Determination of uptake kinetics and sampling rates for 56 organic micropollutants using “pharmaceutical” POCIS

Characterization of The Permeation Properties of Membrane Filters and Sorption Properties of Sorbents Used for Polar Organic Chemical Integrative Samplers

Polar organic chemical integrative samplers (POCIS) are promising devices for measuring the time-weighted average concentrations of hydrophilic compounds in aquatic environments. However, the mechanisms underlying compound uptake by POCIS remain unclear. We investigated the permeation kinetics of polyethersulfone and polytetrafluoroethylene membrane filters, and the sorption kinetics of Oasis HLB (Waters), Envi-Carb (Supelco), and Oasis WAX (Waters) sorbents. The log octanol-water partition coefficient (KOW) values of the 19 targeted compounds ranged from -0.55 to 6.0. The overall mass-transfer coefficients were negatively correlated with KOW, indicating that interactions between hydrophobic compounds and the membrane inhibit permeation. The sorption rate coefficient showed no correlation with KOW and depended on the type of sorbent used. These results imply that the uptake of highly hydrophilic compounds by POCIS is determined by both the membrane and the sorbent kinetics; however, membrane kinetics dominate the uptake of hydrophobic compounds. Environ Toxicol Chem 2024;43:2115-2121. © 2024 SETAC.

Identification of new endocrine disruptive transthyretin ligands in polluted waters using pull-down assay coupled to non-target mass spectrometry

Surface and treated wastewater are contaminated with highly complex mixtures of micropollutants, which may cause numerous adverse effects, often mediated by endocrine disruption. However, there is limited knowledge regarding some important modes of action, such as interference with thyroid hormone (TH) regulation, and the compounds driving these effects. This study describes an effective approach for the identification of compounds with the potential to bind to transthyretin (TTR; protein distributing TH to target tissues), based on their specific separation in a pull-down assay followed by non-target analysis (NTA). The method was optimized with known TTR ligands and applied to complex water samples. The specific separation of TTR ligands provided a substantial reduction of chromatographic features from the original samples. The applied NTA workflow resulted in the identification of 34 structures. Twelve compounds with available standards were quantified in the original extracts and their TH-displacement potency was confirmed. Eleven compounds were discovered as TTR binders for the first time and linear alkylbenzene sulfonates (LAS) were highlighted as contaminants of concern. Pull-down assay combined with NTA proved to be a well-functioning approach for the identification of unknown bioactive compounds in complex mixtures with great application potential across various biological targets and environmental compartments.

Wastewater and seawater monitoring in Antarctica: Passive sampling as a powerful strategy to evaluate emerging pollution

The Ross Sea, among the least human-impacted marine environments worldwide, recently became the first marine protected area in Antarctica. To assess the impact of the Italian research station Mario Zucchelli (MZS) on the surrounding waters, passive sampling - as well as spot sampling for comparison - took place in the effluent of the wastewater treatment plant (WWTP) and the receiving surface marine waters. Polar Organic Chemical Integrative Samplers (POCIS) were deployed for six consecutive 2-week periods from November to February in a reservoir collecting the wastewater effluent. Passive samplers were also deployed at shallow depth offshore from the wastewater effluent outlet from MZS for two separate 3-week periods (November 2021 and January 2022). Grab water samples were collected alongside each POCIS deployment, for comparison with passive sampling results. POCIS, used for the first time in Antarctica, demonstrated to be advantageous to estimate time-averaged concentrations in waters and the results were comparable to those obtained by repeated spot samplings. Among the 23 studied ECs - including drugs, UV-filters, perfluorinated substances, caffeine - 15 were detected in both grab and passive sampling in the WWTP effluent and followed similar concentration profiles in both types of sampling. High concentrations of caffeine, naproxen and ketoprofen in the dozens of μg L-1 were detected. Other compounds, including drugs and several UV filters, were detected down to sub- μg L-1 concentrations. In marine waters close to the effluent output, only traces of a drug (4.8 ng L-1) and two UV filters (up to 0.04 μg L-1) were quantified.

Proposal of a new empirical model with flow velocity to improve time-weighted average concentration estimates from the Polar Organic Chemical Integrative Samplers

It is now widely recognized that the sampling rate of Polar Organic Chemical Integrative Samplers (POCIS) is significantly affected by flow velocity, which can cause a consequent bias when determining time-weighted average concentrations (TWAC). We already observed the desorption of deisopropylatrazine (DIA) over time when added to the receiving phase of a POCIS. This desorption rate was particularly influenced by flow velocity, in an agitated water environment in situ. In the method presented here, we calibrated 30 pesticides under controlled laboratory conditions, varying the flow velocity over four levels. We simultaneously studied the desorption rate of DIA-d5 (a deuterated form of DIA) over time. An empirical model based on a power law involving flow velocity was used to process the information from the accumulation kinetics of the compounds of interest and elimination of DIA-d5. This type of model makes it possible to consider the effect of this crucial factor on exchange kinetics, and then to obtain more accurate TWACs with reduced bias and more acceptable dispersion of results.

Pharmaceutical and pesticide mixtures in a Mediterranean coastal wetland: comparison of sampling methods, ecological risks, and removal by a constructed wetland

Pharmaceuticals and pesticides can be considered hazardous compounds for Mediterranean coastal wetland ecosystems. Although many of these compounds co-occur in environmental samples, only a few studies have been dedicated to assessing the ecotoxicological risks of complex contaminant mixtures. We evaluated the occurrence of 133 pharmaceuticals and pesticides in 12 sites in a protected Mediterranean wetland, the Albufera Natural Park (ANP), based on conventional grab sampling and polar organic chemical integrative samplers (POCIS). We assessed acute and chronic ecological risks posed by these contaminant mixtures using the multi-substance Potentially Affected Fraction (msPAF) approach and investigated the capacity of a constructed wetland to reduce chemical exposure and risks. This study shows that pharmaceuticals and pesticides are widespread contaminants in the ANP, with samples containing up to 75 different compounds. POCIS samplers were found to be useful for the determination of less predictable exposure profiles of pesticides occurring at the end of the rice cultivation cycle, while POCIS and grab samples provide an accurate method to determine (semi-)continuous pharmaceutical exposure. Acute risks were identified in one sample, while chronic risks were determined in most of the collected samples, with 5-25% of aquatic species being potentially affected. The compounds that contributed to the chronic risks were azoxystrobin, ibuprofen, furosemide, caffeine, and some insecticides (diazinon, imidacloprid, and acetamiprid). The evaluated constructed wetland reduced contaminant loads by 45-73% and reduced the faction of species affected from 25 to 6%. Our study highlights the need of addressing contaminant mixture effects in Mediterranean wetlands and supports the use of constructed wetlands to reduce contaminant loads and risks in areas with high anthropogenic pressure.

Performance comparison of three passive samplers for monitoring of polar organic contaminants in treated municipal wastewater

Over the past decades, several types of passive samplers have been developed and used to monitor polar organic compounds in aquatic environments. These samplers use different sorbents and barriers to control the uptake into the sampler, but their performance comparison is usually not well investigated. This study aimed to directly compare the performance of three samplers, i.e., the Polar Organic Chemical Integrative Sampler (POCIS), the Hydrogel-based Passive Sampler (HPS, an upscaled version of o-DGT), and the Speedisk, on a diverse suite of pharmaceuticals, per- and polyfluoroalkylated substances (PFAS), and pesticides and their metabolites. The samplers were deployed side-by-side in the treated effluent of a municipal wastewater treatment plant for different exposure times. All samplers accumulated a comparable number of compounds, and integrative uptake was observed for most compounds detected up to 28 days for POCIS, up to 14 days for HPS, and up to 42 days for Speedisk. In the integrative uptake phase, consistent surface-specific uptake was observed with a significant correlation between samplers (r ≥ 0.76) despite differences in sampler construction, diffusion barrier, and sorbent material used. The low sampling rates compared to the literature and the low estimated overall mass transfer coefficient suggests that the water boundary layer was the main barrier controlling the uptake for all samplers. Although all devices provided comparable performance, Speedisk overcomes POCIS and HPS in several criteria, including time-integrative sampling over a long period and physical durability.

