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Rupali Datta
  • 1400 Townsend Drive, Dow 740
    Houghton, MI 49931
  • 9064871783
Per- and polyfluoroalkyl substances (PFAS) are a group of chemicals widely manufactured for industrial and commercial applications in the past decades due to their remarkable stability as well as hydrophobic and lipophobic nature. PFAS... more
Per- and polyfluoroalkyl substances (PFAS) are a group of chemicals widely manufactured for industrial and commercial applications in the past decades due to their remarkable stability as well as hydrophobic and lipophobic nature. PFAS species have been recognized as emerging environmental contaminants of concern due to their toxicity and environmental persistence, thereby attracting intensive research seeking effective technologies for their removal from the environment. The objective of this review is to provide a thorough analysis of the biodegradation of PFAS in multiple environmental matrices and offer a future outlook. By discussing targeted PFAS species, degradation intermediates, degradation efficiencies, and microbial species, a comprehensive summary of the known microbial species and their degradation pathways are presented. The biodegradation pathways for different types of PFAS species are summarized in two major categories, biodegradation with and without the cleavage of C-F bond. Existing uncertainties and future research directions for PFAS biodegradation are provided.
Inorganic arsenical pesticides were used widely in agriculture for a long time, leaving large tracts of farmlands and orchards contaminated with high levels of arsenic. These contaminated soils pose a significant public health risk as... more
Inorganic arsenical pesticides were used widely in agriculture for a long time, leaving large tracts of farmlands and orchards contaminated with high levels of arsenic. These contaminated soils pose a significant public health risk as residential developments encroach on these lands due to urban sprawl. Several studies have documented the effectiveness of iron and aluminum hydroxides in immobilizing arsenic in contaminated soils. Solid residues left from drinking water treatment (Drinking water treatment residuals, or WTRs) have been proposed as a low-cost and effective amendment, as they contain large amounts of aluminum (Al) and iron (Fe) oxides. By conducting in vitro tests after 1 year of equilibration, our group recently documented the effectiveness of two types of WTRs (Fe- and Al-based) in significantly (p < 0.01) lowering As bioaccessibility. However, long-term studies under realistic conditions are necessary to test the ability of WTRs in reducing soil arsenic bioaccessibility. In the current study, the effect of WTRs on inorganic arsenic bioaccessibility and distribution in two soils (Immokalee and Orelia) with variable properties was evaluated over a 3-year time period in a greenhouse setup. Results show that arsenic bioaccessibility decreased significantly (p < 0.001) from 100 to ~25 % after 3 years of equilibration, compared to the unamended controls. There was a significant (p < 0.001) decline in water-soluble arsenic with time, accompanied by an increase in Fe/Al and Ca/Mg-bound fractions, suggesting that these phases control the mobility of arsenic. The negative correlation between arsenic bioaccessibility Fe/Al- and Ca/Mg-bound fractions can be attributed to the transformation of soluble arsenic to less soluble mineral phases.
Although organoarsenical pesticides are being phased out, sites with high concentrations of organic arsenical residues still exist due to the long-term application of these pesticides. The biotic and abiotic speciation of dimethylarsinic... more
Although organoarsenical pesticides are being phased out, sites with high concentrations of organic arsenical residues still exist due to the long-term application of these pesticides. The biotic and abiotic speciation of dimethylarsinic acid (DMA) can result in the formation of inorganic arsenic (As) species. Oxidation state, retention, and thereby persistence, varies according to temporal changes, influencing the availability and toxicity of contaminants. The current greenhouse study aimed at evaluating temporal changes in the oxidation state of As, geochemical partitioning, and bioaccessibility. Four soils with varying physiochemical properties were contaminated with DMA at two concentrations (675 and 1,500 mg kg(-1) of As). Rice plants were grown for a 6 months period, following which, the soils were allowed to age. The operationally defined forms of As and its bioaccessibility was analyzed at 0, 6 months, 1 year, and 3 years. Changes in oxidation state of As were evaluated immediately after spiking and after 3 years of soil-pesticide equilibration. Results show that geochemical partitioning of As was affected significantly (P<0.05) by soil type, loading rates, and equilibration time. Arsenic was bound mainly to the poorly-crystalline Fe/Al-oxyhydroxides in the soil. However, these interactions did not affect As bioaccessibility, presumably due to the dissolution of the bound fractions of As in the acidic stomach. While 74-94% of the total bioaccessible As was transformed to As(V), 4-19% was transformed to the more toxic As(III). This study indicates that although aging affected the geochemical partitioning of As in the soil, bioaccesibility was controlled by the gastric pH.
