Invisible pollution : emerging marine pollutants

Since the start of the Anthropocene, the planet has been threatened by a number of risks associated with human activity. Among them, chemical pollution is posing conceptual and technical challenges that are particularly difficult to characterise on a global scale. We must ask ourselves, what is a pollutant? What properties are relevant in their definition? Studies on the abundance, persistence, mobility in the environment, and bioaccumulation potential of the chemical compounds we use every day are changing the paradigm of what we consider pollutants. Thus, compounds that do not cause acute toxicity can still be dangerous for the ecosystem when they continually reach the environment, exist in very high concentrations, or disperse easily. Thus, raising awareness about the forgotten pollution that we unknowingly generate but which is affecting our oceans will be essential to protect the planet

Occurrence, Transport and Fate of Persistent Organic Pollutants in the Global Ocean = Presencia, Transporte y Destino de Contaminantes Orgánicos Persistentes en el Océano Global

[eng] The Open Ocean has been recognized as playing a key role on global dynamics of pollutants due to its large coverage of the planet surface, its high degradation potential and its sink and accumulation capacities towards anthropogenic chemicals. Nevertheless, there is a dearth of measurements of contaminants in the Open Ocean lower atmosphere, water column and trophic chain as a result of its remoteness and wide spatial reach. Persistent organic pollutants (POPs) are an important class of chemical contaminants due to their particular characteristics such as persistency, bioaccumulation potential, high toxicity and long range environmental transport capacity. Even though previous studies report their occurrence in the marine environment, the processes and magnitude of their fate, transport and sinks in the Open Ocean remain uncharacterized. In this Thesis two groups of organic contaminants have been selected in order to study POPs dynamics and fate in the oceanic environment. Polycyclic Aromatic Hydrocarbons (PAHs) are organic pollutants generated during incomplete combustion of fossil fuels and organic matter, but as well coming from petrogenic and biogenic natural sources. PAHs are semivolatile and highly mobile between the atmosphere and aqueous systems. Perfluoroalkylated substances (PFASs) are anthropogenic halogenated pollutants, recently developed for industrial and consumer goods usage. They are extremely persistent and exhibit higher solubility and lower hydrophobicity than most POPs, which makes them prone to be found in aqueous matrixes. During the Malaspina 2010 circumnavigation cruise across the Atlantic, Pacific and Indian oceans (35°N- 40°S), 64 PAHs were measured in the gas, aerosol, rainwater, dissolved, particulate and plankton matrixes, and 11 PFASs were quantified in dissolved phase at surface and deep chlorophyll maximum depth seawater. Degradation and atmospheric deposition of PAHs was assessed for dry deposition, wet deposition and diffusive air-water exchange, suggesting approaches for their global estimation, and proposing a global budget for PFAS, PAHs, and other semivolatile aromatic-like compounds, and their effect in the carbon global cycle. Dry deposition was obtained by direct measurements on board and parametrized for the whole tropical and subtropical Ocean; wet deposition was quantified from the precipitation rainwater gathered during the cruise; and diffusive exchange was calculated from the measured PAHs concentrations in the gas and dissolved phases, concurrently with the environmental parameters affecting volatilization and absorption (temperature, wind speed, salinity, dissolved organic carbon among others). Moreover, vertical distribution processes and influencing parameters in the surface mixed layer of the water column were assessed for PAHs and PFASs. Processes evaluated for PAHs include the vertical fluxes associated to the organic matter sinking (biological pump), biomass dilution, planktonic degradation, and air-water-particle exchange. For PFASs, the biological pump and eddy diffusive fluxes (based on turbulence eddy diffusion coefficients measured concurrently to the PFASs sampling) were assessed empirically for the first time in literature. The analysis of the complex feedback established between atmospheric depositional fluxes and the diffusive, degradative and biological pumps fluxes in the marine water column at a global scale is also covered. Furthermore, a wide array of understudied environmental parameters are reviewed as plausible factors affecting POPs fate in the Open Ocean, and a proposal of the research directions to follow and missing gaps to be filled is done. Amongst the innovative outcomes of this study, it can be highlighted the comprehensive sampling covering the tropical and subtropical global oceans, and the large amount of experimentally determined processes and influencing factors in order to better understand the global fate of chemical organic pollutants in the Open Ocean.[spa] El Océano Abierto está reconocido como un ambiente clave en la dinámica global de la contaminación debido a que representa un gran porcentaje de la superficie terrestre, su alto potencial de degradación y su capacidad como sumidero de sustancias químicas antropogénicas. En esta Tesis dos grupos de contaminantes orgánicos han sido seleccionados para ilustrar la dinámica de los COP y su destino en el medio ambiente oceánico: los hidrocarburos aromáticos policíclicos (PAHs) y las sustancias perfluoroalquiladas (PFASs). Durante la campaña de circunnavegación Malaspina 2010 a través de los océanos Atlántico, Pacífico e Índico (35°N- 40°S), se midieron 64 PAHs en las matrices gas, aerosol, agua de lluvia, disuelto, particulado y en el plancton; y 11 PFAS se cuantificaron en la fase disuelta de agua marina superficial y de la profundidad del máximo de clorofila. La degradación y la deposición atmosférica de los PAHs se evaluaron mediante las medidas de deposición seca, deposición húmeda e intercambio difusivo aire-agua, sugiriéndose métodos para su cuantificación global y proponiéndose un cómputo global para estos contaminantes y otros compuestos semivolátiles aromáticos, así como su efecto en el ciclo del carbono. Asimismo, se midieron los procesos de distribución vertical y los parámetros que afectan a las concentraciones de PAHs y PFASs en la capa de mezcla superficial de la columna de agua. Los procesos examinados para PAHs incluyen los flujos verticales asociados con la sedimentación de materia orgánica (bomba biológica), la biodilución, la degradación planctónica, y el equilibrio aire-agua-partícula. Para las PFASs, la bomba biológica y los flujos difusivos turbulentos (basados en medidas de los coeficientes de difusión turbulenta simultáneas con el muestreo de PFASs) fueron medidos empíricamente por primera vez en la literatura. El análisis de los complejos efectos retroactivos establecidos entre los flujos de deposición y los procesos de degradación, difusión y la bomba biológica a escala global también ha sido abordado. De la misma forma, un amplio espectro de parámetros ambientales se ha revisado para dilucidar posibles factores que pudieran afectar al destino de los COP en el Océano Abierto, y se proponen una serie de líneas de investigación y necesidades prioritarias para su futura investigación