Examining the applicability of polar organic chemical integrative sampler for long-term monitoring of groundwater contamination caused by currently used pesticides

The possibilities of expanding a groundwater quality monitoring scheme by passive sampling using polar organic chemical integrative sampler (POCIS) comprising HLB sorbent as the receiving phase were explored. Passive sampling and grab sampling were carried out simultaneously in the regions with vulnerable groundwater resources in Slovakia, between 2013 and 2021. For 27 pesticides and degradation products detected both in POCIS and the grab samples, in situ sampling rates were calculated and statistically evaluated. The limited effectiveness of the receiving phase in POCIS for sampling polar or ionized compounds was confirmed through a comparison of the medians of compound-specific sampling rates. For the majority of the monitored compounds the median sampling rates varied between 0.01 and 0.035 L/day. In some cases, the actual in situ values could be confirmed by parallel exposure of POCIS and silicone rubber sheet employed to obtain a benchmark for maximum attainable sampling rate. Sampling site and sampling period appear to have also some influence on the sampling rates, which was attributed in part to the groundwater velocity varying in both space and time. The influence of physico-chemical parameters (temperature, pH, electrolytic conductivity) remains mostly questionable due to the naturally limited ranges of recorded values over the entire duration of the study. Concentrations of pollutants in POCIS could be used for predicting time weighed average concentrations in water, provided the sampling rates were known and relatively constant. Generally, the compound-specific sampling rate cannot be considered constant due to a combination of naturally varying environmental factors that influence the actual in situ sampling rate. The relative standard deviation of concentration data from POCIS exposed in triplicates varied between approx. 5 %-50 %. Utilizing exploratory data analysis approach and tools enabled us to obtain a relatively complex picture of the situation and progress regarding pesticide pollution of groundwater in the monitored areas.

Calibration comparison between two passive samplers -o-DGT and POCIS- for 109 hydrophilic emerging and priority organic compounds

The Polar Organic Chemical Integrative Samplers (POCIS) is the most widely used passive sampler for hydrophilic compounds, but unsuitable for certain ionic organic contaminants. The Diffusive Gradient in Thin-Film technique (o-DGT) has shown positive results for both ionic and hydrophilic compounds. However, a calibration step is now needed to evaluate kinetic constant of accumulation for a wide range of molecules. In this study, o-DGT and POCIS were compared for the sampling of three families of micropollutants of potential risk to aquatic environments: 53 pesticides, 36 pharmaceuticals and 20 hormones. A calibration experiment was conducted to compare the kinetic models and constants from a scientific and practical perspective. The results are discussed in a single table that summarizes the performance of both passive samplers for the 109 compounds of interest. The advantage of o-DGT is that it allows linear accumulation for 72 compounds versus only 33 with POCIS. The mean times to equilibrium obtained with o-DGT are higher than those obtained with POCIS. These results confirm that the presence of a diffusion gel delays the achievement of equilibrium during compound accumulation. Therefore, o-DGT can be considered for situations where POCIS cannot be used due to non-linear accumulation over a typical 14-day deployment period. However, overall sampling rates and mass transfer coefficients also appear reduced with o-DGT, which is explained by the smaller exchange surface area, as well as the consideration of an additional diffusive layer in this device. This paper also showed that the most appropriate membrane to sample polar compounds with o-DGT was a polyethersulfone polymer with a pore size of 5 μm.

Implications of polar organic chemical integrative sampler for high membrane sorption and suitability of polyethersulfone as a single-phase sampler

Polar organic chemical integrative sampler (POCIS) contains sorbent, which is typically enclosed between two polyethersulfones (PES) membranes. A significant PES uptake is reported for many contaminants, yet, aqueous concentration is mainly correlated with the sorbent uptake using first-order kinetics. Under high PES sorption, the first-order kinetics often provide erroneous sampling rate for the sorbent phase due to increased membrane resistance. This work evaluated the uptake of four high PES sorbing chemicals, i.e., three Cl- and CH₃-substituted nitrobenzenes and one chlorinated aniline using POCIS and the potential of a single-phase PES sampler using laboratory experiments. POCIS calibration results demonstrated that both sorbent and membrane had similar affinity for the target compounds. A rapid PES sorption occurred in the earlier days (<7 days) followed by a gradual increase in the PES phase concentration (equilibrium not achieved after 60 days). Especially, the membrane was the primary sink for 3,4-dichloroaniline and 3,4-dichloronitrobenzene for up to 14 and 31 days, respectively. On the other hand, the single-phase PES sampler showed similar mass uptake as POCIS and reached equilibrium within 19 days under static condition, indicating its potential suitability in the equilibrium regime. PES-water partition coefficient of the target compounds was between 1.2 and 6.5 L/g. Finally, we present a poly-parameter linear-free energy relationship (pp-LFER) using published data to predict the PES-water partition coefficients. The pp-LFER models showed moderate predictability as indicated by R²_adj values between 0.7 and 0.9 for both internal and external data set consisting of a wide range of hydrophobic and hydrophilic compounds (-0.1 ≤ logK_OW ≤ 7.4). The proposed pp-LFER model can be used to screen high PES-sorbing chemicals to increase the reliability and accuracy of aqueous concentration prediction from POCIS sampling and to select the most appropriate sampling approach for new compounds.

A Review of In Situ Methods-Solid Phase Adsorption Toxin Tracking (SPATT) and Polar Organic Chemical Integrative Sampler (POCIS) for the Collection and Concentration of Marine Biotoxins and Pharmaceuticals in Environmental Waters

Solid Phase Adsorption Toxin Tracking (SPATT) and Polar Organic Chemical Integrative Sampler (POCIS) are in situ methods that have been applied to pre-concentrate a range of marine toxins, pesticides and pharmaceutical compounds that occur at low levels in marine and environmental waters. Recent research has identified the widespread distribution of biotoxins and pharmaceuticals in environmental waters (marine, brackish and freshwater) highlighting the need for the development of effective techniques to generate accurate quantitative water system profiles. In this manuscript, we reviewed in situ methods known as Solid Phase Adsorption Toxin Tracking (SPATT) and Polar Organic Chemical Integrative Sampler (POCIS) for the collection and concentration of marine biotoxins, freshwater cyanotoxins and pharmaceuticals in environmental waters since the 1980s to present. Twelve different adsorption substrates in SPATT and 18 different sorbents in POCIS were reviewed for their ability to absorb a range of lipophilic and hydrophilic marine biotoxins, pharmaceuticals, pesticides, antibiotics and microcystins in marine water, freshwater and wastewater. This review suggests the gaps in reported studies, outlines future research possibilities and guides researchers who wish to work on water contaminates using Solid Phase Adsorption Toxin Tracking (SPATT) and Polar Organic Chemical Integrative Sampler (POCIS) technologies.

