Determination of alkylphenol ethoxylates and their degradation products in liquid and solid samples

Quantitative analysis of nonylphenol ethoxylates in textiles using ultrasonic/microwave-assisted extraction coupled with ultra-high-performance supercritical fluid chromatography-photodiode array-tandem mass spectrometry

A sensitive and robust analytical method was developed for the simultaneous determination of nonylphenol ethoxylates (NPEOs) in textiles. The method utilizes ultra-high-performance supercritical fluid chromatography with photodiode array detection (UHPSFC-PDA) to assess monomer proportions across varying polymerization degrees, followed by quantitation via tandem mass spectrometry (UHPSFC-MS/MS) in multiple reaction monitoring (MRM) mode. Under optimized conditions, NPEOs (n = 2-39) were separated within 7 min on a BEH C18 column using compressed CO₂ and methanol as the mobile phase. Additionally, response surface methodology and Box-Behnken design were employed to optimize ultrasonic/microwave-assisted extraction (UMAE) parameters. The method demonstrated excellent linearity (R² > 0.99) for 13 NPEO homologues (n = 2-14), with limits of detection (LODs) and quantitation (LOQs) values ranging from 0.26 to 45.09 μg/kg and 2.28-188.06 μg/kg, respectively. Intra- and inter-day precision values ranged from 0.8 % to 4.23 % and from 1.34 % to 9.59 %, respectively. Recoveries at low, medium, and high spiking levels were between 71.1 % and 102.5 % (RSD ≤ 12.98 %). The method was validated using quality control standards and successfully applied to commercial textile samples, revealing NPEO concentrations up to 2626.63 μg/kg. The combination of UMAE with UHPSFC-PDA-MS/MS offers a rapid, sensitive, and environmentally friendly solution for comprehensive NPEO analysis in textiles.

Occurrence, partitioning behavior, and ecological risk assessment of octylphenol and nonylphenol in surface waters and sediments of Terengganu Rivers, Malaysia

The occurrence, partitioning behavior, and ecological risk assessment of octylphenol (OP) and nonylphenol (NP) were investigated in the surface water and sediment of three rivers in Terengganu, Malaysia, to understand the fate and ecological risk of these chemicals in aquatic ecosystems. Target chemicals were extracted using solvent extractant and cleaned up via solid-phase extraction. This is followed by analysis via high-performance liquid chromatography (HPLC), and verification by liquid chromatography-tandem mass spectrometry (LC-MS/MS). OP was consistently higher in both surface water and sediment, while NP was predominantly found in sediment with minimal detection in surface water. Concentrations in sediment (OP, 0.19-30.88 ng/g dw; NP, 0.38-84.42 ng/g dw) and in surface water (OP, 0.0019-0.0077 ng/mL; NP, 0.0007-0.0023 ng/mL) suggest strong adsorption from water to sediment due to the hydrophobic effects of these compounds. The partitioning behavior of OP was evaluated using two indicators: (1) the sediment-water partition coefficient (Kd) and (2) the carbon-normalized partition coefficient (K'oc). The results indicated that OP is readily adsorbed and released from sediment, with log Kd values ranging from 3.06 to 3.57 and log K'oc values from 3.00 to 3.97. A significant positive correlation was observed between physical water parameters (temperature, salinity, and pH), whereas a significant negative correlation was found between these parameters and the concentrations of OP and NP in sediment. The ecological risk assessment showed that OP in water posed a low risk, while OP and NP in sediment presented varying risks, ranging from low to high risk between 2018 and 2019. This baseline information on the partitioning behavior is invaluable for predicting the environmental fate of these compounds in sediment-water interactions in Malaysia and for assessing the ecological risks they may pose to aquatic organisms.