Dysregulation of photosynthetic genes in oceanic Prochlorococcus populations exposed to organic pollutants

The impact of organic pollutants on oceanic ecosystem functioning is largely unknown. Prochlorococcus, the most abundant known photosynthetic organism on Earth, has been suggested to be especially sensible to exposure to organic pollutants, but the sub-lethal effects of organic pollutants on its photosynthetic function at environmentally relevant concentrations and mixtures remain unexplored. Here we show the modulation of the expression of two photosynthetic genes, rbcL (RuBisCO large subunit) and psbA (PSII D1 protein), of oceanic populations of Prochlorococcus from the Atlantic, Indian and Pacific Oceans when exposed to mixtures of organic pollutants consisting of the non-polar fraction of a seawater extract. This mixture included most persistent organic pollutants, semivolatile aromatic-like compounds, and the unresolved complex mixture of hydrocarbons. Prochlorococcus populations in the controls showed the expected diel cycle variations in expression of photosynthetic genes. However, exposure to a complex mixture at concentrations only 2-fold above the environmental levels resulted in a decrease of expression of both genes, suggesting an effect on the photosynthetic function. While organic pollutant effects on marine phytoplankton have been already demonstrated at the cellular level, this is the first field study showing alterations at the molecular level of the photosynthetic function due to organic pollutants.Versión del edito

