Nematode community structure will be good indicator for any type of stress either chemical or physical. However the changes in different stress factors the community showed various modification because nematodes are species specific indicators.
there is work from Richard Warwick that deals with pollution and nematodes I think (Warwick, R.M., 1981. The Nematode-Copepod Ratio and Its Use in Pollution Ecology. Marine Pollution Bulletin 12 (10), 329-333.; Warwick, R.M., 1986. A new method for detecting pollution effects on marine macrobenthic communities. Marine Biology 92 (4), 557-562; Warwick, R.M., 1988. Effects on Community Structure of a Pollutant Gradient - Introduction. Marine Ecology-Progress Series 46 (1-3), 149-149.; Warwick, R.M., Carr, M.R., Clarke, K.R., Gee, J.M., Green, R.H., 1988. A Mesocosm Experiment on the Effects of Hydrocarbon and Copper Pollution on a Sublittoral Soft-Sediment Meiobenthic Community. Marine Ecology-Progress Series 46 (1-3), 181-191.; Warwick, R.M., Clarke, K.R., 2001. Practical measures of marine biodiversity based on relatedness of species. Oceanography and Marine Biology, Vol 39. Taylor & Francis Ltd, London, pp. 207-231.)
Also a paper/chapter by Balsamo et al., (Balsamo, M., Semprucci, F., Frontalini, F., Coccioni, R., 2012. Meiofauna as a tool for marine ecosystem biomonitoring. In: Cruzado, A. (Ed.), Marine Ecosystems. InTech Publisher, pp. 77-104.) that has a table with species specific nematode responses to hydrocarbon pollution. This should be available on RG; let me know if not