Marina G. Pintado-Herrera

Determining the distribution of triclosan and methyl triclosan in estuarine settings.

We have developed a method for the analysis of two sewage-derived contaminants: triclosan (TCS), an antibacterial agent, and methyl triclosan (MTCS), a TCS metabolite. For solid samples (4 g), extraction and cleanup were integrated into the same step using pressurized liquid extraction (PLE) with in-cell-clean-up (1g of florisil). The extraction was performed using dichloromethane at 100 °C, 1500 psi and 3 static extraction cycles of 5 min each. For water samples (100mL), stir bar sorptive extraction-liquid desorption (SBSE-LD) was used. Bars were stirred for 10h and analytes were later desorbed using acetonitrile. Finally, MTCS and a silylated derivative of TCS were determined by gas chromatography-mass spectrometry (GC-MS). Recovery experiments in water and sediments were performed and the results ranged from 67% to 78%. Limits of detection (LODs) were 5 ng L(-1) for TCS and 1 ng L(-1) for MTCS, in water samples, and 0.1 ng g(-1) for TCS and MTCS in solid samples. The method was applied then to determine the levels of these compounds in the estuary of Guadalete River (SW Spain). TCS and MTCS concentrations up to 9.6 ng g(-1) in sediments and 310 ng L(-1) in water were measured. Their distribution was strongly influenced by the presence of wastewater sources, treated and untreated, along the sampling area, where maximum concentrations were detected. Highest values were reached in the water column during low tides as the water volume in the estuary becomes lower.

Atmospheric pressure gas chromatography-time-of-flight-mass spectrometry (APGC-ToF-MS) for the determination of regulated and emerging contaminants in aqueous samples after stir bar sorptive extraction (SBSE).

This work presents the development, optimization and validation of a multi-residue method for the simultaneous determination of 102 contaminants, including fragrances, UV filters, repellents, endocrine disruptors, biocides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and several types of pesticides in aqueous matrices. Water samples were processed using stir bar sorptive extraction (SBSE) after the optimization of several parameters: agitation time, ionic strength, presence of organic modifiers, pH, and volume of the derivatizing agent. Target compounds were extracted from the bars by liquid desorption (LD). Separation, identification and quantification of analytes were carried out by gas chromatography (GC) coupled to time-of-flight (ToF-MS) mass spectrometry. A new ionization source, atmospheric pressure gas chromatography (APGC), was tested. The optimized protocol showed acceptable recovery percentages (50-100%) and limits of detection below 1ngL(-1) for most of the compounds. Occurrence of 21 out of 102 analytes was confirmed in several environmental aquatic matrices, including seawater, sewage effluent, river water and groundwater. Non-target compounds such as organophosphorus flame retardants were also identified in real samples by accurate mass measurement of their molecular ions using GC-APGC-ToF-MS. To the best of our knowledge, this is the first time that this technique has been applied for the analysis of contaminants in aquatic systems. By employing lower energy than the more widely used electron impact ionization (EI), AGPC provides significant advantages over EI for those substances very susceptible to high fragmentation (e.g., fragrances, pyrethroids).

Distribution, mass inventories, and ecological risk assessment of legacy and emerging contaminants in sediments from the Pearl River Estuary in China

This study focused on comparing the occurrences and environmental toxic risks for diverse priority and emerging contaminants (>100 chemicals) in the sediments from the Pearl River Estuary (PRE, China). The most predominant compounds were cationic surfactants, organophosphate flame retardants (e.g., triisobutylphosphate), and polycyclic aromatic hydrocarbons (PAHs), accounting for >75% of the total mass inventory (∼330 metric tons). Wastewater discharges seem to be one of the main sources of pollution in the area, as the highest concentrations (>1000ngg-1 for some chemicals) were reported in the upper part of the PRE (near Guangzhou city) and Macau. Highest levels of ultraviolet (UV) filters, however, were observed in recreational areas, revealing the importance of direct sources (e.g., outdoor activities). An environmental risk assessment showed that PAHs and dichlorodiphenyl dichloroethylene had the highest hazard quotient (HQ) values (up to 233). Nonylphenol, a metabolite from nonionic surfactant, and two UV filters (2-ethyl-hexyl-4-trimethoxycinnamate and 4-methylbenzylidene camphor) also posed a significant threat to benthic species (HQ>1). Further research through the realization of monitoring campaigns and toxicity tests is encouraged, as the exposure of the resident aquatic organisms and human population to these and other emerging chemicals is expected to increase over the years.

In-cell clean-up pressurized liquid extraction and gas chromatography-tandem mass spectrometry determination of hydrophobic persistent and emerging organic pollutants in coastal sediments.