Lab-in-syringe automated dispersive solid-phase microextraction of alkylphenols coupled online to liquid chromatography using iron (III) thenoyltrifluoroacetonate as dissolvable sorbent

BACKGROUND

Alkylphenols are water contaminants of strong endocrine disruptive potential. Sample preparation is generally imperative to improve sensitivity and minimize matrix effects. Dispersive solid phase extraction is a powerful alternative to cartridge-based sorbent extraction omitting backpressure problems and reducing procedural time. Herein, solvent-dissolvable sorbents offer the advantages of easy and cost-efficient production, efficiency, and full analyte recovery, while eluates can be directly submitted to instrumental determination. Despite the potential to reduce environmental impact and enhance reproducibility, there is a lack of automation attempts.

RESULTS

A fully automated solvent-assisted dispersive solid phase extraction method was developed for selected alkylphenols based on the technique Lab-In-Syringe. The void of automatic bidirectional syringe pump was used as mixing and extraction vessel. The iron(III) thenoyltrifluoroacetonate complex was used as novel dissolvable sorbent. 40 μL complex solution was dispersed in the sample, leading to the precipitation of 0.4 mg sorbent. Extraction occurred within 40 s and was accelerated by in-syringe magnetic stirring. The sorbent was retained on a melamine foam packing in the syringe inlet, dissolved in a methanolic solution of ascorbic acid, and injected into online-coupled HPLC. Linear working ranges were achieved from 1 to 1000 μg/L with sub-ppb detection limits and accuracies ranging from 98.3 to 110 %.

SIGNIFICANCE

In this work, we explored for the first time automated in-syringe automated dispersive SPE based on a dissolvable sorbent. Parallel operation of sample pretreatment and separation enabled throughputs of 4.5/h with typically <5 % RSD and preconcentrations of 16.4-21.2. AGREE greenness evaluation yielded a score of 0.59.

Occurrence of octylphenol and nonylphenol in the sediment of South China Sea and Malacca Strait, Peninsular Malaysia

Sediment is the ultimate reservoir of effluent from landmasses. This includes octylphenol (OP) and nonylphenol (NP), two chemical compounds which are known with the ability to disrupt the normal functions of hormones in the organism. To our knowledge, no study of these compounds in the marine sediment of Malaysia has been published to date. Hence, this study presents the level of OP and NP in the sediment of the South China Sea and Malacca Strait, Malaysia. The extraction of compounds was done using the liquid-liquid extraction method and followed by clean-up using solid-phase extraction cartridges. The range of OP in Malacca Strait (1.00-27.16 ng/g dw) was greater than in the South China Sea (5.12-14.16 ng/g dw) whereas a similar range of NP was found in the South China Sea (1.32-23.76 ng/g dw) and Malacca Strait (0.79-27.59 ng/g dw). The concentration of both compounds was consistently high near Redang Island (E2A) and Penang (W32 and W43) suggesting continuous input of these chemicals from this nearby land. Risk quotient (RQ) values of OP showed the potential risk to benthic communities in 4/7 and 21/47 sampling points of the respective South China Sea and Malacca Strait. Both water bodies are located far from the wastewater effluent and yet able to retain these chemicals in their sediment. This suggests that the wastewater treatment system as well as dilution effects do not prevent these chemicals to be ended up in the marine environment.

Different dissipation potential and dietary risk assessment of tristyrylphenol ethoxylates in cowpea ecosystem in China

Tristyrylphenol ethoxylates (TSPEOn) are widely used as inert ingredients in pesticide formulations in the world. However, the information on the dissipation behavior of different homologs TSPEOn in agro-products is lacking. To investigate the dissipation behavior of TSPEOn, a cowpea field experiment treated with TSPEOn at different doses was carried out in Guangdong province, China. Different 24 TSPEO homologs were all detected in cowpea from the field terminal residue experiments, and the total concentrations of TSPEO homologs in cowpea were 40.0–1,374 μg/kg. The dissipation half-lives of 24 TSPEO homologs in soil were 1.51–2.35 times longer than those in cowpea. The long-chain homologs TSPEOn were dissipated faster than the short-chain homologs TSPEOn, suggesting a homolog-specific degradation of the TSPEOn in the cowpea ecosystem. The characteristic bimodal profiles of TSPEOn (n = 6–29) differing from that of the commercial TSPEOn were observed in the cowpea terminal residues experiment, indicating that the long-chain TSPEOn would degrade to short-chain TSPEOn in cowpea and soil. The acute and chronic dietary exposure risks of ΣTSPEOn in cowpea are within acceptable margins for human consumption across different ages and genders. But the health risks to children should be noticed in future.

