To accurately map a pollution problem some way of differentiating between chemicals present in the environment must be used. Normal vision will not provide all the information needed as sometimes pollutants are invisible to the naked eye(bot). Spectrometry offers a deeper insight into an environment and will be a valuable addition to the info about a cleanup site.

I'll be investigating a number of options and will probably choose the cheapest one for the first build.

Here are a couple possibilities I have come across:

C12666MA Micro-Spectrometer

http://publiclab.org/wiki/spectrometer