Comprehensive determination of phthalate, terephthalate and di-iso-nonyl cyclohexane-1,2-dicarboxylate metabolites in wastewater by solid-phase extraction and ultra(high)-performance liquid chromatography-tandem mass spectrometry

Plasticizers are chemical compounds used in the production of flexible plastics for a large variety of applications. They are present in most of the environments and, hence, we are highly exposed to them via several routes (ingestion, inhalation, etc). Due to the endocrine disruption potential of some of these chemicals and the unknown toxicological effects of their alternatives, assessing human exposure to these contaminants is an issue of emerging concern. Herein we propose an analytical methodology for the determination of several plasticizer metabolites in wastewater as a non-invasive, cheap, and fast exposure monitoring tool complementary to the analysis of urine. A solid-phase extraction procedure followed by an ultra(high)-performance liquid chromatography-tandem mass spectrometry method was optimized and validated for 21 analytes among phthalate, terephthalate, and di-iso-nonyl cyclohexane-1,2-dicarboxylate metabolites. Method quantification limits ranged from 0.079 to 4.4 ng L^-1. The method was applied to the analysis of seven daily composite wastewater samples collected in the NW of Spain. Metabolites of low molecular weight phthalates and of di-2-ethylhexyl phthalate were quantified in all samples, despite the existing regulations limiting the use of phthalates. Metabolites of terephthalates, introduced at the end of the 20th century as phthalate substituents, were also quantified in all samples, being the first time that they were detected in this matrix. Exposure back-calculation highlighted di-2-ethylhexyl terephthalate as the second most common plastic additive after diethyl phthalate in the population considered, reflecting the increasing substitution of di-2-ethylhexyl phthalate by its analogous terephthalate.

Can UV-C laser pulsed irradiation be used for the removal of organic micropollutants from water? Case study with ibuprofen

A novel approach based on the direct pulsed irradiation of UV-C light onto ibuprofen (IBP) solutions was evaluated in this work, as proof of concept for the direct removal of micropollutants. The experiments confirmed that laser irradiation is able to completely degrade IBP in 15 min in distilled water, with a DOC depletion of ca. 25% and with transformation products (TPs) remaining in solution and estimated to represent ca. 10% of the initial IBP concentration. In wastewater spiked samples, removal efficiency is slightly lower but still significant (ca. 5% IBP remaining after 15 min). Hence, this work suggests that low power solid state pulsed lasers, emitting at 266 nm wavelength, show promise for the removal of these type of micropollutants from water. These results open new opportunities towards the development of chemical-free water treatment methods based on direct, selective irradiation using state of the art, miniaturized laser devices.

Transgenerational inheritance of chemical-induced signature: A case study with simvastatin

The hypothesis that exposure to certain environmental chemicals during early life stages may disrupt reproduction across multiple non-exposed generations has significant implications for understanding disease etiology and adverse outcomes. We demonstrate here reproductive multi and transgenerational effects, at environmentally relevant levels, of one of the most prescribed human pharmaceuticals, simvastatin, in a keystone species, the amphipod Gammarus locusta. The transgenerational findings has major implications for hazard and risk assessment of pharmaceuticals and other contaminants of emerging concern given that transgenerational effects of environmental chemicals are not addressed in current hazard and risk assessment schemes. Considering that the mevalonate synthesis, one of the key metabolic pathways targeted by simvastatin, is highly conserved among metazoans, these results may also shed light on the potential transgenerational effects of simvastatin on other animals, including humans.

