Journal of hazardous materials letters, Nov 1, 2021
Introduction Adsorption of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) ont... more Introduction Adsorption of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) onto modified activated carbons (AC-H 3 PO 4) produced from leaf biomass of Vitis vinifera leaf litter in a fixed bed column experiment was investigated in this study. Methods The column bed was packed with the produced activated carbons in a uniform particle size of ˃ 64 μm. Experimental parameters including the initial concentration of the solution, column bed height, the mass of adsorbent and flow rate were optimized to establish the best adsorption efficiency parameters for the system. Breakthrough and saturated time were estimated from the column fixed bed experimental data and analysed using the Adam-Bohart, Thomas model, and Yoon-Nelson models. Results Maximum sorption capacities of produced activated carbon ACH 3 PO 4 based on Thomas model were 159.61 and 208.64 mg/g for PFOA and PFOS, respectively. The results indicated the breakthrough and saturated time of the system increased concurrently with the increase in bed height and initial concentrations, while an increase in flow rate enhanced fractional bed utilization (FBU) efficiency of the column. Thomas and Yoon-Nelson model best describe the prediction of breakthrough data and sorption behaviour of PFOA and PFOS indicating suitability of AC-H 3 PO 4 column design. Conclusion Findings suggest that agro based adsorbent is a good alternative to non-ago based adsorbent. The surface characteristics of the phosphoric acid modified activated carbons AC-H 3 PO 4 affirmed the removal of PFOA and PFOS from the contaminated water.
Widespread use of arsenical pesticides has resulted in increased background arsenic in agricultur... more Widespread use of arsenical pesticides has resulted in increased background arsenic in agricultural soils. Since arsenic is a Group-A carcinogen, an elevated health risk is associated with human exposure to these soils. Encroachment of suburban development on former agricultural lands has tremendously increased the potential for human contact with arsenic. The importance of considering soil ingestion from incidental hand-to-mouth activity by children has been emphasized in several recent studies. Reports indicate that arsenic bioavailability is much higher in water than in soils, indicating that the current practice of health risk assessment using the "water model" overestimates the risk, and hence, soil-cleanup costs. Although studies have been conducted to assess arsenic bioavailability in highly contaminated media, a universal model for assessing arsenic bioavailability in low-contamination soil systems is lacking. A laboratory incubation study is currently in progress to identify the relationship between geochemical speciation and in-vitro bioavailability of arsenic in soils as a function of soil and pesticide properties. Five different soils were chosen based on their potential differences in arsenic reactivity. The soils were amended with two inorganic and one organic arsenic pesticide at three rates. A sequential extraction scheme was developed to identify the various geochemical forms of arsenic in these soils. Concentrations of these operationally defined soil-arsenic forms are being correlated with the in-vitro bioavailable fractions to identify the arsenic species that are most bioavailable. This study will provide realistic starting points in site-and composition-specific health risk assessment associated with exposure to low doses of soil arsenic.
Petroleum contamination results from leaking aboveground and underground storage tanks, spillage ... more Petroleum contamination results from leaking aboveground and underground storage tanks, spillage during transport of petroleum products, abandoned manufactured gas sites and various industrial processes. This contamination is hazardous to soil and water ecosystems, and is expensive to remediate. Bioremediation is an effective, economical and environmentally friendly treatment method in which microbes are used to degrade hydrocarbons. This is done either by bioaugmentation, where cultured microorganisms are introduced into a contaminated system, or biostimulation, in which additional nutrients are introduced primarily as fertilizers to stimulate microbial growth. Since fertilizers are highly soluble, their use could result in eutrophication of aquatic systems. Biosolids (sewage sludge) may be used as alternative nutrient sources, as they release nutrients slowly and in smaller quantities. Factors influencing the rate of microbial growth include soil moisture, temperature, population diversity, pH, oxygen supply and nutrient levels. Concentrations of carbon, nitrogen and phosphorus are a major factor in effective remediation of hydrocarbons in soils. Till date, many remediation efforts to clean up hydrocarbon-contaminated systems have, however, made exclusive use of commonly available inorganic N and P fertilizers to stimulate bacterial growth. Keeping this in mind, an eight-week laboratory incubation study was undertaken with a twofold objective: (1) to demonstrate the ability (or inability) of biosolids in augmenting biodegradation of petroleum hydrocarbons in contaminated soils, and (2) to decipher the role of carbon in the overall rate of biodegradation. Preliminary results indicate that biosolids are capable of enhancing hydrocarbon biodegradation and that the rate of biodegradation decreases in carbon-deficient systems.