Traditionally, plants have been used for a variety of applications in addition to food and feed, including manufacture of industrial products, vaccines and pharmaceuticals. Maize has the potential to be used for numerous non-food... more
Traditionally, plants have been used for a variety of applications in addition to food and feed, including manufacture of industrial products, vaccines and pharmaceuticals. Maize has the potential to be used for numerous non-food purposes. Maize has been used extensively as an energy crop, to produce bioethanol both from grain as well as biomass. In addition, a wide variety of industrial products such as packing and insulating materials, chemicals, explosives, paint, insecticides, organic acids, solvents, antifreeze, etc. are made using maize products. Maize is also being used as a source of recombinant pharmaceutical products. The main advantages of using maize are that it is genetically well characterized, a well-established agricultural production infrastructure is available for its production, the technology for in vitro manipulation and gene transfer exists in maize, and it also is a fast-growing, high biomass plant. Maize has also been studied extensively for use in phytoremed...
Although tea can be beneficial for our health, consuming excess trace elements in tea can be harmful. In this study, the carcinogenic and noncarcinogenic health risk for trace elements in tea influenced by the country of origin, tea type,... more
Although tea can be beneficial for our health, consuming excess trace elements in tea can be harmful. In this study, the carcinogenic and noncarcinogenic health risk for trace elements in tea influenced by the country of origin, tea type, and infusion process was assessed. Tea (Camellia sinensis) purchased from China, India, and the USA, including black and green tea, were analyzed for essential micronutrients (Cu, Se, and Zn) and nonessential trace elements (Ag, As, Ba, Cd, Cr, and Pb) in leaves and three types of infusions. The results showed that country of origin, tea type, and infusion process had a significant influence on the trace element contents in tea leaves and infusions, also on health risk. Country of origin had a significant influence on Ba, Cr, Pb, and Zn contents in tea leaves and on As, Ba, Cd, Cr, Pb, and Zn contents in tea infusions. Black tea had significantly higher (p < 0.05) Cr and Cu content in tea leaves than green tea, but only Cr content was significantly higher (p < 0.05) than that of green tea in tea infusion. The trace element contents were the highest in the first infusion and decreased as the number of infusion steps increased. The results showed that the consumption of tea infusion was not likely to cause noncarcinogenic risk. However, the carcinogenic risk for As was of concern. Our results indicate that avoiding drinking the first infusion can help to reduce both carcinogenic and noncarcinogenic health risks for trace elements.
Acid mine drainage (AMD) is an acidic and metalliferous discharge that imposes oxidative stress on living things through bioaccumulation and physical exposure. The abandoned Tab‐Simco mining site of Southern Illinois generates highly... more
Acid mine drainage (AMD) is an acidic and metalliferous discharge that imposes oxidative stress on living things through bioaccumulation and physical exposure. The abandoned Tab‐Simco mining site of Southern Illinois generates highly acidic AMD with elevated sulfate (SO42−) and various metals. Vetiver grass (Chrysopogon zizanioides) is effective for the remediation of Tab‐Simco AMD at both mesocosm and microcosm levels over extended periods. In this study, we conducted a proteomic investigation of vetiver shoots under short and long‐term exposure to AMD. Our objective was to decipher the physiological responses of vetiver to the combined abiotic stresses of AMD (metal and low pH). Differential regulation was observed for longer‐term (56 days) exposure to AMD, which resulted in 17 upregulated and nine downregulated proteins, whereas shorter‐term (7 days) exposure led to 14 upregulated and 14 downregulated proteins. There were significant changes to photosynthesis, including upregulat...
Large-scale copper (Cu) mining activities in Michigan's Upper Peninsula produced millions of metric tons of mining wastes also known as stamp sands. The stamp sands containing high concentrations of Cu were disposed of into several... more
Large-scale copper (Cu) mining activities in Michigan's Upper Peninsula produced millions of metric tons of mining wastes also known as stamp sands. The stamp sands containing high concentrations of Cu were disposed of into several lakes connected to the Lake Superior. Eventually, as aquatic organisms in these lakes started to exhibit toxicity symptoms, the stamp sands were dredged and discarded on the lake shores. Consequently, these areas turned into degraded, marginal lands and were collectively classified as a Torch Lake Superfund site by the US EPA. Due to the lack of vegetative cover, the Cu-rich stamp sands eroded into the lakes, affecting the aquatic life. To alleviate this issue, a sustainable restoration plan (SRP) was developed and tested in a greenhouse environment prior to field implementation. Cold-tolerant oilseed crops, camelina (Camelina sativa) and field pennycress (Thlaspi arvense), were grown on compost-fertilized stamp sands, which reduced soil erosion by ac...
