Soil Carbamazepine Concentrations – Model Estimates and Field Data Comparisons.

Over the past decade, pharmaceutically active compounds (PhACs) have been routinely detected in the aquatic environment. Despite being subjected to degradation promoting environments during treatment, part per trillion concentrations of PhACs are still routinely detected in wastewater effluent.  Even though these compounds are only present in trace amounts, they can still negatively impact aquatic life and downstream drinking water sources.  The anti-epileptic drug, Carbamazepine, is one of the more persistent PhACs found in wastewater effluent and in waters downstream of wastewater treatment plants.  Applications of wastewater to forested and agricultural lands reduce the mass amounts of carbamazepine to surface waters.  However, there are concerns about ground water impacts as a result.  Therefore, it is of interest to consider the mass loadings of carbamazepine to ground waters beneath forested and cropped lands to which wastewater effluent is applied, as well as to consider the soil solution concentrations of carbamazepine in water moving out of the root zone.  We used published data in a one-dimensional Hydrus model and compared model estimates of soil concentration, and soil solution concentrations, of carbamazepine following 20 years of modeled wastewater application, with concentrations measured from extracts of soils to depths of 120 cm.