First nation-wide estimation of tobacco consumption in Spain using wastewater-based epidemiology

Wastewater-based epidemiology (WBE) has become a very useful tool to monitor a population's drug consumption or exposure to environmental and food contaminants. In this work, WBE has been applied to estimate tobacco consumption in seven Spanish regions. To this end, 24 h composite wastewater samples were taken daily for one week in 17 wastewater treatment plants, covering altogether a population of ca. 6 million inhabitants. The samples were treated by enzymatic deconjugation and the wastewater content of two human-specific nicotine metabolites (namely, cotinine and trans-3'-hydroxycotinine) was measured to estimate the daily consumption of nicotine. The population-weighted average nicotine consumption in the seven analyzed regions was 2.2 g/(day∙1000 inh.), without any daily pattern. This average estimated nicotine consumption value agreed with the value derived from official tobacco sales data. Differences in consumption among the seven studied regions were found, being Galicia, the region with the lowest rate, and the Basque Country and Catalonia those with the highest rates. However, no conclusive correlation was found between those values and the prevalence data taken from two different national surveys, nor sociodemographic and health data. This study demonstrates that this tool can complement other indicators in order to accurately assess tobacco consumption rates at regional and national levels and provides the most extensive application of the approach in the Spanish territory.

Chlorination and bromination of 1,3-diphenylguanidine and 1,3-di-o-tolylguanidine: Kinetics, transformation products and toxicity assessment

This works investigates the chlorination and bromination of two rubber and polymer related chemicals, which have emerged as relevant water contaminants, i.e. 1,3-di-o-tolylguanidine (DTG) and 1,3-diphenylguanidine (DPG). Kinetic constants at different pH values were obtained and modelled, taking into account the pK_a values of DTG/DPG and HClO, showing that the maximum reaction rate (k_app > 10⁴ M^-1 s^-1) is obtained at pH values 8.8 for DPG and 9.1 for DTG. Bromination is also very fast, although unlike chlorination, deviation from the model was observed at neutral pH, which was attributed to formation of metastable transformation product (TP). A total of 35 TPs, corresponding to halogenation, hydroxylation, formation of monophenylguanidine derivatives and cyclization reactions, were tentatively identified. Furthermore it was found that chloroform can be formed up to a 25% molar yield, while dichloroacetonitrile was formed into less than a 3% yield. Several ecotoxicological endpoints were predicted by quantitative structure-activity relationship models (QSAR) for the TPs, some of which were predicted to be more toxic than DPG/DTG. Also a chlorinated solution investigated by a Vibrio Fisheri acute toxicity test, confirmed that toxicity increases with chlorination.

Chronic exposure to environmentally relevant levels of simvastatin disrupts zebrafish brain gene signaling involved in energy metabolism

Simvastatin (SIM), a hypocholesterolaemic drug belonging to the statins group, is a widely prescribed pharmaceutical for prevention of cardiovascular diseases. Several studies showed that lipophilic statins, as SIM, cross the blood-brain barrier and interfere with the energy metabolism of the central nervous system in humans and mammalian models. In fish and other aquatic organisms, the effects of SIM on the brain energy metabolism are unknown, particularly following exposure to low environmentally relevant concentrations. Therefore, the present study aimed at investigating the influence of SIM on gene signaling pathways involved in brain energy metabolism of adult zebrafish (Danio rerio) following chronic exposure (90 days) to environmentally relevant SIM concentrations ranging from 8 ng/L to 1000 ng/L. Real-time PCR was used to determine the transcript levels of several genes involved in different pathways of the brain energy metabolism (glut1b, gapdh, acadm, accα, fasn, idh3a, cox4i1, and cox5aa). The findings here reported integrated well with ecological and biochemical responses obtained in a parallel study. Data demonstrated that SIM modulates transcription of key genes involved in the mitochondrial electron transport chain, in glucose transport and metabolism, in fatty acid synthesis and β-oxidation. Further, SIM exposure led to a sex-dependent transcription profile for some of the studied genes. Overall, the present study demonstrated, for the first time, that SIM modulates gene regulation of key pathways involved in the energy metabolism in fish brain at environmentally relevant concentrations.

Spatio-temporal assessment of illicit drug use at large scale: evidence from 7 years of international wastewater monitoring

BACKGROUND AND AIMS

Wastewater-based epidemiology is an additional indicator of drug use that is gaining reliability to complement the current established panel of indicators. The aims of this study were to: (i) assess spatial and temporal trends of population-normalized mass loads of benzoylecgonine, amphetamine, methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA) in raw wastewater over 7 years (2011-17); (ii) address overall drug use by estimating the average number of combined doses consumed per day in each city; and (iii) compare these with existing prevalence and seizure data.

