RESEARCH ARTICLE Spatial distribution of illicit drugs in surface waters of the natural park of Pego-Oliva Marsh (Valencia, Spain) Pablo Vazquez-Roig & Vicente Andreu & Cristina Blasco & Francisco Morillas & Yolanda Picó Received: 30 March 2011 /Accepted: 11 September 2011 # Springer-Verlag 2011 Abstract Background, aim and scope The Pego-Oliva Marsh is the second most important wetland in the Valencian Community (Spain). It is included in the RAMSAR agreement and represents one key point for migratory birds. Emerging contaminants from the human pressure, such as pharmaceut- icals, illicit drugs and personal care product, are not included in the list of priority contaminants of the Water Framework Directive yet, and are neither monitored nor controlled. However, pollution of emerging contaminants can threaten the environment and even human health. In order to understand the status of the emerging contamination and recommend future rationalization of countermeasures, the occurrence of illicit drugs was investigated. Material and methods Samples were collected at 23 sites from the main irrigation channels and the marsh. Illicit drugs were extracted using solid phase extraction and determined by liquid chromatography tandem mass spec- trometry. The method detection limits ranged from 0.01 to 1.54 ng l -1 and the recoveries from 57% to 120%. Results and discussion 3,4-Methylenedioxymethamphe- tamine, ketamine, morphine, benzoylecgonine, cocaine, methadone, 6-acetylmorphine and nor-9-carboxy-tetrahydro- cannabinol were detected. The mean concentrations were 0.62, 21.33, 1.30, 1.92, 2.25, 0.32, 0.04 and 0.07 ng l -1 , respectively. The highest concentrations were in the north of Pego-Oliva Marsh. Conclusions The pollution status by illicit drugs of the Pego- Oliva Marsh has been established. However, contamination levels in all the area of the natural park were low compared with those reported in other superficial waters. Keywords Trace analysis . Illicit drugs . Pego-Oliva Marsh . Environmental analysis . Surface water 1 Background, aim and scope Among the most important European ecosystems are coastal wetlands, which have suffered during the last decades an increasing human pressure (Soutullo et al. 2008). This has been reflected through the intensification of agriculture and construction of infrastructures in their surroundings, or even draining part of them (Nyman et al. 2009). The Pego-Oliva Marsh Natural Park is a humid area with abundant fauna and autochthonous vegetation, situated at the extreme south of the Gulf of Valencia, in the boundary between Alicante and Valencia provinces in the Valencian Community (Spain) (Cantoral-Uriza and Sanjurjo 2010). This Natural Park, of 1,248 ha, has two main habitats, the reedbeds and the paddy fields, with smaller areas of allotments and orange groves. It is hillsided by the Segaria and Mustalla Mountains that curves around the flat Responsible editor: Philippe Garrigues P. Vazquez-Roig : C. Blasco : Y. Picó (*) Laboratori de Nutrició i Bromatologia, Facultat de Farmàcia, Universitat de València, Av, Vicent Andrés s/n, 46100 Burjassot, València, Spain e-mail: yolanda.pico@uv.es V. Andreu Centro de Investigaciones sobre Desertificacion-CIDE (CSIC-UV-GV), Camí de la Marjal s/n, 46470 Albal, Valencia, Spain e-mail: Vicente.andreu-perez@uv.es F. Morillas Departament d’Economia Aplicada, Facultat d’Economia, Universitat de València, Campus dels Tarongers s/n, 46022 València, Spain Environ Sci Pollut Res (2012) 19:971–982 DOI 10.1007/s11356-011-0617-y