Equilibrium passive sampling
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Total concentrations of hydrophobic organic contaminants (HOCs) in sediment present a poor quality assessment parameter for aquatic organism exposure and environmental risk because they do not reflect contaminant bioavailability. The bioavailability issue of HOCs in sediments can be addressed by application of multi-ratio equilibrium passive sampling (EPS). In this study, riverbed sediment samples were collected during the Joint Danube Survey at 9 locations along the Danube River in 2013. Samples were ex-situ equilibrated with silicone passive samplers. Desorption isotherms were constructed, yielding two endpoints: pore water (CW:0) and accessible (CAS:0) concentration of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers in sediment. CW:0 concentrations of DDT and its breakdown products exhibited elevated levels in the low Danube, with the maximum in the river delta. Other investigated HOCs did not show any clear spatial trends along the river, and only a moderate CW:0 variability. CAS:0 in sediment ranged from 10 to 90% of the total concentration in sediment. CW:0 was compared with freely dissolved concentration in the overlaying surface water, measured likewise by passive sampling. The comparison indicated potential compound release from sediment to the water phase for PAHs with less than four aromatic rings, and for remaining HOCs either equilibrium between sediment and water, or potential compound deposition in sediment. Sorption partition coefficients of HOC to organic carbon correlated well with octanol-water partition coefficients (KOW), showing stronger sorption of PAHs to sediment than that of PCBs and OCPs having equal logKOW. Comparison of CW:0 values with European environmental quality standards indicated potential exceedance for hexachlorobenzene, fluoranthene and benzo[a]pyrene at several sites. The study demonstrates the utility of passive sampling as an innovative approach for risk-oriented monitoring of HOCs in river catchments.
Many semi-volatile organic compounds (SVOCs) accumulate in indoor dust, which serves as a repository for those compounds. The presence of SVOCs in indoor environments is of concern because many of them are suspected to have toxic effects. Total SVOC concentrations in the dust are generally used for exposure assessment to indoor contaminants, assuming that 100% of the SVOCs is accessible for human uptake. However, such an assumption may potentially lead to an overestimated risk related to dust exposure. We applied a multi-ratio equilibrium passive sampling (MR-EPS) for estimation of SVOC accessibility in indoor settled dust using silicone passive samplers and three particle size dust fractions, <0.25 mm, 0.25-0.5 mm, and 1-2 mm in dry and wet conditions. Equilibrations were performed at various sampler-dust mass ratios to achieve different degrees of SVOC depletion, allowing the construction of a desorption isotherm. The desorption isotherms provided accessible fractions (FAS), equivalent air concentrations (CAIR), dust-air partition coefficients (KDUST-AIR) and organic carbon-air partition coefficients (KOC-AIR). The highest FAS were observed in the <0.25 mm dust fraction in wet conditions which is relevant for exposure assessment via oral ingestion. The highest CAIR were estimated for several organophosphorus flame retardants (OPFRs), polycyclic aromatic hydrocarbons (PAHs) and synthetic musks. The logKOC-AIR did not differ between dust particle sizes in dry and wet conditions but within compound groups, different relationships with hydrophobicity were observed. Equivalent lipid-based concentrations (CL⇌DUST) calculated using available lipid-silicone partition coefficients (KLIP-SIL) were compared with lipid-based concentrations (CL) measured in human-related samples collected from Europeans. For hexachlorobenzene (HCB), CL⇌DUST, and CL were similar, indicating equilibrium attainment between environment and human samples. Lipid-based concentrations for persistent legacy contaminants were also similar but lower for PBDEs in human samples. Overall, accessibility estimation using MR-EPS in dust further contributes to human risk assessment.
