The goal of this study is to enhance the identification of unknown compounds in LC chromatograms of untreated raw water used for drinking water production by (1) preconcentration of samples and (2) prioritization of the unknown peaks based on their bioactivity. Preconcentration was done by solid phase extraction (SPE) of 3L large volume (LV) groundwater samples or by 6-week passive sampler (PS) deployment in the groundwater, using divinylbenzene as active phase. Bioactivity of the samples was tested as a decrease in bioluminescence in the Allivibrio fischeri bioassay, which was chosen as a broad-scale bioanalytical tool responding to many different types of pollutants. Samples were collected at three different drinking water production stations with low or high degree of anthropogenic influence. At two stations, different groundwater inlets were sampled. At one station, samples were taken at different stages in the drinking water production process. SPE and PS extracts were used for target analysis and non-target screening, and for testing in the bioassay before and after high-resolution fractionation. More target compounds were detected in the concentrated LV and PS extracts than in a 1 mL direct injection of the water. As expected least compounds and lowest bioassay responses were detected in the raw water from the station with least anthropogenic influence. PS extracts gave much higher bioassay responses than the LV extracts. Both chemical and bioassay analysis of samples collected during subsequent steps in the drinking water production process confirmed the efficient removal of (bioactive) contaminants. In addition to the 4 peaks detected in the bioassay chromatogram of the reference station, the more anthropogenically influenced stations showed additional peaks indicative for the presence of anthropogenic substances. Identification of suspect compounds responsible for these additional peaks will proceed according to a three-step procedure, i.e. based on (1) exact mass and isotopic pattern of compounds available in different suspect lists, (2) fragment ions assigned to a precursor available in spectral libraries, and (3) estimated elemental composition. Reference standards will be obtained for the suspect compounds to confirm their retention time and bioactivity. Results from the identification process are available by the end of May 2020, and will be presented at the SETAC Europe conference.
It has been suggested that domestic animals can serve as sentinels for human exposures. In this study our objectives were to demonstrate that i) silicone collars can be used to measure environmental exposures of (domestic) animals, and that ii) domestic animals can be used as sentinels for human residential exposure. For this, we simultaneously measured polycyclic aromatic hydrocarbons (PAHs) using silicone bands worn by 30 pet cats (collar) and their owner (wristband). Collars and wristbands were worn for 7 days and analyzed via targeted Gas Chromatography-Mass Spectrometry (GC-MS). Demographics and daily routines were collected for humans and cats. Out of 16 PAHs, 9 were frequently detected (>50% of samples) in both wristbands and collars, of which Phenanthrene and Fluorene were detected in all samples. Concentrations of wristbands and collars were moderately correlated for these 9 PAHs (Median Spearman's r = 0.51 (range 0.16-0.68)). Determinants of PAH concentrations of cats and humans showed considerable overlap, with vacuum cleaning resulting in higher exposures and frequent changing of bed sheets in lower exposures. This study adds proof-of-principle data for the use of silicone collars to measure (domestic) animal exposure and shows that cats can be used as sentinels for human residential exposure.
With increasing numbers of chemicals used in modern society, assessing human and environmental exposure to them is becoming increasingly difficult. Recent advances in wastewater-based epidemiology enable valuable insights into public exposure to data-poor compounds. However, measuring all >26,000 chemicals registered under REACH is not just technically unfeasible but would also be incredibly expensive. In this paper, we argue that estimating emissions of chemicals based on usage data could offer a more comprehensive, systematic and efficient approach than repeated monitoring. Emissions of 29 active pharmaceutical ingredients (APIs) to wastewater were estimated for a medium-sized city in the Netherlands. Usage data was collected both on national and local scale and included prescription data, usage in health-care institutions and over-the-counter sales. Different routes of administration were considered as well as the excretion and subsequent in-sewer back-transformation of conjugates into respective parent compounds. Results suggest model-based emission estimation on a city-level is feasible and in good agreement with wastewater measurements obtained via passive sampling. Results highlight the need to include excretion fractions in the conceptual framework of emission estimation but suggest that the choice of an appropriate excretion fraction has a substantial impact on the resulting model performance.
