Capítulo 13. Contaminantes orgánicos regulados y emergentes en el Mar Menor

Abstract

The Mar Menor coastal lagoon is subject to different inputs of pollutants mainly associated with human activities taking place in their environment such as agriculture, tourism, urban development, mining, shipping, transportation, etc. Besides nutrients and trace metals, it is very relevant the contribution of organic pollutants as a result of such activities. In fact, in this work it has been determined the entry of organochlorinated pesticides and current used pesticides, polycyclic aromatic hydrocarbons, pharmaceuticals and surfactants to the Mar Menor through El Albujón watercourse (main catchment area of El Campo de Cartagena). This entry has been characterized according to its spatial, daily, and seasonal variability during the period of 2009- 2011, with the aim of identifying pollution sources and estimating the total annual entrance to the lagoon. The annual input for the group of drugs and pesticides analyzed has been estimated at 29 kg, which corresponded to 18 kg of pesticides and 11 kg to pharmaceuticals. Individually, it has been stressed the importance of the input of the insecticide chlorpyrifos (5.6 kg) and the antibiotic azithromycin (4.2 kg). This entry was surpassed by some surfactants (active fraction of detergents) such as linear alkyl benzene sulfonate which reached 406 kg per year. Once the pollutants entered the Mar Menor lagoon, contaminants were distributed heterogeneously in the lagoon. The observed distribution of contaminants in water has revealed the discharge to the lagoon of pesticides and other pollutants associated not only with El Albujón watercourse, but also associated with groundwater discharge (pesticides) urban and water activities (surfactants), recreational and bathing activities during warm months (pharmaceuticals), etc. Another identified input source was the atmospheric deposition, since both PAHs and pesticides have been detected in air, showing the latter a direct association with their agricultural application periods. It has also been confirmed the importance of flood episodes in the transport of pesticides to the lagoon, both current use pesticides as organochlorine pesticides, no longer in use associated with agricultural practices. Despite the efforts made in this regard, only a small number of the many possible contaminants present in the environment have been studied, therefore, the study should be extended to identify which organic contaminants of current use may constitute a threat, particularly for these semiconfined coastal systems, especially vulnerable. Another pending challenge would be the estimation of pesticides and other pollutants inputs into the lagoon through groundwater, which may be of particular interest especially now that the reuse of wastewater for irrigation has increased.