- MeSH
- hodnocení rizik MeSH
- lidé MeSH
- lipidy MeSH
- monitorování životního prostředí MeSH
- prach analýza MeSH
- retardanty hoření * analýza MeSH
- těkavé organické sloučeniny * analýza MeSH
- znečištění vzduchu ve vnitřním prostředí * analýza MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The freely dissolved concentration (C(w,0)) in the pore water and the accessible (releasable) concentration in the sediment (C(as,0)) are important parameters for risk assessment. These parameters were determined by equilibrating contaminated sediments and passive samplers using largely differing sampler–sediment ratios. This method is based on the principle that incubations at low sampler/sediment ratios yield the concentration in the pore water (minor depletion of the sediment phase) and incubations at high sampler/sediment ratios yield the accessible concentration in the sediment (maximum depletion of the sediment phase). It is shown that equilibration was faster in dense suspensions and at high sampler/sediment ratios when compared to low sampler/sediment ratios. An equilibrium distribution model was used to estimate C(w,0) and C(as,0) by nonlinear least-squares regression. The method was evaluated for three sediments (harbor, estuarine, marine). Accessible concentrations of 13 PAHs were 2 (low K(ow)) to 10 (high K(ow)) times lower than the total concentrations (three sediments). By contrast, the accessible concentrations of 15 PCBs were about 1.2 times lower than the total concentrations and displayed no trend with K(ow) (one sediment). Implications for risk assessment and considerations for application of multi-ratio equilibrium passive sampling with other sediments are discussed.
- MeSH
- chemické látky znečišťující vodu analýza MeSH
- geologické sedimenty analýza MeSH
- hodnocení rizik MeSH
- monitorování životního prostředí metody MeSH
- polychlorované bifenyly analýza MeSH
- polycyklické aromatické uhlovodíky analýza MeSH
- poréznost MeSH
- teoretické modely MeSH
- uhlík analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Passive sampling is widely used to measure levels of contaminants in various environmental matrices, including fish tissue. Equilibrium passive sampling (EPS) of persistent organic pollutants (POP) in fish tissue has been hitherto limited to application in lipid-rich tissue. We tested several exposure methods to extend EPS applicability to lean tissue. Thin-film polydimethylsiloxane (PDMS) passive samplers were exposed statically to intact fillet and fish homogenate and dynamically by rolling with cut fillet cubes. The release of performance reference compounds (PRC) dosed to passive samplers prior to exposure was used to monitor the exchange process. The sampler-tissue exchange was isotropic, and PRC were shown to be good indicators of sampler-tissue equilibration status. The dynamic exposures demonstrated equilibrium attainment in less than 2 days for all three tested fish species, including lean fish containing 1% lipid. Lipid-based concentrations derived from EPS were in good agreement with lipid-normalized concentrations obtained using conventional solvent extraction. The developed in-tissue EPS method is robust and has potential for application in chemical monitoring of biota and bioaccumulation studies.
- MeSH
- chemické látky znečišťující vodu * MeSH
- lipidy * MeSH
- monitorování životního prostředí MeSH
- řízení kvality MeSH
- ryby * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The freely dissolved concentration of persistent organic pollutants (POPs) is one of the most important parameters for risk assessment in aquatic environments, due to its proportionality to the chemical activity. Chemical activity difference represents the driving force for a spontaneous contaminant transport, such as water-aquatic biota or water-sediment. Freely dissolved concentrations in sediment pore water can be estimated from the concentrations in a partition-based passive sampler equilibrated in suspensions of contaminated sediment. Equilibration in the sediment/passive sampler system is slow, since concentrations of most POPs in the water phase, which is the main route for mass transfer, are very low. Adding methanol to sediment in suspension increases the POPs' solubility and, consequently, the permeability in the water phase. The resulting higher aqueous concentrations enhance POPs mass transfer up to three times for investigated POPs (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorine pesticides) and shorten equilibrium attainment to less than 6 weeks. The addition of methanol to the aqueous phase up to a molar fraction of 0.2 changed the POPs equilibrium distribution ratio between sediment and passive sampler by less than a factor of two. As a result, the pore water concentrations of POPs, calculated from their amounts accumulated in a passive sampler, are affected by methanol addition not more than by the same factor.
