J. G. Ayenimo, Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria, Email: ayenimo71@yahoo.com
A. S. Adekunle, Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria, Email: sadek2k@yahoo.com
G. O. Ogunlusi, Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria, Email: roogunlusi2003@yahoo.co.uk
W. O. Makinde, Centre for Energy and Research Development, Obafemi Awolowo University, Ile-Ife, Nigeria, Email: mak2002@yahoo.com

Runoff samples were collected from three different commonly used roofing materials in Ile-Ife, Nigeria.  Some water parameters like pH, Temp, TDS, Cl^-, SO₄^2-,PO₄^2-, NO₃^- and EC were determined in the samples.  Five Heavy metals both as regards total, dissolved and particulate fractions were also analysed.  The quantity of these parameters varies with different roofs.  In terms of dissolved metals, the concentration (mgl ^-1) decrease in this order of magnitude Fe>Zn>Cr>Pd>Cd for all the roofs investigated.  The tendencies of the roofing materials to leach dissolved metals are arranged as follows: Zn and Cr (metal sheet>asbestos>ceramic); Fe (metal sheet>ceramic>asbestos); Cd (asbestos>metal sheet>ceramic) and Pb (asbestos>ceramic>metal sheet) while those of the particulate metals are: Cd and Pb (asbestos>ceramic>metal sheet); Cr (ceramic>asbestos>metal sheet); Zn (ceramic>metal sheet>asbestos) and Fe (metal sheet>ceramic>asbestos).  For all the roofs, both the particulate and dissolved metals except Zn exceed their WHO permissible limits for drinking water.  These high levels of the metals may likely result in consumer complaints since some of the metals are not only carcinogenic but may also impact bad taste in water.  Direct discharge of the runoff could have toxic effects on natural waters and their local infiltration would rapidly lead to soil contamination.  Result of spiking experiments with the runoff samples showed good recoveries for all the metals analysed.  Blank determinations were done for background corrections.

Environmental Cleanup Technology in Industrialized and Transportation Districts of Inorganic Pollutants in Aquatic South Texas

Craig A. Bowe, Department of Biology and Chemistry, Texas A&M International University, 5201 University Boulevard, Laredo, Texas 78041, Tel: 956-326-2568, Fax: 956-326-2439, Email: cbowe@tamiu.edu, wilsonelmo@yahoo.com
Elia C. Garcia, Department of Biology and Chemistry, Texas A&M International University, 5201 University Boulevard, Laredo, Texas 78041, Tel: 956-326-2568, Fax: 956-326-2439  
J.J. Hernandez; Department of Biology and Chemistry, Texas A&M International University, 5201 University Boulevard, Laredo, Texas 78041, Tel: 956-326-2568, Fax: 956-326-2439 

Source pollution by inorganic pollutants is a manifestation of industrialized districts and urbanized areas. Recently we have identified that freshwater sources in the Laredo region of southern Texas is an aspect of the transportation, civil and military defense, tourism and commerce industries that make up the region.  Environmental cleanup technology is a field of environmental science and chemistry that is an emergent and dynamic field.  The removal of inorganic pollutants such as lead(II), cadmium(II), mercury(II), and silver(I) from aquatic areas and media using silica-based materials are currently being employed.   The use of silica-based and clay-based porous composites in the uptake and removal of inorganic particulate matter from freshwater resources such as lakes and rivers which border Mexico will be investigated.

Characterization, Speciation and Remediation of Lead in Urban Garden Soils

Heather Clark, Wellesley College, 106 Central St., Wellesley, MA 02481, Tel: 781-929-7678, Fax: (781) 283-3642, Email: hclark2@wellesley.edu
Rachel Erdil, Wellesley College, 106 Central St., Wellesley, MA 02481, Tel: 781-283-3056, Fax: 781-283-3642, Email: rerdil@wellesley.edu
Daniel J. Brabander, Wellesley College Dept. of Geosciences, 106 Central St Wellesley, MA 02481, Tel: 781-283-3056, Fax: 781-283-3642, Email: dbraband@wellesley.edu

