An environmental forensic procedure to analyse anthropogenic pressures of urban origin on surface water of protected coastal agro-environmental wetlands (L'Albufera de Valencia Natural Park, Spain).

Detection and spatial distribution of 14 drugs of abuse and 17 pharmaceuticals in surface waters was investigated to determine transport hydrological connectivity between urban, agriculture and natural environments. Solid-phase extraction and liquid chromatography tandem mass spectrometry was applied to all samples. To determine spatial incidence of contaminants, analytical results of target compounds were georeferenced and integrated into a geographical information systems structure together with layers of municipal population, location of sewage water treatment plants and irrigation channels and sectors. The methodology was applied to L'Albufera Natural Park in Valencia (Spain). A total of 9 drugs of abuse were detected at 16 points (76% of the sample sites). Cocaine and its metabolite, benzoylecgonine, were the most detected substances, being found in 12 and 16 samples, respectively. Maximum concentrations were found in benzoylecgonine (78.71 ng/L) and codeine (51.60 ng/L). Thirteen pharmaceuticals were found at 16 points. The most detected compounds were carbamazepine (15 samples) and ibuprofen (11 samples). Maximum concentrations were detected in acetaminophen (17,699.4 ng/L), ibuprofen (3913.7 ng/L) and codeine (434.0 ng/L). Spatial distribution of pharmaceuticals showed a clear relationship between irrigation areas, high population densities municipalities (above 1000 h/km(2)) and sewage water treatment plants.