Anju Arora, Centre for Conservation and Utilisation of Blue Green Algae, Indian Agricultural Research Institute, N.Delhi, India.110012, Tel: 91-11-25848431, Email: anjudev@yahoo.com
Sudhir Saxena, Centre for Conservation and Utilisation of Blue Green Algae, Indian Agricultural Research Institute, N.Delhi, India.110012, Tel: 91-11-25848431
Dinesh Kumar Sharma, Division of Environmental Sciences, Indian Agricultural Research Institute, N.Delhi, India.110012

Environmental degradation is a natural outcome of rapid population growth, urbanization, industrialization and increased agricultural practices. Indian capital city N. Delhi is said to be the second most polluted city in the world.  With heightened environmental awareness, Delhi Government is taking steps to alleviate pollution problem.  The most severe are air and water pollution arising from industrial and vehicular emissions and municipal and industrial discharges. Everyday about 1880 mld of wastewater is discharged into Yamuna river from Delhi and this includes 1393 mld sewerage. The industrial wastewater generated is about 70 mgd (million gallons a day and most small scale industries do not have treatment facility.  Of the 380 mgd wastewater treated daily by Delhi Jal Board, only 80 mgd is used by farmers for irrigation purposes in rural Delhi and despite all efforts to recycle it, most of the treated wastewater is going waste. These wastewaters when used for irrigation increase productivity as they supply nutrients to the crops.  But besides, nutrient elements they contain toxic heavy metals, which accumulate in soils and plants and enter food chain.  Thus, they exert toxic effects and are hazardous.  However, these wastewaters can be safely and judiciously used for irrigation or other purposes if the toxic heavy metals content is lowered by treating them biologically.  Aquatic fern Azolla can tolerate and concentrate heavy metals in its biomass and remove them from mobile pools. Azolla is established Nitrogen biofertilizer for paddy and its biomass has several applications as green manure, fish and duck feed, cattle feed supplement and slow release carrier for micro nutrients for vegetable crops. Therefore, study was conducted to use these secondary treated wastewaters for Azolla biomass production. Secondary treated sewage effluents were collected from Wazirabad sewage treatment plant during summer, rainy, autumn and winter seasons and characterized for N, P and metal content. It contained low reactive P

1-5 ppm and all metals tested were within permissible limits prescribed by Bureau of Indian Standards. Azolla microphylla could grow well on these effluents and showed doubling times 2-5 days. The dry biomass had lower P content as compared to controls grown on defined medium or tap water. After analyzing the heavy metal content in dry biomass this biomass can be suitably used as inoculum in paddy fields, animal feed or green manure.

Remediation of Lead Contaminated Soil Using Physicochemical and Phytoremediation Technique: Experience from South West Nigeria

M.K.C. Sridhar, M.Sc., Ph.D., Division of Environmental Health, Faculty of Public Health, College of Medicine, University of Ibadan, Ibadan, Nigeria, Tel: 234-0803-727 3836, Email: mkcsridhar@yahoo.com
J.O. Etaghene, Division of Environmental Health, Faculty of Public Health, College of Medicine, University of Ibadan, Ibadan, Nigeria, Tel: 234-0803-727 3836, Email: joetaghene@yahoo.com
G.O. Adeoye, M.Sc., Ph.D.Department of Agronomy, University of Ibadan, Ibadan, Nigeria

A lead-acid battery manufacturing Industry in Ibadan (South West Nigeria), dumped unspecified amounts of its wastes in a nearby village, Olodo several years ago. Consequently, there were reports of damage to crops, poultry, aquatic life and abortions in goats grazing in the area. The community alerted the State Ministry of Environment who confirmed the toxic effects of the wastes and advised the neighboring communities to keep off the dumpsite environment. This study was undertaken to evaluate the lead levels in the soil and to remediate the soil using physicochemical and biological methods.

Varying concentrations (0.01 - 0.15M) of citric acid, Sodium Potassium Tartrate and Disodium Ethylene Diamine Tetraacetic Acid (EDTA) were tested for their ability to leach lead from the contaminated soils. Physical remediation involved mixing the contaminated soil with relatively clean soil in varying proportions to reduce the lead to acceptable levels of 15 - 30 mg/kg. Phytoremediation was carried out by growing Sunflower (Helianthus annuus) plants in the greenhouse and in a completely randomized design with nine replicates. The phytoremediation incorporated six levels (0,1.5, 2.5, 5.0, 10.0 and 20.0 tons/hectare) of Organic Manure (OM), to improve the fertility of the soil. Sieved uncontaminated composite soil from Olodo served as control. At 30 and 60 days, sets of 3 plants from each level of OM and the control were harvested and their fresh weights and lead levels were determined.