Application of chelating agents to contaminated soils increases solubility of metals, and thus enhances their phytoextraction. Three lead (Pb) contaminated soils with Pb content between 1268-1880 mg/kg were collected from residential... more
Application of chelating agents to contaminated soils increases solubility of metals, and thus enhances their phytoextraction. Three lead (Pb) contaminated soils with Pb content between 1268-1880 mg/kg were collected from residential properties in Baltimore, MD. A field study is currently in progress at Stockton, NJ in custom wooden platforms for phytoextraction of Pb by vetiver grass; with fescue grass used as control. The platforms were loaded with 5 inch of play sand and 5 inch Pb of contaminated soil, then vetiver and fescue grasses were planted. Periodic treatments with a mild biodegradable chelating agent, EDDS is being performed to enhance Pb mobilization. In order to compare the mobilization of lead by EDTA to that of EDDS, EDTA was applied to the Pb-contaminated soils to enhance the solubility of Pb and uptake by vetiver. Three days after the EDTA application, hurricane Sandy hit the experimental site and produced heavy rain and winds. After the hurricane, surface runoff an...
Geochemical fate of antimony (Sb) - a similar oxyanion as arsenic (As) - in a variety of environment is largely unexplored. Kaolinite is an important, naturally occurring clay mineral in soils and aquifers and is known to control the fate... more
Geochemical fate of antimony (Sb) - a similar oxyanion as arsenic (As) - in a variety of environment is largely unexplored. Kaolinite is an important, naturally occurring clay mineral in soils and aquifers and is known to control the fate of several contaminants via a multitude of geochemical processes, primarily adsorption. Here we report adsorption of antimony on kaolinite as a function of solution chemistry: initial antimony concentration, pH, ionic strength, and a competing anion. A surface complexation modeling (SCM) approach was undertaken to understand the potential mechanistic implications of sorption envelope data. In the SCM, a multicomponent additive approach, in which kaolinite is assumed to be a (1:1) mixture of quartz (≡SiOH) and gibbsite (≡AlOH), was tested. Results indicated that ionic strength has a minimal effect on antimony adsorption. For the lower initial antimony concentration (4.11 μM), the additive model with binuclear surface complexes on quartz and gibbsite showed a better fit at pH<6, but somewhat under predicted the experimental data above pH 6. At the higher initial antimony concentration (41.1 μM), the sorption envelope was of different shape than the lower load. The additive model, which considered binuclear surface complexes for quartz and gibbsite, resulted in over prediction of the adsorption data at pH>3.5. However, the additive model with binuclear surface complex on quartz and mononuclear surface complex on gibbsite showed an excellent fit of the data. Phosphate greatly influenced antimony adsorption on kaolinite at both low and high antimony loadings, indicating competition for available surface sites.
Soil lead (Pb) contamination in Pb paint-contaminated homes is a serious health risk in urban areas. Phytoextraction is a green and sustainable technology for soil Pb remediation, but its efficiency depends on the geochemical partitioning... more
Soil lead (Pb) contamination in Pb paint-contaminated homes is a serious health risk in urban areas. Phytoextraction is a green and sustainable technology for soil Pb remediation, but its efficiency depends on the geochemical partitioning of Pb in soil. Following successful laboratory, greenhouse, and panel experiments, a field study was conducted to demonstrate the effectiveness of a chemically catalyzed phytoextraction model for Pb removal. A biodegradable chelating agent, ethylenediaminedisuccinic acid (EDDS) was applied during Pb phytoextraction by vetiver grass (Chrysopogon zizanioides) in a Pb-contaminated community garden in Jersey City, New Jersey. Results showed that soil Pb concentration was reduced from 1144 to 359 mg/kg in 3 years, despite ongoing Pb input to the field plots from a nearby construction site. EDDS was effective in converting non-plant-available forms of Pb (i.e., carbonate-bound, oxide-bound, and organic-bound forms) to plant-available forms (i.e., water-s...
Vetiver grass (Chrysopogon zizanioides) is well-known for its contaminant phytoextraction potential and its capacity to reduce soil erosion, owing to its massive, dense root system. However, the shoots are not major contributors to either... more
Vetiver grass (Chrysopogon zizanioides) is well-known for its contaminant phytoextraction potential and its capacity to reduce soil erosion, owing to its massive, dense root system. However, the shoots are not major contributors to either of these processes, and are either not utilized at all or they become part of the waste stream. It is well-recognized that lignocellulosic biomass can serve as a source of raw material to produce second-generation bioethanol. This study investigated the simultaneous saccharification and fermentation (SSF) of acid–alkali pretreated vetiver (VG) shoots by Saccharomyces cerevisiae. Vetiver shoots were obtained from three sources: (1) shoots from VG grown in clean potting soil, (2) shoots from VG used for antibiotics phytoextraction from a constructed wetland setup, and (3) shoots from VG used for lead phytoextraction during soil remediation. Bioethanol yield from the shoots from clean soil was the highest (19.58 g/L), followed by the one used for lead...
