Research Interests: Environmental Science, Environmental Chemistry, Medicine, Multidisciplinary, Environmental science and technology, and 13 moreChemical Analysis, Sediment, Trend Analysis, Lake superior, Great Salt Lake, Flame Retardant, Ether, Fractionation, Polybrominated Diphenyl Ethers, Cores, Environmental, Isotope dating, and Troposphere
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The present study represents a multi-regional investigation of polyhalogenated carbazoles (PHCZs) contamination in estuarine and freshwater systems from the United States and China. Although recent studies have suggested that PHCZs are... more
The present study represents a multi-regional investigation of polyhalogenated carbazoles (PHCZs) contamination in estuarine and freshwater systems from the United States and China. Although recent studies have suggested that PHCZs are persistent and bioaccumulative, available data are not sufficient to understand their large-scale spatial and temporal distributions in the environment. The present study investigated spatial distributions of PHCZs in surface sediment from multiple freshwater and estuarine systems located in China and the United States (U.S.) during the period of 2012-2017, as well as temporal distributions from vertical trends in selected sediment cores. The results demonstrated large variations of PHCZ contamination across regions, with median concentrations of ΣPHCZs in surface sediment ranging from 3.1 to 134 ng/g. Profiles of PHCZ congener composition also exhibited regional variations and estuarine-freshwater differences. These differences likely reflect the relative contributions of different natural and industrial sources among the locations. Vertical profiles of concentrations and compositions in one Chinese estuarine sediment core and two freshwater sediment cores from the U.S. all demonstrated clear anthropogenic influences to varying degrees. Toxic equivalents (TEQ) of PHCZs were estimated based on their dioxin-like activities, which ranged from <0.001 to 4.94 pg TEQ/g in all sites. The results suggest that PHCZs could add additional ecological risks to the benthos and other aquatic organisms. Our findings constitute an essential contribution to the knowledge body of PHCZ contamination in global aquatic systems and congener-specific contamination characterizations.
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This section covers studies published during the calendar year 2004 on the fate of environmental pollutants in soils, surface water and groundwaters. Studies related to water quality and sources of pollution by environmental pollutants as... more
This section covers studies published during the calendar year 2004 on the fate of environmental pollutants in soils, surface water and groundwaters. Studies related to water quality and sources of pollution by environmental pollutants as well as reaction kinetics and modeling are reviewed in detail. Also included in the coverage of present review is research on pollutants such as nutrients, pathogens, xenobiotics, radionuclides and nanoparticles.
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Although salivary liquid can degrade constituents in resin‐based dental composites in short‐term incubations, there is a knowledge gap on how longer‐term aging impacts their bulk strength. We address this through extended aging studies... more
Although salivary liquid can degrade constituents in resin‐based dental composites in short‐term incubations, there is a knowledge gap on how longer‐term aging impacts their bulk strength. We address this through extended aging studies with resin‐based dental composites in different environments. Two commercial composites (FIL and AEL) were aged aseptically at 37°C in air (A, control), artificial saliva (AS), and esterase enzyme amended AS (EAS). Diametral and pushout strength were measured after periods of 120–180 days. At 120 days, the diametral strength of composites aged in air was 69.9 ± 11.0 and 57.7 ± 3.31 MPa in FIL and AEL, respectively. These were significantly greater compared to composites aged in AS (32.1 ± 7.01 and 46.2 ± 9.38 MPa in FIL and AEL, respectively) or EAS (36.7 ± 8.49 and 43.5 ± 5.51 MPa in FIL and AEL, respectively). In contrast, pushout strength for both composites were smaller in A compared to those aged in AS and EAS, results attributed to AS absorption...