The levels of lead in the topsoil were found to be 39.4 - 9652.0 mg/kg as compared to the subsoil (13.8 - 5110.0 mg/kg). The topsoil of the control soils in the same location showed 0.031mg/kg lead while that of the subsoil was not detectable. Single extraction with 0.15M Citric Acid removed 57.6% lead at pH 5.2, Tartrate (0.15M) removed 38.7% lead at pH 9.1 while 0.15M EDTA removed 61.2% lead at pH 7.3. Two extractions with EDTA, three extractions with Citric Acid and 4 extractions with tartrate were required to reduce the lead content of the soil to acceptable and safe levels. Physical remediation revealed that the contaminated soil requires a 1:1000 mixing with relatively clean soil to reduce its lead content from 7705.5 mg/kg to 31.03 mg/kg. At 60days, OM level of 20 tons/ha produced plants with the highest dry weight (22.6g) while that of the control was 15.0g. At all levels of OM, root tissue concentrations of lead were highest, 31.0-139.8mg/kg compared to 14.3 - 46.4 mg/kg and 0.012 - 0.38 mg/kg found in leaf and stem, respectively. The greenhouse experiments when translated to plot experiments confirmed that excavation of the topsoil, enrichment with organic manure and application of phytoremediation were found to be feasible in remediating the lead contaminated soil.

Metabolism and Breakdown of Methyl Tertiary Butyl Ether in Phytoremediation

Robert H. Kim, Savannah River Ecology Laboratory, Aiken, SC
Lee A. Newman, Ph.D., University of South Carolina, Columbia, SC /Savannah River Ecology Laboratory, Aiken, SC

Since 1979, EPA has mandated the use of octane boosters in gasoline to improve fuel efficiency and reduce atmospheric pollutants.  While many organic compounds were originally tried as replacements for lead, methyl tertiary butyl ether (MTBE) was the compound that had the most widespread use due to its ease of mixing with gasoline.  However, MTBE releases into the environment have moved EPA in the opposite direction with MTBE tentatively planned to be phased out nation-wide as a gasoline additive by 2015 in accordance with the National Energy Bill.  As of January 1, 2004, MTBE is no longer used as an additive in California.

MTBE releases to the environment have proven to be much more problematic than gasoline or BTEX compounds.  MTBE in water moves rapidly through the soil column and then tends to continue moving with the aquifer.  This characteristic of MTBE has led to wide-scale aquifer contamination and, in many places, an inability to determine the exact source of MTBE contamination due to the size of the plumes and the possibility of multiple sources.

Remediation of MTBE is problematic due to this high degree of solubility; air stripping is much more energy-demanding as MTBE prefers to stay in the aqueous phase.  Due to its chemical structure, biodegradation is not common and often requires injection of one of the few isolates that have been shown to degrade MTBE.  Phytoremediation has shown some promise as a remediation technique for MTBE.  Plants that have been studied (poplar, eucalyptus, pine) all take up MTBE readily from soil or water.  The problem with regulator acceptance of phytoremediation as an MTBE solution is that there is no indication as to the fate of MTBE when taken up by plants.  Previous studies have shown that MTBE is taken up by plants and is transpired through the leaves.  Additionally, cell culture studies have shown limited metabolism to carbon dioxide (CO₂).  Studies have demonstrated that volatile organic compounds (VOC’s), such as MTBE, are released through the stems of plants exposed to those VOC’s.  None of these studies, however, addressed the problem of MTBE metabolism and metabolites in plants.  It is known that MTBE self-degrades into tertiary butyl alcohol (TBA) in water and can also be broken down into TBA in metabolic pathways by the MTBE 3-monooxygenase enzyme.  TBA is also a toxin of concern so breakdown of MTBE into TBA is not necessarily beneficial unless this is further metabolized into less toxic compounds.

Research presently in progress at The University of South Carolina and The Savannah River Ecology Laboratory is focusing on the uptake and metabolism of MTBE in hydroponically grown sterile tobacco plants.  A series of laboratory studies are planned which include the hydroponic dosing of sterile tobacco seedlings with MTBE.  Preliminary results have shown the presence of MTBE and TBA in the tobacco seedlings after 24 hours of dosing.

Planned studies include both hydroponic and soil-based exposure of plants to MTBE and tissue analysis of a variety of plants to identify metabolites.  Sterile plant cell cultures and will be performed in an attempt to separate out the role of the plants versus the plant rhizosphere bacteria.  Field sampling of plants will be performed and tissues analyzed for metabolites, transpiration, and volatilization through the trunks and stems of mature plants.

The results of this study could lead to increased regulatory acceptance of phytoremediation as a viable strategy for treating MTBE-contaminated aquifers.  Being able to predict and monitor the fate of MTBE in plant systems may lead to greater implementation of this technology.

