Natural Attenuation of Emerging Contaminants in the Critical Zone
Rachel Maxwell1,2, Leif Abrell1,2, Andrea Conine3, and Jon Chorover 1,2
1Soil, Water and Environmental Science Department, 2Arizona Laboratory for Emerging Contaminants, University of Arizona, 3 Skidmore College
Emerging contaminants (ECs) include chemicals known as endocrine disrupting compounds and pharmaceuticals and personal care products. The presence of these pollutants in water sources has been correlated to their widespread domestic use. Wastewater treatment is only partially effective in their removal prior to effluent discharge into surface waters where they may persist. Connections between trace organic contaminants in water and human health remain equivocal; however, physiological changes have been observed in fish exposed to estrogens and estrogen mimics in waters that receive wastewater effluent. Here we investigate the behavior of anthropogenic pollutants in the context of the critical zone (CZ). We hypothesize that biogeochemical weathering processes in the Earth’s near surface layer affect the fate and transportation of trace organic contaminants. ECs from stream waters at the UA Critical Zone Observatory are known to arise from wastewater effluent from the 1.1 MGY Mount Lemmon treatment plant. The wastewater is sprayed onto a forest floor, infiltrates into perched aquifers and eventually is released to nearby surfaces waters. We aim to determine if biogeochemical processes in the CZ will diminish EC concentrations in surface waters via sorption to soil, biodegradation, transformation, and/or dilution. Soil, stream, sediment, and effluent samples are prepared by solid phase extraction and analyzed with liquid chromatography tandem mass spectroscopy to quantify EC concentrations transported through the CZ.