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1.
J Hazard Mater ; 463: 132734, 2024 02 05.
Article in English | MEDLINE | ID: mdl-37922581

ABSTRACT

Trends in concentration, distribution, and variability of per- and polyfluoroalkyl substances (PFAS) in biosolids are characterized using an extensive dataset of 350 samples from 190 wastewater treatment plants (WWTPs) across Michigan. All samples are comprised of final treated solids generated at the end of the wastewater treatment process. Concentrations of both individual and Σ24 PFAS are lognormally distributed, with Σ24 PFAS concentrations ranging from 1-3200 ng/g and averaging 108 ± 277 ng/g dry wt. PFAS with carboxyl and sulfonic functional groups comprise 29% and 71% of Σ24 PFAS concentrations, respectively, on average. Primary sample variability in concentration is associated with long-chain PFAS with higher tendency for partitioning to biosolids. Short-chain carboxylic compounds, most notably PFHxA, are responsible for secondary concentration variability. Usage of FTSA and PFBS replacements to long-chain sulfonic compounds also contributes to variance in biosolids concentrations. Sulfonamide precursor compounds as a collective group are detected at a similar frequency as PFOS and often have higher concentrations. Trends in PFAS enrichment for individual PFAS vary at least 3 orders-of-magnitude and generally increase with compound hydrophobicity; however, partitioning of PFAS onto solids in WWTPs is a complex process not easily described nor constrained using experimentally-derived partitioning coefficients.


Subject(s)
Fluorocarbons , Water Pollutants, Chemical , Water Purification , Sewage , Biosolids , Fluorocarbons/analysis , Michigan , Water Pollutants, Chemical/analysis
2.
Water Res ; 242: 120268, 2023 Aug 15.
Article in English | MEDLINE | ID: mdl-37390657

ABSTRACT

Approximately 760 liters (200 gallons) of first-generation, PFOS-dominant, Aqueous Film-Forming Foam (AFFF) concentrate entered the sanitary sewer after an accidental release at the Kalamazoo/Battle Creek International Airport and migrated 11.4 km to the Kalamazoo Water Reclamation Plant. Near-daily sampling of influent, effluent, and biosolids generated a high-frequency, long-duration dataset used to understand the transport and fate of accidental PFAS releases to wastewater treatment plants, identify AFFF concentrate composition, and perform a plant-wide PFOS mass balance. Monitored influent concentrations exhibited sharp PFOS declines after 7 days post-spill, yet effluent discharges remained elevated due to return activated sludge (RAS) recirculation, resulting in the exceedance of Michigan's Surface Water Quality Value for 46 days. Mass balance estimates indicate 1.292 kg PFOS entering the plant and 1.368 kg leaving. Effluent discharge and sorption to biosolids account for 55% and 45% of estimated PFOS outputs, respectively. Identification of AFFF formulation and reasonable agreement between computed influent mass and reported spill volume demonstrates effective isolation of the AFFF spill signal and increases confidence in the mass balance estimates. These findings and related considerations provide critical insight for performing PFAS mass balances and developing operational procedures for accidental spills that minimize PFAS releases to the environment.


Subject(s)
Fluorocarbons , Water Pollutants, Chemical , Biosolids , Fluorocarbons/analysis , Water Pollutants, Chemical/analysis
3.
Am J Clin Pathol ; 160(1): 41-48, 2023 07 05.
Article in English | MEDLINE | ID: mdl-36881639