Over the past several decades, the value of drinking water treatment residuals (WTRs), a byproduct of the coagulation process during water purification, has been recognized in various environmental applications, including sustainable... more
Over the past several decades, the value of drinking water treatment residuals (WTRs), a byproduct of the coagulation process during water purification, has been recognized in various environmental applications, including sustainable remediation of phosphorus (P)-enriched soils. Aluminum-based WTRs (Al-WTRs) are suitable adsorbent materials for P, which can be obtained and processed inexpensively. However, given their heterogeneous nature, it is essential to identify an easily analyzable chemical property that can predict the capability of Al-WTRs to bind P before soil amendment. To address this issue, thirteen Al-WTRs were collected from various geographical locations around the United States. The non-hazardous nature of the Al-WTRs was ascertained first. Then, their P adsorption capacities were determined, and the chemical properties likely to influence their adsorption capacities were examined. Statistical models were built to identify a single property to best predict the P adso...
Biochar mediated pollutant removal is gaining attention because of high efficiency of the process. However, effective recycling avenues of the pollutant-saturated biochars are scarce in the knowledge base; while such materials can be a... more
Biochar mediated pollutant removal is gaining attention because of high efficiency of the process. However, effective recycling avenues of the pollutant-saturated biochars are scarce in the knowledge base; while such materials can be a new source of long-range contamination. Therefore, potential of vermitechnology for eco-friendly recycling of pollutant-loaded biochar was assessed by using arsenic-saturated native (NBC) and exfoliated (EBC) biochars as feedstocks for the first time. Interestingly, the bioavailable arsenic fractions (water soluble and exchangeable) considerably reduced by 22-44 % with concurrent increment (~8-15 %) of the recalcitrant (residual and organic bound) fractions in the biochar-based feedstocks. Consequently, ~2-3 folds removal of the total arsenic was achieved through vermicomposting. The earthworm population growth (2.5-3 folds) was also highly satisfactory in the biochar-based feedstocks. The results clearly imply that Eisenia fetida could compensate the arsenic-induced stress to microbial population and greatly augmented microbial biomass, respiration and enzyme activity by 3-12 folds. Moreover, biochar-induced alkalinity was significantly neutralized in the vermibeds, which remarkably balanced the TOC level and nutrient (N, P, and K) availability particularly in EBC + CD vermibeds. Overall, the nutrient recovery potential and arsenic removal efficiency of vermitechnology was clearly exhibited in NBC/EBC + CD (12.5:87.5) feedstocks. Hence, it is abundantly clear that vermitechnology can be a suitable option for eco-friendly recycling of pollutant-saturated sorbing agents, like biochars.
The objective of this study is to design a pilot‐scale permeable reactive barrier (PRB) for the removal of copper from groundwater in Keweenaw Peninsula, Michigan. The reactive material selected for the barrier is drinking water treatment... more
The objective of this study is to design a pilot‐scale permeable reactive barrier (PRB) for the removal of copper from groundwater in Keweenaw Peninsula, Michigan. The reactive material selected for the barrier is drinking water treatment residuals (WTR)—the residuals of alum coagulants used in a local drinking water treatment plant. Physical and chemical properties of the WTR were determined. Synthetic precipitation leaching procedure tests indicated the concentrations of hazardous elements leached from the residuals do not exceed U.S. Environmental Protection Agency limits and, hence, can be safely recycled as PRB material. Batch reactor tests showed that equilibrium sorption of copper is high and fits a Langmuir‐type isotherm. Site characterization studies included groundwater flow direction, pore water velocity, and contaminant concentration to determine optimal dimensions and placement of the PRB. Permeameter tests were performed with various mixtures of the WTR and an inert su...
Acid mine drainage (AMD) is extremely acidic, sulfate-rich effluent from abandoned or active mine sites that also contain elevated levels of heavy metals. Untreated AMD can contaminate surface and groundwater and pose severe ecological... more
Acid mine drainage (AMD) is extremely acidic, sulfate-rich effluent from abandoned or active mine sites that also contain elevated levels of heavy metals. Untreated AMD can contaminate surface and groundwater and pose severe ecological risk. Both active and passive methods have been developed for AMD treatment consisting of abiotic and biological techniques. Abiotic techniques are expensive and can create large amounts of secondary wastes. Passive biological treatment mainly consists of aerobic or anaerobic constructed wetlands. While aerobic wetlands are economical, they are not effective if the pH of the AMD is < 5. Anaerobic wetlands use organic-rich substrates to provide carbon source to iron- and sulfate-reducing bacteria. The efficiency of these systems declines overtime and requires continuous maintenance. Our objective is to develop an alternative, low-cost, and sustainable floating wetland treatment (FWT) system for AMD for the abandoned Tab-Simco coal mining site in Ill...