Occurrences of eight common-used pesticide adjuvants in ten vegetable species and implications for dietary intake in North China

Pesticide adjuvants (PAs) are important components of pesticide products. However, limited information is available regarding their occurrences in foodstuffs. Herein, eight common-used PAs were investigated in vegetables in North China in 2014-2016. The residue levels of total PAs in vegetables from markets and farms were 500 and 661 μg/kg, respectively. The highest residues of total PAs were found in cauliflowers (average: 1.53 × 10³ μg/kg, market vegetables) and spinaches (average: 3.72 × 10³ μg/kg, farm vegetables), respectively. In addition, Tristyrylphenol ethoxylates (TPE) dominated the total 8 PAs concentrations in most vegetable species. Moreover, the risk assessment showed that the human health risks associated with TPE and nonylphenol (NP) exposure via vegetables for adults were acceptable, and the estimated daily intakes (EDIs) of other six PAs were in the range of <0.010-0.89 μg/kg bw/day, which were less likely to pose a threat to human health.

Analysis of Non-Ionic Surfactant Triton X-100 Using Hydrophilic Interaction Liquid Chromatography and Mass Spectrometry

It is well known that surfactants increase the solubility of hydrophobic organic compounds and cause adverse environmental effects. The removal of these compounds from the contaminated soil or ground-water is particularly difficult due to their water soluble feature. In this work, an ultra-high performance hydrophilic interaction liquid chromatographic method was developed for the separation of oligomers of Triton X-100 octylphenol-polyethoxylate non-ionic surfactant. Liquid chromatography-mass spectrometry (LC-MS) was used to identify the Triton X-100 compounds. There was a 44 mass unit difference between two adjacent peaks that is the molar mass of one ethylene oxide group (–CH2CH2O–). A quadratic retention model was applied for the estimation of retention of the examined non-ionic surfactant and the optimization of gradient elution conditions. The optimized method was suitable for the baseline separation of 28 Triton X-100 oligomers in five minutes.

A non-targeted high-resolution mass spectrometry data analysis of dissolved organic matter in wastewater treatment

The dissolved organic matter (DOM) in wastewater is typically described by a limited number of concentration measurements of select DOM fractions or micro-contaminants, which determine the removal efficiency in a wastewater treatment. Current methods do not necessarily reflect the true performance of the treatment with regard to environmental and public health risk. Herein we describe the development and application of a non-targeted liquid chromatography-high resolution mass spectrometry (LC-HRMS) data analysis for the evaluation of wastewater treatment processes. Our data analysis approach was applied to a real wastewater system with secondary biological treatment and tertiary treatment consisting of sand filtration, UV-treatment, and chlorination. We identified significant changes in DOM during wastewater treatment. The secondary treatment removed 1617 of 2409 (67%) detected molecular features (grouped isotopologues belonging to the same molecule) from the influent while 255 of 1047 (24%) new molecular features appeared in the secondary effluent. A reduction in the number of large molecules (>450 Da) and an increase in unsaturated molecular features of the effluent organic matter was observed. Van Krevelen plots revealed the distribution of unsaturation and heteroatoms and Kendrick mass defect plots uncovered CH₂ homologous series implying a removal of heavy constituents in that fraction. The demonstrated approach is a step towards a more comprehensive monitoring of DOM in wastewater and contributes to the understanding of current treatment technologies.

