title: Monitoring priority substances, other organic contaminants and heavy metals in a volcanic aquifer from different sources and hydrological processes.
abstract: Irrigation with reclaimed water (R) is necessary to guarantee the sustainability of semi-arid areas. Results obtained during a two years monitoring network (2009-2011) in Gran Canaria are presented, including the analysis of chemical parameters, N and S isotopes, priority substances (2008/105/EC, 2013/39/EU), other organic contaminants and heavy metals in groundwater and R used to irrigate a golf course. The aims of this work are to evaluate the contamination in a volcanic aquifer, relate the presence of organic contaminants and heavy metals with the hydrogeochemistry and identify pollution sources in the area. No priority substance exceeded the EU thresholds for surface water, although seventeen were detected in R. The most frequent compounds were hexachlorobenzene, chlorpyrifos ethyl, fluorene, phenanthrene and pyrene. These compounds were detected at low concentration, except chlorpyrifos. Chlorpyrifos ethyl, terbuthylazine, diuron, terbutryn, procymidone, atrazine and propazine exceeded the European threshold concentration for pesticides in groundwater (100ngL(-1)). Therefore, the priority substances chlorpyrifos ethyl and diuron must be included in monitoring studies. The priority pesticides chlorfenvinphos and diazinon were always detected in R but rarely in groundwater. Besides, the existence of contaminants not related to the current R irrigation has been identified. Absence of environmental problems related to heavy metals can be expected. The relationship among contaminant presence, hydrogeochemistry, including the stable isotopic prints of δ(18)O, δ(15)N and δ(34)S and preferential recharge paths has been described. The coastal well shows high values of EC, nitrate, a variable chemistry, and 50% of organic contaminants detected above 100ngL(-1). The well located in the recharge area presents a stable hydrochemistry, the lowest value of δ(15)N and the lowest contaminants occurrence. The area is an example of a complex volcanic media with several sources of contaminants such as leakages from septic tanks and sewerage, agriculture practices, irrigation with reclaimed water or urban runoff.
authors.affiliation: Dpt. Física (GEOVOL), Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria, Canary Islands, Spain; Agrifood and Phytopathological Laboratory (Cabildo de Gran Canaria), 35413 Arucas, Canary Islands, Spain. Electronic address: eestevez@proyinves.ulpgc.es.
authors.forename: Esmeralda
authors.initials: E
authors.lastname: Estevez
authors.affiliation: Dpt. Física (GEOVOL), Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria, Canary Islands, Spain; IMDEA Water Institute, Alcalá de Henares, Madrid, Spain. Electronic address: mcarmen.cabrera@ulpgc.es.
authors.forename: María del Carmen
authors.initials: Mdel C
authors.lastname: Cabrera
authors.affiliation: Agrifood and Phytopathological Laboratory (Cabildo de Gran Canaria), 35413 Arucas, Canary Islands, Spain. Electronic address: jrfernandezv@grancanaria.com.
authors.forename: Juan Ramón
authors.initials: JR
authors.lastname: Fernández-Vera
authors.affiliation: Analytical Chemistry Research Group, Department of Physical and Analytical Chemistry, University of Jaen, 23071 Jaen, Spain. Electronic address: amolina@ujaen.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Molina-Díaz
authors.affiliation: Analytical Chemistry Research Group, Department of Physical and Analytical Chemistry, University of Jaen, 23071 Jaen, Spain. Electronic address: jroblesmol@gmail.com.
authors.forename: José
authors.initials: J
authors.lastname: Robles-Molina
authors.affiliation: Dpt. de Patología Animal, Producción Animal, Bromatología y Tecnología de los Alimentos (GEOVOL), Universidad de Las Palmas de Gran Canaria, 35413 Arucas, Canary Islands, Spain. Electronic address: mp.palaciosdiaz@ulpgc.es.
authors.forename: María del Pino
authors.initials: Mdel P
authors.lastname: Palacios-Díaz
mesh_terms: D000383:Agriculture; D004784:Environmental Monitoring; D060587:Groundwater / Q000737:chemistry*; D006581:Hexachlorobenzene / Q000032:analysis; D062070:Hydrology; D019216:Metals, Heavy / Q000032:analysis*; D009566:Nitrates / Q000032:analysis; D010575:Pesticides / Q000032:analysis; D013030:Spain; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D019216:Metals, Heavy; D009566:Nitrates; D010575:Pesticides; D014874:Water Pollutants, Chemical; D006581:Hexachlorobenzene
keywords: Chlorpyrifos ethyl; Diuron; Groundwater; Heavy metals; Organic contaminants; Reclaimed water