The main goal of this work was to develop, optimize and validate a multi-residue method for the simultaneous determination of 97 contaminants, including fragrances, UV filters, repellents, endocrine disruptors, biocides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organophosphorus flame retardants, and several types of pesticides in marine sediment samples. Extraction and cleanup were integrated into the same step using pressurized liquid extraction (PLE) with in-cell clean-up (1g of alumina). The extraction was performed using dichloromethane at 100 °C, 1500 psi and 3 extraction cycles (5 min per cycle). Extracts were derivatized with N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA) to improve the signal and sensitivity of some target compounds (i.e., triclosan, 2-hydroxybenzophenone). Separation, identification and quantification of analytes were carried out by gas chromatography (GC) coupled to tandem mass spectrometry. Under optimal conditions, the optimized protocol showed good recovery percentages (70-100%), linearity (>0.99) and limits of detection below 1 ng g(-1) for all compounds. Finally, the method was applied to the analysis of sediment samples from different coastal areas from Andalusia (Spain), where occurrence and distribution of emerging contaminants in sediments is very scarce. Twenty five compounds out of 98 were detected in all samples, with the endocrine disruptor nonylphenol and the fragrance galaxolide showing the highest concentrations, up to 377.6 ng g(-1) and 237.4 ng g(-1), respectively.

Determination of silicone rubber and low‐density polyethylene diffusion and polymer/water partition coefficients for emerging contaminants

There is a growing interest in assessing the concentration and distribution of new nonregulated organic compounds (emerging contaminants) in the environment. The measurement of freely dissolved concentrations using conventional approaches is challenging because of the low concentrations that may be encountered and their temporally variable emissions. Absorption-based passive sampling enables the estimation of freely dissolved concentrations of hydrophobic contaminants of emerging concern in water. In the present study, calibration was undertaken for 2 polymers, low-density polyethylene (LDPE) and silicone rubber for 11 fragrances, 5 endocrine-disrupting compounds, 7 ultraviolet (UV) filters, and 8 organophosphate flame retardant compounds. Batch experiments were performed to estimate contaminant diffusion coefficients in the polymers (Dp ), which in general decreased with increasing molecular weight. The values for fragrances, endocrine-disrupting compounds, and UV filters were in ranges similar to those previously reported for polycyclic aromatic hydrocarbons, but were 1 order of magnitude lower for organophosphate flame retardant compounds. Silicone rubber had higher Dp values than LDPE and was therefore selected for further experiments to calculate polymer/water partition coefficients (KPW ). The authors observed a positive correlation between log KPW and log octanol/water partition coefficient values. Field testing of silicone rubber passive samplers was undertaken though exposure in the River Alna (Norway) for an exposure time of 21 d to estimate freely dissolved concentration. Some fragrances and UV filters were predominant over other emerging and regulated contaminants, at levels up to 1600 ng L(-1) for galaxolide and 448 ng L(-1) for octocrylene. Environ Toxicol Chem 2016;35:2162-2172.

Solvent bar micro-extraction (SBME) based determination of PAHs in seawater samples

Measuring the impact of PAHs in seawater samples is often difficult due to the low concentrations in which they appear and the complexity of the sample matrix. Traditional methods for sample preparation such as liquid-liquid extraction and solid phase extraction require the use of excessive amounts of solvents and reagents, and sample handling. In this work, hollow fiber liquid phase micro-extraction (HFLPME), in the configuration of solvent bar micro-extraction (SBME), was proposed as an environmentally friendly and more effective tool, for the extraction of the 16 priority PAHs from seawater samples. Extraction was conducted using hexane as a solvent. Enrichment factors from 45 to 163 were obtained after 60min at a stirring rate of 500rpm in the sample. Moreover, a negative linear relationship was observed between the enrichment factor and the molecular weight of the PAHs. Under optimized conditions, the limits of detection were in the range from 0.21 to 0.82ngL-1, the method showed a linear response up to 500μgL-1, and the average relative standard deviation for seawater samples spiked with 5ngL-1 was 11.6%. After calibration, the SBME was applied to extract PAHs in seawater samples from the Bay of Cadiz (SW Spain), showing an average recovery of 99%. In conclusion, the SBME is an environmentally friendly, one-step alternative for sample preparation in the determination of PAHs in seawater samples.

