TESTING A COMMON NEW MATERIAL, MILK FILTER SOCKS, FOR CONSTRUCTION OF DYE RECEPTORS USED IN TRACER STUDIES

Dye receptors for use in tracer studies are typically constructed by hand using activated charcoal, vinyl mesh screening, and staples to create a small packet. Some researchers recently began using milk filter socks, a non-woven fabric filter used in dairy operations, for ease of receptor construction and reduced cost both in terms of materials and effort. This fabric is also specifically designed to prevent fine silt and sediment from flowing through without decreasing the rate of flowthrough. This material is used with the assumption that there is no effect on the infiltration of dye in the water or the concentration adsorbed onto the charcoal, though this has not been tested quantitatively. Here, we find no difference in the amount of dye recovered using the traditional vinyl mesh receptors versus the milk filter socks when tested in the laboratory.

To compare the two materials, controlled laboratory experiments were conducted at both the Kentucky Geological Survey and the Crawford Hydrology Laboratory. Dye receptors of equal dimension containing equal charcoal mass were constructed using each of the two materials. Six of each receptor type were soaked in standards of different dye concentrations, including a blank, for at least 18 hours, then dried thoroughly and divided in triplicate for analysis using standard operating procedures. The experiment was repeated using three fluorescent dyes: Eosin, Fluorescein, and Rhodamine WT. Dye concentrations were consistent between materials and dye concentrations for a qualitative trace, supporting the assumption that the materials have a minimal impact in a lab setting. However, preliminary work conducted by the Crawford Hydrology Laboratory indicates the results are much more variable in a field setting. Additional field testing is needed to understand how flow conditions and sediment accumulation on the milk socks has an appreciable impact on flowthrough and dye recovery.