Most cited article - PubMed ID 26619247
Passive Sampling in Regulatory Chemical Monitoring of Nonpolar Organic Compounds in the Aquatic Environment
Hexachlorobenzene (HCB), listed on the Stockholm Convention on persistent organic pollutants and regulated as a hazardous priority pollutant by the Water Framework Directive (WFD), is ubiquitously distributed in the environment and assumed to mildly biomagnify in aquatic foodwebs. The proposal to include trophic magnification factors (TMFs) in the procedure for comparing contaminant levels in biota at different trophic levels (TLs) with WFD environmental quality standards requires adequate selection of TMFs. In the first step of our study, we compared two independently obtained datasets of pentachlorobenzene (PeCB) and HCB concentration ratios from passive sampling (PS) in water and in fish through routine monitoring programs in Norway to evaluate possible biomagnification. In this procedure, PeCB is used for benchmarking the bioconcentration in fish, and the observed HCB/PeCB ratios in fish are compared with ratios expected in the case of (i) HCB bioconcentration or (ii) biomagnification using published TMF values. Results demonstrate that it is not possible to confirm that HCB biomagnifies in fish species that would be used for WFD monitoring in Norway and challenges the proposed monitoring procedures for such compounds in Norwegian or European waters. In the second step, fish-water chemical activity ratios for HCB and PeCB as well as for polychlorinated biphenyls where biota and PS were conducted alongside were calculated and found to rarely exceed unity for cod (Gadus morhua), a fish species with a TL of approximately 4.
- Keywords
- biota, fish, hexachlorobenzene, passive sampling, polychlorinated biphenyls, water framework directive,
- MeSH
- Bioaccumulation MeSH
- Water Pollutants, Chemical * analysis MeSH
- Hexachlorobenzene analysis MeSH
- Environmental Monitoring methods MeSH
- Polychlorinated Biphenyls * analysis MeSH
- Food Chain MeSH
- Fishes MeSH
- Water MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Water Pollutants, Chemical * MeSH
- Hexachlorobenzene MeSH
- Polychlorinated Biphenyls * MeSH
- Water MeSH
The identification and prioritisation of water bodies presenting elevated levels of anthropogenic chemicals is a key aspect of environmental monitoring programmes. Albeit this is challenging owing to geographical scales, choice of indicator aquatic species used for chemical monitoring, and inherent need for an understanding of contaminant fate and distribution in the environment. Here, we propose an innovative methodology for identifying and ranking water bodies according to their levels of hydrophobic organic contaminants (HOCs) in water. This is based on a unique passive sampling dataset acquired over a 10-year period with silicone rubber exposures in surface water bodies across Europe. We show with these data that, far from point sources of contamination, levels of hexachlorobenzene (HCB) and pentachlorobenzene (PeCB) in water approach equilibrium with atmospheric concentrations near the air/water surface. This results in a relatively constant ratio of their concentrations in the water phase. This, in turn, allows us to (i) identify sites of contamination with either of the two chemicals when the HCB/PeCB ratio deviates from theory and (ii) define benchmark levels of other HOCs in surface water against those of HCB and/or PeCB. For two polychlorinated biphenyls (congener 28 and 52) used as model chemicals, differences in contamination levels between the more contaminated and pristine sites are wider than differences in HCB and PeCB concentrations endorsing the benchmarking procedure.
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The freely dissolved concentration (Cfree) of hydrophobic organic chemicals in sediments and soils is considered the driver behind chemical bioavailability and, ultimately, toxic effects in benthic organisms. Therefore, quantifying Cfree, although challenging, is critical when assessing risks of contamination in field and spiked sediments and soils (e.g., when judging remediation necessity or interpreting results of toxicity assays performed for chemical safety assessments). Here, we provide a state-of-the-art passive sampling protocol for determining Cfree in sediment and soil samples. It represents an international consensus procedure, developed during a recent interlaboratory comparison study. The protocol describes the selection and preconditioning of the passive sampling polymer, critical incubation system component dimensions, equilibration and equilibrium condition confirmation, quantitative sampler extraction, quality assurance/control issues and final calculations of Cfree. The full procedure requires several weeks (depending on the sampler used) because of prolonged equilibration times. However, hands-on time, excluding chemical analysis, is approximately 3 d for a set of about 15 replicated samples.