Environmental Science and Pollution Research, Mar 13, 2019
Production of acid mine drainage (AMD) and acid sulfate soils is one of the most concerning envir... more Production of acid mine drainage (AMD) and acid sulfate soils is one of the most concerning environmental consequences associated with mining activities. Implementation of appropriate post-mining AMD management practices is very important to minimize environmental impacts such as high soil acidity, soil erosion, and metal leachability. The objective of this study was to develop a cost-effective and environment-friendly Bgreen^technology for the treatment of AMD-impacted soils. This study utilized the metal-binding and acid-neutralizing capacity of an industrial by-product, namely drinking water treatment residuals (WTRs), and the extensive root system of a metal hyper-accumulating, fast-growing, non-invasive, high-biomass perennial grass, vetiver (Chrysopogon zizanioides L.) to prevent soil erosion. Aluminum (Al)-based and calcium (Ca)-based WTRs were used to treat AMD-impacted soil collected from the Tab-Simco coal mine in Carbondale, IL. Tab-Simco is an abandoned coal mine, with very acidic soil containing a number of metals and metalloids such as Fe, Ni, Zn, Pb, and As at high concentrations. A 4-monthlong greenhouse column study was performed using 5% and 10% w/w WTR application rates. Vetiver grass was grown on the soil-WTR mixed media. Turbidity and total suspended solid (TSS) analysis of leachates showed that soil erosion decreased in the soil-WTR-vetiver treatments. Difference in pH of leachate samples collected from control (3.06) and treatment (6.71) columns at day 120 indicated acidity removal potential of this technology. A scaled-up simulated field study was performed using 5% WTR application rate and vetiver. Soil pH increased from 2.69 to 7.2, and soil erosion indicators such as turbidity (99%) and TSS (95%) in leachates were significantly reduced. Results from the study showed that this Bgreen^reclamation technique has the potential to effectively treat AMD-impacted soils.
Per- and polyfluoroalkyl substances (PFAS) are a group of chemicals widely manufactured for indus... 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.
One of the biggest environmental impacts of mining is the generation of acid mine drainage (AMD).... more One of the biggest environmental impacts of mining is the generation of acid mine drainage (AMD). In the absence of proper post-mining management practices, AMD pollution can cause massive environmental damage. Current AMD management practices often fail to meet the expectations of cost, efficiency, and sustainability. The objective of this study was to utilize the metal-binding and acid-neutralizing capacity of an industrial by-product that is otherwise landfilled, namely drinkingwater treatment residuals (WTRs), to treat AMD-water, thus offering a green remediation alternative. AMD-water was collected from Tab-Simco coal mine in Carbondale, Illinois. It was highly acidic (pH 2.27), and contaminated with metals, metalloids and sulfate at very high concentrations. A filter media, prepared using locally-generated aluminum (Al) and calcium (Ca)-based WTRs, was used to increase pH and to remove metals and SO 2À 4 from AMD-water. Laboratory-batch sorption studies at various WTRs (Al and Ca):AMD-water ratios were performed to optimize the filter media. WTRs:sand ratio of 1:6 provided optimal permeability, and 1:1 Al-WTRs:Ca-WTRs ratio was the optimal sorbent mix for removal of the metals of concern. A scaled-up study using a 55-gallon WTRs and sand-based filter was designed and tested. The results showed that the filter media removed more than 99% of the initial Fe (137 mg/L), Al (80 mg/L), Zn (11 mg/L), Pb (7 mg/L), As (4 mg/L), Mn (33 mg/L), and 44% of the initial SO 2À 4 (2481 mg/L) from Tab-Simco AMD-water. pH increased from 2.27 to 7.8. Desorption experiments showed that the metals were irreversibly bound to the WTRs and were not released back to the water. Keywords Acid mine drainage • Drinking water treatment residuals • Tab-Simco coal mine • Green remediation • Filter media