In our modern world a large number of man-made chemicals are being used.As a consequence their widespread presence in the environment is becoming increasingly well documented (Vethaak et al, 2002;Peters et al., 2008).They are found in a vast range of consumer products and include plasticizers, emulsifiers, flame retardants, perfluorinated compounds, artificial musks and organotin compounds.While they have undoubtedly improved the quality of our lives, a consequence of their intensive use is a widespread presence in the environment.Human exposure to these compounds may be through contact with consumer products containing such chemicals as additives, but also through food products.Since many of these compounds have a lipophilic nature there is a potential for bio-accumulation through the food chain especially in products with a high fat content.This is reflected in the presence of persistent organic compounds such as organochlorine pesticides and polychlorinated biphenyls that can be found in food products although there use has been seized many years ago.Many of these compounds have also been found in human blood indicating that humans are exposed to these chemicals (CDC, 2001(CDC, , 2003;;Guenther et al., 2002).This exposure may be through different routes.One is the use of these chemicals as additives in consumer products such as carpets, curtains, toys and electronic equipment.The exposure of these chemicals in house dust indicates the potential for human exposure.Another route for human exposure is, of course, through food products.Since many of these compounds have a lipophilic nature, they can be bio-accumulated through the food chain especially in products with a high fat content.This study focused on the presence and concentrations of a number of typical man-made chemicals in food products that many of use daily.The chemicals considered in this study are: brominated flame retardants (BFR's), phthalates, artificial musks, alkylphenols (AP's), organochlorine pesticides (OCP's), polychlorobiphenyls (PCB's), organotin compounds (OT's) and perfluorinated compounds (PFC's). Methods and materials Sampling and sample pre-treatmentAll samples, mostly fresh food products were purchased in regular shops in nine European countries including the Netherlands, the United Kingdom, Germany, Finland, Sweden, www.intechopen.comPesticides in the Modern World -Risks and Benefits 70 Spain, Poland, Italy, Estonia and Greece.Samples were sent to the laboratory where laboratory samples were prepared and stored at -18°C until analysis.In general, solid food samples were cut into small pieces and homogenised with a blender.If not the entire sample was used or homogenised, proportional sub-sampling was applied and the collected subsamples were homogenised.Milk was acidified with formic acid and the solid part containing the proteins and fat was separated from the liquid phase.Both parts were stored for analysis.Orange juice was centrifuged and vacuum filtrated and the solid and liquid parts were stored for analysis.A selected number of chemical parameters were determined in each sample, based on expectations and reports in the literature. Chemical parametersThe chemical parameters determined in this study are listed in table 1, including the abbreviations that are used throughout the text and in the result tables.Note that not all parameters are determined in all samples. Analytical proceduresFor the determination of the OCP's, PCB's, BFR's, phthalates and artificial musks, a weight sub-sample of the homogenised laboratory sample was mixed with anhydrous sodium sulphate in a mortar and spiked with internal standards.The internal standards used were 13 C-labelled standards for PCB's and BFR's, 2 D-labelled standards for OCP's and phthalates, and a surrogate standard for the artificial musks.The samples were Soxhlet extracted for 16 hours using a mixture of 10% diethyl ether in hexane.For milk and orange juice a proportional amount of the liquid phase was pre-extracted with hexane and this hexane extract was used in the Soxhlet extraction of the solid part of these samples.Olive oil was directly diluted in hexane.One procedural blank, consisting of 40 g anhydrous sodium sulphate, was included in every batch of 10 samples.All extracts were concentrated to a volume of 50 ml and split into two equal parts of 25 ml.For the determination of the OCP's, PCB's and BFR's, one part of the extract was washed several times with sulphuric acid of increasing concentration to remove the major part of the lipids.The remaining extract was concentrated and purified over a glass chromatographic column packed with florisil and capped with anhydrous sodium sulphate to isolate the fraction containing the OCP's, PCB's, PBDE's and HBCD.The eluent was concentrated to a small volume and a syringe standard (1,2,3,4-tetrachloronaphthalene) was added.This final extract was analysed on an Agilent 6890 series gas chromatograph coupled to an Agilent 5973 mass spectrometer (GC/MS) and equipped with a HP-5-MS, 30 m × 0.25 mm (i.d.), film thickness 0.25 µm, fused silica capillary column.The mass spectrometer was operated in the selected ion monitoring mode and typically two or three characteristic ion masses were monitored for each analyte.The samples were analyzed for the following OCP's; -, -and -hexachlorohexane (HCH), hexachlorobenzene (HCB), -and -chlordane, o,p'-, p,p'-DDE, o,p'-, p,p'-DDD and o,p'-, p,p'-DDT: The following PCB congeners: 18, 28/31, 22, 41/64, 44, 49, 52, 54, 56/60, 70, 74, 87