Comparison of conventional and dispersive solid phase extraction clean-up approaches for the simultaneous analysis of tetracyclines and sulfonamides in a variety of fresh vegetables

he extensive use of antibiotics in agriculture has led to the occurrence of residual drugs in different vegetables frequently consumed by humans. This could pose a potential threat to human health, not only because of the possible effects after ingestion but also because the transmission of antibiotic-resistant genes could occur. In this work, two accurate sample preparation procedures were developed and validated for the simultaneous analysis of sulfonamides (SAs) and tetracyclines (TCs) in four of the most widely consumed vegetables (lettuce, onion, tomato, and carrot) in Europe. The evaluated protocols were based on QuECHERS for extraction and subsequent clean-up by SPE (solid phase extraction) or dispersive SPE. Parameters affecting both extraction and clean-up were carefully evaluated and selected for accuracy of results and minimal matrix effect. Overall, apparent recoveries were above 70% for most of the target analytes with both analytical procedures, and adequate precision (RSD<30%) was obtained for all the matrices. The procedural limits of quantification (LOQPRO) values for SPE clean-up remained below 4.4 μg kg−1 for TCs in all vegetables except for chlortetracycline (CTC) in lettuce (11.3 μg kg−1) and 3.0 μg kg−1 for SAs, with the exception of sulfadiazine (SDZ) in onion (3.9 μg kg−1) and sulfathiazole (STZ) in carrot (5.0 μg kg−1). Lower LOQPRO values (0.1–3.7 μg kg−1) were obtained, in general, when dSPE clean-up was employed. Both methods were applied to twenty-five market vegetable samples from ecological and conventional agriculture and only sulfamethazine (SMZ) and sulfapyridine (SPD) were detected in lettuce at 1.2 μg kg−1 and 0.5 μg kg−1, respectively.Authors acknowledge financial support from the Elkartek project entitled “Emergencia y diseminación de resistencia a los antibióticos: vínculos entre salud humana, ganadería, alimentación y medioambiente (elkartek 20/88)”, the projects “Evaluación del riesgo de aparición y diseminación de resistencias a antibióticos en productos vegetales frescos y suelos de cultivo de la comunidad autónoma del País Vasco (PA21/05 and PA22/05)” inside the “Research projects targeted to agriculture 2020 program” of the Basque Government (Basque Country, Spain); and the Basque Government through the financial support as consolidated group of the Basque Research System (IT1446-22). I. Vergara-Luis and B. Gonzalez-Gaya are grateful to the University of the Basque Country (UPV/EHU) for their pre-doctoral and post-doctoral fellowships. I. Baciero thanks to the Basque Government for her pre-doctoral fellowship

Oceanic Sink and Biogeochemical Controls on the Accumulation of Polychlorinated Dibenzo-p-dioxins, Dibenzofurans, and Biphenyls in Plankton.

Polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (dl-PCBs) were measured in plankton samples from the Atlantic, Pacific and Indian Oceans collected during the Malaspina circumnavigation cruise. The concentrations of PCDD/Fs and dl-PCBs in plankton averaged 14 and 240 pg gdw-1, respectively, but concentrations were highly variable. The global distribution of PCDD/Fs and dl-PCBs was not driven by proximity to primary sources in continents, but significantly correlated with plankton biomass. These trends are consistent with the interactions between atmospheric deposition, biomass dilution, and settling fluxes of organic matter in the water column, as key processes driving the POPs plankton phase concentrations in the global oceans. The application of a model of the air-water-plankton diffusive exchange of PCDD/Fs and PCBs reproduce in part the influence of biomass on plankton phase concentrations, and suggest future modelling prioritiesThe estimated oceanic sink (Atlantic, Pacific and Indian Oceans) due to settling fluxes of organic matter bound PCDD/Fs and dl-PCBs is of 400 Kg y-1 and 10500 kg y-1, respectively. This oceanic sink is 3 and 8 times lower, for PCDD/Fs and dl-PCBs respectively, than the atmospheric inputs due to gross diffusive absorption and dry deposition. These important atmospheric inputs, among other observations, confirm that atmospheric deposition supports and drives the accumulation of dl-PCBs and PCDD/Fs in plankton from the oligotrophic oceans.MALASPINA (CSD2008 00077)Versión del editor5,228

Effect-directed analysis of a hospital effluent sample using A-YES for the identification of endocrine disrupting compounds