DESIGN

Analysis of daily raw wastewater composite samples collected over 1 week per year from 2011 to 2017.

SETTING AND PARTICIPANTS

Catchment areas of 143 wastewater treatment plants in 120 cities in 37 countries.

MEASUREMENTS

Parent substances (amphetamine, methamphetamine and MDMA) and the metabolites of cocaine (benzoylecgonine) and of Δ⁹ -tetrahydrocannabinol (11-nor-9-carboxy-Δ⁹ -tetrahydrocannabinol) were measured in wastewater using liquid chromatography-tandem mass spectrometry. Daily mass loads (mg/day) were normalized to catchment population (mg/1000 people/day) and converted to the number of combined doses consumed per day. Spatial differences were assessed world-wide, and temporal trends were discerned at European level by comparing 2011-13 drug loads versus 2014-17 loads.

FINDINGS

Benzoylecgonine was the stimulant metabolite detected at higher loads in southern and western Europe, and amphetamine, MDMA and methamphetamine in East and North-Central Europe. In other continents, methamphetamine showed the highest levels in the United States and Australia and benzoylecgonine in South America. During the reporting period, benzoylecgonine loads increased in general across Europe, amphetamine and methamphetamine levels fluctuated and MDMA underwent an intermittent upsurge.

CONCLUSIONS

The analysis of wastewater to quantify drug loads provides near real-time drug use estimates that globally correspond to prevalence and seizure data.

Polyethylene microplastics do not increase bioaccumulation or toxicity of nonylphenol and 4-MBC to marine zooplankton

Global production of synthetic polymers, led by polyethylene (PE), rose steadily in the last decades, and marine ecosystems are considered as a global sink. Although PE is not biodegradable, in coastal areas it fragments into microplastics (MP) readily taken up by biota, and have been postulated as vectors of hydrophobic chemicals to marine organisms. We have tested this hypothesis using two organisms representative of the marine plankton, the holoplanktonic copepod Acartia clausi, and the meroplanktonic larva of the Paracentrotus lividus sea-urchin, and two model chemicals with similar hydrophobic properties, the 4-n-Nonylphenol and the 4-Methylbenzylidene-camphor used as plastic additive and UV filter in cosmetics. Both test species actively ingested the MP particles. However, the presence of MP never increased the bioaccumulation of neither model chemicals, nor their toxicity to the exposed organisms. Bioaccumulation was a linear function of waterborne chemical disregarding the level of MP. Toxicity, assessed by the threshold (EC₁₀) and median (EC₅₀) effect levels, was either independent of the level of MP or even in some instances significantly decreased in the presence of MPs. These consistent results challenge the assumption that MP act as vectors of hydrophobic chemicals to planktonic marine organisms.

Linking chemical exposure to lipid homeostasis: A municipal waste water treatment plant influent is obesogenic for zebrafish larvae

Obesity, a risk factor for the development of type-2 diabetes, hypertension, cardiovascular disease, hepatic steatosis and some cancers, has been ranked in the top 10 health risk in the world by the World Health Organization. Despite the growing body of literature evidencing an association between the obesity epidemic and specific chemical exposure across a wide range of animal taxa, very few studies assessed the effects of chemical mixtures and environmental samples on lipid homeostasis. Additionally, the mode of action of several chemicals reported to alter lipid homeostasis is still poorly understood. Aiming to fill some of these gaps, we combined an in vivo assay with the model species zebrafish (Danio rerio) to screen lipid accumulation and evaluate expression changes of key genes involved in lipid homeostasis, alongside with an in vitro transactivation assay using human and zebrafish nuclear receptors, retinoid X receptor α and peroxisome proliferator-activated receptor γ. Zebrafish larvae were exposed from 4 th day post-fertilization until the end of the experiment (day 18), to six different treatments: experimental control, solvent control, tributyltin at 100 ng/L Sn and 200 ng/L Sn (positive control), and wastewater treatment plant influent at 1.25% and 2.5%. Exposure to tributyltin and to 2.5% influent led to a significant accumulation of lipids, with white adipose tissue deposits concentrating in the perivisceral area. The highest in vitro tested influent concentration (10%) was able to significantly transactivate the human heterodimer PPARγ/RXRα, thus suggesting the presence in the influent of HsPPARγ/RXRα agonists. Our results demonstrate, for the first time, the ability of complex environmental samples from a municipal waste water treatment plant influent to induce lipid accumulation in zebrafish larvae.