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Despite being the largest freshwater lake system in the world, relatively little is known about the sestonic microbial community structure in the Laurentian Great Lakes. The goal of this research was to better understand this ecosystem... more
Despite being the largest freshwater lake system in the world, relatively little is known about the sestonic microbial community structure in the Laurentian Great Lakes. The goal of this research was to better understand this ecosystem using high-throughput sequencing of microbial communities as a function of water depth at six locations in the westernmost Great Lakes of Superior and Michigan. The water column was characterized by gradients in temperature, dissolved oxygen (DO), pH, and other physicochemical parameters with depth. Mean nitrate concentrations were 32 μmol/L, with only slight variation within and between the lakes, and with depth. Mean available phosphorus was 0.07 μmol/L, resulting in relatively large N:P ratios (97:1) indicative of P limitation. Abundances of the phyla Actinobacteria, Bacteroidetes, Cyanobacteria, Thaumarchaeota, and Verrucomicrobia differed significantly among the Lakes. Candidatus Nitrosopumilus was present in greater abundance in Lake Superior co...
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As for lineages of known methanogens, several lineages of uncultured archaea were recurrently retrieved in freshwater sediments. However, knowledge is missing about how these lineages might be affected and structured according to depth.... more
As for lineages of known methanogens, several lineages of uncultured archaea were recurrently retrieved in freshwater sediments. However, knowledge is missing about how these lineages might be affected and structured according to depth. In the present study, the vertical changes of archaeal communities were characterized in the deep sediment of the freshwater meromictic Lake Pavin. For that purpose, an integrated molecular approach was performed to gain information on the structure, composition, abundance and vertical stratification of archaeal communities thriving in anoxic freshwater sediments along a gradient of sediments encompassing 130 years of sedimentation. Huge changes occurred in the structure and composition of archaeal assemblages along the sediment core. Methanogenic taxa (i.e. Methanosaeta and Methanomicrobiales) were progressively replaced by uncultured archaeal lineages (i.e. Marine Benthic Group-D (MBG-D) and Miscellaneous Crenarchaeal Group (MCG)) which are suspect...
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ABSTRACT: One of the main problems associated with remediation of chlorinated solvent groundwater contamination is the presence of NAPLs in the source zone. NAPLs are often better treated through solvent extraction, surfactant washing, or... more
ABSTRACT: One of the main problems associated with remediation of chlorinated solvent groundwater contamination is the presence of NAPLs in the source zone. NAPLs are often better treated through solvent extraction, surfactant washing, or vapor extraction than through bioremediation. Removal of NAPL through solvent extraction would likely leave a substantial residual of both the extraction solvent and the chlorinated solvent. We hypothesized that utilization of the remaining extraction solvent as an electron donor could be exploited to clean up the remaining chlorinated solvent following source zone remediation. The main question is whether a suitable extraction solvent could work as an electron donor to drive reductive dechlorination. Many different compounds have been used as electron donors to stimulate reductive dechlorination, including volatile fatty acids (VFAs), sugars, hydrogen, and polymeric compounds. Generally, it is regarded that fermentation of compounds yields hydroge...
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ABSTRACT: Although remediation scenarios typically focus on one class of pollutants such as metals or hydrophobic organics, most contaminated sediments have mixtures of both. We assayed the performance of several different kinds of active... more
ABSTRACT: Although remediation scenarios typically focus on one class of pollutants such as metals or hydrophobic organics, most contaminated sediments have mixtures of both. We assayed the performance of several different kinds of active capping materials for a large range of sediment contaminants to provide information on their applicability to cap design using a Monte Carlo approach. Five caps were chosen: 25 cm of sand, 2 cm of organoclay, 10 cm of shredded tires, 2 cm of coke, and 2 cm of granular activated carbon (GAC). Their performance in the presence of eight metals, twelve hydrophobic organic compounds and two organo-metals were modeled under both static (diffusion only) and advection flow conditions created by different hydraulic gradients across the sediment water interface. Not surprisingly, it takes a much shorter time for breakthrough of contaminants with advection under all scenarios. This indicates that more strongly binding cap materials (such as GAC) or low permea...
