Josep Sanchís

Emerging food contaminants: a review

Governments throughout the world are intensifying their efforts to improve food safety. These efforts come as a response to an increasing number of food-safety problems and increasing consumer concerns. In addition, the variety of toxic residues in food is continuously increasing as a consequence of industrial development, new agricultural practices, environmental pollution, and climate change. This paper reviews a selection of emerging contaminants in food, including the industrial organic pollutants perfluorinated compounds (PFCs), polybrominated diphenyl ethers (PBDEs), and nanomaterials; the pharmaceutical residues antibiotics and coccidiostats; and emerging groups of marine biotoxins. The main analytical approaches for their detection and quantification in food will be presented and discussed with special emphasis on biological techniques, when these are feasible. In the last section, a summary of recent publications reporting the concentrations of these compounds in food will be presented and discussed.

Occurrence of aerosol-bound fullerenes in the Mediterranean Sea atmosphere.

This work describes the assessment of a selection of fullerenes including C(60) and C(70) fullerene, N-methylfulleropyrrolidine, C(60) pyrrolidine tris-acid ethyl ester, [6,6]-Phenyl-C(61) butyric acid butyl ester and [6,6]-Thienyl C(61) butyric acid methyl ester, in airborne particulate from the Mediterranean Sea collected during two sampling campaigns from Barcelona to Istanbul and Alexandria, respectively. The analysis of the samples was carried out using a new method based on liquid chromatography coupled to mass spectrometry (LC-MS) presenting sensitivities between 5.4 and 20.9 pg/m(3). A total number of 43 samples covering the different basins of Mediterranean Sea were analyzed. Fullerenes were detected in all analyzed samples and quantifiable concentrations were found in 28 of the analyzed samples. The median of C(60) and C(70) fullerenes aerosol phase concentrations were 0.06 ng/m(3) and 0.48 ng/m(3) respectively for the Mediterranean Sea atmosphere. C(70) fullerene was the most frequently detected compound and also it was found in the higher concentrations for most samples, reaching 233.8 ng/m(3). The modeled back-trajectories disclose that those samples with higher concentrations of fullerenes were related to air masses which had been circulating over regions with an intense industrial activity, but the variability of the C(70)/C(60) ratio suggests multiple different sources. These results are related to the incidental emissions from urban and industrial development, underpinning the need of studying the possible risks associated to carbon nanoparticles in the environment and the need of evaluating the possible consequences of their ubiquitous occurrence.

Liquid chromatography–atmospheric pressure photoionization–Orbitrap analysis of fullerene aggregates on surface soils and river sediments from Santa Catarina (Brazil)

In the present work, a new analytical approach is proposed for the analysis of seven fullerenes (C₆₀, C₇₀, N-methylfulleropyrrolidine, [6,6]-phenyl C₆₁ butyric acid methyl ester, [6,6]-thienyl C61 butyric acid methyl ester, C60 pyrrolidine tris-acid ethyl ester and [6,6]-phenyl C₇₁ butyric acid methyl ester fullerenes) in soils and sediments. This procedure combines an ultrasound-assisted solvent extraction (UAE) with toluene followed by liquid chromatography (LC), using a pyrenylpropyl group bonded silica based column, coupled to a high-resolution mass spectrometer (HRMS) using atmospheric pressure photoionisation (APPI) in negative ion mode. The analytical performance for fullerene separation of the pyrenylpropyl group bonded silica column was compared to the C18 column. For the ultra-trace analysis of fullerenes in complex environmental samples, the use of the APPI source and the use of the electrospray ionisation (ESI) source were compared. Using this approach for the analysis of fullerenes in complex matrices, a series of advantages, in terms of sensitivity and specificity, have been demonstrated. The method limits of detection (MLOD) and the method limits of quantification (MLOQ) in soils and sediments ranged from 0.022 to 0.39 pg/g and from 0.072 to 1.3 pg/g, respectively. Recoveries were between 68 and 106%. The analytical method was applied in order to assess the occurrence of selected fullerenes in 45 soils of Sul Catarinense (Santa Catalina State, Brazil) and 15 sediments from the Tubarão River, presenting different pressures of contamination: a coal-combustion power plant, car exhaust, coal mining industry and wastewater effluents. C₆₀ and C₇₀ fullerenes have been detected at concentrations ranging from the MLOD to 0.150 ng/g. None of the functionalised fullerenes were detected in any of the samples. Combustion processes, in particular car exhaust, were identified as the main source of fullerenes. However, the potential degradation of residual concentrations of engineered fullerenes to more stable forms, such as C₆₀ and C₇₀, should also be considered.

Occurrence of linear and cyclic volatile methylsiloxanes in wastewater, surface water and sediments from Catalonia.