ABSTRACT

OBJECTIVES: Large B-cell lymphomas (LBCLs) are a heterogeneous group of lymphoid neoplasms whose molecular and cytogenetic profile has predictive and prognostic implications. The concept of double-hit lymphomas (DHLs) was recently updated in the fifth edition of the World Health Organization classification, with the exclusion of MYC and BCL6 rearranged tumors from the group. Now, DHLs are referred to as diffuse large B-cell lymphoma/high-grade B-cell lymphoma with MYC and BCL2 rearrangements. Fluorescence in situ hybridization (FISH) is the current gold standard for detecting rearrangements in LBCLs, but comprehensive genomic profiling (CGP) has recently been suggested to be at least as accurate as FISH in classifying these neoplasms and providing additional genetic information. METHODS: We analyzed a cohort of 131 patients in whom FISH and CGP studies were performed as part of our normal clinical workflow and compared the effectiveness of FISH and CGP in detecting these clinically relevant rearrangements. RESULTS: Our findings are in agreement with our previously published study, which analyzed a cohort of 69 patients, supporting our hypothesis that the best approach to maximize detection of DHLs while limiting waste seems to be a combination of CGP and MYC break-apart FISH testing, the latter to capture the presence of non-IGH::MYC events. CONCLUSIONS: Our study supports the combined use of FISH and GCP rather than either method alone to better detect MYC and BCL2 (and BCL6) gene rearrangements.


Subject(s)
Lymphoma, Large B-Cell, Diffuse , Proto-Oncogene Proteins c-myc , Humans , In Situ Hybridization, Fluorescence , Proto-Oncogene Proteins c-bcl-6/genetics , Proto-Oncogene Proteins c-myc/genetics , Proto-Oncogene Proteins c-bcl-2/genetics , Lymphoma, Large B-Cell, Diffuse/diagnosis , Lymphoma, Large B-Cell, Diffuse/genetics , Lymphoma, Large B-Cell, Diffuse/pathology , Gene Rearrangement , Genomics
6.
Appl Immunohistochem Mol Morphol ; 30(3): 225-235, 2022 03 01.
Article in English | MEDLINE | ID: mdl-35262526

ABSTRACT

Immunohistochemical analysis has become an integral component in the diagnostic work up of hematopoietic neoplasms. It is not uncommon that visualization of single protein expression by immunohistochemistry among cells of interest may become a difficult task. Common scenarios of such include extensive colonization of germinal centers in the differential diagnosis of marginal zone lymphoma and follicular lymphoma, low-level bone marrow involvement by lymphoma and paucity of neoplastic lymphocytes in the setting of numerous background reactive lymphocytes, among others. For this reason, we have developed a variety of easy-to-employ dual-color dual-antibody immunohistochemical assays to aid in solving these diagnostic dilemmas. Herein, we share examples of our use of dual immunohistochemistry to illustrate its beneficial and practical objective.


Subject(s)
Lymphoma, B-Cell, Marginal Zone , Lymphoma, Follicular , Diagnosis, Differential , Germinal Center/pathology , Humans , Immunohistochemistry , Lymphoma, B-Cell, Marginal Zone/diagnosis , Lymphoma, Follicular/diagnosis
7.
Water Res ; 210: 117983, 2022 Feb 15.
Article in English | MEDLINE | ID: mdl-34954365

ABSTRACT

Concentrations of Per- and Polyfluorinated Alkyl Substances (PFAS) from public and private sources in Michigan compiled for wastewater treatment plants (WWTPs) (influent, effluent, biosolids), contaminated sites, and landfill leachates reveal complex cycling within the natural and engineered environment. Analysis of 171 contaminated sites in Michigan by source release indicate four dominant PFAS sources - landfills, aqueous film-forming foams (AFFF), metal platers, and automotive/metal stamping - account for 75% of the contamination. Diverse chemical signatures were observed for leachates collected from 19 landfills (mostly type II municipal) with the dominant PFAS ranging from perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) to shorter-chained compounds, perfluorohexanoic acid (PFHxA), perfluorobutanoic acid (PFBA), and perfluorobutanesulfonic acid (PFBS). Analysis of PFAS carbon chain length as a function of landfill age shows the transition of C8s in leachate from older landfills to C4s and C6s in younger landfills, consistent with the phasing out and replacement of C8s. PFAS mass flux in leachate for landfills studied range between 5 - 2,000 g/yr and are highest for active landfills, which generate greater leachate volumes and contain fresh PFAS wastes. Detailed study of 10 WWTPs with industrial pretreatment programs indicate numerous chemical transformations across the plants that yield effluent PFAS concentrations as much as 19 times greater than influent, attributed to transformations of unmeasured precursors in the influent to measured, stable PFAS in the effluent. PFOA, PFHxA, perfluoropentanoic acid (PFPeA), PFBA, and PFBS show the greatest increases across the plant ranging from 20% to nearly 2,000%. PFOS concentrations decreased across 6 WWTPs, consistent with a strong tendency to adsorb onto biosolids. Estimated mass of discharge of (mostly unregulated) PFAS from WWTPs to receiving waters range from 40 g/yr to 128 kg/yr.