Determination of 18 organophosphorus flame retardants/plasticizers in mussel samples by matrix solid-phase dispersion combined to liquid chromatography-tandem mass spectrometry

This study presents the development and validation of a new analytical method based on matrix solid-phase dispersion (MSPD), integrating sample extraction and clean-up in one single step, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of 18 organophosphorus flame retardants and/or plasticizers (OPEs) in marine mussel (Mytilus edulis and Mytilus galloprovincialis) samples. Among these OPEs, 5 (tetraethyl 1,2-ethanediylbis(phosphonate), 6H-dibenzo[c,e] [1,2]oxaphosphinine 6-oxide, tris(2,3-dibromopropyl) phosphate, 2,2-propanediyldi-4,1-phenylene bis(phosphate) and resorcinol bis(diphenyl phosphate)) are considered here for the first time in marine samples. Different parameters affecting the MSPD (clean-up sorbent and elution solvent) were optimized to obtain a good compromise between analyte recoveries and extract clean-up. Also, particular attention was paid to tackle blank issues. The overall method was validated in terms of trueness, precision and detection and quantification limits. Percentages of recovery varied from 69% to 122% with relative standard deviations below 24%. Detection limits ranged from 0.06 to 5 ng g^-1 and quantification limits from 0.19 to 17 ng g^-1 dry weight. Finally, the method was applied to the analysis of 7 mussel samples collected in the coast of Galicia (Spain). 8 OPEs were detected in these samples at concentrations ranging from the LOQ to 291 ng g^-1 dry weight.

Legacy and emerging pollutants in marine bivalves from the Galician coast (NW Spain)

The presence of pollutants in estuary and oceanic systems is a global problem and a serious concern to human and environmental health. Usually, environmental monitoring studies consider classical persistent organic pollutants (POPs). However, the lists of POPs keep continuously growing and new POPs and other emerging pollutants should be considered in new monitoring programs. So, this study aimed to investigate the distribution and profile of classical POPs (polychlorinated biphenyl (PCBs), organochlorine pesticides (OCPs), and polycyclic aromatic hydrocarbons (PAHs)), new POPs and emerging pollutants (polybrominated diphenyl ethers (PBDEs), perfluorinated compounds (PFCs), novel halogenated flame retardants (NFRs) and UV filters) in bivalve mollusc samples (both raft-cultivated and wild mussel, Mytilus galloprovincialis; cockle, Cerestoderma edule; and clam, Ruditapes descussatus) collected in nine Galician Rias during the period February 2012 to February 2013. A predominance of PAHs (6.8-317 ng/g dry weight (dw)) followed by PCBs (0.47-261 ng/g dw), UV filters (1.4-157 ng/g dw), PFCs (0.53-62 ng/g dw), OCPs (0.07-29 ng/g dw), PBDEs (0.31-6.6 ng/g dw) and NFRs (0.07-3.2 ng/g dw) was found in the studied bivalves, being the UV filter octocrylene the compound found at the highest concentration (141 ng/g dw in a cockle sample), while the PAHs chrysene and benzo(b)fluoranthene were the compounds with the highest average concentration (20 and 14 ng/g dw, respectively). Inter-species, temporal and geographical variations on pollutants concentration were assessed by multifactorial analysis of variance. Statistically significant differences among the type of mollusc were observed for levels of organochlorinated and organobrominated pollutants considered (PCBs, OCPs and PBDEs), which were detected at higher concentrations in wild mussel. On the other hand, the main PFCs and UV filters showed a higher detection frequency in cockle samples. Location played significant role for PAHs, PCBs and the main PBDEs, being the most polluted rias those more industrialized and populated, i.e. A Coruña, Ferrol and/or Vigo. Finally, sampling timepoint was also a significant factor for most of the families considered but with different profiles. Thus, PAHs and PCBs showed higher concentrations in both February 2012 and 2013 and lower in August 2012, while the main PBDEs were measured at higher concentrations in November 2012 and lower in February 2012; and the main NFRs, PFCs and UV filters were present at lower levels in February 2013.