In the present work, a new method is proposed for the analysis of linear (lVMS) and cyclic methylsiloxanes (cVMS) in waters and sediments. The method is based on liquid-liquid extraction followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) using a triple quadrupole analyser (QqQ) working in selected reaction monitoring (SRM) mode. The instrumental parameters were optimized taking into account the interaction between different parameters and not only individual effects of variables. The method was validated yielding to convenient linearity and precision (RSD% <16%), and limits of quantification in the low ng/L and ng/g orders for wastewaters and river sediments, respectively. To the authors knowledge it is the first time that GC-MS/MS is used for analyzing methylsiloxanes in waters and sediments. The method was applied to the analysis of surface water and river sediments from the Llobregat River and Riera de Rubí (Catalonia, NE of Spain) and the influents and effluents of 17 wastewater treatment plants (WWTPs). The main results of this study showed that methylsiloxanes were present in all the analyzed wastewater samples, with cVMS being found at higher concentrations. Decamethylcyclopentasiloxane (D5) was the predominant compound, the maximum concentration was 8915 ng/L in influent wastewater and treated effluents, and the median concentration was 273 ng/L. Although these samples were collected primarily for method development purposes and have limited statistical value for characterizing spatial and temporal patterns, they represent a significant contribution to dataset needed to verify exposure calculations in environmental risk assessment studies, for a significantly wide range of dimethylsiloxane analytes.

New Insights on the Influence of Organic Co-Contaminants on the Aquatic Toxicology of Carbon Nanomaterials.

At present, there is a lack of understanding of the combined ecotoxicity of carbon-based nanomaterials and co-contaminants. In this paper, we report on the toxicity of three carbon nanomaterials (fullerene-soot, multiwall carbon nanotubes, and graphene). Two standardized toxicity bioassays, the immobilization of the invertebrate Daphnia magna and the bioluminescence inhibition of the marine bacteria Vibrio fischeri, have been used. Synergistic and antagonistic effects of binary mixtures composed of fullerene soot and organic co-contaminants as malathion, glyphosate, diuron, triclosan, and nonylphenol were assessed. The isobologram method was used to evaluate the concentrations producing an effect, in comparison to those effects expected by a simple additive approach. In this study, antagonism was the predominant effect. However, synergism was also observed as in the case of D. magna exposed to mixtures of malathion and fullerene soot. D. magna was shown to be the most sensitive assay when carbon nanomaterials were present. Toxicity to D. magna was as follows: fullerene soot > multiwall carbon nanotubes > graphene. These results were proportional to the size of aggregates, smaller aggregates being the most toxic. The vector function of nanomaterials aggregates and the unexpected release inside living organisms was proven for malathion. These results highlight new insights on the risks associated with the release of carbon nanomaterials into the environment.

Investigating the formation and toxicity of nitrogen transformation products of diclofenac and sulfamethoxazole in wastewater treatment plants.

Diclofenac (DCF) and sulfamethoxazole (SMX) are highly consumed pharmaceuticals and concentrated in effluents from conventional wastewater treatment plants (WWTPs) since they are not completely eliminated. Under microbial mediated nitrification/denitrification processes occurring in nitrifying activated sludge DCF biotransformed into its nitroso and nitro derivatives (NO-DCF and NO2-DCF, respectively). SMX was biotransformed under denitrification conditions in water/sediment batch reactors into its nitro and desamino derivatives (NO2-SMX and Des-SMX, respectively). Four transformation products (TPs) from DCF and SMX were analized in wastewaters (WW) and receiving surface waters (SW). Nitrifying/denitrifying-derivatives of DCF and SMX were detected for the first time in WW and SW at one order of magnitude lower than their parent compounds. Relationships observed among levels of NO-DCF, NO2-DCF and nitrogen-species tentatively suggested that nitrification/denitrification processes are involved in nitration and nitrosation of DCF during biological WW treatment. Acute toxicity of analytes to Daphnia magna and Vibrio fischeri was assessed individually and in mixtures with other relevant micropollutants. Individual effects showed these compounds as not harmful and not toxic. However, synergism effects observed in mixtures evidenced that contribution of these compounds to overall toxicity of complex environmental samples, should not be dismissed.

Ecotoxicological effects of carbon based nanomaterials in aquatic organisms

An increasing amount of carbon-based nanomaterials (CNM) (mostly fullerenes, carbon nanotubes and graphene) has been observed in aquatic systems over the last years. However, the potential toxicity of these CNM on aquatic ecosystems remains unclear. This paper reviews the existing literature on the toxic effects of CNM in aquatic organisms as well as the toxic effects of CNM through influencing the toxicity of other micro-pollutants, and outlines a series of research needs to reduce the uncertainty associated with CNMs toxic effects. The results show that environmental concentrations of CNM do not pose a threat on aquatic organisms on their own. The observed concentrations of CNM in aquatic environments are in the order of ngL-1 or even lower, much below than the lowest observed effect concentrations (LOEC) on different aquatic organisms (in the order of mgL-1). Toxic effects have been mainly observed in short-term experiments at high concentrations, and toxicity principally depends on the type of organisms, exposition time and CNM preparation methods. Moreover, we observed that CNM interact (establishing synergistic and/or antagonistic effects) with other micro-pollutants. Apparently, the resulting interaction is highly dependent on the chemical properties of each micro-pollutant, CNM acting either as carriers or as sorbents, thereby modifying the original toxicity of the contaminants. Results stress the need of studying the interactive effects of CNM with other micro-pollutants at environmental relevant concentrations, as well as their effects on biological communities in the long-term.

