Measurement of Biological Contamination of Water

Laser-induced fluorescence (LIF) can sometimes be used as a diagnostic device in biology and medicine. In general, LIF has difficulties in relating the fluorescence spectra to the concentration of the emitters within the tissue, in identifying different species, and in the possibility of destroying the molecules being probed if the wrong excitation wavelength is chosen. Many of the problems associated with fluorescence can be eliminated by the use of Raman scattering. Raman techniques allow the measurement of multiple species even in aqueous solutions (not accessible by infrared methods because of water absorption). However, spontaneous Raman techniques give very weak signals. Signal enhancement is possible by utilizing resonance Raman techniques. Both of these methods still suffer from the fact that spatial and, to some extent, temporal information is lost. This Phase I project will investigate a noninvasive, real-time, high resolution device for the detection of lifeforms such as Cryptosporidium or Giardia in situ in water. It also can be used to identify viable cysts and oocysts. This unique device is based on a variation of Raman scattering and can simultaneously measure the concentrations and temporal evolution of several different molecular species. Therefore, the technology may have applications in the medical field (virus and cholesterol measurements), in drug manufacturing and monitoring, and blood gas analysis. Furthermore, it may find applications in environment-related monitoring and analysis.