Profiling cocaine residues and pyrolytic products in wastewater by mixed-mode liquid chromatography-tandem mass spectrometry

This work provides a new analytical method for the determination of cocaine, its metabolites benzoylecgonine and cocaethylene, the pyrolytic products anhydroecgonine and anhydroecgonine methyl ester, and the pharmaceutical levamisole in wastewater. Samples were solid-phase extracted and extracts analyzed by liquid chromatography-tandem mass spectrometry using, for the first time in the illicit drug field, a stationary phase that combines reversed-phase and weak cation-exchange functionalities. The overall method performance was satisfactory, with limits of detection below 1 ng/L, relative standard deviations below 21%, and percentages of recovery between 93% and 121%. Analysis of 24-hour composite raw wastewater samples collected in Santiago de Compostela (Spain) and Brasilia (Brazil) highlighted benzoylecgonine as the compound showing the highest population-normalized mass loads (300-1000 mg/day/1000 inhabitants). In Brasilia, cocaine and levamisole loads underwent an upsurge on Sunday, indicating a high consumption, and likely a direct disposal, of cocaine powder on this day. Conversely, the pyrolytic product resulting from the smoke of crack, anhydroecgonine methyl ester, and its metabolite anhydroecgonine were relatively stable over the four days, agreeing with a non-recreational-associated use of crack.

Occurrence of emerging persistent and mobile organic contaminants in European water samples

The release of persistent and mobile organic chemicals (PMOCs) into the aquatic environment puts the quality of water resources at risk. PMOCs are challenging to analyze in water samples, due to their high polarity. The aim of this study was to develop novel analytical methods for PMOCs and to investigate their occurrence in surface and groundwater samples. The target compounds were culled from a prioritized list of industrial chemicals that were modeled to be persistent, mobile, and emitted into the environment. Analytical screening methods based on mixed-mode liquid chromatography (LC), hydrophilic interaction LC, reversed phase LC, or supercritical fluid chromatography in combination with mass spectrometric detection were successfully developed for 57 target PMOCs and applied to 14 water samples from three European countries. A total of 43 PMOCs were detected in at least one sample, among them 23 PMOCs that have not been reported before to occur in environmental waters. The most prevalent of these novel PMOCs were methyl sulfate, 2-acrylamino-2-methylpropane sulfonate, benzyltrimethylammonium, benzyldimethylamine, trifluoromethanesulfonic acid, 6-methyl-1,3,5-triazine-diamine, and 1,3-di-o-tolylguanidine occurring in ≥50% of the samples at estimated concentrations in the low ng L^-1 up to μg L^-1 range. The approach of focused prioritization combined with sensitive target chemical analysis proved to be highly efficient in revealing a large suite of novel as well as scarcely investigated PMOCs in surface and groundwater.

Determination of Persistent and Mobile Organic Contaminants (PMOCs) in Water by Mixed-Mode Liquid Chromatography-Tandem Mass Spectrometry