Long-term monitoring of drug consumption patterns during the COVID-19 pandemic in a small-sized community in Brazil through wastewater-based epidemiology

The abuse of legal and illegal drugs is a global public health problem, also affecting the social and economic well-being of the population. Thus, there is a significant interest in monitoring drug consumption. Relevant epidemiological information on lifestyle habits can be obtained from the chemical analysis of urban wastewater. In this work, passive sampling using polar organic chemical integrative samplers (POCIS) was used to quantify licit and illicit drugs biomarkers in wastewater for the application of wastewater-based epidemiology (WBE). In this WBE study, a small urban community of approximately 1179 inhabitants was monitored from 18 March 2020 to 3 March 2021, covering the mobility restriction and flexibilization periods of the COVID-19 pandemic in Brazil. Consumption was estimated for amphetamine, caffeine, cocaine, MDMA, methamphetamine, nicotine, and THC. The highest estimated consumption among illicit drugs was for THC (2369 ± 1037 mg day-1 1000 inh-1) followed by cocaine (353 ± 192 mg day-1 1000 inh-1). There was a negative correlation between consumption of caffeine, cocaine, MDMA, nicotine, and THC with human mobility, expressed by cellular phone mobility reports (P-value = 0.0094, 0.0019, 0.0080, 0.0009, and 0.0133, respectively). Our study is the first long-term drug consumption evaluation during the COVID-19 pandemic, with continuous sampling for almost a whole year. The observed reduction in consumption of both licit and illicit drugs is probably associated with stay-at-home orders and reduced access, which can be due to the closure of commercial facilities during some time of the evaluated period, smaller drug supply, and reduced income of the population due to the shutdown of companies and unemployment. The assay described in this study can be used as a complementary and cost-effective tool to the long-term monitoring of drug use biomarkers in wastewater, a relevant epidemiological strategy currently limited to short collection times.

Nanostructured Hypercrosslinked Porous Organic Polymers: Morphological Evolution and Rapid Separation of Polar Organic Micropollutants

Nanostructured hypercrosslinked porous organic polymers have triggered immense research interest for a broad spectrum of applications ranging from catalysis to molecular separation. However, it still remains a challenge to tune their nanoscale morphology. Herein, we demonstrated a remarkable variation of morphologies of triptycene-based hypercrosslinked microporous polymers starting from irregular aggregates (FCTP) to rigid spheres (SCTP) to two-dimensional nanosheets (SKTP) from three distinct polymerization methodologies, Friedel-Crafts knitting using an external crosslinker, Scholl reaction, and solvent knitting, respectively. Further, the dramatic role of reaction temperatures, catalysts, and solvents resulting in well-defined morphologies was elucidated. Mechanistic investigations coupled with microscopic and computational studies revealed the evolution of 2D nanosheets of a highly porous solvent-knitted polymer (SKTP, 2385 m² g^-1), resulting from the sequential hierarchical self-assembly of nanospheres and nanoribbons. A structure-activity correlation of hypercrosslinked polymers and their sulfonated counterparts for the removal of toxic polar organic micropollutants from water was delineated based on the chemical functionalities, specific surface area, pore size distribution, dispersity, and nanoscale morphology. Furthermore, a sulfonated 2D sheet-like solvent-knitted polymer (SKTPS) exhibited rapid adsorption kinetics (within 30 s) for a large array of polar organic micropollutants, including plastic components, steroids, antibiotic drugs, herbicides, and pesticides with remarkable uptake capacity and excellent recyclability. The current study provides the impetus for designing morphology-controlled functionalized porous polymers for task-specific applications.

Lab-scale investigation of the ability of Polar Organic Chemical Integrative Sampler to catch short pesticide contamination peaks

In this lab-scale study, the POCIS capacity to integrate short contamination peaks of variable intensity and duration was evaluated. POCIS were immersed for 14 days in tanks filled with tap water and spiked at different concentrations with 12 pesticides of various polarities (log K_ow = 1.1-4.7) and classes (herbicides, fungicides, and insecticides). Concentrations were kept relatively constant at 1 μg L^-1 and 5 μg L^-1, respectively, in two "background" exposure tanks. Three contamination peaks of increasing intensity and decreasing duration were simulated (10 μg L^-1 for 24 h, 40 μg L^-1 for 6 h, and 60 μg L^-1 for 1 h). This lab-scale study demonstrated that ten moderately polar compounds (2 < log K_ow < 4) showed a linear uptake, as observed in previous studies, while a non-linear model fits the data of the two most polar pesticides (log K_ow < 2). Depending on chemical polarity, some compounds exhibited a "burst effect" or "lag effect" during the first 3 days of exposure. After 14 days of exposure, contamination peaks appeared integrated for seven compounds, showing the ability of POCIS to catch very short pollution events and to provide acceptable time-weighted average concentration estimates under laboratory-controlled conditions.

Spatiotemporal trends and annual fluxes of pharmaceuticals in a Scottish priority catchment

Pharmaceuticals (a class of emerging contaminants) are continuously introduced into effluent-receiving surface waters due to their incomplete removal within wastewater treatment plants (WWTPs). This work investigated the presence and distribution of eight commonly used human pharmaceuticals in the River Dee (Scotland, UK), a Scottish Environment Protection Agency priority catchment that is a conservation site and important raw water source. Grab sampling and passive sampling (Polar Organic Chemical Integrative Sampler, POCIS) was performed over 12 months, targeting: paracetamol, ibuprofen, and diclofenac (analgesics/anti-inflammatories); clarithromycin and trimethoprim (antibiotics); carbamazepine and fluoxetine (psychoactive drugs); and 17α-ethynylestradiol (estrogen hormone). Sampling sites spanned from the river's rural source to the heavily urbanised estuary into the North Sea. Ibuprofen (ranging 0.8-697 ng/L), paracetamol (ranging 4-658 ng/L), trimethoprim (ranging 3-505 ng/L), diclofenac (ranging 2-324 ng/L) and carbamazepine (ranging 1-222 ng/L) were consistently detected at the highest concentrations through grab sampling, with concentrations generally increasing down river with increasing urbanisation. However, POCIS revealed trace contamination of most compounds throughout the river (commonly <0.5 ng/L), indicating pollution may be related to diffuse sources. Analysis of river flows revealed that low flow and warm seasons corresponded to statistically significantly higher concentrations of diclofenac and carbamazepine, two compounds of environmental and regulatory concern. Below the largest WWTP, annual average fluxes ranged 0.1 kg/yr (clarithromycin) to 143.8 kg/yr (paracetamol), with 226.2 kg/yr for total target compounds. It was estimated that this source contributed >70% of the total mass loads (dissolved phase) of the target compounds in the river. As the River Dee is an important raw water source and conservation site, additional catchment monitoring is warranted to safeguard water quality and assess environmental risk of emerging contaminants, particularly in relation to unusual weather patterns, climate change and population growth.

Evaluation of Illicit Drug Consumption by Wastewater Analysis Using Polar Organic Chemical Integrative Sampler as a Monitoring Tool

Illicit drug abuse is a worldwide social and health problem, and monitoring illicit drug use is of paramount importance in the context of public policies. It is already known that relevant epidemiologic information can be obtained from the analysis of urban residual waters. This approach, named wastewater-based epidemiology (WBE), is based on the measurement of specific markers, resulting from human biotransformation of the target drugs, as indicators of the consumption of the compounds by the population served by the wastewater treatment installation under investigation. Drug consumption estimation based on WBE requires sewage sampling strategies that express the concentrations along the whole time period of time. To this end, the most common approach is the use of automatic composite samplers. However, this active sampling procedure is costly, especially for long-term studies and in limited-resources settings. An alternative, cost-effective, sampling strategy is the use of passive samplers, like the polar organic chemical integrative sampler (POCIS). POCIS sampling has already been applied to the estimation of exposure to pharmaceuticals, pesticides, and some drugs of abuse, and some studies evaluated the comparative performances of POCIS and automatic composite samplers. In this context, this manuscript aims to review the most important biomarkers of drugs of abuse consumption in wastewater, the fundamentals of POCIS sampling in WBE, the previous application of POCIS for WBE of drugs of abuse, and to discuss the advantages and disadvantages of POCIS sampling, in comparison with other strategies used in WBE. POCIS sampling is an effective strategy to obtain a representative overview of biomarker concentrations in sewage over time, with a small number of analyzed samples, increased detection limits, with lower costs than active sampling. Just a few studies applied POCIS sampling for WBE of drugs of abuse, but the available data support the use of POCIS as a valuable tool for the long-term monitoring of the consumption of certain drugs within a defined population, particularly in limited-resources settings.