Subject(s)
Fluorocarbons , Water Pollutants, Chemical , Water Purification , Fluorocarbons/analysis , Michigan , Waste Disposal Facilities , Water Pollutants, Chemical/analysis
8.
Arch Pathol Lab Med ; 146(9): 1144-1159, 2022 09 01.
Article in English | MEDLINE | ID: mdl-34919643

ABSTRACT

CONTEXT.­: Although rare in everyday practice, the initial presentation of hematopoietic neoplasms other than lymphoma in the musculoskeletal system and other extranodal sites can generate challenging diagnostic problems for surgical pathologists. OBJECTIVE.­: To review the morphologic and immunophenotypic features of various nonlymphoid hematopoietic diseases presenting at extranodal sites, with emphasis on the inherent diagnostic pitfalls and differential diagnoses of these entities to aid surgical pathologists in their accurate recognition. DATA SOURCES.­: Cases reviewed herein represent both in-house and consult cases seen at our institution between 2010 and 2021. CONCLUSIONS.­: Entities that present in this way include myeloid neoplasms and histiocytic/dendritic cell neoplasms. These tumors commonly cause nonspecific symptoms, and their histologic appearance can overlap with a variety of benign neoplasms and reactive processes. This can lead to delay in diagnosis and intervention with potentially lifesaving therapy; thus, accurate and expedient recognition is of paramount importance.


Subject(s)
Hematologic Diseases , Lymphoma , Musculoskeletal System , Hematologic Diseases/diagnosis , Histiocytes , Humans , Immunophenotyping , Lymphoma/diagnosis
9.
Environ Pollut ; 285: 117250, 2021 Sep 15.
Article in English | MEDLINE | ID: mdl-33957513

ABSTRACT

Interactive effects of inorganic arsenic (As) species and polycyclic aromatic hydrocarbons (PAHs) on their uptake, accumulation and translocation in the hyperaccumulator Pteris vittata L. (P. vittata) were studied hydroponically. The presence of PAHs hindered As uptake and acropetal translocation by P. vittata, decreasing As concentrations by 29.8%-54.5% in pinnae, regardless of the initial As speciation. The inhibitive effect of PAHs was 1.6-8.7 times greater for arsenite [As(III)] than for arsenate [As(V)]. Similarly, inorganic As inhibited the uptake of fluorene (FLU) and benzo[a]pyrene (BaP) by P. vittata roots by 0.4%-21.7% and by 33.1%-69.7%, respectively. Interestingly, coexposure to As and PAHs slightly enhanced the translocation of PAHs by P. vittata with their concentrations increased 0.3 to 0.8 times in shoots, except for the As(III)+BaP treatment. The antagonistic interaction between As and PAHs uptake is likely caused by competitive inhibition or oxidative stress injury. By using synchrotron radiation micro X-ray fluorescence imaging, high concentrations of As were found distributed throughout the microstructures far from main vein of the pinnae when coexposed with PAHs, the opposite of what was observed with exposure to As only. PAHs could also significantly inhibit the accumulation and distribution of As in vascular bundles in rachis treated with As(III). The results of two-photon laser scanning confocal microscopy revealed that PAHs were mainly distributed in the vascular cylinder, epidermal cells, vascular bundles, epidermis and vein tissues, and this was independent of As speciation and treatment. This work offers new positive evidence for the interaction between As and PAHs in P. vittata, presents new information on the underlying mechanisms for interactions of As and PAHs affecting their uptake and translocation within P. vittata L., and provides direction for future research on the mechanisms of PAHs uptake by plants.


