Tuesday, December 2, 2014
Landfills are a veritable hotspot for pharmaceuticals and other emerging contaminants. That is what researchers at the U.S. Geological Survey (USGS) uncovered after testing landfill leachate—runoff that picks up contaminants as it flows through the waste. It may not sound too surprising. But, as the study reveals, the fate of emerging contaminants in landfills is far more complicated.
The study looked for a range of pharmaceuticals, hygiene products, household chemicals, pesticides, plastics, and other emerging contaminants in 19 landfills across the country, making it the first-ever nationwide survey of its kind. Altogether, the researchers found 129 chemicals—with as many 82 in a single sample. In fact, every leachate sample collected contained at least six of the chemicals tested for.
That is where the similarities end. The chemicals were found in radically different concentrations spanning six orders of magnitude. At the bottom of the scale, were steroid hormones measuring in the parts per trillion, less than a drop of water in a swimming pool. In contrast, household and industrial chemicals were found in the parts per million, roughly a cup of water in a pool.
Among those at the top of the scale was bisphenol A (BPA), a chemical used in many plastics and resins. A weakly estrogenic compound, BPA was found in nearly every landfill and made up a large portion of the total concentrations measured. Cotinine, DEET, lidocaine, and camphor—common in medicines and lotions—were also found in at least 84 percent of the samples. But as a class, prescription pharmaceuticals were found more than any other chemical group, although their concentrations were much, much lower.
And in any one landfill, the make-up of chemicals and their concentrations depend at least in part on characteristics like location and the type of waste it holds. For example, household chemicals were found more often and at higher total concentrations in leachate draining from a mix of municipal and industrial waste. Concentrations and detections also varied by region, with the Midwest ranking fourth in both.
Perhaps unsurprisingly, one of the largest factors effecting detections and concentrations appears to be rainfall. Landfills in wetter environments were responsible for 90 percent of the total chemical concentrations measured.
These are just a few of the results from the USGS leachate study, but this study only begins to scratch the surface of what researchers hope to learn about emerging contaminants in landfill leachate. That is why USGS has several other projects in the works examining how chemicals breakdown in these unique environments and what happens to them when the leachate leaves the landfill. Watch here for those results!
And in the meantime, hear Dana Kolpin talk more about USGS efforts to understand emerging contaminants and their effects in our latest issue of UpClose.
Masoner, J.R., D.W. Kolpin, E.T. Furlong, I.M. Cozzarelli, J.L. Gray, and E.A. Schwab. Contaminants of emerging concern in fresh leachate from landfills in the conterminous United States. Environmental Science: Process & Impacts 16:2335-2354.