Effects of extreme rainfall events on the distribution of selected emerging contaminants in surface and groundwater: The Guadalete River basin (SW, Spain)

This study is focused on the Guadalete River basin (SW, Spain), where extreme weather conditions have become common, with and alternation between periods of drought and extreme rainfall events. Combined sewer overflows (CSOs) occur when heavy rainfall events exceed the capacity of the wastewater treatment plants (WWTP), as well as pollution episodes in parts of the basin due to uncontrolled sewage spills and the use of reclaimed water and sludge from the local WWTP. The sampling was carried out along two seasons and three campaigns during dry (March 2007) and extreme rainfall (April and December 2010) in the Guadalete River, alluvial aquifer and Jerez de la Frontera aquifer. Results showed minimum concentrations for synthetic surfactants in groundwater (<37.4μg·L-1) during the first campaign (dry weather conditions), whereas groundwater contaminants increased in December 2010 as the heavy rainfall caused the river to overflow. In surface water, surfactant concentrations showed similar trends to groundwater observations. In addition to surfactants, pharmaceuticals and personal care products (PPCPs) were analyzed in the third campaign, 22 of which were detected in surface waters. Two fragrances (OTNE and galaxolide) and one analgesic/anti-inflammatory (ibuprofen) were the most abundant PPCPs (up to 6540, 2748 and 1747ng·L-1, respectively). Regarding groundwater, most PPCPs were detected in Jerez de la Frontera aquifer, where a synthetic fragrance (OTNE) was predominant (up to 1285ng·L-1).

Biochemical responses of Solea senegalensis after continuous flow exposure to urban effluents

Urban effluent potential toxicity was assessed by a battery of biomarkers aimed at determining sub-lethal effects after continuous exposure on the marine organism Solea senegalensis. Specimens were exposed to five effluent concentrations (1/2, 1/4, 1/8, 1/16, 1/32) during 7-days, simulating the dispersion plume at the discharge point. Three different groups of biomarkers were selected in the present study: biomarkers of exposure (Phase I: EROD and DBF; Phase II: GST), biomarkers with antioxidant responses (GR and GPX) and biomarkers of effects (DNA damage and LPO). Additionally, a biological depuration treatment (photobiotreatment (PhtBio)) was tested in order to reduce the adverse effects on aquatic organisms. Effluent exposure caused sub-lethal responses in juvenile fish suggesting oxidative stress. After PhtBio application, concentrations of the major part of measured contaminants were reduced, as well as their bioavailability and adverse effects.

Are the TiO2 NPs a “Trojan horse” for personal care products (PCPs) in the clam Ruditapes philippinarum?

In recent years, increasing quantities of personal care products (PCPs) are being released into the environment. However, data about bioaccumulation and toxicity are scarce; and extraction and analytical approaches are not well developed. In this work, the marine clam Ruditapes philippinarum, selected as model organism, has been employed to investigate bioaccumulation, antioxidant enzyme activities and DNA damage due to exposure to TiO2 nanoparticles and bulk TiO2 (inorganic compounds that are frequent components of PCPs, plastics, paints and coatings, foods and disinfectant water treatments). We have also studied the joint effect of both forms of inorganic TiO2 combined with four organic compounds (mixture exposures) commonly used in PCPs: an antimicrobial (triclosan), a fragrance (OTNE) and two UV filters (benzophenone-3 and octocrylene). Bioaccumulation of the inorganic compound, TiO2, was almost immediate and constant over exposure time. With respect to the organic compounds in mixtures, they were mediated by TiO2 and bioaccumulation is driven by reduced size of the particles. In fact, nanoparticles can be considered as a vector to organic compounds, such as triclosan and benzophenone-3. After a week of depuration, TiO2 NPs and TiO2 bulk in clams showed similar levels of concentration. Some organic compounds with bioactivity (Log Kow >3), like OTNE, showed low depuration after one week. The joint action of the organic compound mixture and either of the two forms of TiO2 provoked changes in enzyme activity responses. However, for the mixtures, DNA damage was found only after the depuration period.

Determination of Pharmaceuticals in Coastal Systems Using Solid Phase Extraction (SPE) Followed by Ultra Performance Liquid Chromatography – tandem Mass Spectrometry (UPLC-MS/MS)

This paper describes the optimization and validation of an analytical method for the determination of 83 13 pharmaceutically active compounds (PhACs) in aqueous samples using solid-phase extraction (SPE) followed by 14 ultra performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-QqQ-MS/MS). First, several 15 experiments were conducted to optimize different SPE extraction parameters such as pH, elution solvents, and 16 Na2EDTA addition. Extraction recovery percentages were between 17 and 146%, being higher than 70% for 47 target 17 analytes. The method limits of detection (LOD) and quantification (LOQ) were below 1 ng L for most compounds 18 (> 90%), and the precision of the method, calculated as the relative standard deviation (RSD) of replicate extractions 19 and analyses, was less than 20%. The optimized method was successfully applied to the analysis of real water 20 samples in estuarine and coastal systems from SW Spain (Cadiz Bay and Huelva Estuary). 49 out of 83 target 21 compounds were found in 75% of samples. Ibuprofen, atenolol, gemfibrozil and caffeine were the most commonly 22 substances detected, reaching concentrations up to 195 ng L. These are among the first data available on the 23 occurrence of a wide range of pharmaceuticals in European coastal waters. 24