Distribution of Possible Disease Causing Inorganic Tracers from Lignite in Wilcox Aquifer in Caddo Parish, Louisiana

Previous investigators have demonstrated that the presence of lignite within aquifers in Europe and North America, including Louisiana, will impact the water quality of aquifers with chemical and biological agents that are suspected to cause various kidney diseases. These studies suggest that the potential disease-causing agents include nutrients, heavy metals, organic compounds or bacterial and/or fungal agents. Previous investigators have also noted that these disease-causing agents are present in domestic wells and other non-community water supply wells that are untreated, while treatment within public wells removes the disease-causing agents. This study considered how pervasive these disease-causing agents are within domestic wells and other non-community water supply wells located in Caddo Parish, Louisiana. This study involved comparison of the concentration of selected nutrients (ammonia nitrogen and phosphate) and elements (boron, chloride, chromium, fluoride, sodium, phosphorus, rubidium and strontium) that have the strongest correlation with kidney disease occurrence, according to a previous study performed in Louisiana.

This study included three sets of approximately 35 to 50 wells, selected from wells in Caddo Parish which are screened in the Wilcox Aquifer. The three sets of wells selected for comparison exhibited one of the following characteristics: (1) set with lignite present within their screened interval; (2) set with lignite present within their borehole, but not within their screened interval; and (3) wells in stratigraphic units that are suspected to contain lignite, but said condition was not reported in previous well reports. The results of the three data sets were statistically compared using a t-test, a median test, and a Wilcoxon Mann-Whitney test. For some of the species (ammonia nitrogen, boron, chloride, fluoride, sodium, and strontium), there is a significant increase in concentration of the parameters of for wells that include lignite within the boring, compared to other wells in Wilcox that lack lignite.