- MeSH
- chemické látky znečišťující vodu analýza MeSH
- chlorované uhlovodíky analýza MeSH
- geologické sedimenty analýza MeSH
- methanol chemie MeSH
- monitorování životního prostředí metody MeSH
- pesticidy analýza MeSH
- polychlorované bifenyly analýza MeSH
- polycyklické aromatické uhlovodíky analýza MeSH
- rozpustnost MeSH
- Publikační typ
- časopisecké články MeSH
The applicability of a polar organic chemical integrative sampler (POCIS) for detection and determination of perfluorinated acids and sulfonates in water was studied under field conditions. Standard POCIS configurations (i.e., pharmaceutical and pesticide) were deployed in effluent from a wastewater treatment plant for 1, 2, and 3 weeks. Ten of 15 target compounds were found in POCIS, five of which were quantified in wastewater. Pest-POCIS appeared more effective for the sampling, while Pharm-POCIS had a more rapid uptake kinetic, which leads to faster saturation or equilibrium. The results showed that the pesticide configuration is probably more suitable for the sampling of this class of compounds. Based on average concentration in water over the sampling period and amount of compound adsorbed in the POCIS, we calculated sampling rates for five studied compounds and obtained values of 0.034 to 0.222 L day(-1).
- MeSH
- alkylsulfonany analýza MeSH
- chemické látky znečišťující vodu analýza MeSH
- fluorokarbony analýza MeSH
- monitorování životního prostředí přístrojové vybavení metody MeSH
- odpadní voda analýza MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
- polymery analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Hydrophilic divinylbenzene (DVB) (Bakerbond) has surfaced as a promising sorbent for active sampling of analytes from aqueous matrices over a very broad polarity range. Given this, hydrophilic DVB may likewise offer potential for passive sampling, if sorbent/water partitioning coefficients (Ksw) were to be available. In this work, static exposure batch experiments were performed to quantitatively study the equilibrium sorption of 131 environmentally relevant organic contaminants (P values ranging from -1.30 to 9.85) on hydrophilic DVB. The superior affinity of hydrophilic DVB, as compared to Oasis HLB, for compounds with a broad polarity range was confirmed by functional Fourier-transform infrared spectroscopy and Raman characterization, demonstrating the presence of carboxyl moieties. Concentration effects were studied by increasing compound concentrations in mixture experiments and resulted in the steroidal endocrine disrupting compounds in higher Ksw, while lower Ksw were obtained for the (alkyl)phenols, personal care products, pesticides, pharmaceuticals, and phthalates. Nevertheless, Ksw remained constant in the said design for equilibrium water concentrations at environmentally relevant seawater levels. An independent analysis of thermodynamic parameters (change in enthalpy, entropy, and Gibbs free energy) revealed the nature of the main partitioning processes. While polar (log P < 4) compounds were mainly served by physisorption, nonpolar (log P > 4) compounds also exhibited binding by multiple hydrogen bonding. In conclusion, this research facilitates the future application of hydrophilic DVB for active as well as passive sampling in the analysis of organic contaminants for monitoring purposes and for toxicity testing.
Nowadays, passive sampling is a widely applied technique to determine freely dissolved aqueous concentrations of hydrophobic organic chemicals (HOCs), such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Crucial to the measurements are sampler-water partition coefficients, which are generally determined in the laboratory under "standard conditions" (in freshwater at 20 °C). Theoretically, however, the coefficients are dependent on environmental conditions, such as temperature and salinity. Yet, there are insufficient experimental data in the scientific literature to prove this for different polymers. Several polymers are already being applied during field monitoring, however, and neglecting any effects may lead to imprecise results. In the present study, we therefore quantified the effects of temperature and salinity on the sampler-water partition coefficients of PAHs and PCBs for silicone rubber, a material used in Dutch passive sampling monitoring campaigns. The results demonstrated a chemical-specific and hydrophobicity-dependent temperature effect, being independent of salinity, and a chemical- and temperature-independent salinity effect. Based on the obtained data, location-specific silicone rubber-water partition coefficients (Ksr-w; adjusted for temperature and salinity) can be calculated. The impact of applying such location-specific values was demonstrated using the Dutch passive sampling field monitoring database, covering ten years of PAH and PCB data for several locations. Adjusting the Ksr-w values resulted in aqueous concentrations that were lowered by a factor of 1.6 on average. The reduction was rather constant because of the manner of sampling (under nonequilibrium conditions and using performance reference compounds) and calculating. When sampling under equilibrium conditions in seawater at temperatures at about freezing, and/or applying different calculation approaches, the adjustment effect can potentially increase up to a factor of about 5-6 for the more hydrophobic PAHs and PCBs. Although this study exclusively focused on silicone rubber, qualitatively the results will also apply to other passive sampling materials.