Liquid chromatography coupled to quadrupole-Orbitrap high resolution mass spectrometry based method for target analysis and suspect screening of non-ionic surfactants in textiles

In this study, we describe a high-throughput and sensitive method for textiles analysis, using liquid chromatography coupled to quadrupole-Orbitrap high resolution mass spectrometry (LC-Q-Orbitrap HRMS), for the simultaneously quantitative analysis of 40 target alkylphenol polyethoxylates (APEO) oligomers with reference standards and screening of 160 alcohol polyethoxylates (AEO) oligomers without standards in textiles. The APEOs contain nonylphenol ethoxylates (NPEOs) and octylphenol ethoxylates (OPEOs) with an EO number of ethylene oxide of 1-20, while AEOs focus on C₁₁EOs-C₁₈EOs with an EO number of 1-20. After ultrasonic extraction in methanol, the extract was directly separated using a core-shell CORTECS C₁₈⁺ column and analyzed by Full MS/dd-MS² (data dependent acquisition) scan in ESI positive mode. Two best sensitivity experimental conditions for APEOs with short EO chains (AP(EO)_1-2) and long EO chains (AP(EO)_3-20) were investigated, respectively. Most APEO oligomers had wide concentration ranges and the correlation coefficients (R²) were higher than 0.999. The limit of quantitation (LOQ) values for NP(EO)_3-20 oligomers ranges from 16.00 to 52.80μg/kg and for OP(EO)_3-20 oligomers is from 2.40 to 8.00μg/kg. LOQ for NP(EO)₁ and NP(EO)₂, OP(EO)₁ and OP(EO)₂ was 2.40mg/kg and 0.24mg/kg, 1.20mg/kg and 0.16mg/kg, respectively. The average recovery for each APEO oligomer in cotton and polyester matrix was between 78% and 110% at three spiked levels and the relative standard deviation (RSD%) was below 10%. As to AEOs suspects, a HRMS compound database containing 160 AEO oligomers was built and several parameters such as exact m/z, isotopic patterns, predicted product ions and predicted retention time were used for screening and confirmation. The established method was successfully applied for analysis of 40 commercial textile samples. Compared with OPEOs, NPEOs, especially NP(EO)_3-15 oligomers, were widely detected in samples and the total concentration ranged from 1.56 to 1376.31mg/kg. AEOs were also found in most samples, among which C_12-14, C₁₆ and C₁₈ compounds appeared more frequently and the EO chains mainly ranged from 3 to 15.

Distribution and bioaccumulation of endocrine disrupting chemicals in water, sediment and fishes in a shallow Chinese freshwater lake: Implications for ecological and human health risks

The occurrence, distribution and bioaccumulation of six endocrine disrupting compounds (EDCs) were investigated in water, sediment and biota samples from Luoma Lake, a shallow Chinese freshwater lake. Total concentrations of ∑phenolic EDCs were much higher than ∑estrogens EDCs in both waters and sediments. There were not obvious differences on the concentrations of target compounds [except nonylphenol (NP)] in upstream, lake and downstream locations, these may be suggested that they were mainly affected by non-point discharges in this area. However, the high concentration of NP in water may be associated with the discharge of rural domestic wastewater without thorough treatment. Furthermore, concentrations of NP were about 2-3 order magnitude higher than those of OP in both water and sediment compartments. Relatively higher bioaccumulation factors (BAF) were obtained for DES and EE2. Ecological risk assessment revealed greater risk of NP in surface water, which may pose a serious threat to aquatic ecosystems. The estrogen equivalent concentration (EEQ) of male were higher than those in female, and occurred in the order of city >rural-urban>countryside.

