In-vitro estimation of bioaccessibility of chlorinated organophosphate flame retardants in indoor dust by fasting and fed physiologically relevant extraction tests.

This paper reports the evaluation of in-vitro physiologically relevant extraction tests for ascertainment of the bioaccessible fractions of emerging flame retardants from indoor dust in the gastric and gastrointestinal compartments. Standardized bioaccessibility tests under both fasting (UBM-like test) and fed (FOREhST test) conditions simulating the macronutrient composition of an average child diet were harnessed for investigation of the oral bioaccessibility of chlorinated organophosphate esters, namely, tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP) and tris(1,3-dichloro-2-propyl) phosphate (TDCP), in household and automobile cabin dust samples with varying concentration levels of contaminants. Minimal processing of the biomimetic extracts (only protein precipitation using acetonitrile) was proven feasible by analysis with liquid chromatography-mass spectrometric detection (LC-MS/MS). An inversely proportional relationship was identified between log Kow and oral bioaccessibility concentrations for TCEP, TCPP and TDCP in both dust samples with maximum bioaccessibility fractions for TCEP within the range of 50-103%. Non-bioaccessible fractions were determined by matrix-solid phase dispersion. Limits of quantification of LC-MS/MS in surrogate digestive fluids ranging from 0.4-0.8ng/mL suffice for determination of freely dissolved fractions of the two less hydrophobic species. Our results indicate that lipophilic food commodities used under fed-state gastrointestinal extraction conditions do not increase availability of TCEP, TCPP and TDCP in body fluids, and therefore conservative conditions in human health risk explorations for the target moderately polar flame retardants might be obtained with simplified tests under fasting conditions. This also holds true for the UBM/FOREhST bioaccessibility data for SRM 2585 (organic contaminants in house dust). Estimated average daily intake doses for toddlers incorporating oral bioaccessibility data afforded body burdens for the three chlorinated alkyl phosphates of ca. 3000 to 700 times below reference dose values, which indicate that long-term exposure to chlorinated organophosphate esters via accidental ingestion of indoor dust does not pose health risks to toddlers.

Alcohol and cocaine co-consumption in two European cities assessed by wastewater analysis.

The quantitative determination of urinary biomarkers in raw wastewater has emerged in recent years as a promising tool for estimating the consumption of illicit drugs, tobacco and alcohol in a population and for comparing local and temporal trends. In this study, a three-year monitoring campaign (2012-2014) was conducted to compare alcohol and cocaine use in two European cities (Santiago de Compostela, Spain, and Milan, Italy) by wastewater analysis. Ethyl sulphate and benzoylecgonine were used, respectively, as biomarkers of ethanol and cocaine consumption and cocaethylene as an indicator of co-consumption of both substances. Biomarkers were measured using liquid chromatography-tandem mass spectrometry and concentrations were converted to rates of consumption using specific correction factors. Results were statistically compared in terms of geographic and temporal tendencies. Alcohol intake was significantly higher in Santiago than in Milan (13.6L versus 5.1L ethanol/1000 people day, averages). Cocaine use was higher in Milan than in Santiago de Compostela (800 versus 632 mg/1000 people day, averages). A significant higher consumption of both alcohol and cocaine was observed during the weekends (~23-75% more than on weekdays) in both cities. In terms of years, slight changes were observed, but no clear trends as representative of the whole year could be identified because of the limited number of days sampled. Co-consumption was evaluated using the cocaethylene/benzoylecgonine ratio, which was higher during the weekend in both cities (58% in Santiago and 47% in Milan over the non-weekend day means), indicating a greater co-consumption when cocaine is used as a recreational drug. Wastewater-based epidemiology gave estimates of alcohol and cocaine use in agreement with previous wastewater studies and with recent European surveillance and prevalence data, and weekly profiles of use and preferential patterns of consumption could be plot.

Reactivity of ß-blockers/agonists with aqueous permanganate. Kinetics and transformation products of salbutamol.

The possible oxidation of two ß-blockers, atenolol and propranolol, and one ß-agonist, salbutamol, with aqueous potassium permanganate (KMnO4) was investigated by liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-QTOF-MS). Under strong oxidation conditions (2 mg L(-1) KMnO4, 24 h), only salbutamol did significantly react. In this way, the oxidation kinetics of salbutamol was further investigated at different concentrations of KMnO4, chloride, phosphate and sample pH by means of a full factorial experimental design. Depending on these factors, half-lives were in the range 1-144 min for drug and it was observed that KMnO4 concentration was the most significant factor, resulting in increased reaction rate as it is increased. Moreover, the reaction of salbutamol is also enhanced at basic pH and to a minor extent by the presence of phosphates, being both factors more relevant at low KMnO4 concentrations. The use of an accurate-mass LC-QTOF-MS system permitted the identification of a total of seven transformation products (TPs). The transformation path of the drug begins by the attack of KMnO4 on two double bonds of the aromatic ring of salbutamol via 3 + 2 and 2 + 2 addition reactions, which resulted in the ring opening and that continues with oxidative reactions to finally produce smaller size TPs, ending with tert-butyl-formamide, as the smallest TP identified. Reaction in real samples showed a slower and partial oxidation of the pharmaceutical, due to other competing water organic constituents, but still exceeding 60%. Moreover, the software predicted toxicity of TPs indicates that they are expected not to be more toxic than salbutamol, in contrast to the results obtained for the predicted toxicity of chlorination TPs, excepting predicted developmental toxicity.

