EVOLUTION OF THE LIGNITE-WATER HYPOTHESIS IN THE U.S.: ADVANCES, CHALLENGES, AND THE NEED FOR FUTURE COLLABORATION

The Pliocene-lignite hypothesis, now more generally termed the lignite-water hypothesis, states that organic material leaching from low-rank coal (lignite) may passively contaminate local groundwater. Residents that rely on this drinking water supply consume the organic matter, which in turn may contribute to the development of renal disease. The Pliocene-lignite hypothesis was first proposed as a contributing factor development of Balkan Endemic Nephropathy (BEN), and over the last decade there has been an effort to explore the lignite-water hypothesis to the United States (U.S.). Although the geologic framework between the Balkans and the U.S. is similar– in both cases lignite is hydrologically connected to local and regional aquifers– there are several considerations that must be taken into account when translating the lignite-water hypothesis to the United States. First, drinking water in the U.S. is typically connected to the public supply and is treated, leaving the population that relies on un-treated domestic water supplies (i.e. well water), and those at risk for ingesting organic matter from lignite represent only a fraction of the population. Secondly, the population in the U.S. is more mobile than the rural villages in the Balkans where the apparent effect could be concentrated by several generations relying on the same source(s) of water. The health effect in the U.S. might be diluted and difficult to deconvolute from other confounding factors for renal disease. Lastly, there are several analytical and experimental design factors that come into play tracing the organic material from source to sink, which is complicated by the fact that the toxic agent(s) and the mechanism(s) of action have not been clearly identified. Here, a summary of the most recent efforts to study the lignite-water hypothesis in the U.S. is outlined, advances and challenges unique to the U.S. are discussed, and the importance of collaboration between geologists, environmental scientists, and those working in public health is highlighted.