The High Potential of Scented Geranium Plants (Pelargonium Roseum) for Phytoremediation of Cadmium

Majid Mahdiyeh, Department of Biology, School of Science, Arak University, Shahid Beheshti Street, P.O.Box 879, Arak, Iran, Tel: 98-0861-2777401, Email: m-mahdiyeh@araku.ac.ir 
Abolfazle Taghavi, Department of Biology, School of Science, Arak University, Shahid Beheshti Street, P.O.Box 879, Arak, Iran, Tel: 98-0861-2777401, Email: a-taghavi@araku.ac.ir
Malek Soleimani, Department of Biology, School of Science, Arak University, Shahid Beheshti Street, P.O.Box 879, Arak, Iran, Tel: 98-0861-2777401, Email: m-soleimani@araku.ac.ir
Mohamad R. Sangi, Department of Biology, School of Science, Arak University, Shahid Beheshti Street, P.O.Box 879, Arak, Iran, Tel: 98-0861-2777401, Email:mr-sangi@araku.ac.ir

Phytoremediation, the use of plants to reduce the risk associated with metal contaminated soils, is now being actively investigated as a low-cost option that causes no deterioration in soil quality.The major objective of this investigation was to evaluate the potential of  scented geranium plant, Pelargonium roseum to uptake and accumulate Cadmium under greenhouse conditions.Plants were grown in an artificial soil system and exposed to a range of metal concentrations(0-1000 mg.L^-1 Cd(NO3)2.4H2O) over a 14 day treatment period.Scented geranium plants accumulate in excess of 31267 mg of cadmium kg^-1 DW of root ,1690 mg cadmium kg^-1 DW of stem and 302.6 mg of cadmium kg^-1 DW of leaf tissue within 14 d.The high concentrations of cadmium found in the shoots of scented geranium plants has far exceeded 0.01% DW which is considered as a standard for defining cadmium hyperaccumulator plants in natureal environment, thus this species is likely be a new hyperaccumulator plant and indicates the efficacy of this plant species for phytoremediation of cadmium polluted sites.  

Plant Response and Accumulation of Lead, Cadmium, and Barium from a Superfund Site Soil

Quentin M. Flory, Ball State University, Natural Resources and Environmental Management, Muncie, IN 47306-0495, Tel: 765-285-2182, Fax: 765-285-2606, Email: quentinflory@hotmail.com
John Pichtel, Professor, Ball State University, Natural Resources and Environmental Management, Muncie, IN 47306-0495, Tel: 765-285-2182, Fax: 765-285-2606, Email: jpichtel@bsu.edu

The ability of green plants to extract lead (Pb), cadmium (Cd), and barium (Ba) from a Superfund soil in Indiana was studied in the greenhouse and in the field.  In the greenhouse, maize (Zea mays), soybean (Glycine max), Indian mustard (Brassica juncea), and sunflower (Helianthus annuus) were grown on soil containing average Pb, Cd, and Ba concentrations of 29,000, 3.9, and 1100 mg/kg, respectively.  All species were capable of both accumulating and distributing soil Pb to upper plant parts.  Addition of diethylenetriaminepentaacetate (DTPA) and dilute HNO₃ augmented Pb phytoextraction. No species extracted soil Ba and some extracted trace Cd into various plant parts.  Metal uptake was partly a function of the forms occurring in the soil.  For example, tissue Pb correlated with soluble and exchangable soil Pb concentrations.  Significant (p<0.05) differences were measured in chlorophyll a, chlorophyll b, and carotenoid concentrations with regard to treatment.  Chlorophyll content in G. max was particularly affected by soil Pb concentration.  In a column study, significant (p<0.01) differences in Pb mobility were measured with regard to both treatment and time.  Scanning electron microscopy/energy dispersive x-ray analysis indicated Pb accumulation in discrete aggregates on both leaf and root tissue.  Field plots were established at the Superfund site, treated with a mixed NPK fertilizer, ethylenedinitrilotetraacetic acid (EDTA), dilute HNO₃, or a mixture of EDTA and acid.  Plots were seeded with mixed grasses (Festuca, Poa, Phleum) and redclover (Trifolium pratense).  Preliminary results indicate that soil Pb and Cd tended to accumulate in roots with variable translocation to upper plant parts.  Barium uptake from the soil was negligible for all treatments.  Dry matter production was greatest for the NPK treatment and lowest for the EDTA + acid treatment.  No significant leaching of Pb, Cd, or Ba occurred in any treatment. 