Subject(s)
Arsenic , Polycyclic Aromatic Hydrocarbons , Pteris , Soil Pollutants , Arsenic/analysis , Biodegradation, Environmental , Plant Roots/chemistry , Soil Pollutants/analysis
10.
Leuk Lymphoma ; 62(5): 1116-1122, 2021 05.
Article in English | MEDLINE | ID: mdl-33283568

ABSTRACT

We reviewed 341 consecutive cases of marginal zone lymphoma (MZL) (47) or follicular lymphoma (FL) (294) of which 7 were difficult to distinguish due to perceived coexpression of BCL6 and BCL2 by tumor cells in follicular foci. This stimulated us to develop dual BCL6/BCL2 immunohistochemistry, allowing us to assess coexpression among individual cells. Dual staining confirmed coexpression in 6 of 7 cases, all extranodal MZL (ENMZL) based on overall features and representing 13% of MZL in this series. These findings confirm that MZL cells have plasticity regarding protein expression within the germinal center (GC) microenvironment, an important diagnostic pitfall. Intriguingly, in all MZL expressing BCL6, non-neoplastic GC B cells within colonized follicles showed diminished or absent CD10 expression but preserved BCL6 and high ki67. This finding suggests plasticity of CD10 expression in non-neoplastic GC B cells in the context of colonization by MZL, possibly related to NF-kB dysregulation.


Subject(s)
Lymphoma, B-Cell, Marginal Zone , Lymphoma, Follicular , Biomarkers, Tumor , Diagnosis, Differential , Germinal Center , Humans , Lymphoma, B-Cell, Marginal Zone/diagnosis , Lymphoma, B-Cell, Marginal Zone/genetics , Lymphoma, Follicular/diagnosis , Tumor Microenvironment
11.
Sci Total Environ ; 721: 137770, 2020 Jun 15.
Article in English | MEDLINE | ID: mdl-32182465

ABSTRACT

This study quantified influences of interactions between anthropogenic and natural factors on trace element accumulation and pollution risk in karst soils at regional and local scales and identified the dominant interacting factors. A total of 513 soil samples were collected from Hechi, southern China to measure concentrations of arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb), which were compared with published background values. Descriptive statistics and occurrence characteristics were developed with geostatistical methods and the comprehensive pollution risk was calculated using the Nemerow pollution index (NPI). Geo-detector models were used to further examine and quantify the influence of 14 factors (5 anthropogenic and 9 natural) on trace element concentrations and NPI, both individually and interacting with the other 13 factors. The results clearly demonstrate that anthropogenic factors interact with natural factors to enhance nonlinearly and significantly trace element accumulation in karst soils. Watershed was the natural factor that most enhanced trace element accumulation when interacting with anthropogenic factors. Land use and smelting industry were the anthropogenic factors that most enhanced trace element accumulation when interacting with natural factors. Land use-watershed interaction accounted for 56% of Cd accumulation and smelting industry-watershed interaction for 19% of As accumulation. Land use-watershed, land use-lithology, and pH-watershed interactions accounted for 51%, 19%, and 15%, respectively of NPI values. The findings indicate that changing land use and reducing pollutant discharge from the smelting industry should be considered.

12.
Am J Clin Pathol ; 153(3): 353-359, 2020 02 08.
Article in English | MEDLINE | ID: mdl-31872861

ABSTRACT

OBJECTIVES: To compare fluorescence in situ hybridization (FISH) and a commercially available sequencing assay for comprehensive genomic profiling (CGP) to determine the best approach to identify gene rearrangements (GRs) in large B-cell lymphomas (LBCLs). METHODS: Comparison of standard-of-care FISH assays (including a two-probe approach for MYC; break-apart and fusion probes) and an integrated genomic DNA/RNA sequencing CGP approach on a set of 69 consecutive LBCL cases. RESULTS: CGP detected GRs, including those involving MYC (1), BCL-2 (3), and BCL-6 (3), not detected by FISH. FISH detected non-IgH-MYC (4) and BCL-6 (2) GRs that were not detected by CGP. In four instances, standalone CGP or FISH testing would have missed a double-hit lymphoma. CONCLUSIONS: CGP was superior to FISH in the detection of IgH-MYC rearrangements but was inferior for the detection of non-IgH-MYC rearrangements. Our study demonstrates the rationale for development of a customized approach to identify GRs in LBCLs.


