Lina Kantiani

Ecotoxicity and analysis of nanomaterials in the aquatic environment

Nanotechnology is a major innovative scientific and economic growth area. However nanomaterial residues may have a detrimental effect on human health and the environment. To date there is a lack of quantitative ecotoxicity data, and recently there has been great scientific concern about the possible adverse effects that may be associated with manufactured nanomaterials. Nanomaterials are in the 1- to 100-nm size range and can be composed of many different base materials (carbon, silicon and metals, such as gold, cadmium and selenium) and they have different shapes. Particles in the nanometer size range do occur both in nature and as a result of existing industrial processes. Nevertheless, new engineered nanomaterials and nanostructures are different because they are being fabricated from the “bottom up”. Nanomaterial properties differ compared with those of the parent compounds because about 40–50% of the atoms in nanoparticles (NPs) are on the surface, resulting in greater reactivity than bulk materials. Therefore, it is expected that NPs will have different biological effects than parent compounds. In addition, release of manufactured NPs into the aquatic environment is largely an unknown. The surface properties and the very small size of NPs and nanotubes provide surfaces that may bind and transport toxic chemical pollutants, as well as possibly being toxic in their own right by generating reactive radicals. This review addresses hazards associated and ecotoxicological data on nanomaterials in the aquatic environment. Main weaknesses in ecotoxicological approaches, controversies and future needs are discussed. A brief discussion on the scarce number of analytical methods available to determinate nanomaterials in environmental samples is included.

Achievements and future trends in the analysis of emerging organic contaminants in environmental samples by mass spectrometry and bioanalytical techniques.

Several groups of organic compounds have emerged as particularly relevant as environmental pollutants. These compounds, including new brominated flame retardants, disinfection by-products, drugs of abuse and their metabolites, hormones and other endocrine disrupting compounds, nanomaterials, perfluoroalkyl substances, pharmaceuticals and siloxanes among others, constitute new risks for environmental and human health. In order to face up to these new risk challenges there is an increasing need to assess their occurrence and behaviour in the environment, as well as, that of their degradation products. Therefore, during recent years an important part of research has been focused on to the improvement of analytical schemes for complex matrices, in which the new tendencies in sample preparation (e.g. online clean up systems), the development of new materials and new mass spectrometry analysers have played an important role. This paper presents a general overview of new analytical trends and potentials in trace analysis of emerging pollutants in the environment, including chromatographic techniques coupled to mass spectrometry, and bio analytical approaches (biosensors).

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.

Assessment of the acute toxicity of triclosan and methyl triclosan in wastewater based on the bioluminescence inhibition of Vibrio fischeri

In this work, the contributions of triclosan and its metabolite methyl triclosan to the overall acute toxicity of wastewater were studied using Vibrio fischeri. The protocol used in this paper involved various steps. First, the aquatic toxicities of triclosan and methyl triclosan were determined for standard substances, and the 50% effective concentrations (EC50) were determined for these compounds. Second, the toxic responses to different mixtures of triclosan, methyl triclosan, and surfactants were studied in different water matrices, i.e., Milli-Q water, groundwater and wastewater, in order to evaluate (i) the antagonistic or synergistic effects, and (ii) the influence of the water matrices. Finally, chemical analysis was used in conjunction with the toxicity results in order to assess the aquatic toxicities of triclosan and its derivative in wastewaters. In this study, the toxicities of 45 real samples corresponding to the influents and effluents from eight wastewater treatment works (WWTW) were analyzed. Thirty-one samples were from a wastewater treatment plant (WWTP) equipped with two pilot-scale membrane bioreactors (MBR), and the influent and the effluent samples after various treatments were characterized via different chromatographic approaches, including solid-phase extraction (SPE), liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS), and SPE coupled to gas chromatography–mass spectrometry (GC–MS). The toxicity was determined by measuring the bioluminescence inhibition of Vibrio fischeri. In order to complete the study and to extrapolate the results to different WWTPs, the toxicity to V. fischeri of samples from seven more plants was analyzed, as were their triclosan and methyl triclosan concentrations. Good agreement was established between the overall toxicity values and concentrations of the biocides, indicating that triclosan is one of the major toxic organic pollutants currently found in domestic wastewaters.

Rapid residue analysis of fluoroquinolones in raw bovine milk by online solid phase extraction followed by liquid chromatography coupled to tandem mass spectrometry

Online solid phase extraction followed by liquid chromatography coupled to tandem mass spectrometry was used for the determination of 15 fluoroquinolones and one quinolone antibiotic in raw bovine and skimmed commercial milk. Milk samples were partially deproteinized and defatted by 15 min centrifugation and then subjected to online solid phase extraction. Chromatographic separation was achieved in less than 15 min. Identification and quantification of the compounds of interest were performed by selected reaction monitoring, using an electrospray ionization source. Relative recoveries were calculated for raw milk (at 0.5, 1 and 1.5 times the MRL, or assuming 30 ng/mL for non permitted compounds) and skimmed milk (at 30 ng/mL) and ranged between 65% and 123% (raw milk) or 78% and 109% (skimmed milk). Matrix interferences were also assessed and yielded significant suppression and enhancement effects, which, at the time of quantification, were corrected by the use of six isotopically labeled standards. Quality parameters of the method were established, and limits of detection of selected antibiotics in raw milk ranged from 0.01 to 1.93 ng/mL, while in skimmed milk from 0.03 to 4.23 ng/mL. The validation of the method has been carried out according to the requirements set by the 2002/657/EC regulation. Finally, the applicability of the method was tested by analysing 28 milk samples.

Microfluidic Devices: Biosensors

The rapid and reliable detection of chemical contaminants, toxins, and pathogens in food calls for new analytical tools. During recent years, a great labor of development has been carried out to develop real-time biosensing systems that offer robust and reliable responses. Now microfluidic devices with enhanced capabilities open a new window in food security analysis. Most of recent developments have been based on the use of new nanomaterials. This book chapter presents the recent advances on biosensors systems for food analysis. More used and emerging biological recognition elements for food analysis application are reviewed. The advances in nanobiosensors, microfluidics, and lab-on-a-chip, as well as the recent applications of these new devices to the analysis of pesticides residues, veterinary drugs, growth-promoting agents, pathogenic bacteria, and natural toxins are presented, revised, and discussed.

Response to Letter to the Editor regarding “Determination of glyphosate in groundwater samples using an ultrasensitive immunoassay and confirmation by on-line solid phase extraction followed by liquid chromatography coupled to tandem mass spectrometry”

2. The aquifers sampled were, with few exceptions, mainly unconfined porous aquifers of sandy and gravel composition. It is clear that the presence of pesticides and nitrates in groundwater is associated with well known recharge processes and is affected by surface waters. This does not, however, prevent these samples qualifying as “groundwater”, because they came from the saturated zone of these aquifers.