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We have previously reported on anaerobic pure cultures that degrade naphthalene in the strict absence of oxygen. One of these pure cultures NAP-3 was phylogenetically most closely related to Pseudomonas stutzeri based on 16S rDNA... more
We have previously reported on anaerobic pure cultures that degrade naphthalene in the strict absence of oxygen. One of these pure cultures NAP-3 was phylogenetically most closely related to Pseudomonas stutzeri based on 16S rDNA sequences. Further studies in our laboratory have shown that the degradation of naphthalene was slow or nearly absent when volatile fatty acids (VFAs) were not present. To investigate this further, we analyzed NAP-3 during incubations with acetate and found that it stimulates naphthalene transformation. Naphthalene significantly increased denitrification in nearly exact stiochiometric balances of nitrate and nitrite as would be expected based on the metabolism. NAP-3 was sensitive to the amount of naphthalene in the culture; with naphthalene removal rates higher when present at 20mg/l compared to 40mg/l. Investigation of the culture supernatant by GC/MS showed the transient production and consumption of the nitrogen-containing bicyclic indole. Production of...
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Although not a group of persistent bioaccumulative toxics (PBTs) particularly specified in EPA’s RFP, PBDEs are more environmentally persistent than PCBs due to their higher resistance to various degradations (de Boer et al., 1998). Their... more
Although not a group of persistent bioaccumulative toxics (PBTs) particularly specified in EPA’s RFP, PBDEs are more environmentally persistent than PCBs due to their higher resistance to various degradations (de Boer et al., 1998). Their high lipophilicity (log Kow = 4.3 to 9.9, compared with 4.5 to 8.0 for PCBs) indicates a strong bioaccumulation potential. Evidence of their toxic, carcinogenic, and hormone-disrupting effects is also mounting rapidly. A review of the current state of knowledge on PBDEs is given by Darnerud, et al. (2001). The Abstracts of the Second International Workshop on Brominated Flame Retardants (BFR, 2001; Betts, 2001) compile the most up-to-date research achievements.
Department of Civil Engineering, University of Illinois at Chicago, 842 West Taylor St., M/C 246, Chicago, IL USA In 2009: Centre d’Enseignement et de Recherche sur l’Eau, la Ville, et l’Environnement, L’École Nationale des Ponts et... more
Department of Civil Engineering, University of Illinois at Chicago, 842 West Taylor St., M/C 246, Chicago, IL USA In 2009: Centre d’Enseignement et de Recherche sur l’Eau, la Ville, et l’Environnement, L’École Nationale des Ponts et Chaussées, 6-8 Avenue Blaise Pascal, Champs sur Marne, F 77455 Marne-la-Vallée, Cedex 2, France Phone: +33-(0)-1 64 15 37 56 E-mail: krockne@uic.edu; kjrockne@gmail.com
A major concern in sediment capping effectiveness is gas ebullition from organic matter biodegradation in sediments. Gases may open advective channels that can result in substantial pollution release. The aim of this study was to... more
A major concern in sediment capping effectiveness is gas ebullition from organic matter biodegradation in sediments. Gases may open advective channels that can result in substantial pollution release. The aim of this study was to determine the gas ebullition rate in sediments in preparation for construction of an active capping technology demonstration at the Collateral Channel site in the Chicago River. Sediment samples were collected from five sites along a transection of Collateral Channel from the combined sewer outfall at the Channel terminus. Biogenic gas production was measured in samples incubated at 5° to 35° C. Gas production followed a first order reaction trend and Arrhenius plots were obtained to determine the temperature dependence of the kinetic rate. These allowed us to predict gas ebullition for the annual temperature variation in the sediments. CO2/CH4 ratios change with temperature, with lower ratios at lower temperatures suggesting dominance by acetoclastic metha...