Limitations of Integrative Passive Samplers as a Tool for the Quantification of Pharmaceuticals in the Environment - A Critical Review with the Latest Innovations

This review starts with a presentation of the theory of kinetic uptake by passive sampling (PS), which is traditionally used to distinguish between integrative and equilibrium samplers. Demonstrated limitations of this model for the passive sampling of pharmaceuticals from water were presented. Most notably, the contribution of the protective membrane in the resistance to mass transfer of lipophilic analytes and the well documented effect of external parameters on sampling rates contributed to the greatest uncertainty in PS application. The diffusion gradient in thin layer (DGT) technique seems to reduce the effect of external parameters (e.g., flow rate) to some degree. The laboratory-determined integrative uptake periods over defined sampler deployments was compared, and the discrepancy found suggests that the most popular Polar Organic Chemical Integrative Sampler (POCIS) could in some cases utilized as an equilibrium sampler. This assertion is supported by own calculations for three pharmaceuticals with extremely different lipophilic characters. Finally, the reasons performance reference compounds (PRCs) are not recommended for the reduction in uncertainty of the TWAC found by adsorptive samplers were presented. It was concluded that techniques of passive sampling of pharmaceuticals need a new uptake model to fit the current situation.

Impact of environmental factors on the sampling rate of β-blockers and sulfonamides from water by a carbon nanotube-passive sampler

Passive techniques are a constantly evolving approach to the long-term monitoring of micropollutants, including pharmaceuticals, in the aquatic environment. This paper presents, for the first time, the calibration results of a new CNTs-PSDs (carbon nanotubes used as a sorbent in passive sampling devices) with an examination of the effect of donor phase salinity, water pH and the concentration of dissolved humic acids (DHAs), using both ultrapure and environmental waters. Sampling rates (R_s) were determined for the developed kinetic samplers. It has been observed that the impact of the examined environmental factors on the R_s values strictly depends on the type of the analytes. In the case of β-blockers, the only environmental parameter affecting their uptake rate was the salinity of water. A certain relationship was noted, namely the higher the salt concentration in water, the lower the R_s values of β-blockers. In the case of sulfonamides, water salinity, water pH 7-9 and DHAs concentration decreased the uptake rate of these compounds by CNTs-PSDs. The determined R_s values differed in particular when the values obtained from the experiments carried out using ultrapure water and environmental waters were compared. The general conclusion is that the calibration of novel CNTs-PSDs should be carried out under physicochemical conditions of the aquatic phase that are similar to the environmental matrix.

Comparative field study on bioassay responses and micropollutant uptake of POCIS, Speedisk and SorbiCell polar passive samplers

Routine water quality monitoring is generally performed with chemical analyses of grab samples, which has major limitations. First, snapshot samples will not give a good representation of the water quality. Second, it is not sufficient to analyze only a limited number of (priority) pollutants. These limitations can be circumvented by an alternative environmental risk assessment that combines time-integrated passive sampling (PS) with effect-based methods. This study aimed to select which of three polar PS devices was best suited for effect-based monitoring strategies. In the first part of this study, Speedisk, SorbiCell and POCIS polar PS devices were compared by simultaneous deployment at five sites. Chemical analyses of 108 moderately polar compounds (-1.82 < log D < 6.28) revealed that highest number of compounds, with the widest range of log K_OW, log D and pKa, were detected in extracts of POCIS, followed by Speedisk. SorbiCell samplers accumulated the lowest numbers and concentrations of compounds, so they were not further investigated. In a follow-up study, bioassay responses were compared in extracts of POCIS and Speedisk devices deployed at eight sites. The passive sampler extracts were subjected to bioassays for non-specific toxicity, endocrine disruption, and antibiotics activities. More frequent and higher responses were induced by POCIS extracts, leading to more exceedances of effect-based trigger values for environmental risks. As POCIS outperformed Speedisk, it is better suited as PS device targeting polar compounds for semi-quantitative effect-based water quality monitoring.

In situ calibration of polar organic chemical integrative sampler (POCIS) for monitoring of pharmaceuticals in surface waters

POCIS is the most widely applied passive sampler of polar organic substances, because it was one of the first commercially available samplers for that purpose on the market, but also for its applicability for a wide range of substances and conditions. Its main weakness is the variability of sampling performance with exposure conditions. In our study we took a pragmatic approach and performed in situ calibration for a set of 76 pharmaceuticals and their metabolites in five sampling campaigns in surface water, covering various temperature and flow conditions. In individual campaigns, R_S were calculated for up to 47 compounds ranging from 0.01 to 0.63 L d^-1, with the overall median value of 0.10 L d^-1. No clear changes of R_S with water temperature or discharge could be found for any of the investigated substances. The absence of correlation of experimental R_S with physical-chemical properties in combination with the lack of mechanistic understanding of compound uptake to POCIS implies that practical estimation of aqueous concentrations from uptake in POCIS depends on compound-specific experimental calibration data. Performance of POCIS was compared with grab sampling of water in seven field campaigns comprising multiple sampling sites, where sampling by both methods was done in parallel. The comparison showed that for 25 of 36 tested compounds more than 50% of POCIS-derived aqueous concentrations did not differ from median of grab sampling values more than by a factor of 2. Further, for 30 of 36 compounds, more than 80% of POCIS data did not differ from grab sampling data more than by a factor of 5. When accepting this level of accuracy, in situ derived sampling rates are sufficiently robust for application of POCIS for identification of spatial and temporal contamination trends in surface waters.

Sampling rates for passive samplers exposed to a field-relevant peak of 42 organic pesticides

Pesticide concentrations in agricultural streams are often characterised by a low level of baseline exposure and episodic peak concentrations associated with heavy rainfall events. Traditional sampling methods such as grab sampling, which are still largely used in governmental monitoring, typically miss peak concentrations. Passive sampling represents a cost-efficient alternative but requires the additional determination of sampling rates to calculate time-weighted average (TWA) water concentrations from the accumulated pesticide mass in the sampler. To date, sampling rates have largely been determined in experiments with constant exposure, which does not necessarily reflect field situations. Using Empore styrene-divinylbenzene (SDB) passive sampler disks mounted in metal holders, we determined sampling rates for 42 organic pesticides, of which 27 sampling rates were lacking before. The SDB disks were in an artificial channel system exposed to a field-relevant pesticide peak. We used an open-source algorithm to estimate coefficients of equations for the accumulated pesticide mass in disks and to determine exposure time-dependent sampling rates. These sampling rates ranged from 0.02 to 0.98 L d^-1 and corresponded to those from previous studies determined with constant exposure. The prediction of sampling rates using compound properties was unreliable. Hence, experiments are required to determine reliable sampling rates. We discuss the use of passive sampling to estimate peak concentrations. Overall, our study provides sampling rates and computer code to determine these under peak exposure designs and suggests that passive sampling is suitable to estimate peak pesticide concentrations in field studies.

