractory elements (such as Al,Ti..) which will help you to assess non-crustal sources.

If you wish to see bioavailable fraction, you may carry out sequential extraction studies.

Good luck

What geological period are you possibly going to look at? There are different types of evaluation for recent than there are ancient. Is there any sort of processes that you are looking for specifically?

Right now there are numerous things you can do for sediment tracing, which can show you rates of erosion (impacted by construction), a few modern things you can do with dye tracing to trace current rates of water drainage (impacted by water run-off, and can trace chemicals from landuse), among others.

You can also do heavy metal analysis, which might indicate use of a industrial plants nearby, but for that you'd just get the quantity. Nature does it's own thing, and some of those elements are taken up by plants and fungi.

If I were your professor, I'd start by taking an elemental analysis of the samples and seeing what is there, then asking why. You can do this with a simple ICP-OES analysis which can give you a ppm range of as many elements as you put into the standards.

I know it's a broad way to start, but it's a good place to start so you know what's possible and don't waste your time with things that aren't there. If you need any more ideas, just send a message! :)

Another possible option is the study of molecular biomarkers. Some classes of lipids can be associated with specific human activities.

For example, the hydrocarbons (such as the polycyclic aromatic hydrocarbons - PAHs and the petroleum biomarkers – steranes, terpanes and hopanes) are usually associated with petroleum introduction, both petrogenic as pyrolytic origin. Polychlorinated biphenyls (PCBs) are usually associated with inadequate landfills, while organochlorine pesticides (OCPs) are usually related to agricultural activities and/or control of tropical diseases. Fecal sterols, such as coprostanol and epicoprostanol, are used to determine the direct input of sewage in coastal environments, and the degree of sewage treatment. New studies are also using pharmaceutics and medicines such as contraceptives and analgesics, to trace sewage input.

For more information on the use of these compounds, you can read Abreu-Mota et al., 2014 (PAHs), Combi et al., 2013 (PCBs), Martins et al., 2014 (sterols) and Gavrilescu et al., 2014 (emerging pollutants).

Hope this helps.

Thanks for your answers. They are helpful indeed. 

My prof. hope to focus on the pollution within hundred years scale so that he can conduct some research in coastal management. As a student of geology, I know little about the influence to evironment by humans. 

I also have some question about how to conduct the chemical measure? I mean how to preserve and sub-sample the surfacial and downcore samples?

In addition, if I want to know the influence by human activities, I should also study the natual evolution of the focus area in the same research time scale, isn't it?

May I suggest that you use the elemental analysis suggested by Grace.  The technique can determine many elements (30-50).  ICP refers to inductively coupled plasma spectrophotometry.  If you do not have access to this analytical instrument, then you will have to plan your sampling based on what analytical instruments you do have.   The different patterns of elemental distribution should be evident if your cores sample pre- and post-industrial periods.  You can use multivariate statistical analysis to confirm the patterns.

Once you get a geochemical set of data, you may use the following indices. But, bear in mind they 1) are all indicative and may not always represent the composition.

1) Enrichment factor( Ergin et al. 1991)

2) contamination factor classification (Pekey et al., 2004)

3) Pollution Load Index (PLI) (Tomlinson et al., 1980)

4) Index of Geo accumulation proposed by Muller (1979)

Check with ERL limits

Since you are interested in last 100 years, look at radionuclides 210Pb, 137Cs, 7Be... for dating as well as to see if any mixing takes place. The estuarine areas are prone to intense sediment mixing and removal from tidal forcing, so may not be ideal sites for studying the chronology of human impacts.

Always analyse refractory elements (such as Al,Ti..) which will help you to assess non-crustal sources.

If you wish to see bioavailable fraction, you may carry out sequential extraction studies.

Good luck