Hydrochemistry and emerging contaminants in industrial urban wastewater in Morelia, Michoacán, Mexico

In Mexico, 54 [%] of the wastewater generated is not treated and it is discharged into the water bodies, soils and irrigation canals, leading to a severe pollution problem. This represents a high risk to human health and aquatic biota. In recent decades, emerging contaminants have been detected in surface water in contact with raw and treated sewage. These compounds and their reactive metabolites cause severe toxicological effects on aquatic organisms and soil microorganisms even at low concentrations. The objective of this work was to analyze the physical and chemical properties: pH, electrical conductivity (EC), total dissolved solids (TDS), Ca2+, Mg2+, Na+, boron (B), total phosphorus (P) and trace metals (Mn, Zn, Fe and Cu), and to identify and quantify emerging contaminants (pharmaceuticals and drugs of abuse) in the influent and effluent of Wastewater Treatment Plant (WWTP) of Morelia, using standardized methodologies, such as infrared spectroscopy FT-IR and mass spectrometry ESI-TOF-MS. The values of pH, EC, TDS, sodium adsorption ratio (SAR), B, P and trace metals were within the limits set by Mexican standards and international guidelines for wastewater reuse in agriculture. Emerging contaminants identified by ESI-TOF-MS were tetracycline, cefaclor, cefadroxil, ampicillin, clonazepam, lormetazepam, secobarbital, maprotiline, levothyroxine, cis-androsterone, paracetamol, lidocaine, brompheniramine, fexofenadine, amphetamine, morphine, benzoylecgonine, 11-nor-?9-THC-9-COOH, dimetilamfetamina, phencyclidine, methadone y polyethyleneglycol. The removal efficiency of these pollutants in the effluent was 25.8 [%], with extremes of 0 and 74.5 [%] for polyethyleneglycol and methadone, respectively.