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PurposeNo studies to date have compared directly the ebullition-facilitated organic and metal contaminant fluxes to direct benthic contaminant fluxes measured in the field. To address this knowledge gap, we measured benthic organic and... more
PurposeNo studies to date have compared directly the ebullition-facilitated organic and metal contaminant fluxes to direct benthic contaminant fluxes measured in the field. To address this knowledge gap, we measured benthic organic and metal contaminant fluxes at the sediment-water interface and compared them to simultaneously measured ebullition-facilitated contaminant fluxes at nine sites in a contaminated waterway in the Chicago River, IL, USA, to determine the relative importance of each transport mechanism to total sediment release.Materials and methodsTwo benthic flux chambers with integrated gas ebullition samplers were built to measure both gas ebullition and in situ fluxes of polycyclic aromatic hydrocarbons (PAHs), metals, sulfide, ammonia, nitrate, dissolved organic carbon (DOC), total filtered phosphorus (TFP), and dissolved oxygen (DO) across the sediment-water interface over time. Aqueous pH and oxidation-reduction potential (ORP) within the chamber were also monitored. The gas ebullition collection system trapped heavy metals and the 16 United States Environmental Protection Agency (USEPA) priority-pollutant PAHs (Σ16PAH) transported with gas bubbles through sorption and particle entrainment on a pre-combusted glass wool trap as in our previous studies.Results and discussionThe results demonstrate that gas ebullition contaminant transport is a significant source of pollution release to the water column, as great as or greater than direct benthic transport. In several sites, release rates of Σ16PAHs and some metals from the sediment by gas ebullition were more than an order of magnitude higher than from direct benthic release. The average total PAH ebullition-facilitated release of all sites is predicted to be nearly 0.5 g m−2 on an annual basis.ConclusionsGas ebullition is an important pathway for release of PAHs and heavy metal pollutants to the water column and monitoring of this important release pathway should be performed to adequately address the true environmental impacts of polluted sediments.
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Abstract Healthcare is a major emitter of environmental pollutants that adversely affect health. Within the healthcare community, awareness of these effects is low, and recognition of the duty to address them is only beginning to gain... more
Abstract Healthcare is a major emitter of environmental pollutants that adversely affect health. Within the healthcare community, awareness of these effects is low, and recognition of the duty to address them is only beginning to gain traction. Healthcare sustainability science explores dimensions of resource consumption and environmental emissions associated with healthcare activities. This emerging field provides tools and metrics to quantify the unintended consequences of healthcare delivery and evaluate effective approaches that improve patient safety while protecting public health. This narrative review describes the scope of healthcare sustainability research, identifies knowledge gaps, introduces a framework for applications of existing research methods and tools to the healthcare context, and establishes research priorities to improve the environmental performance of healthcare services. The framework was developed through review of the current state of healthcare sustainability science and expert consensus by the Working Group for Environmental Sustainability in Clinical Care. Key recommendations include: development of a comprehensive life cycle inventory database for medical devices and drugs; application of standardized sustainability performance metrics at the clinician, hospital/health system, and national levels; revision of infection control standards driving non-evidence-based uptake of single-use disposable devices; call for increased federal research funding; and formation of a Global Commission on the Advancement of Environmental Sustainability in Healthcare. There is an urgent need for research that informs policy and practice to address the public health crisis arising from healthcare pollution. A transformational vision is required to align research priorities to achieve a sustainable healthcare system that advances quality, safety and value.
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Most hydrophobic halogenated flame retardants (HFRs) are highly accumulative and persistent in aquatic sediments. The objective of this study was to reveal spatial distributions, temporal trends, and transformation of selected legacy and... more
Most hydrophobic halogenated flame retardants (HFRs) are highly accumulative and persistent in aquatic sediments. The objective of this study was to reveal spatial distributions, temporal trends, and transformation of selected legacy and emerging HFRs in sediments of Lakes Superior, Michigan, and Huron. We collected Ponar grab samples at 112 locations and sediment cores at 28 sites in the three lakes, and measured concentrations of 19 brominated FRs and 12 chlorinated FRs. Based on grab samples, concentrations were higher at southeastern and sites near Sleeping Bear Dunes of Lake Michigan, and Saginaw Bay and the North Channel of Lake Huron. The annual loadings of polybrominated diphenyl either (PBDEs) and Dechlorane Plus (DPs) to sediment have leveled off or been declining since 2000, while loadings of DBDPE and Dec604 have increased since the 1960s in most cores. The concentration ratio of BB101 to BB153 increased with sediment depth, suggesting the occurrence of in situ debromination of BB153. The ratio of dechlorinated anti-Cl11DP over anti-DP increases with the increasing latitude of sampling locations, suggesting the occurrence of dechlorination of anti-DP to anti-Cl11DP during transport. This ratio also increases with increasing sediment age in most cores, implying in situ dechlorination over time.