Reducing Dilution and Analysis Time in Online Comprehensive Two-Dimensional Liquid Chromatography by Active Modulation

Online comprehensive two-dimensional liquid chromatography (LC × LC) offers ways to achieve high-performance separations in terms of peak capacity (exceeding 1000) and additional selectivity to realize applications that cannot be addressed with one-dimensional chromatography (1D-LC). However, the greater resolving power of LC × LC comes at the price of higher dilutions (thus, reduced sensitivity) and, often, long analysis times (>100 min). The need to preserve the separation attained in the first dimension ((1)D) causes greater dilution for LC × LC, in comparison with 1D-LC, and long analysis times to sample the (1)D with an adequate number of second dimension separations. A way to significantly reduce these downsides is to introduce a concentration step between the two chromatographic dimensions. In this work we present a possible active-modulation approach to concentrate the fractions of (1)D effluent. A typical LC × LC system is used with the addition of a dilution flow to decrease the strength of the (1)D effluent and a modulation unit that uses trap columns. The potential of this approach is demonstrated for the separation of tristyrylphenol ethoxylate phosphate surfactants, using a combination of hydrophilic interaction and reversed-phase liquid chromatography. The modified LC × LC system enabled us to halve the analysis time necessary to obtain a similar degree of separation efficiency with respect to UHPLC based LC × LC and of 5 times with respect to HPLC instrumentation (40 compared with 80 and 200 min, respectively), while at the same time reducing dilution (DF of 142, 299, and 1529, respectively) and solvent consumption per analysis (78, 120, and 800 mL, respectively).

Use of oleic-acid functionalized nanoparticles for the magnetic solid-phase microextraction of alkylphenols in fruit juices using liquid chromatography-tandem mass spectrometry

Magnetic nanoparticles of cobalt ferrite with oleic acid as the surfactant (CoFe2O4/oleic acid) were used as sorbent material for the determination of alkylphenols in fruit juices. High sensitivity and specificity were achieved by liquid chromatography and detection using both diode-array (DAD) and electrospray-ion trap-tandem mass spectrometry (ESI-IT-MS/MS) in the selected reaction monitoring (SRM) mode of the negative fragment ions for alkylphenols (APs) and in positive mode for ethoxylate APs (APEOs). The optimized conditions for the different variables influencing the magnetic separation procedure were: mass of magnetic nanoparticles, 50mg, juice volume, 10mL diluted to 25mL with water, pH 6, stirring for 10min at room temperature, separation with an external neodymium magnet, desorption with 3mL of methanol and orbital shaking for 5min. The enriched organic phase was evaporated and reconstituted with 100µL acetonitrile before injecting 30µL into a liquid chromatograph with a mobile phase composed of acetonitrile/0.1% (v/v) formic acid under gradient elution. Quantification limits were in the range 3.6 to 125ngmL(-1). The recoveries obtained were in the 91-119% range, with RSDs lower than 14%. The ESI-MS/MS spectra permitted the correct identification of both APs and APEOs in the fruit juice samples.

Microextraction techniques coupled to liquid chromatography with mass spectrometry for the determination of organic micropollutants in environmental water samples

Until recently, sample preparation was carried out using traditional techniques, such as liquid–liquid extraction (LLE), that use large volumes of organic solvents. Solid-phase extraction (SPE) uses much less solvent than LLE, although the volume can still be significant. These preparation methods are expensive, time-consuming and environmentally unfriendly. Recently, a great effort has been made to develop new analytical methodologies able to perform direct analyses using miniaturised equipment, thereby achieving high enrichment factors, minimising solvent consumption and reducing waste. These microextraction techniques improve the performance during sample preparation, particularly in complex water environmental samples, such as wastewaters, surface and ground waters, tap waters, sea and river waters. Liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS) and time-of-flight mass spectrometric (TOF/MS) techniques can be used when analysing a broad range of organic micropollutants. Before separating and detecting these compounds in environmental samples, the target analytes must be extracted and pre-concentrated to make them detectable. In this work, we review the most recent applications of microextraction preparation techniques in different water environmental matrices to determine organic micropollutants: solid-phase microextraction SPME, in-tube solid-phase microextraction (IT-SPME), stir bar sorptive extraction (SBSE) and liquid-phase microextraction (LPME). Several groups of compounds are considered organic micropollutants because these are being released continuously into the environment. Many of these compounds are considered emerging contaminants. These analytes are generally compounds that are not covered by the existing regulations and are now detected more frequently in different environmental compartments. Pharmaceuticals, surfactants, personal care products and other chemicals are considered micropollutants. These compounds must be monitored because, although they are detected in low concentrations, they might be harmful toward ecosystems.