Subject(s)
Gene Rearrangement , Lymphoma, Large B-Cell, Diffuse/diagnosis , Proto-Oncogene Proteins c-bcl-2/genetics , Proto-Oncogene Proteins c-bcl-6/genetics , Proto-Oncogene Proteins c-myc/genetics , Adult , Aged , Aged, 80 and over , Female , Genetic Profile , Humans , In Situ Hybridization, Fluorescence , Lymphoma, Large B-Cell, Diffuse/genetics , Lymphoma, Large B-Cell, Diffuse/pathology , Male , Middle Aged
13.
Case Rep Hematol ; 2019: 1825491, 2019.
Article in English | MEDLINE | ID: mdl-31827948

ABSTRACT

Involvement of the central nervous system by chronic lymphocytic leukemia/small lymphocytic lymphoma is exceedingly rare, and currently no risk factors have been described. We report the case of a patient with concomitant chronic lymphocytic leukemia/small lymphocytic lymphoma and an embolic cerebrovascular accident related to a cardiac myxoma, who developed parenchymal central nervous system involvement of lymphoma on the ischemic bed. The patient was successfully treated with a high-dose fludarabine-based chemotherapy regimen, achieving a sustained remission. We propose that embolic breakage of the blood-brain barrier may be a major risk factor in producing central nervous system involvement. We also propose that a high-dose fludarabine-based chemotherapy regimen may be adequate to achieve a better CNS penetration and improved outcomes.

14.
Analyst ; 144(22): 6698-6705, 2019 Nov 21.
Article in English | MEDLINE | ID: mdl-31599884

ABSTRACT

A simple surface-enhanced Raman spectroscopy (SERS) sensor based on an undecorated gold-colloid substrate was developed for the rapid and effective detection of polycyclic aromatic hydrocarbons (PAH). The SERS enhancement of the bare Au nanoparticles for PAH was achieved by adjusting chemical reduction conditions and Cl- content. The strongest SERS response of this system was achieved with 2.0 mL of trisodium citrate (1%) and 80 µL of NaCl (1 M). With this simple SERS sensor, qualitative and quantitative determination of trace-level naphthalene (NaP), phenanthrene (PHE) and pyrene (PYR) were achieved using a portable Raman spectrometer at detection limits of 1.38 µg L-1, 0.23 µg L-1, and 0.45 µg L-1, respectively. Plots of SERS intensity vs. PAH concentrations were linear, with correlation coefficients (R2) ranging from 0.8729 to 0.9994. More importantly, the SERS sensor was able to accurately identify each PAH in complex mixtures. This SERS technique shows great promise for the rapid and direct detection of aromatic hydrocarbons organic pollutants in field.

16.
Am J Clin Pathol ; 149(1): 42-49, 2017 Dec 20.
Article in English | MEDLINE | ID: mdl-29228090

ABSTRACT

OBJECTIVES: Posttransplant lymphoproliferative disorders (PTLDs) are a heterogeneous group of hematolymphoid proliferations arising in the context of chronic immunosuppression. The common and indolent B-cell lymphomas, including extranodal marginal zone lymphomas (ENMZLs) of mucosa-associated lymphoid tissue (MALT), are excluded from the category of PTLD in the current World Health Organization classification. METHODS: We report a case of Epstein-Barr virus (EBV)-positive bronchial-associated lymphoid tissue (BALT) lymphoma involving the lungs of a transplant patient. RESULTS: Aside from history of cardiac transplant, young patient age, and EBV positivity, the histopathologic findings were indistinguishable from usual BALT lymphoma. CONCLUSIONS: We review the literature of ENMZL occurring in immunocompromised patients and present this case for consideration that this specific entity is a PTLD. We believe that additional studies might lend strength to the hypothesis that this particular group of EBV-positive, posttransplant ENMZLs merits classification and management as PTLDs.