Gardening is an important element of community life and food security in the urban communities of Roxbury and Dorchester, MA that is threatened by extensive lead contamination of area soils. Our lab has formed a partnership with The Food Project, a community organization that promotes sustainable and organic agriculture, and we have been able to form relationships with many local residents to educate members of the community about the health of their soil and the potential risks they face as a result of their interactions with the soil. We have used field portable x-ray fluorescence to test over 500 soil samples and have found that 90% of samples contain concentrations of lead greater than the MA Department of Environmental Protection (MA-DEP) reportable level of 300 µg/g lead in soil. The principle goals of our research are to: 1) characterize the spatial variability of the lead at the neighborhood scale, 2) fingerprint the sources of lead in the gardens, 3) assess the chemical speciation and bioavailability of lead and 4) devise and test a phytoremediation scheme for the area. We are using textural-analytical approaches coupled with trace element ratio analysis and lead isotope analysis to evaluate the mass balance and geochemical characteristics of the lead found in garden soils. Preliminary results indicate that lead concentrations are highest in the finest particle size of soil and that lead is often associated with an identifiable suite of trace elements. Initial observations suggest that point and non-point sources, including lead-based paint chips and particulate matter from leaded gasoline, contribute to the overall soil lead burden. Phytoremediation data is still inconclusive but eight gardens of test crops are currently being planned with sunflowers, collards and mustards as heavy-metal hyperaccumulators.  A detailed geochemical assessment of lead in urban garden soils will provide insight into the severity of lead contamination in this high exposure setting and help to design a successful remediation scheme.

Establishing Baseline Concentrations of Trace Metals at an Old Landfill

Kelly Ashton, Richard Stockton College, RSC#2133, PO Box 195, Pomona, NJ, 08240, Tel:  973-978-3703, Email: stk23728@loki.stockton.edu
Justine Cook, Richard Stockton College, RSC#2123, PO Box 195, Pomona, NJ, 08240, Tel: 908-461-4594, Email: stk24318@loki.stockton.edu
Robert Fromtling, Richard Stockton College, RSC#4165, PO Box 195, Pomona, NJ, 08240, Tel: 609-626-3500 ext.2297, Email: stk20709@loki.stockton.edu
Tait Chirenje (Ph.D.), B108 NAMS, The Richard Stockton College of New Jersey, Pomona, NJ 08240-0195, Tel: 609 652 4588, Email: tait.chirenje@stockton.edu

Old Buzby Brothers landfill was an active waste disposal site from the late 1950s until the late 1970s—receiving waste from over forty companies and municipalities.  Voorhees Township owns approximately 57 acres, which they have decided to develop after remediating the site. Based on data gathered from the site, the township developed an end use plan which includes gardens, an amphitheater, office building, children’s play area, bird sanctuary, and open land with trails. The NJDEP, however, has expressed concern regarding the extent of pollution and the possibility of mercury and other trace metal contamination in the Kirkwood-Cohansey aquifer. We will collect soil samples from sites chosen based on the proposed end land use map. These samples will establish baseline concentrations of trace metals and nutrients. Eight onsite sample locations were chosen because their proposed uses have the potential to affect soil quality. Soil samples will be sieved, digested and analyzed for arsenic, copper, chromium, cadmium, selenium, manganese, nickel, and lead using USEPA procedures. Other parameters to be measured include pH, EC and organic carbon. Preliminary testing on site has already detected elevated levels of benzene, mercury, arsenic, and other agents. We expect to find elevated levels nutrients in areas designated for lawns but the distribution of trace elements will depend on the intensity and type of construction activities on the site. Our study will also help NJDEP’s concerns on whether the concentrations of some of the aforementioned chemicals are decreasing with time due to natural processes, such as rainfall. Establishing baseline concentrations of trace metals at Buzby Landfill will contribute in assessing the public health risk from the developed areas of the former landfill.  Additionally, these values will act as a yardstick against which future changes in soil chemistry can be measured.