Occurrence of eight household micropollutants in urban wastewater and their fate in a wastewater treatment plant. Statistical evaluation

The occurrence in urban wastewater of eight micropollutants (erythromycin, ibuprofen, 4-nonylphenol (4-NP), ofloxacin, sucralose, triclosan, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS)) originating from household activities and their fate in a biological wastewater treatment plant (WWTP) were investigated. Their concentrations were assessed in the liquid and solid phases (sewage particulate matter and wasted activated sludge (WAS)) by liquid chromatography-tandem mass spectrometry. The analysis of sewage from two different urban catchments connected to the WWTP showed a specific use of ofloxacin in the mixed catchment due to the presence of a hospital, and higher concentrations of sucralose in the residential area. The WWTP process removed over 90% of ibuprofen and triclosan from wastewater, while only 25% of ofloxacin was eliminated. Erythromycin, sucralose and PFOA were not removed from wastewater, the influent and effluent concentrations remaining at about 0.7 μg/L, 3 μg/L and 10 ng/L respectively. The behavior of PFOS and 4-nonylphenol was singular, as concentrations were higher at the WWTP outlet than at its inlet. This was probably related to the degradation of some of their precursors (such as alkylphenol ethoxylates and polyfluorinated compounds resulting in 4-NP and PFOS, respectively) during biological treatment. 4-NP, ofloxacin, triclosan and perfluorinated compounds were found adsorbed on WAS (from 5 ng/kg for PFOA to 1.0mg/kg for triclosan). The statistical methods (principal component analysis and multiple linear regressions) were applied to examine relationships among the concentrations of micropollutants and macropollutants (COD, ammonium, turbidity) entering and leaving the WWTP. A strong relationship with ammonium indicated that some micropollutants enter wastewater via human urine. A statistical analysis of WWTP operation gave a model for estimating micropollutant output from the WWTP based on a measurement of macropollution parameters.

Identification and composition of emerging quaternary ammonium compounds in municipal sewage sludge in China

Quaternary ammonium compounds (QACs) have raised considerable attention due to their wide commercial applications and recent discovery of unknown persistent analogues in aqueous environment. In this work, the occurrence and distribution of alkyltrimethylammonium (ATMAC), benzylakyldimethylethylammonium (BAC) and dialkyldimethylammonium (DADMAC) homologues were investigated in fifty-two municipal sewage sludge samples. ATMAC C10-18, BAC C8-18 and paired DADMAC C8:8-C18:18 as well as emerging homologues such as ATMAC-20, 22 and mixed DADMAC-16:18 and 14:16 were present. Furthermore, paired DADMAC-20:20 and mixed DADMAC-14:18, 18:20 were identified for the first time by nontarget qualitative strategies. A triple quadruple mass spectrometer quantification method was also initially verified with the aid of laboratory synthesized standards for the analysis of the mixed DADMACs with no certificated commercial standards currently available. The total concentrations of ATMACs, BACs and DADMACs were in the range of 0.38-293, 0.09-191 and 0.64-344 μg/g dry weight, respectively, and particularly, mixed DADMACs constituted 39 ± 7% of total DADMAC concentrations. The concentrations and profiles of individual homologues further suggested different QAC applications and fate in China. Significant correlations were also found among the concentrations of various QAC homologues as well as wastewater treatment plant (WWTP) characteristics (total organic carbon contents and daily treatment volumes).

