Ultra-trace analysis of cyanotoxins by liquid chromatography coupled to high-resolution mass spectrometry

The increasing frequency of episodes of harmful algal blooms of cyanobacterial origin is a risk for ecosystems and human health. The main human hazard may arise from drinking water supply and recreational water use. For this reason, efficient multiclass analytical methods are needed to assess the level of cyanotoxins in water reservoirs and tackle these problems. This work describes the development of a fast, sensitive and robust analytical method for multiclass cyanotoxins determination based on dual solid-phase extraction (SPE) procedure using a polymeric cartridge first Oasis HLB (Waters Corporation, USA), and second, a graphitized non-porous carbon cartridge, SupelcleanTM ENVI-CarbTM (Sigma-Aldrich, USA), followed by ultra-high performance liquid chromatography high-resolution mass spectrometry (SPE-UHPLC-HRMS). This method enabled the analysis of cylindrospermopsin, anatoxin-a, nodularin and seven microcystins (MC-LR, MC-RR, MC-YR, MC-LA, MC-LY, MC-LW, MC-LF). The method limits of detection (MLOD) of the validated approach were between 4 and 150 pg/L. The analytical method was applied to assess the presence of the selected toxins in 21 samples collected in 3 natural water reservoirs in the Ter River in Catalonia (NE of Spain) used to produce drinking water for Barcelona city (Spain)

Recent advances in detection of natural toxins in freshwater environments

Natural toxins can be classified according to their origin into biotoxins produced by microorganisms (fungal biotoxins or mycotoxins, algal and bacterial toxins), plant toxins or phytotoxins and animal toxins. Biotoxins are generated to protect organisms from external agents also in the act of predation. Among the different groups, bacterial toxins, mycotoxins and phytotoxins can produce damages in the aquatic environment including water reservoirs, with the consequent potential impact on human health. In the last few decades, a substantial labour of research has been carried out to obtain robust and sensitive analytical methods able to determine their occurrence in the environment. They range from the immunochemistry to analytical methods based on gas chromatography or liquid chromatography coupled to mass spectrometry analysers. In this article, the recent analytical methods for the analysis of biotoxins that can affect freshwater environments, drinking water reservoirs and supply are reviewed

Analysis, levels and seasonal variation of cyanotoxins in freshwater ecosystems

Nutrient over-enrichment in freshwater environments, together with the on-going climate change, favour the toxin-producing cyanobacteria bloom. Human health hazard may arise from drinking contaminated water. Additionally, cyanobacterial blooms affect other economic areas such as tourism, recreation, commercial fishery, water management and monitoring. Nowadays there is a scarcity of information on seasonal variations of cyanotoxins in various regions. Understanding of historical trends and seasonal variation patters is a foundation for forecasting and will help to develop effective water management strategies. This review gives an overview of cyanotoxins' analysis and levels in freshwater environments with particular emphasis on seasonal variations in Europe. Recent analytical approaches are discussed and the seasonal patterns for three major European climate zones (Mediterranean, continental, and Atlantic) were distinguished. Additionally, data from multi-year studies showed a tendency of increasing cyanotoxins' levels

Suspect screening of natural toxins in surface and drinking water by high-performance liquid chromatography high-resolution mass spectrometry

Besides anthropogenic contamination, freshwater environments can also be affected by the presence of natural toxins. Mycotoxins, plant toxins and cyanotoxins are the most relevant groups that can be found in the aquatic system. However, until now, only cyanotoxins have been more carefully studied. In the present work, single workflow for the assessment of natural toxins in waters, based on suspect screening and target screening of a selected group of toxins is presented. The approach is based on a triple-stage solid-phase extraction (SPE) able to isolate a wide range of natural toxins of different polarities, followed by liquid chromatography coupled to high-resolution mass spectrometry (HPLC-ddHRMS2) using a Q-Exactive Orbitrap analyser. The acquisition was performed in full-scan (FS) and data-dependant acquisition (ddMS2) mode, working under positive and negative mode. For the tentative identification, different on-line databases such as ChemSpider and MzCloud and an in-house natural toxins list with 2384 structures, that includes cyanotoxins, plant toxins and mycotoxins, were used. Also, thanks to the MS2 data, it was possible to achieve a high level of tentative identification confidence, but confirmation was only possible comparing the standards of the suspected compounds. For those, the analytical parameters of the developed method were also validated, and the quantification was possible by external calibration. Validation showed recoveries in the range between 53 and 95 %, and method limits of detection (MDL) between 0.02 and 1.22 μg/L. This approach was applied to study natural toxins in 4 sampling sites along the Ter River in Catalonia (NE Spain). In this preliminary study 23 natural toxins were tentatively identified, and 9 of them confirmed (aflatoxin B1, anatoxin-a, nodularin, microcystin-LR, baicalein, kojic acid, cinchonine, B-asarone and atropine). The results of the quantification of these compounds showed concentrations below 1 μg/L in all cases, that is considered safe according to the actual legislation. This suspect screening approach allows a more comprehensive assessment of natural toxins in natural waters