The arsenic (As) hyperaccumulating fern species Pteris vittata (PV) is capable of accumulating large quantities of As in its aboveground tissues. Transformation to AsIII and vacuolar sequestration is believed to be the As detoxification... more
The arsenic (As) hyperaccumulating fern species Pteris vittata (PV) is capable of accumulating large quantities of As in its aboveground tissues. Transformation to AsIII and vacuolar sequestration is believed to be the As detoxification mechanism in PV. Here we present evidence for a preponderance of exocellular As in fronds of Pteris vittata despite numerous reports of a tolerance mechanism involving intracellular compartmentalization. Results of an extraction experiment show that 43–71% of the As extruded out of the fronds of PV grown in 0.67, 3.3 and 6.7 mM AsV. SEM-EDX analysis showed that As was localized largely on the lower pinna surface, with smaller amounts on the upper surface, as crystalline deposits. X-ray fluorescence imaging of pinna cross-sections revealed preferential localization of As on the pinna surface in the proximity of veins, with the majority localized near the midrib. Majority of the As in the pinnae is contained in the apoplast rather than vacuoles. Our re...
2,4-bis(Isopropylamino)-6-methylthio-s-triazine (prometryn) poses a risk to aquatic environments in several countries, including China, where its use is widespread, particularly due to its chemical stability and biological toxicity.... more
2,4-bis(Isopropylamino)-6-methylthio-s-triazine (prometryn) poses a risk to aquatic environments in several countries, including China, where its use is widespread, particularly due to its chemical stability and biological toxicity. Vetiver grass (Chrysopogon zizanioides L.) was tested for its potential for phytoremediation of prometryn. Vetiver grass was grown in hydroponic media in a greenhouse, in the presence of prometryn, with appropriate controls. Plant uptake and removal of prometryn from the media were monitored for a period of 67 days. The results showed that the removal of the prometryn in the media was expedited by vetiver grass. The removal half-life (t1/2) was shortened by 11.5 days. Prometryn removal followed first-order kinetics (Ct = 1.8070e(-0.0601t)). This study demonstrated the potential of vetiver grass for the phytoremediation for prometryn.
Abstract In 1996, the Tab-Simco site, an abandoned coal mine 10 km southeast of Carbondale, Illinois, was listed as one of the most highly contaminated AMD sites in the mid-continent region. A suite of impacted soil and water samples were... more
Abstract In 1996, the Tab-Simco site, an abandoned coal mine 10 km southeast of Carbondale, Illinois, was listed as one of the most highly contaminated AMD sites in the mid-continent region. A suite of impacted soil and water samples were collected from various locations to characterize the current extent of AMD pollution, following standard U.S. EPA protocols. The mean pH of soil and water samples were found to be 2.69 and 2.07, respectively. The mean sulfur content of the soil samples was 0.5 %. The AMD-impacted soils contained high concentrations of Fe, Zn, Ni, Cr, Cu, Pb, and As. The AMD also contained high concentrations of Fe, As, Zn, Pb, Cr, Al, Cd, Cu, and Ni, as well as $${\text{SO}}_{4}^{2 - }$$SO42-, all of which were significantly above their U.S. EPA permissible limits for surface water.Zusammenfassung1996 wurde das Tab-Simco Areal, ein stillgelegtes Kohlebergwerk ca. 10 km südöstlich von Carbondale, Illinois, als eines der am stärksten durch saures Grubenwasser (AMD) kontaminierten Gebiete in den zentralen USA ausgewiesen. An verschiedenen Stellen wurden entsprechend den Standards der US-EPA Boden- und Wasserproben entnommen, um das aktuelle Ausmaß der Kontamination durch AMD zu erfassen. Der mittlere pH-Wert des Bodens lag bei 2,69 und der des Wassers 2,07. Der mittlere Schwefelgehalt des Bodens betrug 0,5%. Die durch AMD kontaminierten Böden hatten hohe Konzentrationen an Fe, Zn, Ni, Cr, Cu, Pb und As. Das saure Grubenwasser hatte hohe Konzentrationen an Fe, As, Zn, Pb, Cr, Al, Cd, Cu und Ni sowie SO42-, die alle signifikant über den zulässigen Grenzwerten der US-EPA für Oberflächengewässer lagen.ResumenEn 1996, el sitio Tab-Simco, una mina de carbón abandonada que está ubicada 10 Km al sudeste de Carbondale, Illinois, fue listada como uno de los sitios más altamente contaminados por drenaje ácido de minas (AMD) en la región media continental. Muestras de aguas y de suelo impactado fueron colectada desde varios puntos del sitio para caracterizar la extensión actual de la polución por AMD, siguiendo protocolos estándar de U.S. EPA. Los valores promedio de pH en el suelo y en las muestras de agua fueron 2,69 y 2,07, respectivamente. El contenido promedio de azufre en el suelo fue 0,5%. Los suelos impactados por el AMD contenían altas concentraciones de Fe, Zn, Ni, Cr, Cu, Pb y As. El AMD también contenía altas concentraciones de Fe, As, Zn, Pb, Cr, Al, Cd, Cu y Ni, así como SO42-, todas significativamente superiores a los límites permitidos U.S. EPA para agua superficial. 摘要Tab-Simco煤矿为伊利诺斯州(Illinois)卡本代尔(Carbondale)东南10km的废弃煤矿,1996年被列为中部大陆最严重酸性废水污染区之一。依照美国环保局标准协议,多点采集了受污染土样和水样,以研究AMD当前污染程度。土壤和水样的平均pH值分别为2.69和2.07。土样的平均硫含量为0.5%。AMD污染土样含有高浓度的Fe、Zn、Ni、Cr、Cu、Pb和As。AMD中同样也含有高浓度的Fe、As、Zn、Pb、Cr、Al、Cd、Cu、Ni及SO42-,都明显超过美国环保局地表水质界限。