Sampling Rate of Polar Organic Chemical Integrative Sampler (POCIS): Influence Factors and Calibration Methods

As a passive sampling device, the polar organic chemical integrative sampler (POCIS) has the characteristics of simple operation, safety, and reliability for assessing the occurrence and risk of persistent and emerging trace organic pollutants. The POCIS, allowing for the determination of time-weighted average (TWA) concentration of polar organic chemicals, exhibits good application prospects in aquatic environments. Before deploying the device in water, the sampling rate (Rs), which is a key parameter for characterizing pollutant enrichment, should be determined and calibrated accurately. However, the Rs values strongly depend on experimental hydrodynamic conditions. This paper provides an overview of the current situation of the POCIS for environmental monitoring of organic pollutants in an aquatic system. The principle and theory of the POCIS are outlined. In particular, the effect factors such as the ambient conditions, pollutant properties, and device features on the Rs are analyzed in detail from aspects of impact dependence and mechanisms. The calibration methods of the Rs under laboratory and in situ conditions are summarized. This review offers supplementary information on comprehensive understanding of mechanism and application of the POCIS. Nevertheless, the Rs were impacted by a combined effect of solute–sorbent–membrane–solution, and the influence extent of each variable was still unclear. On this basis, the ongoing challenges are proposed for the future application of the POCIS in the actual environment, for instance, the need for this device to be improved in terms of quantitative methods for more accurate measurement of the Rs.

Detection of pharmaceuticals in wastewater effluents-a comparison of the performance of Chemcatcher® and polar organic compound integrative sampler

Chemcatcher^® and POCIS passive sampling devices are widely used for monitoring polar organic pollutants in water. Chemcatcher^® uses a bound Horizon Atlantic™ HLB-L sorbent disk as receiving phase, whilst the POCIS uses the same material in the form of loose powder. Both devices (n = 3) were deployed for 21 days in the final effluent at three wastewater treatment plants in South Wales, UK. Following deployment, sampler extracts were analysed using liquid chromatography time-of-flight mass spectrometry. Compounds were identified using an in-house database of pharmaceuticals using a metabolomics workflow. Sixty-eight compounds were identified in all samplers. For the POCIS, substantial losses of sorbent (11-51%) were found during deployment and subsequent laboratory analysis, necessitating the use of a recovery factor. Percentage relative standard deviations varied (with 10 compounds exceeding 30% in both samplers) between individual compounds and between samplers deployed at the three sites. The relative performance of the two devices was evaluated using the mass of analyte sequestered, measured as an integrated peak area. The ratio of the uptake of the pharmaceuticals for the POCIS versus Chemcatcher^® was lower (1.84x) than would be expected on the basis of the ratio of active sampling areas (3.01x) of the two devices. The lower than predicted uptake may be attributable to the loose sorbent material moving inside the POCIS when deployed in the field in the vertical plane. In order to overcome this, it is recommended to deploy the POCIS horizontally inside the deployment cage.

Experimental Estimation of 44 Pharmaceutical Polar Organic Chemical Integrative Sampler Sampling Rates in an Artificial River under Various Flow Conditions

The present study pertains to a polar organic chemical integrative sampler (POCIS) laboratory calibration to estimate the sampling rates for 44 pharmaceuticals featuring a wide range of polarity (-0.6 < octanol/water partition coefficient [log K_OW ] < 5.4). The calibration was performed at 16.0 ± 1.5 °C for 4 water flow velocities (0, 2-3, 6-7, and 20 cm/s) in both a tank (for calibration at 0 cm/s) and a laboratory-scale artificial river filled with 200 and 500 L of tap water spiked with 0.3 µg/L of each compound, respectively. Twelve new sampling rates and 26 sampling rates already available in the literature were determined, whereas the sampling rates for 6 pharmaceuticals could not be determined due to nonlinearity or poor accumulation in POCIS. An increase in the sampling rate value with flow velocity was observed, which is consistent with a decrease in the effective thickness of the water boundary layer at the POCIS membrane surface. Environ Toxicol Chem 2020;39:1186-1195. © 2020 SETAC.

Estimating 42 pesticide sampling rates by POCIS and POCIS-MIP samplers for groundwater monitoring: a pilot-scale calibration

Pesticides occur in groundwater as a result of agricultural activity. Their monitoring under the Water Framework Directive is based on only a few spot-sampling measurements per year despite their temporal variability. Passive sampling, which was successfully tested in surface water to provide a more representative assessment of contamination, could be applied to groundwater for a better definition of its contamination. However, few reliable calibration data under low water flow are available. The objective of our study thus consisted in determining sampling rates by two types of passive samplers, a POCIS (polar organic chemical integrative sampler) for polar pesticides, and a POCIS-MIP sampler based on a receiving phase of molecular imprinted polymers, specific for AMPA and glyphosate under low flow conditions as exist in groundwater. To our knowledge, this is the first time that sampling rates (sampling rate represents the volume of water from which the analyte is quantitatively extracted by the sampler per unit time) are estimated for groundwater applications. Our calibrations took place in an experimental pilot filled with groundwater and with low water flow (a few metres per day). Pesticide uptake in POCIS showed good linearity, with up to 28 days before reaching equilibrium. Two types of accumulation in POCIS were noted (a linear pattern up to 28 days, and after a time lag of 7 to 14 days). Sampling rates for 38 compounds were calculated and compared with those available in the literature or obtained previously under laboratory conditions. The values obtained were lower by a factor 1 to 14 than those estimated under stirring conditions in the literature, whereas water flow velocity (m s^-1) differed by a factor of 2000 to 10,000.

Development of quantitative structure-property relationship model for predicting the field sampling rate (Rs) of Chemcatcher passive sampler

Passive sampling technology has been considered as a promising tool to measure the concentration of environmental contaminants. With this technology, sampling rate (R_s) is an important parameter. However, as experimental methods employed to obtain the R_s value of a given compound were time-consuming, laborious, and expensive. A cost-effective method for deriving R_s is urgent. In addition, considering the great dependence of R_s value on water matrix properties, the laboratory measured R_s may not be a good alternative for field R_s. Thus, obtaining the field R_s is very necessary. In this study, a multiparameter quantitative structure-property relationship (QSPR) model was constructed for predicting the field R_s of 91 polar to semi-polar organic compounds. The determination coefficient (R²_Train), leave-one-out cross-validated coefficient (Q²_LOO), bootstrap coefficient (Q²_BOOT), and root mean square error (RMSE_Train) of the training set were 0.772, 0.706, 0.769, and 0.230, respectively, while the external validation coefficient (Q²_EXT) and RMSE_EXT of the validation set were 0.641 and 0.253, respectively. According to the acceptable criteria (Q² > 0.600, R² > 0.700), the model had good robustness, goodness-of-fit, and predictive performances. Therefore, we could use the model to fill the data gap for substances within the applicability domain on their missing R_s value.

Semi-continuous pharmaceutical and human tracer monitoring by POCIS sampling at the watershed-scale in an agricultural rural headwater river

Pharmaceutical monitoring (37 pharmaceuticals and 3 human tracers) was conducted in a headwater streams in southwest France, an area characterized by a low population density with an elderly population (30% > 60 years old) and extensive agriculture (cow cattle breeding). Polar Organic Chemical Integrative Sampler (POCIS) were exposed for 14-day consecutive periods in 2016 at three sampling points. Three human wastewater tracers and 20 pharmaceuticals commonly used for human and/or cattle were quantified in headwaters. Succession of small Wastewater Treatment Plant (WWTP), non-collective sanitation, discharges of untreated effluents as well as the river ability to dilute discharged wastewater, mainly explain the pharmaceuticals and human tracers concentrations. Pharmaceutical loads were time-dependent and were higher during cold season due to increase of pharmaceutical consumption. In contrast, better degradation and/or sorption onto river biofilms in warm season induced the decrease of headwater pharmaceutical content. The headwaters streams were contaminated by compounds found in other type of watershed, but β-blocker were the compounds quantified in higher concentration with frequencies of 100%, which was consistent with the elderly population living in the watershed. Specific compounds (sulfamerazine and sulfamethoxazole) used to cattle medical care were detected in waters, but at a low content.