The bioconcentration and degradation of nonylphenol and nonylphenol polyethoxylates by Chlorella vulgaris

Nonylphenol polyethoxylates (NPnEOs), a major class of nonionic surfactants, can easily enter into aquatic environments through various pathways due to their wide applications, which leads to the extensive existence of their relative stable metabolites, namely nonylphenol (NP) and mono- to tri-ethoxylates. This study investigated the bioconcentration and degradation of NP and NPnEO oligomers (n = 1–12) by a green algae, Chlorella vulgaris. Experimental results showed that C. vulgaris can remove NP from water phase efficiently, and bioconcentration and degradation accounted for approximately half of its loss, respectively, with a 48 h BCF (bioconcentration factor) of 2.42 × 10³. Moreover, C. vulgaris could concentrate and degrade NPnEOs, distribution profiles of the series homologues of the NPnEOs in algae and water phase were quite different from the initial homologue profile. The 48 h BCF of the NPnEO homologues increased with the length of the EO chain. Degradation extent of total NPnEOs by C. vulgaris was 95.7%, and only 1.1% remained in water phase, and the other 3.2% remained in the algal cells. The algae removed the NPnEOs mainly through degradation. Due to rapid degradation, concentrations of the long chain NPnEO homologous in both water (n ≥ 2) and the algal phase (n ≥ 5) was quite low at the end of a 48 h experiment.

Analytical methodologies for the determination of endocrine disrupting compounds in biological and environmental samples

Endocrine-disruptor compounds (EDCs) can mimic natural hormones and produce adverse effects in the endocrine functions by interacting with estrogen receptors. EDCs include both natural and synthetic chemicals, such as hormones, personal care products, surfactants, and flame retardants, among others. EDCs are characterised by their ubiquitous presence at trace-level concentrations and their wide diversity. Since the discovery of the adverse effects of these pollutants on wildlife and human health, analytical methods have been developed for their qualitative and quantitative determination. In particular, mass-based analytical methods show excellent sensitivity and precision for their quantification. This paper reviews recently published analytical methodologies for the sample preparation and for the determination of these compounds in different environmental and biological matrices by liquid chromatography coupled with mass spectrometry. The various sample preparation techniques are compared and discussed. In addition, recent developments and advances in this field are presented.

Prioritization of chemicals in the aquatic environment based on risk assessment: analytical, modeling and regulatory perspective

The extensive and intensive use of chemicals in our developed, highly technological society includes more than 100,000 chemical substances. Significant scientific evidence has lead to the recognition that their improper use and release may result in undesirable and harmful side-effects on both the human and ecosystem health. To cope with them, appropriate risk assessment processes and related prioritization schemes have been developed in order to provide the necessary scientific support for regulatory procedures. In the present paper, two of the elements that constitute the core of risk assessment, namely occurrence and hazard effects, have been discussed. Recent advances in analytical chemistry (sample pre-treatment and instrumental equipment, etc.) have allowed for more comprehensive monitoring of environmental pollution reaching limits of detection up to sub ng L(-1). Alternative to analytical measurements, occurrence models can provide risk managers with a very interesting approach for estimating environmental concentrations from real or hypothetical scenarios. The most representative prioritization schemes used for issuing lists of concerning chemicals have also been examined and put in the context of existing environmental policies for protection strategies and regulations. Finally, new challenges in the field of risk-assessment have been outlined, including those posed by new materials (i.e., nanomaterials), transformation products, multi-chemical exposure, or extension of the risk assessment process to the whole ecosystem.

Chemiluminescence immunoassay for a nonionic surfactant using a compact disc-type microfluidic platform

A simple and pump-free chemiluminescence immunoassay based on a compact disc (CD)-type microfluidic platform for the determination of alkylphenol polyethoxylates (APnEOs) is described. The method is based on a competitive immunoreaction of the anti-APnEOs antibody immobilized on the magnetic microbeads between APnEOs and horseradish peroxidase (HRP)-labeled APnEOs in the sample solution. The luminol solution containing H2O2 and enhancer is caused to flow from one reservoir in the platform to another by appropriate adjustment of the speed of the rotation of the disc. The detection limit was similar to that reported in our previous paper, i.e., 10 ppb according to IC80.