Development of a Genome-wide Screening Method to Identify Gene Candidates Involved in the Degradation of Halogenated Hydrocarbons Using Ion Chromatography

Sarah Strycharz, Norman J. Arnold School of Public Health, University of South Carolina, Columbia, SC
Lee Newman, Norman J. Arnold School of Public Health, University of South Carolina, Columbia, SC and Savannah River Ecology Lab, Aiken, SC

As the use of phytoremediation for cleanup of halogenated hydrocarbons becomes increasingly widespread, it is imperative to determine the route of metabolism of such chemicals in plants to increase effectiveness and efficiency of degradation.  In humans and other organisms, cytochrome P450s are involved in degradation of the common groundwater contaminant trichloroethylene (TCE). TCE and ethylene dibromide (EDB) are both metabolized by the same primary enzyme in humans, cytochrome P450 2E1. Other potential enzymes that may be involved in TCE degradation in plants include additional cytochrome P450s, peroxidases, dehalogenases, laccases, and reductases. In order to screen for multiple enzyme types, we have developed an assay in which bacterial cultures expressing a commercially purchased tobacco leaf (Nicotiana tabacum) cDNA library can be examined for the ability to degrade a halogenated hydrocarbon, EDB. EDB is being used instead of TCE as the bromide ion (Br-) is not prevalent in culture media whereas chloride ion (Cl-) can be found at high levels. Following 72 hours of growth to high density, cultures are concentrated and resuspended in a phosphate buffer containing glucose and 100 ppm EDB. Degradation of EDB is measured by detection of Br- release using an ion chromatograph.  We hope to narrow the number of possible candidate genes by comparing the ability of cDNA library cultures to degrade EDB, with the ability of a control culture expressing a gene known to degrade EDB.

Comparison of Native Southeastern Conifers to Hybrid Poplar for Suitability to Phytoremediate Trichloroethylene

Sarah Strycharz and Daniel Heenan, Norman J. Arnold School of Public Health, University of South Carolina, Columbia, SC
Lee Newman, Norman J. Arnold School of Public Health, University of South Carolina, Columbia, SC and Savannah River Ecology Lab, Aiken, SC

Phytoremediation of trichloroethylene (TCE) from contaminated groundwater has been extensively studied using the hybrid poplar tree (Populus spp.). Hybrid poplars are capable of rapid growth in which they take up large quantities of water and also possess the capacity to effectively metabolize TCE.  Several metabolites of TCE have been identified in the tissue of poplar including trichloroethanol (TCEOH) and di- and trichloroacetic acids (DCAA, TCAA). This study follows a greenhouse-based comparison of four different native Southeastern conifers to a hybrid poplar species for the ability to take up and degrade TCE. Longleaf pine (Pinus palustris), Leyland cypress (x Cupressocyparis leylandii), two varieties of Loblolly pine (Pinus taeda), and hybrid poplar species OP-367 (Populus deltoides x P. nigra) were examined for the concentration of TCE and its metabolites in their tissue using gas chromatography following treatment with either a low dose of TCE (50 ppm) or a high dose of TCE (150 ppm) for two months. The amount of water taken up, height of the tree, TCE transpiration, and total fresh weight were also recorded. Our goal is to expand the effectiveness of phytoremediation in combination with land reclamation by supplying the option of creating a heterogeneous forest system for contaminated groundwater treatment.

Phytoremediation to Oil Contaminated Wetland Soil Treatment by Aquatic Plant (Typha orientalis Presl)

Jui-Yann Wang, Department of Biological Engineering, Yung Ta Institute of Technology and Commerce, 316 Chung Shan Road, Lin Ti-Village, Lin-Lou, Pingtong County 909, Taiwan, Tel: 886-8-72337330 #225, Fax: 886-8-7217730, Email: juen@mail.ytit.edu.tw
Hung-Ta Lin, Department of Marine Environment Science and Engineering, Sun Yat-sen University, 70 Lien-hai Rd., Kaohsiung 804, Taiwan, Tel: 886-7-525-2000#5177, Fax: 886-7-525-5060, Email: m9154629@student.nsysu.edu.tw , radhon@sinamail.com
Lei Yang, Department of Marine Environment Science and Engineering, Sun Yat-sen University, 70 Lien-hai Rd., Kaohsiung 804, Taiwan, Tel: 886-7-525-2000#5068, Fax: 886-7-525-5060, Email: leiyang@mail.nsysu.edu.tw

Oil contaminated on land was occurred via oil transportation, oil spills or producing sites in many countries of the world. Physically removing oil can also result in more ecological and physical damages than using natural treatment processes. The objectives of this study were to determine the potential of phytoremediation for diesel contaminated wetland soil, to compare aquatic plant (Typha orientalis Presl) presence or absence of soil microbial activity, and to determine the fertilizer in enhancing phytoremediation induced oil degradation. After 75 days incubated inside a greenhouse, the degradation rate TPH-D in wetland system planted with Typha orientalis Presl was measured equal to 70% at day 45, while the control system without vegetation was measured equal to about 60%. Thus, it was concluded that the wetland systems with vegetation could enhance the microbial activity on the rhizosphere of wetland plants, which would help to biodegradate the TPH-d in wetland soil contaminated by oil spills.

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