Risk estimation and annual fluxes of emerging contaminants from a Scottish priority catchment to the estuary and North Sea

Emerging contaminants (ECs) such as endocrine-disrupting chemicals (EDCs) and pharmaceuticals and personal care products (PPCPs) attracted global concern during the last decades due to their potential adverse effects on humans and ecosystems. This work is the first study to assess the spatiotemporal changes, annual fluxes and ecological risk of ECs (4 EDCs and 6 PPCPs) by different monitoring strategies (spot and passive sampling) over 12 months in a Scottish priority catchment (River Ugie, Scotland, 335 km²). Overall, the total concentration in water ranged from <LOD to 55.13 ng/l (mean 5.14 ng/l) for EDCs and 0.24 to 361.2 ng/l (mean 51.16 ng/l) for PPCPs, respectively. Ibuprofen and carbamazepine were observed to be the dominant contaminants in the River Ugie. The total annual fluxes of 4 EDCs transported to the Ugie estuary and North Sea were estimated to be 409 and 294 g based on the spot and passive sampling data, respectively, while they were 4636 and 4517 g for 6 PPCPs by spot and passive sampling, respectively. The spatiotemporal trend suggested that human activities and medication usages were the primary source of the contaminants. The overall comparison of the two sampling strategies supported the hypothesis that passive sampling tends to integrate the contaminants over a period of exposure and allows quantification of contamination at low concentration. The ecological risk assessment showed that bisphenol A posed the highest risks with 21.5% of the spot samples, resulting in a risk quotient >1. This suggests that mitigation measures might need to be taken to reduce the input of emerging contaminants into the river and its adjacent estuary and sea.

Effects of hydrodynamic conditions and temperature on polar organic chemical integrative sampling rates

The effects of changing hydrodynamic conditions and changing temperatures on polar organic chemical integrative sampler (POCIS) sampling rates (R_s ) were investigated for 12 crop protection chemicals. Exposure concentration was held constant in each laboratory experiment, and flow velocities were calculated from measured mass transfer coefficients of the water boundary layer near the surface of POCIS devices. At a given temperature R_s generally increased by a factor of 2 to 5 between a stagnant condition and higher flow velocities (6-21 cm/s), but R_s for most compounds was essentially constant between the higher flow velocities. When temperature was varied between 8 and 39 °C for a given flow condition, R_s increased linearly. In general, R_s increased by a factor of 2 to 4 and 2 to 8 over this temperature range under flow and stagnant conditions, respectively. An Arrhenius model was used to describe the dependence of POCIS sampling rates on temperature. Adjustments of R_s for temperature did not fully explain observed differences between time-weighted average concentrations of atrazine determined from POCIS and from composite water sampling in a field setting, suggesting that the effects of other competing factors still need to be evaluated. Environ Toxicol Chem 2018;37:2331-2339. © 2018 SETAC.

Review of atrazine sampling by polar organic chemical integrative samplers and Chemcatcher

A key success factor for the performance of passive samplers is the proper calibration of sampling rates. Sampling rates for a wide range of polar organic compounds are available for Chemcatchers and polar organic chemical integrative samplers (POCIS), but the mechanistic models that are needed to understand the effects of exposure conditions on sampling rates need improvement. Literature data on atrazine sampling rates by these samplers were reviewed with the aim of assessing what can be learned from literature reports of this well-studied compound and identifying knowledge gaps related to the effects of flow and temperature. The flow dependency of sampling rates could be described by a mass transfer resistance model with 1 (POCIS) or 2 (Chemcatcher) adjustable parameters. Literature data were insufficient to evaluate the temperature effect on the sampling rates. An evaluation of reported sampler configurations showed that standardization of sampler design can be improved: for POCIS with respect to surface area and sorbent mass, and for Chemcatcher with respect to housing design. Several reports on atrazine sampling could not be used because the experimental setups were insufficiently described with respect to flow conditions. Recommendations are made for standardization of sampler layout and documentation of flow conditions in calibration studies. Environ Toxicol Chem 2018;37:1786-1798. © 2018 SETAC.

Calibration of silicone rubber rods as passive samplers for pesticides at two different flow velocities: Modeling of sampling rates under water boundary layer and polymer control

There is a need to determine time-weighted average concentrations of polar contaminants such as pesticides by passive sampling in environmental waters. Calibration data for silicone rubber-based passive samplers are lacking for this class of compounds. The calibration data, sampling rate (R_s ), and partition coefficient between silicone rubber and water (K_sw ) were precisely determined for 23 pesticides and 13 candidate performance reference compounds (PRCs) in a laboratory calibration system over 14 d for 2 water flow velocities, 5 and 20 cm s^-1 . The results showed that an in situ exposure duration of 7 d left a silicone rubber rod passive sampler configuration in the linear or curvilinear uptake period for 19 of the pesticides studied. A change in the transport mechanism from polymer control to water boundary layer control was observed for pesticides with a log K_sw of approximately 3.3. The PRC candidates were not fully relevant to correct the impact of water flow velocity on R_s . We therefore propose an alternative method based on an overall resistance to mass transfer model to adjust R_s from laboratory experiments to in situ hydrodynamic conditions. We estimated diffusion coefficients (D_s ) and thickness of water boundary layer (δ_w ) as adjustable model parameters. Log D_s values ranged from -12.13 to -10.07 m²  s^-1 . The estimated δ_w value showed a power function correlation with water flow velocity. Environ Toxicol Chem 2018;37:1208-1218. © 2017 SETAC.

Kinetic accumulation processes and models for 43 micropollutants in "pharmaceutical" POCIS

The "pharmaceutical" polar organic integrative sampler (POCIS) is a passive sampler composed of an outer polyethersulfone (PES) membrane and an inner receiving Hydrophilic-Lipophilic Balance (HLB) phase. Target micropollutants can accumulate in the POCIS HLB phase following different uptake patterns. Two of the most common ones are a first-order kinetic uptake (Chemical Reaction Kinetic 1, CRK1 model), and a first-order kinetic uptake with an inflexion point (CRK2 model). From a previous study, we identified 30 and 13 micropollutants following CRK1 and CRK2 accumulation model in the POCIS HLB phase, respectively. We hypothesized that uptake in the outer PES membrane of POCIS may influence the uptake pathway. Thus, novel measurements of uptake in PES membrane were performed for these micropollutants to characterise kinetic accumulation in the membrane with and without the HLB phase. We determined, for the first time, the membrane-water distribution coefficient for 31 micropolluants. Moreover, the lag times for molecules to breakthrough the POCIS membrane increased with increasing hydrophobicity, defined by the octanol-water dissociation constant D_ow. However, D_ow alone was insufficient to predict whether uptake followed a CRK1 or CRK2 model in the POCIS HLB phase. Thus, we performed a factorial discriminant analysis considering several molecular physico-chemical properties, and the model of accumulation for the studied micropollutants can be predicted with >90% confidence. The most influent properties to predict the accumulation model were the log D_ow and the polar surface area of the molecule (>70% confidence with just these two properties). Molecules exhibiting a CRK1 uptake model for the POCIS HLB phase tended to have log D_ow>2.5 and polar surface area <50Ǻ².

