Many springs and other karst features show a characteristic cloudiness even at low flow. This appearance is usually attributed to fine-grained colloids that remain in the water column regardless of water velocity. The composition and nature of these colloids should play an important role in contaminant transport, but few attempts have been made to characterize this material. The prevalent techniques, based on scanning electron microscopy and energy-dispersive x-ray spectroscopy give only elemental composition rather than mineralogy and have the potential for significant chemical alteration during sample preparation. To address this, we analyzed a concentrated aqueous suspension using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and atomic force microscopy (AFM).  Colloids from Smullton Sinks, a series of karst windows in Centre County, PA, which display cloudiness particularly at low flow were analyzed. Quartz and layer silicates dominated the colloidal fraction, and no evidence of organic material or carbonate species appeared.

New technique for identifying colloid mineralogy in karst waters: Applying ATR-FTIR spectroscopy and AFM to karst colloids

245th National Meeting (2013)

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