INVESTIGATING A LINK BETWEEN LOW-RANK COAL BEARING CARRIZO-WILCOX AQUIFER WATER AND KIDNEY DISEASE IN EAST TEXAS

Low-rank coal (lignite and subbituminous) contains a myriad of organic compounds, but little is known about the impact of these toxic compounds on human health when they are mobilized into groundwater and consumed. Ingestion of coal-tainted water has been previously linked to widespread kidney disease and urinary tract cancers, including idiopathic Balkan endemic nephropathy (BEN). One example of a low-rank coal-bearing aquifer is the Carrizo-Wilcox, which provides groundwater supply to nearly sixty counties in rural east Texas. Four coal samples collected from active mines along the aquifer trend were analyzed for structural and functional characteristics through Soxhlet leaching experiments. Forty-eight groundwater samples from rural public drinking water supplies along the aquifer trend were collected from nine rural counties and analyzed for the presence of organic compounds. The purpose was to determine whether there exists any similarity between the suites of organics identified in the water wells to the organics leached out from coal samples in the laboratory leaching experiments. The coal samples exhibited the presence of nitrogen, sulfur and oxygen (NSO) heterocyclic compounds along with the presence of phenols and benzene derivatives. Most well water samples also revealed the presence of a similar suite of compounds with an estimated concentration ranging from 0.1 to 3.9 μg/L. The geochemical variations of the nature and concentration of the organic compounds along the aquifer trend were also examined by using spatial interpolation (kriging) method. These geochemical variations were attributed to spatial variation coal rank and thickness of coal seams along the aquifer trend. Non-parametric statistical test (Kruskal-Wallis) indicated that there exists a significant statistical difference between the concentration of organics detected in the wells intersected by coal either in boring hole or screened interval and the wells devoid of coal. Spearman correlation showed a significant (p < 0.05) to highly significant (p < 0.01) correlation exists between the incidence rates of kidney disease (end stage renal disease and renal/pelvis cancer) and the concentration of both aliphatic and aromatic compounds.