Veterinary antibiotics (VAs) are emerging contaminants of concern in the environment, mainly due to the potential for development of antibiotic-resistant bacteria and effect on microbiota that could interfere with crucial ecosystem... more
Veterinary antibiotics (VAs) are emerging contaminants of concern in the environment, mainly due to the potential for development of antibiotic-resistant bacteria and effect on microbiota that could interfere with crucial ecosystem functions such as nutrient cycling and decomposition. High levels of VAs such as tetracyclines (TCs) have been reported in agricultural soils amended with manure, which also has the potential to cause surface and groundwater contamination. Several recent studies have focused on developing methods to immobilize VAs such as composting with straw, hardwood chips, commercial biochar, aeration, mixing, heat treatment, etc. The major shortcomings of these methods include high cost and limited effectiveness. In the current study, we assessed the effectiveness of aluminum-based drinking water treatment residuals (Al-WTR) as a "green" sorbent to immobilize TCs in manure and manure-applied soils with varying physicochemical properties by laboratory incubation study. Results show that Al-WTR is very effective in immobilizing tetracycline (TTC) and oxytetracycline (OTC). The presence of phosphate resulted in significant (p < 0.01) decrease in TTC/OTC sorption by Al-WTR, but the presence of sulfate did not. attenuated total reflection (ATR)-FTIR spectroscopy indicate that TTC and OTC likely forming surface complexes via inner-sphere-type bonds in soils, manure, and manure-applied soils amended with Al-WTR.
ABSTRACT Long-term application of arsenical pesticides in agricultural lands has resulted in high levels of arsenic (As). Conversion of former agricultural lands to residential areas has resulted in increased human contact with soil As.... more
ABSTRACT Long-term application of arsenical pesticides in agricultural lands has resulted in high levels of arsenic (As). Conversion of former agricultural lands to residential areas has resulted in increased human contact with soil As. Soil ingestion from incidental hand-to-mouth activity by children is now a very important issue in assessing human health risk associated with exposure to arsenical pesticide-applied former agricultural soils. Human health risk from direct exposure to soil As via hand to mouth action is restricted only to those fractions of As in the soil that are available to the human gastrointestinal system. Thus this study aimed at addressing the issue of soil variability on As bioavailability as a function of soil physiochemical properties in a dynamic interaction between soils, water and plants and pesticides. In the current greenhouse study two soils with drastically different chemical characteristics w.r.t As reactivity (Immokalee-low As retention potential and Millhopper-high As retention potential) and one pesticide (sodium arsenate) were used. Soils were amended with sodium arsenate at two rates representing the high and low ends of As contamination, generally representative of Superfunds site conditions: 675 and 1500 mg/kg As. Rice (Oryza sativa) was used as the test crop. Sequential digestion to estimate in-vitro As in the stomach phase and the intestinal phase was employed on soils sampled at 4 times: 0-time, after 3 mo, 6 mo and 9 mo of soil-pesticide equilibration. In-vitro bioavailability experiments were also performed with the same soils in order to obtain an estimate of the amount of As that would be absorbed to the intestinal linings in simulated systems. Following the greenhouse study, selective in-vivo bioavailability studies using As-contaminated soils will be conducted on male and female mice to correlate in-vitro results with the in-vivo data. Treatments will consist of a soil group (As in soil), a positive control group (only As) and a negative control group (no soil, no As). Results from the in-vitro and in-vivo studies will help understand the effects of soil properties on As bioavailability. Keywords: Bioavailability, pesticide, soil, arsenic, greenhouse.