Phytoremediation technology is emerging as a promising environment-friendly method for large-scal... more Phytoremediation technology is emerging as a promising environment-friendly method for large-scale cleanup of arsenic (As) contaminated water and soil. In this study we investigated the effect of arbuscular mycorrhizal fungi (AMF-Glomus spp.) on the growth of the vetiver grass (Chrysopogon zizanioides L.) and its As uptake from contaminated hydroponic and soil systems. An ameliorative effect of the AMF inoculation in enhancing plants growth was found, mainly by stimulating the development of their root system. In addition, AMF-inoculated plants also took up more As from both contaminated systems compared to non-inoculated plants, although the differences were not always statistically significant (p < 0.05). Nevertheless, more efficient As uptake by vetiver grass from contaminated hydroponic solutions than spiked soils was observed, essentially because of the higher phytoavailability in the former contaminated system. Furthermore, plants grown hydroponically also translocated higher amounts of As from their roots to shoots. Therefore, the findings of this study reveals that the use of vetiver grass technology in conjunction with AMF would be more appropriate to decontaminate As-contaminated water than soils.
Inorganic arsenical pesticides were used widely in agriculture for a long time, leaving large tra... 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 organ... 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&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;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, ... 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 harm... 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 o... 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...
Environmental science and pollution research international, 2018
Large-scale copper (Cu) mining activities in Michigan's Upper Peninsula produced millions of ... 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...
Journal of hazardous materials letters, Nov 1, 2021
Introduction Adsorption of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) ont... more Introduction Adsorption of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) onto modified activated carbons (AC-H 3 PO 4) produced from leaf biomass of Vitis vinifera leaf litter in a fixed bed column experiment was investigated in this study. Methods The column bed was packed with the produced activated carbons in a uniform particle size of ˃ 64 μm. Experimental parameters including the initial concentration of the solution, column bed height, the mass of adsorbent and flow rate were optimized to establish the best adsorption efficiency parameters for the system. Breakthrough and saturated time were estimated from the column fixed bed experimental data and analysed using the Adam-Bohart, Thomas model, and Yoon-Nelson models. Results Maximum sorption capacities of produced activated carbon ACH 3 PO 4 based on Thomas model were 159.61 and 208.64 mg/g for PFOA and PFOS, respectively. The results indicated the breakthrough and saturated time of the system increased concurrently with the increase in bed height and initial concentrations, while an increase in flow rate enhanced fractional bed utilization (FBU) efficiency of the column. Thomas and Yoon-Nelson model best describe the prediction of breakthrough data and sorption behaviour of PFOA and PFOS indicating suitability of AC-H 3 PO 4 column design. Conclusion Findings suggest that agro based adsorbent is a good alternative to non-ago based adsorbent. The surface characteristics of the phosphoric acid modified activated carbons AC-H 3 PO 4 affirmed the removal of PFOA and PFOS from the contaminated water.