Occurrence of C60 and related fullerenes in the Sava River under different hydrologic conditions

The presence of nanomaterials in the environment has caught the attention of the scientific because of the uncertainties in their fate, mobility and potential toxic effects. However, few studies have determined experimentally their concentration levels in aquatic systems up to date, which complicates the development of an adequate risk assessment. In the present study, the occurrence of ten fullerenes has been assessed in the Sava River (Southeastern Europe): 27 freshwater samples and 12 sediment samples from 12 sampling points have been analysed during two sampling campaigns. C was the most ubiquitous fullerene, with concentrations of 8 pg/l–59 ng/l and 108–895 pg/g in water and sediments, respectively. Statistically significant differences existed between the levels in 2014 and 2015, which has been attributed to the extreme hydrologic conditions (severe floods and drought, respectively). C fullerene has been detected in most of the samples and the fullerene derivatives [6,6]-phenyl C butyric acid methyl ester and N‑methyl fulleropyrrolidine have been detected eventually, which highlights that nanotechnology research and development activities are responsible for emitting these emerging contaminants to the environment. The role of diverse potential anthropogenic sources (including oil refinery, general industrial activity, river navigation, urban emissions and nanotechnology) is discussed

Cyanobacteria and their secondary metabolites in three freshwater reservoirs in the United Kingdom

Background Bloom-forming cyanobacteria occur globally in aquatic environments. They produce diverse bioactive metabolites, some of which are known to be toxic. The most studied cyanobacterial toxins are microcystins, anatoxin, and cylindrospermopsin, yet more than 2000 bioactive metabolites have been identified to date. Data on the occurrence of cyanopeptides other than microcystins in surface waters are sparse. Results We used a high-performance liquid chromatography-high-resolution mass spectrometry/tandem mass spectrometry (HPLC-HRMS/MS) method to analyse cyanotoxin and cyanopeptide profiles in raw drinking water collected from three freshwater reservoirs in the United Kingdom. A total of 8 cyanopeptides were identified and quantified using reference standards. A further 20 cyanopeptides were identified based on a suspect-screening procedure, with class-equivalent quantification. Samples from Ingbirchworth reservoir showed the highest total cyanopeptide concentrations, reaching 5.8, 61, and 0.8 µg/L in August, September, and October, respectively. Several classes of cyanopeptides were identified with anabaenopeptins, cyanopeptolins, and microcystins dominating in September with 37%, 36%, and 26%, respectively. Samples from Tophill Low reservoir reached 2.4 µg/L in September, but remained below 0.2 µg/L in other months. Samples from Embsay reservoir did not exceed 0.1 µg/L. At Ingbirchworth and Tophill Low, the maximum chlorophyll-a concentrations of 37 µg/L and 22 µg/L, respectively, and cyanobacterial count of 6 × 10 cells/mL were observed at, or a few days after, peak cyanopeptide concentrations. These values exceed the World Health Organization's guideline levels for relatively low probability of adverse health effects, which are defined as 10 µg/L chlorophyll-a and 2 × 10 cells/mL. Conclusions This data is the first to present concentrations of anabaenopeptins, cyanopeptolins, aeruginosins, and microginins, along with icrocystins, in U.K. reservoirs. A better understanding of those cyanopeptides that are abundant in drinking water reservoirs can inform future monitoring and studies on abatement efficiency during water treatment

Interferometric nanoimmunosensor for label-free and real-time monitoring of Irgarol 1051 in seawater

An interferometric nanobiosensor for the specific and label-free detection of the pollutant Irgarol 1051 directly in seawater has been settled. Due to the low molecular weight of Irgarol pollutant and its expected low concentration in seawater, the sensor is based on a competitive inhibition immunoassay. Parameters as surface biofunctionalization, concentration of the selective antibody and regeneration conditions have been carefully evaluated. The optimized immunosensor shows a limit of detection of only 3 ng/L, well below the 16 ng/L set by the EU as the maximum allowable concentration in seawater. It can properly operate during 30 assay-regeneration cycles using the same sensor biosurface and with a time-to-result of only 20 min for each cycle. Moreover, the interferometric nanosensor is able to directly detect low concentrations of Irgarol 1051 in seawater without requiring sample pre-treatments and without showing any background signal due to sea matrix effect