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ABSTRACT Arsenic (As) is one of the most toxic elements present in the environment. Over the years, arsenic has found its way to the environment due to its extensive use in agriculture and in industrial practices as pesticides,... more
ABSTRACT Arsenic (As) is one of the most toxic elements present in the environment. Over the years, arsenic has found its way to the environment due to its extensive use in agriculture and in industrial practices as pesticides, fertilizers, wood preservatives, smelter wastes and coal combustion ash, all of which are of great environmental concern. Arsenic contamination affects biological activities because it is a carcinogen and a mutagen, which has detrimental effects on the immune system of animals. Remediation of arsenic-contaminated soils has become a major environmental issue in the recent years. Several physical and chemical treatment methods, such as soil washing, co-precipitation, and excavation, have used to remediate As, but all of these methods are rather expensive and can disturb soil physiology and ecology. Phytoremediation, a plant based technology for the removal of toxic contaminants from soil and water is an attractive approach. Of late, this technology has received a high degree of attention from the scientific community because it is environment-friendly and also because of its tremendous cost efficiency compared to the conventional methods. Chinese Brake Fern (Pteris vittata L.) is a known arsenic hyperaccumulator that is being used extensively at present to remove As from soils. However, the degree of efficiency of this plant in accumulating As is likely to be a function of the soil properties. The objective of the reported study was to investigate arsenic uptake by Chinese Brake Fern in As-contaminated soils from the Immokalee (acid sand with minimal As-retention potential) and Millhopper series (sandy loam with high Fe/Al content, hence, high As-retention potential). A greenhouse experiment was designed to evaluate the effects on As uptake by Chinese Brake Fern at two pesticide application rates: 225 mg/kg and 500 mg/kg As in two chemical forms, namely sodium arsenate (AsV) and dimethylarsinic acid (DMA). Each treatment was replicated three times in separate columns. The leaf tissues were collected at time-intermediate (3 months) and at time-final (6 months, when root tissues were also collected) to measure As accumulation after acid-digesting the plants, followed by metal analysis using a graphite furnace atomic absorption spectrophotometer. Plant biomass was monitored for potential growth inhibition. Results showed that As accumulation in shoot was much higher root in both Millhopper and Immokalee soils. Higher As concentrations in plant tissues were observed at the higher application rate treatments in both soils for both arsenate and DMA. However, plant biomass decreased at high As concentration. The results indicate possible biochemical mechanisms in Chinese Brake Fern that enhance As uptake and its translocation from root to shoot.
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ABSTRACT Lead (Pb) is a toxic heavy metal that is released into the environment from a variety of sources. Sources of Pb contamination in soils can be divided into three broad categories: industrial activities, such as mining and smelting... more
ABSTRACT Lead (Pb) is a toxic heavy metal that is released into the environment from a variety of sources. Sources of Pb contamination in soils can be divided into three broad categories: industrial activities, such as mining and smelting processes, agricultural activities, such as application of insecticide and municipal sewage sludge, and urban activities, such as use of Pb in gasoline, paints, and other materials. Severe Pb contamination of soils may cause a variety of environmental problems, including loss of vegetation, groundwater contamination and Pb toxicity in plants, animals and humans. The use of plants to remove toxic metals from soils (phytoremediation) is fast emerging as an acceptable strategy for cost-effective and environmentally sound remediation of contaminated soils. The objective of this study was to gain insight into the lead uptake potential and biochemical stress response mechanism in vetiver grass (Vetiveria zizanioides L.) upon exposure to Pb in contaminated soils. We investigated the effect of increasing concentrations of Pb on vetiver grass grown in a hydroponic system. Plant response to the addition of phosphate in the presence of Pb was also studied. Biochemical stress response was studied by monitoring the activities of Superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymes. The results indicated that exposure to Pb in the range of 0 ppm -1200 ppm had no significant negative effects on the growth of vetiver grass. There was no considerable decrease in vetiver biomass, implying the potential of this grass for Pb phytoremediation. The translocation of Pb from the root to the shoot was up to 20%. The SOD activity was in positive correlation with Pb concentrations in the solution, but no such trend was observed with GPx. In systems containing phosphate fertilizer, lead precipitated out immediately, thereby decreasing the soluble concentration of lead, resulting in less availability of Pb to the grass.
Research Interests:
Research Interests:
Land-applied arsenical pesticides have contributed elevated soil arsenic (As) levels. Many baseline risk assessments As-contaminated sites assume that all As present in the soil is bioavailable, thereby potentially overestimating the... more
Land-applied arsenical pesticides have contributed elevated soil arsenic (As) levels. Many baseline risk assessments As-contaminated sites assume that all As present in the soil is bioavailable, thereby potentially overestimating the actual health risk. However, risk from As exposure is associated only with those forms of As that are potentially extractable by the human gastrointestinal juices. It has been demonstrated that
Arsenic is one of the most harmful and toxic metals, being a Group A human carcinogen. Mining activities as well as the use of arsenic-containing pesticides have resulted in the contamination of a wide variety of sites including mine... more
Arsenic is one of the most harmful and toxic metals, being a Group A human carcinogen. Mining activities as well as the use of arsenic-containing pesticides have resulted in the contamination of a wide variety of sites including mine tailings, cattle dip ...