Strategies for selecting optimal sampling and work-up procedures for analysing alkylphenol polyethoxylates in effluents from non-activated sludge biofilm reactors

Trace-level analysis of alkylphenol polyethoxylates (APEOs) in wastewater containing sludge requires the prior removal of contaminants and preconcentration. In this study, the effects on optimal work-up procedures of the types of alkylphenols present, their degree of ethoxylation, the biofilm wastewater treatment and the sample matrix were investigated for these purposes. The sampling spot for APEO-containing specimens from an industrial wastewater treatment plant was optimized, including a box that surrounded the tubing outlet carrying the wastewater, to prevent sedimented sludge contaminating the collected samples. Following these changes, the sampling precision (in terms of dry matter content) at a point just under the tubing leading from the biofilm reactors was 0.7% RSD. The findings were applied to develop a work-up procedure for use prior to a high-performance liquid chromatography-fluorescence detection analysis method capable of quantifying nonylphenol polyethoxylates (NPEOs) and poorly investigated dinonylphenol polyethoxylates (DNPEOs) at low microg L(-1) concentrations in effluents from non-activated sludge biofilm reactors. The selected multi-step work-up procedure includes lyophilization and pressurized fluid extraction (PFE) followed by strong ion exchange solid phase extraction (SPE). The yields of the combined procedure, according to tests with NP10EO-spiked effluent from a wastewater treatment plant, were in the 62-78% range.

Determination of various estradiol mimicking-compounds in sewage sludge by the combination of microwave-assisted extraction and LC-MS/MS

In this work, we present the development and application of a microwave assisted extraction followed by liquid chromatography-tandem mass spectrometry methodology (MAE-LC-MS/MS) for the determination of various estradiol-mimicking compounds in sewage sludge samples. For the purification of the MAE extracts, we have employed a solid phase extraction (SPE) clean-up procedure, previously optimised. The entire method provides recoveries between 71.7% and 103.1%, with relative standard deviation lower than 11.1% and limits of detection ranging from 0.6 to 3.5 ng g(-1). The developed method was applied to samples from three wastewater treatment plants (WWTPs) located in Las Palmas of Gran Canaria (Spain), two of which had a conventional activated sludge treatment (AST), whereas the third treatment plant had an advanced membrane bioreactor treatment (MBR). All of the analytes in the study, including (nonylphenol (NP), octylphenol (OP), and some of their ethoxylated chains AP(n)EOs (n ≤ 7), 17β-estradiol (E2), estriol (E3), 17α-ethynylestradiol (EE) and bisphenol-A (BPA)), were found in almost all samples in concentrations ranging from 0.9 to 710.2 ng g(-1).

Determination of alkylphenol polyethoxylates, bisphenol-A, 17α-ethynylestradiol and 17β-estradiol and its metabolites in sewage samples by SPE and LC/MS/MS

Recently, many chemicals released into the environment have been shown to mimic endogenous hormones such as estradiol. It has been demonstrated that these compounds cause several adverse effects on wildlife and humans, such as the feminization of animal species, development of physical abnormalities and birth defects, and reproductive failure. In an effort to model the behaviour of some endocrine-disrupting chemicals (EDCs) and to establish the level of contamination in sewage samples, a quantitative method for the simultaneous determination of nonylphenol, octylphenol and corresponding ethoxylates (1-12), 17α-ethynylestradiol, bisphenol-A, and 17β-estradiol and two of its metabolites have been developed. Identification and quantification were achieved by high performance liquid chromatography-tandem mass spectrometry (LC-ESI-MS/MS). Satisfactory detection limits (between 0.5-6 ng L(-1) in the dissolved phase and 1.4-12.7 ng g(-1) in the particulate phase) and analyte recoveries (between 60% and 108%) were achieved for target compounds. The optimised method was applied to the determination of EDCs in liquid sewage samples collected from a wastewater treatment plant (WWTP) in Las Palmas de Gran Canaria (Spain). Concentrations of EDCs ranged from <10 ng L(-1) to nearly 1200 ng L(-1) in the dissolved phase, and from 0.005 μg g(-1) to 2.8 μg g(-1) in the suspended particulate matter.