The presence of persistent and mobile organic contaminants (PMOC) in aquatic environments has become a matter of concern due to their ability of breaking through natural and anthropogenic barriers, even reaching drinking water. The presence of many of these compounds in surface and drinking water has been reported in screening studies, but there is still a lack of analytical methods capable of quantifying them. Herein, we propose a method combining mixed-mode-solid-phase extraction (MM-SPE) as preconcentration technique and mixed-mode liquid chromatography (MMLC) coupled to tandem mass spectrometry as a determination technique for the quantitative determination of 23 target PMOCs in surface and drinking water samples. When compared to reversed-phase liquid chromatography, the MMLC protocol has proven to be superior in both retentive capabilities and peak shape for ionic compounds, while performing also well for neutrals. The overall method performance was satisfactory with limits of quantification under 50 ng L^-1 for most of analytes in both surface and drinking water. The relative standard deviation was lower than 20%, and the average recovery was 78 and 80% in surface and drinking water, respectively. The method was applied to 15 water samples collected in Spain, where 17 out of the 23 target PMOCs were quantified in at least one sample. Among them, 6 chemicals (e.g., benzyltrimethylammonium) are reported and/or quantified here for the first time.

Modeling Dispersal of UV Filters in Estuaries

Lagrangian ocean analysis, where virtual parcels of water are tracked through hydrodynamic fields, provides an increasingly popular framework to predict the dispersal of water parcels carrying particles and chemicals. We conduct the first direct test of Lagrangian predictions for emerging contaminants using (1) the latitude, longitude, depth, sampling date, and concentrations of UV filters in raft cultured mussel ( Mytilus galloprovincialis) of the estuary Ria de Arousa, Spain (42.5°N, 8.9°W); (2) a hydrodynamic numerical model at 300 m spatial resolution; and (3) a Lagrangian dispersion scheme to trace polluted water parcels back to pollution sources. The expected dispersal distances (mean ± SD) are 2 ± 1 km and the expected dispersal times (mean ± SD) are 6 ± 2 h. Remarkably, the probability of dispersal of UV filters from potential sources to rafts decreases 5-fold over 5 km. In addition to predicting dispersal pathways and times, this study also provides a framework for quantitative investigations of concentrations of emerging contaminants and source apportionment using turbulent diffusion. In the coastline, the ranges of predicted concentrations of the UV-filters 4-methylbenzylidene-camphor, octocrylene, and benzophenone-4 are 3.2 × 10^-4 to 0.023 ng/mL, 2.3 × 10^-5 to 0.009 ng/mL, and 5.6 × 10^-4 to 0.013 ng/mL, respectively. At the outfalls of urban wastewater treatment plants these respective ranges increase to 8.9 × 10^-4 to 0.07 ng/mL, 6.2 × 10^-5 to 0.027 ng/mL, and 1.6 × 10^-3 to 0.040 ng/mL.

[Wastewater-based epidemiology: applications towards the estimation of drugs of abuse consumption and public health in general. The Spanish network ESAR-Net]

This manuscript introduces Wastewater-Based Epidemiology (WBE) and its potential in the assessment of diverse aspects related to public health. This methodology can provide data in a relatively short temporal and local scale (typically dialy-weekly at the municipal level) on consumption patterns of illicit drugs (e.g. cocaine or cannabis), licit substances of abuse (e.g. alcohol) by measuring their consumption biomarkers (i.e. the original unmetabolized substance or some of its metabolite) in wastewater. Besides discussing the fundaments, advantages and shortcomings of WBE, it reviews some of the main precedents at international level and most remarkable activities that have been taken place in this field in Spain. Finally, the Spanish Network of Wastewater-Based Epidemiology (ESAR-Net) as is presented. ESAR-Net is an Excellence Network that sums up the efforts of the most relevant Spanish researchers in the field of WBE, aiming to investigate future perspectives of this methodology and its impact on Public Health competences in Spain.