Widespread use of arsenical pesticides has resulted in increased background arsenic in agricultur... more Widespread use of arsenical pesticides has resulted in increased background arsenic in agricultural soils. Since arsenic is a Group-A carcinogen, an elevated health risk is associated with human exposure to these soils. Encroachment of suburban development on former agricultural lands has tremendously increased the potential for human contact with arsenic. The importance of considering soil ingestion from incidental hand-to-mouth activity by children has been emphasized in several recent studies. Reports indicate that arsenic bioavailability is much higher in water than in soils, indicating that the current practice of health risk assessment using the "water model" overestimates the risk, and hence, soil-cleanup costs. Although studies have been conducted to assess arsenic bioavailability in highly contaminated media, a universal model for assessing arsenic bioavailability in low-contamination soil systems is lacking. A laboratory incubation study is currently in progress to identify the relationship between geochemical speciation and in-vitro bioavailability of arsenic in soils as a function of soil and pesticide properties. Five different soils were chosen based on their potential differences in arsenic reactivity. The soils were amended with two inorganic and one organic arsenic pesticide at three rates. A sequential extraction scheme was developed to identify the various geochemical forms of arsenic in these soils. Concentrations of these operationally defined soil-arsenic forms are being correlated with the in-vitro bioavailable fractions to identify the arsenic species that are most bioavailable. This study will provide realistic starting points in site-and composition-specific health risk assessment associated with exposure to low doses of soil arsenic.
Petroleum contamination results from leaking aboveground and underground storage tanks, spillage ... more Petroleum contamination results from leaking aboveground and underground storage tanks, spillage during transport of petroleum products, abandoned manufactured gas sites and various industrial processes. This contamination is hazardous to soil and water ecosystems, and is expensive to remediate. Bioremediation is an effective, economical and environmentally friendly treatment method in which microbes are used to degrade hydrocarbons. This is done either by bioaugmentation, where cultured microorganisms are introduced into a contaminated system, or biostimulation, in which additional nutrients are introduced primarily as fertilizers to stimulate microbial growth. Since fertilizers are highly soluble, their use could result in eutrophication of aquatic systems. Biosolids (sewage sludge) may be used as alternative nutrient sources, as they release nutrients slowly and in smaller quantities. Factors influencing the rate of microbial growth include soil moisture, temperature, population diversity, pH, oxygen supply and nutrient levels. Concentrations of carbon, nitrogen and phosphorus are a major factor in effective remediation of hydrocarbons in soils. Till date, many remediation efforts to clean up hydrocarbon-contaminated systems have, however, made exclusive use of commonly available inorganic N and P fertilizers to stimulate bacterial growth. Keeping this in mind, an eight-week laboratory incubation study was undertaken with a twofold objective: (1) to demonstrate the ability (or inability) of biosolids in augmenting biodegradation of petroleum hydrocarbons in contaminated soils, and (2) to decipher the role of carbon in the overall rate of biodegradation. Preliminary results indicate that biosolids are capable of enhancing hydrocarbon biodegradation and that the rate of biodegradation decreases in carbon-deficient systems.
Environmental Science and Pollution Research, Mar 13, 2019
Production of acid mine drainage (AMD) and acid sulfate soils is one of the most concerning envir... more Production of acid mine drainage (AMD) and acid sulfate soils is one of the most concerning environmental consequences associated with mining activities. Implementation of appropriate post-mining AMD management practices is very important to minimize environmental impacts such as high soil acidity, soil erosion, and metal leachability. The objective of this study was to develop a cost-effective and environment-friendly Bgreen^technology for the treatment of AMD-impacted soils. This study utilized the metal-binding and acid-neutralizing capacity of an industrial by-product, namely drinking water treatment residuals (WTRs), and the extensive root system of a metal hyper-accumulating, fast-growing, non-invasive, high-biomass perennial grass, vetiver (Chrysopogon zizanioides L.) to prevent soil erosion. Aluminum (Al)-based and calcium (Ca)-based WTRs were used to treat AMD-impacted soil collected from the Tab-Simco coal mine in Carbondale, IL. Tab-Simco is an abandoned coal mine, with very acidic soil containing a number of metals and metalloids such as Fe, Ni, Zn, Pb, and As at high concentrations. A 4-monthlong greenhouse column study was performed using 5% and 10% w/w WTR application rates. Vetiver grass was grown on the soil-WTR mixed media. Turbidity and total suspended solid (TSS) analysis of leachates showed that soil erosion decreased in the soil-WTR-vetiver treatments. Difference in pH of leachate samples collected from control (3.06) and treatment (6.71) columns at day 120 indicated acidity removal potential of this technology. A scaled-up simulated field study was performed using 5% WTR application rate and vetiver. Soil pH increased from 2.69 to 7.2, and soil erosion indicators such as turbidity (99%) and TSS (95%) in leachates were significantly reduced. Results from the study showed that this Bgreen^reclamation technique has the potential to effectively treat AMD-impacted soils.
