Analysis and Sorption of Psychoactive Drugs onto Sediment

Abstract

An analytical method was developed to analyze eight psychoactive pharmaceuticals--including the antiepileptic carbamazepine, the opiates morphine, codeine, dihydrocodeine, the opiode tramadol, and the tranquilizers diazepam, oxazepam, temazepam--and the antibiotic sulfamethoxazole as well as three metabolites (10,11-dihydrocarbamazepine (DHC), 10,11-dihydroxy-10, 11-dihydrocarbamazepine, and N4-acetylsulfamethoxazole) in river sediments. Relative recoveries of all analytes exceeded 97% using either deuterated or 13C15N-labeled surrogate standards. Sorption isotherms of all analytes were constructed at pH 6.5-6.6 on two natural river sediments (Burgen and Dausenau) that differed in organic carbon contents and particle size distributions. Affinities of all analytes were up to an order of magnitude higher for the Dausenau sediment in comparison to the Burgen sediment. Isotherms were well described by the Freundlich model. Sorption of all analytes was linear on the Burgen sediment except for structurally similar carbamazepine (n = 0.90) and DHC (n = 0.88). Conversely, most analytes showed pronounced nonlinear sorption to the Dausenau sediment (n = 0.77-0.92) except for positively charged codeine, dihydrocodeine, and tramadol. Linear sorption of the latter was taken to arise from concentration-independent electrostatic interactions of the organocations with negatively charged surfaces on clay minerals or in the sediment organic matter. Desorption gave rise to hysteresis in 13 out of 16 investigated analyte-sorbent systems. Hysteresis was likely due to slow desorption kinetics beyond 24 h used in the experiment.

Impacts of compound properties and sediment characteristics on the sorption behaviour of pharmaceuticals in aquatic systems

“…the octanol-water partitioning coefficients (Kow)), the sorption of pharmaceuticals, which are typically ionisable compounds, to environmental solids is thought to be through a combination of interactions e.g. hydrogen bonds, electrostatic interactions, ionic exchange and hydrophobic interactions [26][27][28][29][30]. Moreover, while the organic carbon content (OC) of sediments is known to be important in explaining the differences in the sorption behaviour of a neutral organic chemical across different soil or sediment types, factors such as the solid phase component (clay and metal content), surface exchangeable cations and pH probably play an important role in determining sorption of ionisable compounds [30][31][32].…”

“…While research into the sorption of pharmaceuticals in water-sediment systems has recently increased [13,20,27,[33][34][35][36] data are still only available for a few active ingredients so our understanding of the factors and processes affecting sorption of pharmaceuticals is limited. A number of studies have also proposed predictive models for estimating the sorption behaviour of pharmaceuticals in sewage sludge and soil [37,38].…”

Sedimentary organic biomarkers suggest detrimental effects of PAHs on estuarine microbial biomass during the 20th century in San Francisco Bay, CA, USA

“…Rounds et al (2009) detected several of the same compounds in influent at the Durham WWTP headworks as were measured in sediment at the Tualatin River and Fanno Creek sites for this study; however, only two of the same compounds, namely, carbamazepine and cotinine, were detected in the Durham WWTP effluent. Carbamazepine has been shown to be a persistent contaminant in wastewater-influenced surface water (Miao et al, 2005;Guo and Krasner, 2009) and in sediment (Stein et al, 2008). Four of the same compounds (caffeine, cotinine, carbamazepine, and codeine) were also detected in water samples from the Tualatin River and/or Fanno Creek (Rounds et al, 2009) Caffeine persistence in treated effluent depends on the wastewater treatment process (Phillips and Chalmers, 2009).…”

On the Frontier: Analytical Chemistry and the Occurrence of Illicit Drugs into Surface Waters in the United States

“…Stein et al (2008) describe a PLE method for extracting psychoactive compounds from sediments and Jones-Lepp and Stevens (2007) also describe a PLE method for extracting methamphetamine and MDMA from biosolids (Stein et al, 2008;Jones-Lepp and Stevens, 2007). Because of the complexity and variable sizes of environmental solids, the samples usually need to be dried, pulverized, and homogenized before extraction.…”

“…Briefly, small amounts of homogenized solid samples (usually Ͻ 2 g) are subsampled and extracted. Depending upon what matrix and what analytes are being extracted, the proper solvents, pressures, and temperatures are chosen (Stein et al, 2008;JonesLepp and Stevens, 2007).…”