Chronic environmentally relevant levels of simvastatin disrupt embryonic development, biochemical and molecular responses in zebrafish (Danio rerio)

Simvastatin (SIM), a hypocholesterolaemic compound, is among the most prescribed pharmaceuticals for cardiovascular disease prevention worldwide. Several studies have shown that acute exposure to SIM causes multiple adverse effects in aquatic organisms. However, uncertainties still remain regarding the chronic effects of SIM in aquatic ecosystems. Therefore, the present study aimed to investigate the effects of SIM in the model freshwater teleost zebrafish (Danio rerio) following a chronic exposure (90 days) to environmentally relevant concentrations ranging from 8 ng/L to 1000 ng/L. This study used a multi-parameter approach integrating distinct ecologically-relevant endpoints, i.e. survival, growth, reproduction and embryonic development, with biochemical markers (cholesterol and triglycerides). Real Time PCR was used to analyse the transcription levels of key genes involved in the mevalonate pathway (hmgcra, cyp51, and dhcr7). Globally, SIM induced several effects that did not follow a dose-response relationship; embryonic development, biochemical and molecular markers, were significantly impacted in the lower concentrations, 8 ng/L, 40 ng/L and/or 200 ng/L, whereas no effects were recorded for the highest tested SIM levels (1000 ng/L). Taken together, these findings expand our understanding of statin effects in teleosts, demonstrating significant impacts at environmentally relevant concentrations and highlight the importance of addressing the effects of chemicals under chronic low-level concentrations.

Bioaccumulation of UV filters in Mytilus galloprovincialis mussel

In this study the bioaccumulation kinetics of organic UV filters, such as 4-MBC, BP-3, BP-4, OC and OD-PABA in wild Mytilus galloprovincialis mussels was investigated. The uptake and accumulation of waterborne 4-MBC, BP-4 and OC was very rapid, and after only 24 h of exposure to 1 μg L^-1, the tissular concentrations were 418, 263 and 327 μg kg^-1d.w., respectively. The kinetics of bioaccumulation of BP-4 and OC significantly fitted to an asymptotic model with BCF values of 905 L kg^-1 and 2210 L kg^-1, respectively. Measured bioaccumulation of the hydrophilic chemical BP-4 was much higher than predicted by K_ow-based bioconcentration models, which would lead to a marked underestimation of actual risk. On the other hand, the patterns of uptake found for BP-3 and OD-PABA suggest biotransformation ability of mussels for these two chemicals.

Reaction of diazepam and related benzodiazepines with chlorine. Kinetics, transformation products and in-silico toxicological assessment

In this work, the reaction of four benzodiazepines (diazepam, oxazepam, nordazepam and temazepam) during water chlorination was studied by means of liquid chromatography-quadrupole-time of flight-mass spectrometry (LC-QTOF-MS). For those compounds that showed a significant degradation, i.e. diazepam, oxazepam and nordazepam, parameters affecting to the reaction kinetics (pH, chlorine and bromide level) were studied in detail and transformation products were tentatively identified. The oxidation reactions followed pseudofirst-order kinetics with rate constants in the range of 1.8-42.5 M^-1 s^-1, 0.13-1.16 M^-1 s^-1 and 0.04-20.4 M^-1 s^-1 corresponding to half-life values in the range of 1.9-146 min, 1.8-87 h and 2.5-637 h for oxazepam, nordazepam and diazepam, respectively, depending of the levels of studied parameters. Chlorine and pH affected significantly the reaction kinetics, where an increase of the pH resulted into a decrease of the reaction rate, whereas higher chlorine dosages led to faster kinetics, as expected in this case. The transformation of the studied benzodiazepines occurs mainly at the 1,4-diazepine 7-membered-ring, resulting in ring opening to form benzophenone derivatives or the formation of a 6-membered pyrimidine ring, leading to quinazoline derivatives. The formation of these by-products was also tested in real surface water samples observing kinetics of oxazepam degradation slower in river than in creek water, while the degradation of the two other benzodiazepines occurred only in the simpler sample (creek water). Finally, the acute and chronical toxicity and mutagenicity of precursors and transformation products were estimated using quantitative structure-activity relationship (QSAR) software tools: Ecological Structure Activity Relationships (ECOSAR) and Toxicity Estimation Software Tool (TEST), finding that some transformation products could be more toxic/mutagenic than the precursor drug, but additional test would be needed to confirm this fact.

