[en] Triazines are one of herbicides groups most widely used for the control of weeds. Currently, they are considered environmentally dangerous because of their persistence, toxicity, bioaccumulation and being endocrine disruptors. Their indiscriminate use can be observed not only in soils, fruits and vegetables, but also in water when these pollutants are washed away by rain. After their application, a large amount remains in the environment and, because of their persistence and mobility, can reach the marine environment. Although there are no maximum limits regulated for most of the triazines in water, sediment or biota, the Directive 2013/39/EU calls the attention on the importance of monitoring emerging pollutants which are not considered in the control programs, but can have toxic effects. The European Union has included Simazine and Atrazine in the list of 33 priority substances in the Water Framework Directive (2000/60/EC), by way of Decision 2455/2001/EC. Moreover, the Directive 2008/105/EC sets the Environmental Quality Standards (EQS) for these compounds in surface waters and committees the Member States to set EQS for these compounds in sediments and biota at national level. Finally, the Directive 2013/39/EU adds Terbutryn to the list of priority substances. On the other hand, the Marine Strategy Framework Directive 2008/56/EC establishes, between descriptors of good environmental health, "contaminants in fish and other fishery products destined to human consumption should not exceed the levels established by Community legislation". In this way, the Regulation 396/2005/EC, relative to the maximum residue levels of pesticides in food and feed of plant and animal origin, sets limits for Simazine and Terbuthylazine in algae; however this Regulation has not established yet maximum levels for pesticides in aquatic animals. Regarding to it, the U.S Food and Drug Administration has set tolerance levels for pesticides, including Simazine, in fish and fishery products. Triazinic herbicides may be transformed by chemical and biological processes. Because of their mobility, the degradation products can reach water bodies more easily than triazines; therefore, the impact due to herbicides tends to be underestimated when only the triazines are analyzed, being necessary to include their main degradation products to obtain a better knowledge regarding herbicides pollution. Therefore, it is necessary to provide precise, effective, simple and quick analytical methods for these compounds. Thus, throughout this Thesis, analytical methodology for the determination of these compounds in seawater, sediment and biota at trace levels was developed. The proposed methods have improved the previous methodologies found in the literature, are sensitive, selective and simple, besides complying with Green Chemistry principles. Once analytical methods were validated, a sampling of seawater, sediment and aquatic biota (algae, fish, and mollusks) was held.

[gl] As triazinas constitúen un dos grupos de herbicidas máis amplamente utilizados para eliminar as malas herbas. Actualmente son considerados medioambientalmente perigosos por mor da súa persistencia, toxicidade, capacidade de bioacumulación e por seren disruptores endócrinos. O seu emprego indiscriminado ponse de manifesto nos solos, froitas e verduras, pero tamén nas augas, cando estes contaminantes son arrastrados polas choivas e os regatos. Tras a súa aplicación, unha grande proporción permanece no medio ambiente e, debido á súa persistencia e mobilidade, acadan o medio mariño. A pesar de que para a meirande parte das triazinas non se teñen regulado límites máximos nas augas, sedimentos ou biota, a Directiva 2013/39/UE advirte sobre a importancia de monitorizar contaminantes emerxentes que aínda que non estean considerados nos programas de control, poidan ter efectos tóxicos. A Unión Europea incluiu Simazina e Atrazina no listado das 33 sustancias prioritarias na Directiva Marco da Auga (2000/60/CE), mediante a Decisión 2455/2001/CE. Ademais, a Directiva 2008/105/CE estabelece as normas de calidade ambiental (NCA) para estes compostos nas augas superficiais, e insta aos Estados Membros a estabelecer parámetros de calidade para estes compostos en sedimentos e biota a nivel nacional. Por último, a Directiva 2013/39/UE inclúe a Terbutrina no listado de sustancias prioritarias. Por outra banda, a Directiva Marco de Estratexia Mariña 2008/56/CE estabelece entre os descritores de boa saúde ambiental que "os contaminantes presentes nos peixes e produtos da pesca destinados ao consumo humano non superen os niveis estabelecidos pola normativa comunitaria". Neste senso, o Regulamento 396/2005/CE, relativo aos límites máximos de residuos de praguicidas en alimentos e pensos de orixe vexetal e animal, estabelece límites para Simazina e Terbutilazina en algas, emporiso aínda non ten estabelecido límites máximos para pesticidas en animais acuáticos. A este respecto, a Axencia Americana Food and Drug Administration ten estabelecido niveis de tolerancia para pesticidas, entre os que se atopa a Simazina, en peixes e produtos da pesca. Os herbicidas triazínicos poden ser transformados por procesos químicos e biolóxicos. Debido á súa mobilidade, os produtos de degradación poden chegar aos corpos de auga máis doadamente cás triazinas; como consecuencia, o impacto debido aos herbicidas tende a subestimarse cando só as triazinas son analizadas, resultando necesario incluír os seus principais produtos de degradación para obter un mellor coñecemento en relación á contaminación por herbicidas. Por todo o exposto, cómpre dispoñer de métodos de análise precisos, eficaces, sinxelos e rápidos para estes compostos. Así, ao longo desta Tese Doutoral, desenvolveuse metodoloxía analítica para a determinación destes compostos a niveis traza tanto en auga de mar como en sedimento e biota. Estes métodos melloran os propostos na bibliografía, son sensíbeis, selectivos e sinxelos, cumprindo ademais cos principios da Química Verde. Unha vez validados os métodos de análise, realizouse unha mostraxe de augas de mar, sedimentos e biota acuática (algas, peixes e moluscos).