Thanks guys for your valuable answers. just more details what I have done so far on my thesis. I have taken 10 soil samples from the site ( used to be several industrial facilities since at least1967 manufacturing) different depth from 1 feet to 10 feet. chemical analysis for 10 michigan heavy metals Arsenic, Barium, Chromium, Copper, Lead, Zinc, Cadmium, Selenium, Silver and Mercury with different concentration of contamination. also VOCs and PNAs. the same soil samples have analysised for microorganism and showed contaminated with plenty of different type of microbial. what should I do of both results to come up in my thesis? I know complicated but get stuck. thanks