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Current and historical concentrations of 22 poly- and perfluorinated compounds (PFASs) in sediment collected from Lake Superior and northern Lake Michigan in 2011 and Lake Huron in 2012 are reported. The sampling was performed in two... more
Current and historical concentrations of 22 poly- and perfluorinated compounds (PFASs) in sediment collected from Lake Superior and northern Lake Michigan in 2011 and Lake Huron in 2012 are reported. The sampling was performed in two ways, Ponar grabs of surface sediments for current spatial distribution across the lake and dated cores for multi-decadal temporal trends. Mean concentrations of the sum of PFASs (∑PFASs) were 1.5, 4.6 and 3.1 ng g dry mas (dm) in surface sediments for Lakes Superior, Michigan and Huron, respectively. Of the five Laurentian Lakes, the watersheds of Superior and Huron are the less densely populated by humans, and concentrations observed were typically less and from more diffuse sources, due to lesser urbanization and industrialization. However, some regions of greater concentrations were observed and might indicate more local, point sources. In core samples concentrations ranged from <LOQ to 46.6 ng g dm among the three lakes with concentrations typic...
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The temporal and spatial trends in sediment of 22 poly- and perfluorinated (PFAS) compounds were investigated in the southern Great Lakes Erie and Ontario as well as Lake St. Clair. Surface concentrations measured by Ponar grab samples... more
The temporal and spatial trends in sediment of 22 poly- and perfluorinated (PFAS) compounds were investigated in the southern Great Lakes Erie and Ontario as well as Lake St. Clair. Surface concentrations measured by Ponar grab samples indicated a trend for greater concentrations near to urban sites. Mean concentrations ∑PFAS were 15.6, 18.2 and 19 ng gdm for Lakes St. Clair, Erie and Ontario, respectively. Perfluoro-n-butanoic acid (PFBA) and Perfluoro-n-hexanoic acid (PFHxA) were frequently determined in surface sediment and upper core samples indicating a shift in use patterns. Where PFBA was identified it was at relatively great concentrations typically >10 ng gdm. However as PFBA and PFHxA are less likely to bind to sediment they may be indicative of pore water concentrations Sedimentation rates between Lake Erie and Lake Ontario differ greatly with greater rates observed in Lake Erie. In Lake Ontario, in general concentrations of PFAS observed in core samples closely follow...
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Our growing awareness of the microbial world's importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and... more
Our growing awareness of the microbial world's importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete ...
Research Interests: Ecology, Biodiversity, Multidisciplinary, Nature, Humans, and 6 moreAnimals, Archaea, Bacteria, Plants, Gene Dosage, and Microbiota
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Surface grab and core sediment samples were collected from Lakes Michigan, Superior, and Huron from 2010 to 2012, and concentrations of herbicides atrazine, simazine, and alachlor, as well as desethylatrazine (DEA), were determined.... more
Surface grab and core sediment samples were collected from Lakes Michigan, Superior, and Huron from 2010 to 2012, and concentrations of herbicides atrazine, simazine, and alachlor, as well as desethylatrazine (DEA), were determined. Concentrations of atrazine in surface grabs ranged from 0.01 to 1.7 ng/g dry weight and are significantly higher in the southern basin of Lake Michigan (latitude <44°) than other parts of the three lakes. The highest concentration of alachlor was found in sediments of Saginaw Bay in Lake Huron. The inventory and net fluxes of these herbicides were found to decline exponentially from the south to the north. The concentration ratio of DEA to atrazine (DEA/ATZ) increased with latitude, suggesting degradation of atrazine to DEA during atmospheric transport. DEA/ATZ also increased with sediment depth in the sediment cores. Diffusion of deposited herbicides from the upper sediment into deeper sediments has occurred, on the basis of the observed patterns of ...