Contaminants of emerging concern in freshwater fish from four Spanish Rivers

This study investigated the occurrence of 135 contaminants of emerging concern (CECs) – pharmaceuticals, pesticides, a set of endocrine disrupting compounds (EDCs) (parabens, bisphenols, hormones, triazoles, organophosphorus flame retardants and triclosan), UV-filters, perfluoroalkyl substances (PFASs) and halogenated flame retardants (HFRs) – in 59 fish samples, collected in 2010 in 4 Spanish Rivers (Guadalquivir, Júcar, Ebro and Llobregat). Of the 135 CECs, 76 including 8 pharmaceuticals, 25 pesticides, 10 EDCs, 5 UV-filters, 15 PFASs and 13 HFRs were detected. Pharmaceuticals were the less frequently found and at lower concentrations. Pesticides, EDCs, UV-filters, PFASs and HFRs were detected more frequently (>50% of the samples). The maximum concentrations were 15 ng/g dry weight (dw) for pharmaceuticals (diclofenac), 840 ng/g dw for pesticides (chlorpyrifos), 224 ng/g dw for EDCs (bisphenol A), 242 ng/g dw for UV-filters (EHMC), 1738 ng/g dw for PFASs (PFHxA) and 64 ng/g dw for HFRs (Dec 602). The contaminants detected in fish are commonly detected also in sediments. In light of current knowledge, the risk assessment revealed that there was no risk for humans related to the exposure to CECs via freshwater fish consumption. However, results provide detailed information on the mixtures of CECs accumulated that would be very useful to identify their effects on aquatic biota.This research has been supported by the European Union 7th Framework Programme funding under Grant Agreement No. 603629-ENV-2013-6.2.1-Globaqua, by the Generalitat de Catalunya (Consolidated Research Groups 2017 SGR 1404 - Water and Soil Quality Unit) and by the Generalitat Valenciana (ANTROPOCEN@, PROMETEO/2018/155).Peer reviewe

Remote and in situ devices for the assessment of marine contaminants of emerging concern and plastic debris detection

There is an increasing sense of alarm due to the constant accumulation of contaminants of emerging concern in the oceans. This fact was reflected in one of the significant challenges that are included in the United Nations Sustainable Development Goals which refer to climate change, conservation, and use of forests and oceans. Autonomous environmental monitoring techniques are required to set effective measures to conserve oceans. These detection systems are crucial tools for ambient data acquisition, remote monitoring, and mapping of the spatial extent of contaminants spills and plastic litter. Among the different technological operations that can be supported by these systems, the localisation of pollution sources has drawn increasing interest during recent years. This paper surveys recent advances in the new technologies for detection, mapping and new environmental monitoring strategies to detect marine contaminants of emerging concern and plastic litter.This study was funded by the Ministry of Science, Innovation and Universities through the project PLAS-MED (CTM 2017–89701C3-1-R)

Suspect and target screening of natural toxins in the Ter River catchment area in NE Spain and prioritisation by their toxicity

This study presents the application of a suspect screening approach to screen a wide range of natural toxins including mycotoxins, bacterial toxins, and plant toxins in surface waters. The method is based on a generic solid-phase extraction procedure, using three sorbent phases in two cartridges that are connected in series, hence covering a wide range of polarities, followed by liquid chromatography coupled to high-resolution mass spectrometry. The acquisition was performed in full-scan and data-dependent modes while working under positive and negative ionisation conditions. This method was applied in order to assess natural toxins in the Ter River water reservoirs, which are used to produce drinking water for Barcelona city (Spain). The study was carried out during a period of seven months, covering the expected prior, during, and post-peak blooming period for natural toxins. Fifty-three (53) compounds were tentatively identified, and nine of these were confirmed and quantified. Phytotoxins were identified as the most frequent group of natural toxins in water, particularly the alkaloids group. Finally, the toxins identified to levels 2 and 1 were prioritised according to their bioaccumulation factor, biodegradability, frequency of detection and toxicity. This screening and prioritisation approach resulted in different natural toxins that should be further assessed for their ecotoxicological effects and considered in future studies