Human urine is an abundant, renewable resource that can be used as a valuable source of fertilizer because it is rich in nitrogen, phosphorus and potassium. As fertilizers derived from urine become more widely used, it is important to understand how excreted pharmaceuticals are transported from urine to the environment. Many pharmaceuticals are excreted from the human body in their native form; therefore, when urine is used as a fertilizer, biologically active pharmaceuticals can be released into the environment. The goal of this study was to develop sensitive methods for the analysis of pharmaceuticals in urine, struvite, lysimeter water, soil, and food crops using liquid chromatography with tandem mass spectrometry (LC-MS/MS). The ability to detect low levels of pharmaceutical residues in various environmental matrices will aid in assessing the potential risks associated with the field application of urine that is used to fertilize croplands. The optimized method reported in this paper, which utilizes solid phase extraction for sample clean-up and pre-concentration, offers analyte recoveries ranging from 29 to 112 percent, and detection limits ranging from 0.89 ng L⁻¹ to 0.0047 μg g⁻¹. The optimized extraction method provides intra-day and inter-day reproducibility of less than 10% for all analytes in all matrices investigated, with the exception for ciprofloxacin in urine. The use of isotope dilution for quantification proved necessary to compensate for matrix effects, especially in urine where matrix effects can range from about 21% to 79%. Overall, the method described here is robust and widely applicable to various types of environmental samples.

The paper presents lysimeter tests, which have been conducted since 1974 on the amount of water runoff from sodded soil profile under conditions of its diversified use and watering. On the tested area a major portion of the total yearly runoff from grasslands occurs during the growing season due to the amount and distribution of precipitation in this region (c.a. 68 of the total yearly precipitation falls during the growing season). Runoff values from grasslands recorded during the study period varied from 113.7 to 247.1 mm. A significant relationship has been found betwen the amount of water draining away from grassland soil profile and the amount of yield, which was caused either by a method of use (meadow, pasture or 8-15 cm high sward) or by the amount of applied nitrogen fertilization