- MeSH
- časové faktory MeSH
- hydrofobní a hydrofilní interakce * MeSH
- monitorování životního prostředí přístrojové vybavení metody MeSH
- organické látky analýza MeSH
- polychlorované bifenyly analýza MeSH
- polycyklické aromatické uhlovodíky analýza MeSH
- referenční standardy MeSH
- salinita * MeSH
- silikonové elastomery analýza MeSH
- teplota * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Passive samplers based on diffusive gradients in thin hydrogel films (DGT) were recently modified for sampling of polar organic compounds in water. However, since the sampling rates of the commonly used DGT design with the surface area of 3.1 cm2 are low, we propose to increase them by applying a two-sided design with a larger sampling surface area of 22.7 cm2. The sampler design consists of two sorptive hydrogel disks compressed between two diffusive hydrogel disk layers strengthened by nylon netting and held together by two stainless steel rings. Sorbent/water distribution coefficients (KSW) were determined, and the sampler was calibrated for monitoring 11 perfluoroalkyl substances and 12 pharmaceuticals and personal care products in water at laboratory conditions using a closed system with artificial flow generated by submersible pumps. A field performance test was conducted at five locations in the Morava River basin in Czech Republic. The median value of laboratory-derived sampling rates was 43 mL day-1 with extreme values of 2 mL day-1 and 90 mL day-1 for perfluorotridecanoic and perfluoroheptanoic acids, respectively. The log KSW values of tested compounds ranged from 3.18 to 5.47 L kg-1, and the estimated halftime to attain sampler-water equilibrium ranged from 2 days to more than 28 days, which is the maximum recommended exposure period, considering potential issues with the stability of hydrogel. The sampler can be used for assessment of spatial trends as well as estimation of aqueous concentration of investigated polar compounds.
- MeSH
- chemické látky znečišťující vodu analýza MeSH
- difuze MeSH
- fluorokarbony chemie MeSH
- hydrogely chemie MeSH
- kyseliny heptylové chemie MeSH
- organické látky chemie MeSH
- řeky chemie MeSH
- sefarosa chemie MeSH
- voda MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
The concentrations of hydrophobic organic compounds (HOCs) in aquatic biota are used for compliance, as well as time and spatial trend monitoring in the aqueous environment (European Union water framework directive, OSPAR). Because of trophic magnification in the food chain, the thermodynamic levels of HOCs, for example, polychlorinated biphenyl congeners, dichlorodiphenyltrichloroethane, and brominated diphenyl ether congeners, in higher trophic level (TL) organisms are expected to be strongly elevated above those in water. This work compares lipid-based concentrations at equilibrium with the water phase derived from aqueous passive sampling (CL⇌water) with the lipid-based concentrations in fillet and liver of fish (CL) at different TLs for three water bodies in the Czech Republic and Slovakia. The CL values of HOCs in fish were near CL⇌water, only after trophic magnification up to TL = 4. For fish at lower TL, CL progressively decreased relative to CL⇌water as KOW of HOCs increased above 106. The CL value decreasing toward the bottom of the food chain suggests nonequilibrium for primary producers (algae), which is in agreement with modeling passive HOC uptake by algae. Because trophic magnification and the resulting CL in fish exhibit large natural variability, CL⇌water is a viable alternative for monitoring HOCs using fish, showing a twofold lower confidence range and requiring less samples.
- MeSH
- chemické látky znečišťující vodu * analýza MeSH
- monitorování životního prostředí * MeSH
- potravní řetězec MeSH
- ryby MeSH
- sladká voda MeSH
- voda MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
- Slovenská republika MeSH
