A NOVEL METHOD FOR DETECTING PHARMACEUTICALS IN SURFACE WATERS, CENTRAL ARKANSAS, USA

An area of emerging concern is the presence of pharmaceuticals and other potentially harmful organic compounds in surface water. Until recently, the technology to test for these compounds in water in trace amounts was not available. The presence of pharmaceuticals in surface water is concerning as they are potentially harmful to individuals that drink the water, to the organisms that reside in the water, and to overall ecosystem health.

The purpose of this research was to test for common pharmaceuticals in the Lake Maumelle Watershed, Arkansas using ultra performance liquid chromatography (UPLC) and mass spectroscopy (MS). The Lake Maumelle Watershed is an area of approximately 88,000 acres containing 290 miles of rivers, creeks, and streams that drain into Lake Maumelle. This research is significant as Lake Maumelle is a very important natural resource. It is a drinking water reservoir, impounded in 1956 by a dam across the Big Maumelle River. Currently, it meets 60% of the water demands for 15 cities and communities. This includes providing the primary raw water supply for the commercial, industrial, and domestic needs of more than 400,000 people. Additionally, it provides recreational boating and fishing opportunities, and habitat for fish and wildlife. Protecting this water source is essential for maintaining the quality of life in central Arkansas.

Samples were collected from ten sites within the watershed. Water samples were extracted using solid-phase extraction (either a 200mg Oasis HLB or 150mg Oasis MCX cartridge). All analyses were quantified using isotope dilution and UPLC/MS/MS with multiple reaction monitoring (MRM) detection. The analyses were performed using a Waters Acquity I-class UPLC system coupled to a Waters Xevo TQS triple quadrupole mass spectrometer equipped with an electrospray interface operating in both positive and negative ion mode. Laboratory water was spiked with varying levels of pharmaceutical compounds (sertraline, atenolol, lisinopril, hydrocodone, hydrochlorothiazide and ethyinyl estradiol) for method validation studies. The newly validated method was then used to quantify the levels of the pharmaceuticals of interest in water collected.