- MeSH
- Geologic Sediments analysis MeSH
- Hydrophobic and Hydrophilic Interactions MeSH
- Soil Pollutants analysis MeSH
- Solid Phase Microextraction methods MeSH
- Soil chemistry MeSH
- Environmental Pollution MeSH
- Publication type
- Journal Article MeSH
- Evaluation Study MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Names of Substances
- Soil Pollutants MeSH
- Soil 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.
- Keywords
- Diffusive gradients in thin films (DGT), Hydrogel, Passive sampling, Polar organic compounds, Water monitoring,
- MeSH
- Water Pollutants, Chemical analysis MeSH
- Diffusion MeSH
- Fluorocarbons chemistry MeSH
- Hydrogels chemistry MeSH
- Heptanoic Acids chemistry MeSH
- Organic Chemicals chemistry MeSH
- Rivers chemistry MeSH
- Sepharose chemistry MeSH
- Water MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Czech Republic MeSH
- Names of Substances
- Water Pollutants, Chemical MeSH
- Fluorocarbons MeSH
- Hydrogels MeSH
- Heptanoic Acids MeSH
- Organic Chemicals MeSH
- perfluoro-n-heptanoic acid MeSH Browser
- Sepharose MeSH
- Water MeSH
This work presents the results of an international interlaboratory comparison on ex situ passive sampling in sediments. The main objectives were to map the state of the science in passively sampling sediments, identify sources of variability, provide recommendations and practical guidance for standardized passive sampling, and advance the use of passive sampling in regulatory decision making by increasing confidence in the use of the technique. The study was performed by a consortium of 11 laboratories and included experiments with 14 passive sampling formats on 3 sediments for 25 target chemicals (PAHs and PCBs). The resulting overall interlaboratory variability was large (a factor of ∼10), but standardization of methods halved this variability. The remaining variability was primarily due to factors not related to passive sampling itself, i.e., sediment heterogeneity and analytical chemistry. Excluding the latter source of variability, by performing all analyses in one laboratory, showed that passive sampling results can have a high precision and a very low intermethod variability (
- MeSH
- Water Pollutants, Chemical * MeSH
- Geologic Sediments * MeSH
- Risk Assessment MeSH
- Environmental Monitoring MeSH
- Organic Chemicals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, N.I.H., Extramural MeSH
- Names of Substances
- Water Pollutants, Chemical * MeSH
- Organic Chemicals MeSH
Water is a vital resource for natural ecosystems and human life, and assuring a high quality of water and protecting it from chemical contamination is a major societal goal in the European Union. The Water Framework Directive (WFD) and its daughter directives are the major body of legislation for the protection and sustainable use of European freshwater resources. The practical implementation of the WFD with regard to chemical pollution has faced some challenges. In support of the upcoming WFD review in 2019 the research project SOLUTIONS and the European monitoring network NORMAN has analyzed these challenges, evaluated the state-of-the-art of the science and suggested possible solutions. We give 10 recommendations to improve monitoring and to strengthen comprehensive prioritization, to foster consistent assessment and to support solution-oriented management of surface waters. The integration of effect-based tools, the application of passive sampling for bioaccumulative chemicals and an integrated strategy for prioritization of contaminants, accounting for knowledge gaps, are seen as important approaches to advance monitoring. Including all relevant chemical contaminants in more holistic "chemical status" assessment, using effect-based trigger values to address priority mixtures of chemicals, to better consider historical burdens accumulated in sediments and to use models to fill data gaps are recommended for a consistent assessment of contamination. Solution-oriented management should apply a tiered approach in investigative monitoring to identify toxicity drivers, strengthen consistent legislative frameworks and apply solutions-oriented approaches that explore risk reduction scenarios before and along with risk assessment.