Monitoring tylosin and sulfamethazine in a tile-drained agricultural watershed using polar organic chemical integrative sampler (POCIS)

This study evaluated the influence of temporal variation on the occurrence, fate, and transport of tylosin (TYL) and sulfamethazine (SMZ); antibiotics commonly used in swine production. Atrazine (ATZ) was used as a reference analyte to indicate the agricultural origin of the antibiotics. We also assessed the impact of season and hydrology on antibiotic concentrations. A reconnaissance study of the South Fork watershed of the Iowa River (SFIR), was conducted from 2013 to 2015. Tile drain effluent and surface water were monitored using polar organic integrative sampler (POCIS) technology. Approximately 169 animal feeding operations (AFOs) exist in SFIR, with 153 of them being swine facilities. All analytes were detected, and detection frequencies ranged from 69 to 100% showing the persistence in the watershed. Antibiotics were detected at a higher frequency using POCIS compared to grab samples. We observed statistically significant seasonal trends for SMZ and ATZ concentrations during growing and harvest seasons. Time weighted average (TWA) concentrations quantified from the POCIS were 1.87ngL^-1 (SMZ), 0.30ngL^-1 (TYL), and 754.2ngL^-1 (ATZ) in the watershed. SMZ and TYL concentrations were lower than the minimum inhibitory concentrations (MIC) for E. coli. All analytes were detected in tile drain effluent, confirming tile drainage as a pathway for antibiotic transport. Our results identify the episodic occurrence of antibiotics, and highlights the importance identifying seasonal fate and occurrence of these analytes.

Monitoring alkylphenols in water using the polar organic chemical integrative sampler (POCIS): Determining sampling rates via the extraction of PES membranes and Oasis beads

Polar organic chemical integrative samplers (POCIS) have previously been used to monitor alkylphenol (AP) contamination in water and produced water. However, only the sorbent receiving phase of the POCIS (Oasis beads) is traditionally analyzed, thus limiting the use of POCIS for monitoring a range of APs with varying hydrophobicity. Here a "pharmaceutical" POCIS was calibrated in the laboratory using a static renewal setup for APs (from 2-ethylphenol to 4-n-nonylphenol) with varying hydrophobicity (log K_ow between 2.47 and 5.76). The POCIS sampler was calibrated over its 28 day integrative regime and sampling rates (R_s) were determined. Uptake was shown to be a function of AP hydrophobicity where compounds with log K_ow < 4 were preferentially accumulated in Oasis beads, and compounds with log K_ow > 5 were preferentially accumulated in the PES membranes. A lag phase (over a 24 h period) before uptake in to the PES membranes occurred was evident. This work demonstrates that the analysis of both POCIS phases is vital in order to correctly determine environmentally relevant concentrations owing to the fact that for APs with log K_ow ≤ 4 uptake, to the PES membranes and the Oasis beads, involves different processes compared to APs with log K_ow ≥ 4. The extraction of both the POCIS matrices is thus recommended in order to assess the concentration of hydrophobic APs (log K_ow ≥ 4), as well as hydrophilic APs, most effectively.

SIMONI (Smart Integrated Monitoring) as a novel bioanalytical strategy for water quality assessment: Part II-field feasibility survey

Because it is impossible to chemically analyze all relevant micropollutants, the implementation of bioanalytical tools is essential to estimate ecological risks of chemical mixtures in regular water-monitoring programs. The first tier of the Smart Integrated Monitoring (SIMONI) strategy, which was described in part I, is based on the combination of passive sampling and bioanalytical measurements. Bioassay responses are compared with effect-based trigger values (EBT), and an overall SIMONI score on all bioassay data was designed to indicate environmental risks. The present study is focused on analyzing the feasibility of the hazard identification tier by evaluating results of 45 field campaigns at sites with different pollution profiles near the city of Amsterdam. A Daphnia assay was performed in situ, while silicon rubber or polar organic chemical integrative sampler (POCIS) extracts were tested with 4 nonspecific (daphnids, algae, bacteria, and cell culture) and 10 specific (9 Chemical Activated Luciferase Gene Expression [CALUX] assays and antibiotics scan) bioassays. Sensitivity analyses demonstrated the relevance of 2 classification variables in the SIMONI score formula on all bioanalytical data. The model indicated increased risks for the ecosystem at surface waters in greenhouse areas and undiluted wastewater-treatment plant (WWTP) effluents. The choice of testing specific bioassays on either polar or nonpolar passive sampling extracts is cost-effective and still provided meaningful insights on micropollutant risks. Statistical analyses revealed that the model provides a relevant overall impact assessment based on bioassay responses. Data analyses on the chemically determined mixture toxic pressure and bioanalytical methods provided similar insights in relative risk ranking of water bodies. The SIMONI combination of passive sampling and bioanalytical testing appears to be a feasible strategy to identify chemical hazards. Environ Toxicol Chem 2017;36:2400-2416. © 2017 SETAC.

Equilibrium partitioning of organic compounds to OASIS HLB® as a function of compound concentration, pH, temperature and salinity

Oasis hydrophilic lipophilic balance^® (Oasis HLB) is commonly employed in solid phase extraction (SPE) of environmental contaminants and within polar organic chemical integrative passive samplers (POCIS). In this study batch experiments were carried out to evaluate the relative affinity of a range of relevant organic pollutants to Oasis HLB in aqueous systems. The influence of sorbate concentration, temperature, pH, and salinity on the equilibrium sorption was investigated. Equilibrium partition ratios (K_D) of 28 compounds were determined, ranging over three orders of magnitude from 1.16 × 10³ L/kg (atenolol) to 1.07 × 10⁶ L/kg (isoproturon). The Freundlich model was able to describe the equilibrium partitioning to Oasis HLB, and an analysis of the thermodynamic parameters revealed the spontaneous and exothermic nature of the partitioning process. Ionic strength had only a minor effect on the partitioning, whereas pH had a considerable effect but only for ionizable compounds. The results show that apolar interactions between the Oasis HLB and analyte mainly determine the equilibrium partitioning. These research findings can be used to optimize the application of SPE and POCIS for analyses of environmental contaminants even in complex mixtures.

Ionic liquids for the passive sampling of sulfonamides from water-applicability and selectivity study

Ionic liquids (ILs) are new-generation, non-volatile solvents which are designable, and their structure may be specifically adjusted to the current application needs. Therefore, it is possible to create and apply ILs which efficiently and selectively extract various analytes from different matrices. It has already been examined that ILs may be applied as receiving phases in passive sampling for the long-term water monitoring of PAHs and pharmaceuticals in water. In this paper, the concept of passive sampling with ILs (PASSIL applied as receiving phases) was continued and developed using phosphonium-, imidazolium-, and morpholinium-cation-based ILs. The target group of analytes was pharmaceuticals which represent one of the most common categories of water contaminants. Fourteen-day-long extractions using various ILs were performed in stirred conditions at a constant temperature (20 °C). The best extraction efficiency was achieved for trihexyl(tetradecyl)phosphonium dicyanamide ([P666-14][N(CN)₂]). For this preliminary calibration, the sampling rates were calculated for each sulfonamide. Once again, selectivity was observed in passive sampling using [P666-14][N(CN)₂]. Therefore, PASSIL is seen as a very promising method for pharmaceutical monitoring in water.