An effect-directed analysis (EDA) approach was used to identify the compounds responsible for endocrine disruption in a hospital effluent (Basque Country). In order to facilitate the identification of the potentially toxic substances, a sample was collected using an automated onsite large volume solid phase extraction (LV-SPE) system. Then, it was fractionated with a two-step orthogonal chromatographic separation and tested for estrogenic effects with a recombinant yeast (A-YES) in-vitro bioassay. The fractionation method was optimized and validated for 184 compounds, and its application to the hospital effluent sample allowed reducing the number of unknowns from 292 in the raw sample to 35 after suspect analysis of the bioactive fractions. Among those, 7 of them were confirmed with chemical standards. In addition, target analysis of the raw sample confirmed the presence of mestranol, estrone and dodemorph in the fractions showing estrogenic activity. Predictive estrogenic activity modelling using quantitative structure-activity relationships indicated that the hormones mestranol (5840 ng/L) and estrone (128 ng/L), the plasticiser bisphenol A (9219 ng/L) and the preservative butylparaben (1224 ng/L) were the main contributors of the potential toxicity. Derived bioanalytical equivalents (BEQs) pointed mestranol and estrone as the main contributors (56 % and 43 %, respectively) of the 50 % of the sample's explained total estrogenic activity.Authors acknowledge financial support from the Agencia Estatal de Investigación (AEI) of Spain and the European Regional Development Fund through CTM2017-84763-C3-1-R and CTM2020-117686RB-C31 projects and the Basque Government through the financial support as a consolidated group of the Basque Research System (IT1213-19). The authors are grateful to the Consorcio de Aguas de Bilbao and especially to Iñigo González. Naroa Lopez is grateful to the Spanish Ministry of Economy, Industry and Competitivity for her predoctoral scholarship FPI 2018. Belen González-Gaya and Leire Mijangos acknowledge the University of the Basque Country for their postdoctoral scholarships (FPI 2018). Iker Alvarez-Mora is grateful to the University of the Basque Country and the Université de Pau et des Pays de L' Adour for his cotutelle predoctoral scholarship. Finally, the authors acknowledge support from the AEI and the Ministry of Science, Innovation and Universities (MICIU) to support the Thematic Network of Excellence (NET4SEA) on emerging contaminants in marine settings (CTM2017-90890-REDT, MICIU/AEI/FEDER, EU)

Suspect Screening of Chemicals in Hospital Wastewaters Using Effect-Directed Analysis Approach as Prioritization Strategy

The increasing number of contaminants in the environment has pushed water monitoring programs to find out the most hazardous known and unknown chemicals in the environment. Sample treatment-simplification methods and non-target screening approaches can help researchers to not overlook potential chemicals present in complex aqueous samples. In this work, an effect-directed analysis (EDA) protocol using the sea urchin embryo test (SET) as a toxicological in vivo bioassay was used as simplified strategy to identify potential unknown chemicals present in a very complex aqueous matrix such as hospital effluent. The SET bioassay was used for the first time here to evaluate potential toxic fractions in hospital effluent, which were obtained after a two-step fractionation using C18 and aminopropyl chromatographic semi-preparative columns. The unknown compounds present in the toxic fractions were identified by means of liquid chromatography coupled to a Q Exactive Orbitrap high-resolution mass spectrometer (LC-HRMS) and using a suspect analysis approach. The results were complemented by gas chromatography-mass spectrometry analysis (GC-MS) in order to identify the widest range of chemical compounds present in the sample and the toxic fractions. Using EDA as sample treatment simplification method, the number of unknown chemicals (>446 features) detected in the raw sample was narrowed down to 94 potential toxic candidates identified in the significantly toxic fractions. Among them, the presence of 25 compounds was confirmed with available chemical standards including 14 pharmaceuticals, a personal care product, six pesticides and four industrial products. The observations found in this work emphasize the difficulties in identifying potential toxicity drivers in complex water samples, as in the case of hospital wastewater.Authors acknowledge financial support from the Agencia Estatal de Investigación (AEI) of Spain and the European Regional Development Fund through CTM2017-84763-C3-1-R and CTM2020-11686RB-C31 projects and the Basque Government through the financial support as a consolidated group of the Basque Research System (IT1446-22). The authors are grateful to the Consorcio de Aguas de Bilbao and especially to Iñigo González. Naroa Lopez-Herguedas is grateful to the Spanish Ministry of Economy, Industry and Competitivity for her predoctoral scholarship FPI 2018 (PRE2018-086493)