Per- and polyfluoroalkyl substances (PFAS) are a group of chemicals widely manufactured for indus... 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.
One of the biggest environmental impacts of mining is the generation of acid mine drainage (AMD).... more One of the biggest environmental impacts of mining is the generation of acid mine drainage (AMD). In the absence of proper post-mining management practices, AMD pollution can cause massive environmental damage. Current AMD management practices often fail to meet the expectations of cost, efficiency, and sustainability. The objective of this study was to utilize the metal-binding and acid-neutralizing capacity of an industrial by-product that is otherwise landfilled, namely drinkingwater treatment residuals (WTRs), to treat AMD-water, thus offering a green remediation alternative. AMD-water was collected from Tab-Simco coal mine in Carbondale, Illinois. It was highly acidic (pH 2.27), and contaminated with metals, metalloids and sulfate at very high concentrations. A filter media, prepared using locally-generated aluminum (Al) and calcium (Ca)-based WTRs, was used to increase pH and to remove metals and SO 2À 4 from AMD-water. Laboratory-batch sorption studies at various WTRs (Al and Ca):AMD-water ratios were performed to optimize the filter media. WTRs:sand ratio of 1:6 provided optimal permeability, and 1:1 Al-WTRs:Ca-WTRs ratio was the optimal sorbent mix for removal of the metals of concern. A scaled-up study using a 55-gallon WTRs and sand-based filter was designed and tested. The results showed that the filter media removed more than 99% of the initial Fe (137 mg/L), Al (80 mg/L), Zn (11 mg/L), Pb (7 mg/L), As (4 mg/L), Mn (33 mg/L), and 44% of the initial SO 2À 4 (2481 mg/L) from Tab-Simco AMD-water. pH increased from 2.27 to 7.8. Desorption experiments showed that the metals were irreversibly bound to the WTRs and were not released back to the water. Keywords Acid mine drainage • Drinking water treatment residuals • Tab-Simco coal mine • Green remediation • Filter media
Phytoremediation technology is emerging as a promising environment-friendly method for large-scal... more Phytoremediation technology is emerging as a promising environment-friendly method for large-scale cleanup of arsenic (As) contaminated water and soil. In this study we investigated the effect of arbuscular mycorrhizal fungi (AMF-Glomus spp.) on the growth of the vetiver grass (Chrysopogon zizanioides L.) and its As uptake from contaminated hydroponic and soil systems. An ameliorative effect of the AMF inoculation in enhancing plants growth was found, mainly by stimulating the development of their root system. In addition, AMF-inoculated plants also took up more As from both contaminated systems compared to non-inoculated plants, although the differences were not always statistically significant (p < 0.05). Nevertheless, more efficient As uptake by vetiver grass from contaminated hydroponic solutions than spiked soils was observed, essentially because of the higher phytoavailability in the former contaminated system. Furthermore, plants grown hydroponically also translocated higher amounts of As from their roots to shoots. Therefore, the findings of this study reveals that the use of vetiver grass technology in conjunction with AMF would be more appropriate to decontaminate As-contaminated water than soils.
Inorganic arsenical pesticides were used widely in agriculture for a long time, leaving large tra... 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 organ... 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&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;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, ... 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 harm... 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 o... 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...
Environmental science and pollution research international, 2018
Large-scale copper (Cu) mining activities in Michigan's Upper Peninsula produced millions of ... 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...
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Papers by Rupali Datta