Subject(s)
Epstein-Barr Virus Infections/diagnosis , Heart Transplantation/adverse effects , Herpesvirus 4, Human/isolation & purification , Lymphoma, B-Cell, Marginal Zone/diagnosis , Lymphoproliferative Disorders/diagnosis , Adolescent , Bronchi/pathology , Bronchi/virology , Epstein-Barr Virus Infections/pathology , Epstein-Barr Virus Infections/virology , Female , Humans , Lung/pathology , Lung/virology , Lymphoid Tissue/pathology , Lymphoid Tissue/virology , Lymphoma, B-Cell, Marginal Zone/pathology , Lymphoma, B-Cell, Marginal Zone/virology , Lymphoproliferative Disorders/pathology , Lymphoproliferative Disorders/virology , Mucous Membrane/pathology , Mucous Membrane/virology
17.
Chemosphere ; 154: 590-598, 2016 Jul.
Article in English | MEDLINE | ID: mdl-27088536

ABSTRACT

Eight in situ solidification/stabilization (ISS) amendments were tested to promote in situ chemical oxidation (ISCO) with activated persulfate (PS) in a contaminated soil. A 3% (by weight) dose of all ISS amendments selected for this study completely activated a 1.5% dose of PS within 3 h by raising temperatures above 30 °C (heat activation) and/or increasing pH above 10.5 (alkaline activation). Heat is released by the reaction of CaO with water, and pH increases because this reaction produces Ca(OH)2. Heat activation is preferred because it generates 2 mol of oxidizing radicals per mole of PS, whereas alkaline activation releases only 1. The relative contribution of heat vs. alkaline activation increased with CaO content of the ISS amendment, which was reflected by enhanced contaminant oxidation with increasing CaO content, and was confirmed by comparing to controls promoting purely heat or alkaline (NaOH) activation. The test soil was contaminated with benzene, toluene, ethylbenzene, and xylenes (BTEX) and polycyclic aromatic hydrocarbons (PAH), particularly naphthalene (NAP). ISS-activated PS oxidized between 47% and 84% of the BTEX & NAP, and between 13% and 33% of the higher molecular weight PAH. ISS-activated PS reduced the leachability of BTEX & NAP by 76%-91% and of the 17 PAH by 83%-96%. Combined ISCO/ISS reduced contaminant leachability far than ISCO or ISS treatments alone, demonstrating the synergy that is possible with combined remedies.


Subject(s)
Benzene Derivatives/isolation & purification , Naphthalenes/isolation & purification , Polycyclic Aromatic Hydrocarbons/isolation & purification , Sodium Compounds/chemistry , Soil Pollutants/isolation & purification , Soil/chemistry , Sulfates/chemistry , Benzene/chemistry , Benzene/isolation & purification , Benzene Derivatives/chemistry , Biodegradation, Environmental , Naphthalenes/chemistry , Oxidation-Reduction , Polycyclic Aromatic Hydrocarbons/chemistry , Soil Pollutants/chemistry , Toluene/chemistry , Toluene/isolation & purification , Xylenes/chemistry , Xylenes/isolation & purification
18.
J Hazard Mater ; 297: 347-55, 2015 Oct 30.
Article in English | MEDLINE | ID: mdl-26093352

ABSTRACT

Laboratory batch reactors were maintained for 32 weeks to test the potential for an in situ remedy that combines chemical oxidation, stabilization, and anaerobic bioremediation in a single application to treat soil from a manufactured gas plant, contaminated with polycyclic aromatic hydrocarbons (PAH) and benzene, toluene, ethylbenzene, and xylenes (BTEX). Portland cement and slaked lime were used to activate the persulfate and to stabilize/encapsulate the contaminants that were not chemically oxidized. Native sulfate-reducing bacteria degraded residual contaminants using the sulfate left after persulfate activation. The ability of the combined remedy to reduce contaminant mass and leachability was compared with NaOH-activated persulfate, stabilization, and sulfate-reducing bioremediation as stand-alone technologies. The stabilization amendments increased pH and temperature sufficiently to activate the persulfate within 1 week. Activation with both stabilization amendments and NaOH removed between 55% and 70% of PAH and BTEX. However, combined persulfate and stabilization significantly reduced the leachability of residual BTEX and PAH compared with NaOH activation. Sulfide, 2-naphthoic acid, and the abundance of subunit A of the dissimilatory sulfite reductase gene (dsrA) were used to monitor native sulfate-reducing bacteria, which were negatively impacted by activated persulfate, but recovered completely within weeks.