Assessment of local tobacco consumption by liquid chromatography-tandem mass spectrometry sewage analysis of nicotine and its metabolites, cotinine and trans-3'-hydroxycotinine, after enzymatic deconjugation.

Cotinine (COT), trans-3'-hydroxycotinine (OH-COT), cotinine-N-ß-glucuronide (COT-GLUC), and trans-3'-hydroxycotinine-O-ß-glucuronide (OH-COT-GLUC) are excreted in urine following the intake of nicotine (NIC), and, as such, they have been detected in sewage. Thus, they also constitute convenient biomarkers for NIC tracing through the sewage epidemiology approach at the local scale. Such estimation requires granting a good stability of the target biomarkers in sewage. However, it was found that glucuronides are not stable, particularly in the case of OH-COT-GLUC, which could render variable concentrations of COT, OH-COT, and their glucuronides, depending on sampling and storage time or temperature. Thus, an enzymatic deconjugation with ß-glucuronidase was optimized. With the optimized method, after enzymatic deglucuronization, the limits of quantification obtained were in the range of 0.2-1 µg L(-1), relative standard deviations were <10%, and the trueness in terms of recovery was in the 95%-112% range. The application of the method to composite sewage samples collected during 1 week in three different years in Santiago de Compostela (Galicia, Spain) showed COT and OH-COT concentrations of 0.3-1.9 µg L(-1) and 1.0-3.3 µg L(-1), respectively. Thereby, the average NIC consumption derived was in the 1.7-1.9 mg per day and person range, being comparable to those derived from tobacco sales statistics.

Ion-pair reversed-phase liquid chromatography-quadrupole-time-of-flight and triple-quadrupole-mass spectrometry determination of ethyl sulfate in wastewater for alcohol consumption tracing.

Ethyl sulfate (EtS) is excreted in urine as a minor metabolite (0.010-0.016% on molar basis) after intake of alcoholic beverages, being a convenient biomarker for ethanol tracing after its determination in sewage. In this work, a new method for the direct determination of EtS in wastewater by liquid chromatography-(tandem) mass spectrometry (LC-MS(/MS)) has been developed. Different LC columns, mobile phases, and detection systems have been tested. Convenient retention by ion-pair reversed-phase LC was achieved by addition of 50mM tetrabutylamonium bromide to the sample. Also, a triple-quadrupole (QqQ) instrument and a quadrupole time-of-flight (QTOF) system were compared. The repeatability of both systems and linearity was comparable, with RSD≤10% in sewage samples. The QqQ instrument provided a better limit of detection (LOD=0.1µgL(-1)) than the QTOF system LOD (0.2µgL(-1)). However, the LOD of this last instrument was still good enough for wastewater concentrations, while avoiding problems with interferences on the QqQ not permitting positive identification with this last system. The stability of EtS was tested and it has proven to be stable in wastewater for at least one week at room temperature and more than one month at -20°C. The application of the method to samples collected during a week in a Galician (NW Spain) city showed EtS concentrations between 4 and 12µgL(-1). This translated into a per capita consumption of pure ethanol in the range from 9 to 24mLday(-1)inh(-1), observing an increase during the weekend compared to weekdays.

Oxidation of non-steroidal anti-inflammatory drugs with aqueous permanganate.

Potassium permanganate is a strong oxidant widely used in drinking water treatment, that can react with organic micropollutants. Thus, the oxidation kinetics and transformation route of seven non-steroidal anti-inflammatory drugs (NSAIDs) upon reaction with potassium permanganate was investigated. A liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-Q-TOF-MS) system was used to follow the time course of pharmaceuticals concentrations and for the identification of their by-products. Under strong oxidation conditions (2 mg L(-1) KMnO4, 24 h), only two NSAIDs were significantly degraded: indomethacine and diclofenac. The degradation kinetics of these two drugs was investigated at different concentrations of permanganate, chlorides, phosphates and sample pH by means of a full factorial experimental design. Depending on these factors, half-lives were in the range: 2-270 h for indomethacine and 3-558 h for diclofenac, equivalent to apparent second order constants between 0.65 and 9.5 M(-1) s(-1) and 0.27 and 7.4 M(-1) s(-1), respectively. Permanganate concentration was the most significant factor on NSAIDs oxidation kinetics, but the pH also played a significant role in diclofenac reaction, being faster at acidic pH. In the case of indomethacine, the dose of permanganate seemed also to play an autocatalytic effect. The use of an accurate-mass high resolution LC-Q-TOF-MS system permitted the identification of a total of 13 by-products. The transformation path of these drugs consisted mainly of hydroxylations, decarboxylations and oxidation of aromatic double bonds, with ring opening. The software predicted toxicity of these products indicates that they are expected not to be more toxic than the NSAIDs, with the exception of two indomethacine by-products. Reaction in real samples was slower and/or incomplete for both pharmaceuticals, depending on the organic matter content of the sample. However, still all transformation products could be detected for indomethacine in permanganate treated surface water samples, and two out of five in the case of diclofenac.