Analysis and fate of organic nanomaterials in environmental samples.

Abstract Due to their unique properties, nanomaterials (NMs) have attracted considerable interest in many fields of research, including materials sciences, microelectronics and biomedicine. The potential growing use and mass production of engineered NMs and nanoparticles (NPs) have stimulated the research on their potential impact on the environment and human health. To gather proper information about hazards of NMs, it is important to have reliable analytical data on them, to find out how they behave in the environment and to evaluate ecotoxicological information about them. This chapter presents the latest research carried out to assess occurrence, fate and environmental behaviour of organic NMs, with special attention to their surface properties and the interactions with natural organic matter that can alter their behaviour in natural systems.

Cytotoxic effects of commonly used nanomaterials and microplastics on cerebral and epithelial human cells

ABSTRACT Plastic wastes are among the major inputs of detritus into aquatic ecosystems. Also, during recent years the increasing use of new materials such as nanomaterials (NMs) in industrial and household applications has contributed to the complexity of waste mixtures in aquatic systems. The current effects and the synergism and antagonisms of mixtures of microplastics (MPLs), NMs and organic compounds on the environment and in human health have, to date, not been well understood but instead they are a cause for general concern. The aim of this work is to contribute to a better understanding of the cytotoxicity of NMs and microplastics/nanoplastics (MPLs/NPLs), at cell level in terms of oxidative stress (evaluating Reactive Oxygen Species effect) and cell viability. Firstly, the individual cytotoxicity of metal nanoparticles (NPs) (AgNPs and AuNPs), of metal oxide NPs (ZrO2NPs, CeO2NPs, TiO2NPs, and Al2O3NPs), carbon nanomaterials (C60fullerene, graphene), and MPLs of polyethylene (PE) and polystyrene (PS) has been evaluated in vitro. Two different cellular lines T98G and HeLa, cerebral and epithelial human cells, respectively, were employed. The cells were exposed during 24–48 h to different levels of contaminants, from 10 ng/mL to 10 &mgr;g/mL, under the same conditions. Secondly, the synergistic and antagonistic relationships between fullerenes and other organic contaminants, including an organophosphate insecticide (malathion), a surfactant (sodium dodecylbenzenesulfonate) and a plasticiser (diethyl phthalate) were assessed. The obtained results confirm that oxidative stress is one of the mechanisms of cytotoxicity at cell level, as has been observed for both cell lines and contributes to the current knowledge of the effects of NMs and MPLs‐NPLs. HighlightsCell viability and ROS effect was explored in HeLa and T98G cells.Exposure was carried out at low concentrations and cell viability was not affected.The behaviour of the two cells lines exposed to different materials was different.

Volatile dimethylsiloxanes in market seafood and freshwater fish from the Xúquer River, Spain.

Volatile dimethylsiloxanes are a family of synthetic organosilicon-compounds, which have received rising attention because of their widespread use and occurrence in the environment. In the present work, an analytical method based on ultrasound-assisted solid-liquid extraction (USAE) followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) has been optimized and applied to assess the presence of eight volatile dimethyl siloxanes (VMS) (hexamethylcyclotrisiloxane (D3), octamethylcyclotetra-siloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6), octamethyltrisiloxane (MDM), decamethyltetrasiloxane (MD2M) and dodecamethylpentasiloxane (MD3M) and tetradecamethylhexasiloxane (MD4M)) in fish. The optimized method presented limits of quantification between 0.1 and 1.3 pg/g for linear volatile dimethylsiloxanes (lVMS) and between 13 and 39 pg/g for cyclic volatile dimethylsiloxanes (cVMS) and intraday relative standard deviation (between 1.9 and 7.0%). Recovery yields were between 71 and 92%. 40 fish samples collected in different markets in Barcelona, (Spain), and 16 samples of fish directly collected at the Xúquer River were analysed. cVMS were detected in almost all the river fish samples at concentrations between pg/g and ng/g, with a significant correlation between the fat content and VMS concentrations in fish. In addition, significant higher concentrations were found in market samples, suggesting sources of contamination from their manipulation and storage in indoor environments. Multivariate analyses were applied to the results and the siloxane profiles and analyte correlations are discussed.