Subject(s)
Biodegradation, Environmental , Oxygen/chemistry , Sodium Hydroxide/chemistry , Soil Pollutants/analysis , Soil , Sulfates/chemistry , Anaerobiosis , Benzene/analysis , Benzene Derivatives/analysis , Construction Materials , Groundwater , Hydrogen-Ion Concentration , Naphthalenes/chemistry , Polycyclic Aromatic Hydrocarbons/analysis , Soil/chemistry , Sulfides/chemistry , Temperature , Toluene/analysis , Water Pollutants/analysis , Xylenes/analysis
19.
Chemosphere ; 113: 56-61, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25065790

ABSTRACT

Modified Fenton (MF) chemistry was tested in the laboratory to treat three diesel fuel-contaminated soils from the Canadian arctic rich in soil organic matter (SOM) and Fe oxides. Reactors were dosed with hydrogen peroxide (HP), and treatment was compared in reactors with SOM as the only chelate vs. reactors to which ethylenediaminetetraacetate (EDTA) was added. Concentrations of diesel fuel and HP were measured over time, and the oxidation of both diesel fuel and SOM were quantified in each soil. A distinct selectivity for oxidation of diesel fuel over SOM was observed. Reactors with EDTA showed significantly less diesel fuel oxidation and lower oxidant efficiency (diesel fuel oxidized/HP consumed) than reactors with SOM as the only chelate. The results from these studies demonstrate that MF chemistry can be an effective remedial tool for contaminated arctic soils, and challenge the traditional conceptual model that SOM reduces the efficiency of MF treatment through excessive scavenging of oxidant.


Subject(s)
Environmental Restoration and Remediation/methods , Gasoline/analysis , Soil Pollutants/analysis , Arctic Regions , Canada , Chelating Agents , Edetic Acid , Ferric Compounds/chemistry , Humic Substances/analysis , Hydrogen Peroxide/chemistry , Iron/chemistry , Models, Chemical , Oxidation-Reduction
20.
Biotechnol Bioeng ; 88(7): 861-8, 2004 Dec 30.
Article in English | MEDLINE | ID: mdl-15538720

ABSTRACT

A soil with aged contamination from lubricating oil (LO) and polychlorinated biphenyls (PCBs) was treated in a bioslurry reactor to investigate in-soil biosurfactant production by Pseudomonas aeruginosa, the most abundant indigenous, culturable, hydrocarbon-degrading microorganism. After 2 days of growth on LO, a depletion of nitrogen stimulated the production and accumulation of rhamnolipids to levels roughly 20 times the critical micelle concentration. Surface tensions and concentrations of monorhamnolipid and dirhamnolipid, PCBs, and total petroleum hydrocarbons (TPH) were measured in a slurry filtrate. Soil-bound PCBs and TPH were also quantified. Rhamnolipid production was observed within 1 to 2 days after nitrogen depletion in each of the 10 batches tested. By day 6, total rhamnolipid concentrations increased from below detection to average values over 1,000 mg/L, which caused over 98% of soil-bound PCBs and over 99% of TPH to be emulsified and recovered in the filtrate. After 70 days, rhamnolipid concentrations were only reduced by 15%, because of nitrogen-limited rates of rhamnolipid biodegradation. The results show that in-soil biosurfactant production can be stimulated in a controlled way with nutrient limitation and can be used to achieve soil washing.


Subject(s)
Bioreactors/microbiology , Glycolipids/biosynthesis , Industrial Oils , Nitrogen/metabolism , Polychlorinated Biphenyls/metabolism , Pseudomonas aeruginosa/metabolism , Soil Microbiology , Soil Pollutants/metabolism , Cell Culture Techniques/methods , Glycolipids/chemistry , Industrial Waste/prevention & control , Polychlorinated Biphenyls/chemistry , Sewage/microbiology , Surface-Active Agents/chemistry , Surface-Active Agents/metabolism
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