Lead (Pb) contamination in soils of residential properties due to peeling and chipping of Pb-based paint can cause human health problems. Phytoextraction is a green technology that has the potential to remediate soil Pb. The efficiency of... more
Lead (Pb) contamination in soils of residential properties due to peeling and chipping of Pb-based paint can cause human health problems. Phytoextraction is a green technology that has the potential to remediate soil Pb. The efficiency of phytoextraction is dependent on the geochemical forms of Pb in soil. A biodegradable chelating agent, ethylenediaminedisuccinic acid (EDDS), was previously shown to enhance Pb removal by facilitating phytoextraction. In this study, EDDS was tested at various concentrations for its potential in mobilizing Pb in urban residential soils in Jersey City, New Jersey, and San Antonio, Texas. Results show that the concentrations of plant-available forms of Pb increased with the increasing dosage of EDDS from 2 to 30 mmol/L. The addition of EDDS at 30 mmol/L resulted in the conversion of up to 61.2% and 68.9% of the total Pb to plant-available forms in Jersey City and San Antonio soils, respectively. Further analysis showed that, after EDDS application, car...
Northern wild rice is of great dietary and cultural importance to the Native American population in the Upper Peninsula of Michigan. Millions of tons of mine tailings were discharged into Lake Superior and other inland lakes during the... more
Northern wild rice is of great dietary and cultural importance to the Native American population in the Upper Peninsula of Michigan. Millions of tons of mine tailings were discharged into Lake Superior and other inland lakes during the copper mining boom in the early 20th century in this area. This includes L’Anse Bay, located within the Keweenaw Bay Indian Community (KBIC) reservation. Since wild rice restoration is being encouraged by the KBIC, we investigated the distribution of toxic metals in sediments, water, and wild rice and their potential impact on human health from two locations. Sand Point sloughs on L’Anse Bay and a nearby inland lake, Lake Plumbago, were sampled for sediment, water, and wild rice, and the potential human health risk from dietary exposure to toxic metals in wild rice was assessed. Arsenic stood out as the element that had the highest bioaccumulation at both locations. Risk calculations showed that the hazard index (HI) value for wild rice seeds from bot...
The use of insensitive munitions such as 3-nitro-1,2,4-triazol-5-one (NTO) is rapidly increasing and is expected to replace conventional munitions in the near future. Various NTO treatment technologies are being developed for the... more
The use of insensitive munitions such as 3-nitro-1,2,4-triazol-5-one (NTO) is rapidly increasing and is expected to replace conventional munitions in the near future. Various NTO treatment technologies are being developed for the treatment of wastewater from industrial munition facilities. This is the first study to explore the potential phytoremediation of industrial NTO-wastewater using vetiver grass (Chrysopogon zizanioides L.). Here, we present evidence that vetiver can effectively remove NTO from wastewater, and also translocated NTO from root to shoot. NTO was phytotoxic and resulted in a loss of plant biomass and chlorophyll. The metabolomic analysis showed significant differences between treated and control samples, with the upregulation of specific pathways such as glycerophosphate metabolism and amino acid metabolism, providing a glimpse into the stress alleviation strategy of vetiver. One of the mechanisms of NTO stress reduction was the excretion of solid crystals. Scann...
Copper mining in the Upper Peninsula of Michigan in the mid-19th century generated millions of tons of mining waste, called stamp sand, which was deposited into various offshoots of Lake Superior. The toxic stamp sand converted the area... more
Copper mining in the Upper Peninsula of Michigan in the mid-19th century generated millions of tons of mining waste, called stamp sand, which was deposited into various offshoots of Lake Superior. The toxic stamp sand converted the area into barren, fallow land. Without a vegetative cover, stamp sand has been eroding into the lakes, adversely affecting aquatic life. Our objective was to perform a greenhouse study, to grow cold-tolerant oilseed crops camelina (Camelina sativa) and field pennycress (Thlaspi arvense) on stamp sand, for the dual purpose of biofuel production and providing a vegetative cover, thereby decreasing erosion. Camelina and field pennycress were grown on stamp sands in columns, using compost to supply nutrients. A greenhouse study in wooden panels was also done to evaluate the effectiveness of camelina in reducing erosion. Results show that camelina significantly reduced erosion and can also be used commercially for generating biodiesel. A 25-fold reduction in C...

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