The exposure to some chemicals can lead to hormone disrupting effects. Presently, much attention is focused on so-called xeno-estrogens, synthetic compounds that interact with hormone receptors causing a number of reactions that eventually lead to effects related to reproduction and development. The current study was initiated to investigate the presence of a number of such compounds in precipitation as a follow-up on a previous study in which pesticide concentrations in air and precipitation were determined. Rainwater samples were collected at about 50 locations in The Netherlands in a four week period. The samples were analysed for bisphenol-A, alkylphenols and alkylphenol ethoxylates, phthalates, flame retardants and synthetic musk compounds. The results clearly indicated the presence of these compounds in precipitation. The concentrations ranged from the low ng l(-1) range for flame retardants to several thousands of ng l(-1) for the phthalates. Bisphenol-A was found in 30% of the samples in concentrations up to 130 ng l(-1), while alkylphenols and alkylphenol ethoxylates were found in virtually all locations in concentrations up to 920 ng l(-1) for the individual compounds. Phthalates were by far the most abundant xeno-estrogens in the precipitation samples and were found in every sample. Di-isodecyl phthalate was found in a surprisingly high concentration of almost 100 000 ng l(-1). Polybrominated flame retardants were found in the low ng l(-1) range and generally in less than 20% of the samples. Noticeable was the finding of hexabromocyclododecane, a replacement for the polybrominted diphenyl ethers at one location in a concentration of almost 2000 ng l(-1). Finally, as expected, synthetic musk compounds were detected in almost all samples. This is especially true for the polycyclic musks HHCB and AHTN. Nitro musks were found, but only on a few locations. Kriging techniques were used to calculate precipitation concentrations in between actual sampling locations to produce contour plots for a number of compounds. These plots clearly show located emission sources for a number of compounds such as bisphenol-A, nonylphenol ethoxylate, phthalates and AHTN. On the contrary, the results for HHCB and some phthalates indicated diffuse emission patterns, probably as the result of the use of consumer products containing these compounds.
Compounds originating from animal husbandry can pollute surface water through the application of manure to soil. Typically, grab sampling is employed to detect these residues, which only provides information on the concentration at the time of sampling. To better understand the emission patterns of these compounds, we utilized passive samplers in surface water to collect data at eight locations in a Dutch agricultural region, during different time intervals. As a passive sampler, we chose the integrative-based Speedisk® hydrophilic DVB. In total, we targeted 46 compounds, among which 25 antibiotics, three hormones, nine antiparasitics, and nine disinfectants. From these 46 compounds, 22 compounds accumulated in passive samplers in amounts above the limit of quantification in at least one sampling location. Over the 12-week deployment period, a time integrative uptake pattern was identified in 53% of the examined cases, with the remaining 47% not displaying this behavior. The occurrences without this behavior were primarily associated with specific location, particularly the most upstream location, or specific compounds. Our findings suggest that the proposed use of passive samplers, when compared in this limited context to traditional grab sampling, may provide enhanced efficiency and potentially enable the detection of a wider array of compounds. In fact, a number of compounds originating from animal husbandry activities were quantified for the first time in Dutch surface waters, such as flubendazole, florfenicol, and tilmicosine. The set-up of the sampling campaign also allowed to distinguish between different pollution levels during sampling intervals on the same location. This aspect gains particular significance when considering the utilization of different compounds on various occasions, hence, it has the potential to strengthen ongoing monitoring and mitigation efforts.
The combination of integrative passive sampling and bioassays is a promising approach for monitoring the toxicity of polar organic contaminants in aquatic environments. However, the design of integrative passive samplers can affect the accumulation of compounds and therewith the bioassay responses. The present study aimed to determine the effects of sampler housing and sorbent type on the number of chemical features accumulated in polar passive samplers and the subsequent bioassay responses to extracts of these samplers. To this end, four integrative passive sampler configurations, resulting from the combination of polar organic chemical integrative sampler (POCIS) and Speedisk housings with hydrophilic-lipophilic balance and hydrophilic divinylbenzene sorbents, were simultaneously exposed at reference and contaminated surface water locations. The passive sampler extracts were subjected to chemical non-target screening and a battery of five bioassays. Extracts from POCIS contained a higher number of chemical features and caused higher bioassay responses in 91% of cases, while the two sorbents accumulated similar numbers of features and caused equally frequent but different bioassay responses. Hence, the passive sampler design critically affected the number of accumulated polar organic contaminants as well as their toxicity, highlighting the importance of passive sampler design for effect-based water quality assessment.