Screening for Polar Chemicals in Water by Trifunctional Mixed-Mode Liquid Chromatography-High Resolution Mass Spectrometry

The presence of persistent and mobile organic contaminants (PMOC) in aquatic environments is a matter of high concern due to their capability of crossing through natural and anthropogenic barriers, even reaching drinking water. Most analytical methods rely on reversed-phase liquid chromatography (RPLC), which is quite limited for the detection of very polar chemicals. Thus, many of these PMOCs may have not been recognized as water pollutants yet, due to the lack of analytical methods capable to detect them. Mixed-mode LC (MMLC), providing the combination of RP and ion-exchange functionalities is explored in this work with a trifunctional column, combining RPLC, anion and cation exchange, which allows the simultaneous determination of analytes with extremely different properties. A nondiscriminant sample concentration step followed by a MMLC-high resolution mass spectrometry method was developed for a group of 37 very polar model chemicals with different acid/base functionalities. The overall method performance was satisfactory with a mean limit of detection of 50 ng/L, relative standard deviation lower than 20% and overall recoveries (including matrix effects) higher than 60% for 54% of model compounds. Then, the method was applied to 15 real water samples, by a suspect screening approach. For those detected PMOC with standard available, a preliminary estimation of concentrations was also performed. Thus, 22 compounds were unequivocally identified in a range of expected concentrations from 6 ng/L to 540 μg/L. Some of them are well-known PMOC, such as acesulfame, perfluorobutanoic acid or metformin, but other novel pollutants were also identified, as for example di-o-tolylguanidine or trifluoromethanesulfonic acid, which had not or were scarcely studied in water so far.

Ecotoxicological Evaluation of the UV Filters Ethylhexyl Dimethyl p-Aminobenzoic Acid and Octocrylene Using Marine Organisms Isochrysis galbana, Mytilus galloprovincialis and Paracentrotus lividus

The growing concern regarding the negative effects of solar radiation on the skin has led to a drastic increase in the use of sunscreens containing in its composition up to 10% of aromatic chemicals, such as ethylhexyl dimethyl p-aminobenzoic acid (OD-PABA) and octocrylene (OC). The objective of this study was to evaluate the toxicity and to assess the environmental risk posed by these two ultraviolet filters, widely used in cosmetics and as plastic additives, in the marine environment. Several ecotoxicological bioassays were performed with three model organisms belonging to different trophic levels: the microalgae Isochrysis galbana, the mussel Mytilus galloprovincialis, and the sea urchin Paracentrotus lividus. The results show remarkable toxicity to marine species for both OD-PABA (EC₁₀ values range 26,5-127 µg L^-1) and OC (EC₁₀ range 103-511 µg L^-1). The cell division in the microalgae I. galbana was the most sensitive endpoint tested. To determine the environmental risk of these substances, the risk coefficient (RQ) was calculated. Due to the higher concentrations reported, OC showed remarkable risk (RQ = 0.27), whereas for OD-PABA the risk was low (RQ = 0.007).

Wastewater-Based Epidemiology as a New Tool for Estimating Population Exposure to Phthalate Plasticizers

This study proposes the monitoring of phthalate metabolites in wastewater as a nonintrusive and economic alternative to urine analysis for estimating human exposure to phthalates. To this end, a solid-phase extraction-liquid chromatography-tandem mass spectrometry method was developed, allowing for the determination of eight phthalate metabolites in wastewater (limits of quantification between 0.5 and 32 ng L^-1). The analysis of samples from the NW region of Spain showed that these substances occur in raw wastewater up to ca. 1.6 μg L^-1 and in treated wastewater up to ca. 1 μg L^-1. Concentrations in raw wastewater were converted into levels of exposure to six phthalate diesters. For two of them, these levels were always below the daily exposure thresholds recommended by the U.S. Environmental Protection Agency and the European Food Safety Authority. For the other four, however, estimates of exposure surpassed such a threshold (especially the toddler threshold) in some cases, highlighting the significance of the exposure to phthalates in children. Finally, concentrations in wastewater were also used to estimate metabolite concentrations in urine, providing a reasonable concordance between our results and the data obtained in two previous biomonitoring studies.