In situ exposure to wastewater effluent reduces survival but has little effect on the behaviour or physiology of an invasive Great Lakes fish

Treated effluents from wastewater treatment plants (WWTP) are a significant source of anthropogenic contaminants, such as pharmaceuticals, in the aquatic environment. Although our understanding of how wastewater effluent impacts fish reproduction is growing, we know very little about how effluent affects non-reproductive physiology and behaviours associated with fitness (such as aggression and activity). To better understand how fish cope with chronic exposure to wastewater effluent in the wild, we caged round goby (Neogobius melanostomus) for three weeks at different distances from a wastewater outflow. We evaluated the effects of this exposure on fish survival, behaviour, metabolism, and respiratory traits. Fish caged inside the WWTP and close to the outfall experienced higher mortality than fish from the reference site. Interestingly, those fish that survived the exposure performed similarly to fish caged at the reference site in tests of aggressive behaviour, startle-responses, and dispersal. Moreover, the fish near WWTP outflow displayed similar resting metabolism (O₂ consumption rates), hypoxia tolerance, haemoglobin concentration, haematocrit, and blood-oxygen binding affinities as the fish from the more distant reference site. We discuss our findings in relation to exposure site water quality, concentrations of pharmaceutical and personal care product pollutants, and our test species tolerance.

Monitoring contaminants of emerging concern from tertiary wastewater treatment plants using passive sampling modelled with performance reference compounds

The Lake Simcoe watershed in Ontario, Canada is an important recreational area and a recharge zone for groundwater resources. Lake Simcoe is a relatively shallow lotic system that has been impacted by urban development, recreation, industry and agriculture. As part of a watershed management plan, six wastewater treatment plants (WWTPs) located in this catchment basin were selected to measure the inputs of contaminants of emerging concern (CECs) of wastewater origin. These WWTPs were recently upgraded to tertiary treatment for phosphorus removal. Polar organic chemical integrative samplers (POCIS) and semipermeable membrane devices (SPMDs) were used to monitor for hydrophilic and hydrophobic CECs, respectively, in treated and untreated wastewater. The passive samplers were calibrated with performance reference compounds (PRCs) by measuring the loss of deuterated beta blocker drugs spiked into POCIS and the loss of PCB congeners spiked into SPMDs over the course of 14-day deployment periods. From the PRC data, field sampling rates of CECs were determined and applied to estimate time-weighted average (TWA) concentrations and mass loadings in mg/day/1000 members of the population serviced. In treated wastewater, TWA concentrations of an antibiotic, sulfamethoxazole, the prescription drugs, carbamazepine, naproxen and gemfibrozil, and the non-prescription drug, ibuprofen, were estimated to be in the low (<18 ng/L) range. The artificial sweeteners, sucralose and acesulfame, were particularly useful chemical tracers, with estimated TWA concentrations in treated wastewater ranging from 128 to 213 ng/L and 4 to 33 ng/L, respectively. The steroid hormones were detected only rarely in treated wastewater. Triclosan, triclocarban and the synthetic musks, HHCB and AHTN, were removed efficiently (>77 %), possibly because of the tertiary treatment technologies. Therefore, the mass loadings for these personal care products were all <5 mg/day/1000 people. Overall, this study indicates that tertiary treatment technologies designed for phosphorus removal do not entirely remove the target CECs.

Development and Calibration of an Organic-Diffusive Gradients in Thin Films Aquatic Passive Sampler for a Diverse Suite of Polar Organic Contaminants

A unique configuration of the diffusive gradients in thin films sampler for polar organics (o-DGT) without a poly(ether sulfone) membrane was developed, calibrated, and field-evaluated. Diffusion coefficients (D) through agarose diffusive gels ranged from (1.02 to 4.74) × 10^-6 cm²/s for 34 pharmaceuticals and pesticides at 5, 13, and 23 °C. Analyte-specific diffusion-temperature plots produced linear (r² > 0.85) empirical relationships whereby D could be estimated at any environmentally relevant temperature (i.e., matched to in situ water conditions). Linear uptake for all analytes was observed in a static renewal calibration experiment over 25 days except for three macrolide antibiotics, which reached saturation at 300 ng (≈15 d). Experimental sampling rates ranged from 8.8 to 16.1 mL/d and were successfully estimated with measured and modeled D within 19% and 30% average relative error, respectively. Under slow flowing (2.4 cm/s) and static conditions, the in situ diffusive boundary layer (DBL) thickness ranged from 0.023 to 0.075 cm, resulting in a maximum contribution to mass transfer of <45%. Estimated water concentrations by o-DGT at a wastewater treatment plant agreed well with grab samples and appeared to be less influenced by the boundary layer compared to that of polar organic chemical integrative samplers (POCIS) deployed simultaneously. The o-DGT sampler is a promising monitoring tool that is largely insensitive to the DBL under typical flow conditions, facilitating the application of measured/modeled diffusion-based sampling rates. This significantly reduces the need for sampler calibration, making o-DGT more widely applicable, reliable, and cost-effective compared to current polar passive samplers.

Improving Toxicity Assessment of Pesticide Mixtures: The Use of Polar Passive Sampling Devices Extracts in Microalgae Toxicity Tests

Complexity of contaminants exposure needs to be taking in account for an appropriate evaluation of risks related to mixtures of pesticides released in the ecosystems. Toxicity assessment of such mixtures can be made through a variety of toxicity tests reflecting different level of biological complexity. This paper reviews the recent developments of passive sampling techniques for polar compounds, especially Polar Organic Chemical Integrative Samplers (POCIS) and Chemcatcher® and the principal assessment techniques using microalgae in laboratory experiments. The progresses permitted by the coupled use of such passive samplers and ecotoxicology testing as well as their limitations are presented. Case studies combining passive sampling devices (PSD) extracts and toxicity assessment toward microorganisms at different biological scales from single organisms to communities level are presented. These case studies, respectively, aimed (i) at characterizing the "toxic potential" of waters using dose-response curves, and (ii) at performing microcosm experiments with increased environmental realism in the toxicant exposure in term of cocktail composition and concentration. Finally perspectives and limitations of such approaches for future applications in the area of environmental risk assessment are discussed.

Liquid chromatography-tandem mass spectrometry and passive sampling: powerful tools for the determination of emerging pollutants in water for human consumption

Among the wide range of emerging pollutants, perfluorinated compounds and various pharmaceuticals, such as nonsteroidal anti-inflammatory drugs, are showing growing concern. These contaminants can be found in freshwater ecosystems because of their incomplete removal during wastewater treatments so, their water solubility and poor degradability result in their continuous discharge and pseudo-persistent contamination. Usually, expected levels of these analytes are particularly low; therefore, sensitive and selective analytical techniques are required for their determination. Moreover, sampling and preconcentration are fundamental steps to reach the low detection limits required. The polar organic chemical integrative sampler (POCIS) represents a modern sampling approach that allows the in-situ preconcentration of ultra-trace pollutants. In this work, a fast liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method was developed for the determination of diclofenac, ketoprofen, mefenamic acid, naproxen, ibuprofen, perfluorooctanoic acid, perfluorooctanesulfonate and caffeine in water for human consumption. The chromatographic separation of analytes was achieved in less than 6 min. Quantitative analysis was performed in multiple reaction monitoring mode using ketoprofen-d3 as internal standard. Two different sites of Northern Italy were studied deploying POCIS for four weeks in both inlet and outlet of two drinking water treatment plants. The evaluation of time-weighted average concentration of contaminants was accomplished after the calibration of POCIS; to this aim, the sampling rate values for each compound were obtained by means of a simple calibration system developed in our laboratory. Ketoprofen, perfluorooctane sulfonate, perfluorooctanoate and caffeine were measured in both sites at the ng l(-1) level. Copyright © 2016 John Wiley & Sons, Ltd.