11 research outputs found
Advancing the use of passive sampling in risk assessment and management of contaminated sediments: Results of an international passive sampling inter-laboratory comparison
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
Updated and validated solar irradiance reference spectra for estimating environmental photodegradation rates
Irradiance reference spectra are used to calculate environmentally relevant photodegradation half-lives, but the currently used spectra were originally published in the 1980s with limited validation. The goal of this work is to provide updated irradiance reference spectra using the Simple Model of the Atmospheric Radiative Transfer of Sunshine (SMARTS). The SMARTS irradiance spectra were validated against measurements from several high-resolution spectroradiometers, and the updated irradiance reference spectra use current measurements for atmospheric species that can affect the irradiance that reaches the Earth's surface. These updated irradiance spectra are provided in 1 nm increments from 280 to 800 nm for 0° to 70° latitude at 10° increments in both the northern and southern hemisphere. Lastly, the influence of the input parameters on the modeled irradiance spectra was investigated. This work will allow users to calculate more accurate photodegradation half-lives using the updated irradiance reference spectra, and it also provides insight for users to calculate their own location- and time-specific irradiance spectra using SMARTS.ISSN:2050-7887ISSN:2050-789
Correction: Updated and validated solar irradiance reference spectra for estimating environmental photodegradation rates
Correction for ‘Updated and validated solar irradiance reference spectra for estimating environmental photodegradation rates’ by Jennifer N. Apell and Kristopher McNeill, Environ. Sci.: Processes Impacts, 2019, 21, 427–437.ISSN:2050-7887ISSN:2050-789
Validating the Use of Performance Reference Compounds in Passive Samplers to Assess Porewater Concentrations in Sediment Beds
Hydrophobic organic compounds (HOCs)
like polycyclic aromatic hydrocarbons
(PAHs) and polychlorinated biphenyls (PCBs) tend to accumulate in
sediment beds when they are released into aquatic environments. Due
to this buildup of HOCs in the sediment, the highest water concentrations
are often in the pore water. Passive samplers can be used in the field
(i.e., in situ) to measure freely dissolved porewater concentrations
if target contaminants diffusing through the sediment and into the
sampler exhibit the same diffusive retardation factors as performance
reference compounds (PRCs) that are diffusing out of the sampler and
into the sediment. To test this assumption, polyethylene (PE) passive
samplers were placed in an organic- and black- carbon-rich sediment
bed in the laboratory with samplers removed every 30 days for 4 months.
The concentrations of target contaminants in the PE at each time point,
corrected using measures of the losses of PRCs, were in good agreement
with separately measured equilibrium concentrations in a well-mixed
system. Concentrations in the PE passive samplers, normalized by their
polyethylene-water partition coefficients, were also in good agreement
with directly measured porewater concentrations. Finally, PE-deduced
porewater concentrations were compared with the traditional equilibrium
partitioning models and showed that considering sorption to only organic
carbon substantially overestimated porewater concentrations. However,
predictions improved greatly if sorption to black carbon was also
considered
Linking Triclosan's Structural Features to Its Environmental Fate and Photoproducts
Triclosan is a high-production volume chemical, which has become widely detected in environmental systems because of its widespread usage. Photodegradation has been identified as a major degradation pathway, but the identified photoproducts are also chemicals of concern. In this study, lower chlorinated derivatives of triclosan were synthesized to investigate the impact the chlorine substituents have on the photodegradation rate and the photoproducts produced. In addition, the photodegradation of two classes of photoproducts-dibenzo-p-dioxins (DDs) and 2,2'-dihydroxylated biphenyls-was also investigated. Degradation of triclosan in near-surface sunlit waters was relatively fast (t1/2 < 5 h). Calculated degradation rates were slower for DDs and faster for dihydroxylated biphenyls in comparison to that for triclosan. In addition, the 2'-Cl substituent was critical for the high quantum yield measured for triclosan and necessary for the photodegradation mechanism that forms DDs and dihydroxylated biphenyls. The 4-Cl substituent was responsible for higher rates of light absorption and the environmentally relevant pKa. Without either of these substituents, the environmental fate of triclosan would be markedly different.ISSN:0013-936XISSN:1520-585
In situ passive sampling of sediments in the Lower Duwamish Waterway Superfund site: Replicability, comparison with ex situ measurements, and use of data
Advancing the Use of Passive Sampling in Risk Assessment and Management of Sediments Contaminated with Hydrophobic Organic Chemicals: Results of an International Ex Situ Passive Sampling Interlaboratory Comparison Michiel T. O. Jonker*†, Stephan A. van der He
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 (Advancing the Use of Passive Sampling in Risk Assessment and Management of Sediments Contaminated with Hydrophobic Organic Chemicals: Results of an International Ex Situ Passive Sampling Interlaboratory Comparison Michiel T. O. Jonker*†, Stephan A. van der HepublishedVersio
Advancing the Use of Passive Sampling in Risk Assessment and Management of Sediments Contaminated with Hydrophobic Organic Chemicals : Results of an International Ex Situ Passive Sampling Interlaboratory Comparison
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 (<factor of 1.7). It is concluded that passive sampling, irrespective of the specific method used, is fit for implementation in risk assessment and management of contaminated sediments, provided that method setup and performance, as well as chemical analyses are quality-controlled
Advancing the Use of Passive Sampling in Risk Assessment and Management of Sediments Contaminated with Hydrophobic Organic Chemicals: Results of an International Ex Situ Passive Sampling Interlaboratory Comparison
Advancing the Use of Passive Sampling in Risk Assessment and Management of Sediments Contaminated with Hydrophobic Organic Chemicals: Results of an International Ex Situ Passive Sampling Interlaboratory Comparison
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