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

J.O. Etaghene, B.Sc., M.P.H., Delta State School of Health Technology, Ughelli, Nigeria, Tel: 234–08023468257; Fax: 234–08023025891, Email: joetaghene@ yahoo.com
M.K.C. Sridhar M.Sc., Ph.D., Division of Environmental Health, Faculty of Public Health, College of Medicine, University of Ibadan, Nigeria
G.O. Adeoye, M.Sc., Ph.D, Department of Agronomy, University of Ibadan, Ibadan, Nigeria

Industrial wastes dumped in Olodo (outskirts of Ibadan) over a decade ago has been posing serious health hazards to the inhabitants.  The State Ministry of Health confirmed lead as the main contaminant of the wastes.  This study was undertaken to evaluate the lead levels in the soil and to remediate it 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, dry 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 60 days, 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, 31.0-139.8 mg/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.

Remediation of Heavy Metals Contaminated Sediments by Stabilization/Solidification Technology

Gianluca Intini, Department of Environmental Engineering and Sustainable Development, Technical University of Bari, Viale del Turismo, 8-74100 Taranto, Italy, Email: g.intini@poliba.it
Lorenzo Liberti, Department of Environmental Engineering and Sustainable Development, Technical University of Bari, Viale del Turismo, 8-74100 Taranto, Italy, Email: l.liberti@poliba.it
Michele Notarnicola, Department of Environmental Engineering and Sustainable Development, Technical University of Bari, Viale del Turismo, 8-74100 Taranto, Italy, Email: notarnicola@poliba.it
Tiziano Pastore, Department of Environmental Engineering and Sustainable Development, Technical University of Bari, Viale del Turismo, 8-74100 Taranto, Italy, Email: t.pastore@tiscali.it
Vittoriano Di Tommaso, Department of Environmental Engineering and Sustainable Development, Technical University of Bari, Viale del Turismo, 8-74100 Taranto, Italy, Email: vidi06@libero.it  

The most widely used procedure for reducing the contamination effects of marine sediments is dredging and disposal of material in controlled dumps. This method is becoming impracticable because it is increasingly difficult to find adequate space.

This study was carried out to design an effective treatment method for heavy metals contaminated sediments using stabilization/solidification (S/S) technology. In particular, experimental investigation on laboratory scale has been carried out to highlight the effect of organic pollutants (PAHs) on the hydration kinetics, physico-chemical properties and leaching behaviour of cement-based solidified materials. 

To better understanding S/S process, both artificially spiked and field samples of Taranto harbour sediments contaminated by heavy metals and PAHs were treated with different kinds of cement and water/cement/sediment ratios.

The results of laboratory tests indicated that the treatment of sediment requires an increase of water/cement ratio, due to its remarkable presence of fine fraction. A good immobilization of copper, lead and nickel after only seven days of curing, due to high Ph values (8-9) and percentage of silica (approx. 15% in weight) in harbour sediment, limiting metals leaching from solidified matrix was observed. Moreover the presence of organic compounds implied a negative effect on the cement hydration, retarding setting time.

In conclusion the experimental results generally show that cement based stabilization/solidification process is capable of successfully treating marine sediments contaminated by heavy metals and PAHs. With its proven effectiveness in pollutants immobilization this technology is promising for large scale application.

River Hrazdan Water Assessment under Conditions of Unstable Economy

A. Saghatelyan, M.A. Nalbandyan, L.P. Grigoryan, M.G. Michaelyan, Center for Ecological-Noosphere Studies of NAS RA. Abovian Str. 68, Yerevan 375025, Armenia, Tel: (374-1) 56-93-31, Email: ecocentr@sci.am

Today, the assessment of the role of man-made factors of environmental pollution of urban agglomerations is of great scientific and practical interest.

River Hrazdan is one of Armenia’s most important water objects. It flows out from Lake Sevan, runs southwestward – up toYerevan, crosses the Ararat Valley and flows into transboundary River Araks at a height 820 m a.s.l.

The investigations covered 7 monitoring points within Yerevan’s bounds in period 2001-2003.

Heavy metals (HM). The seasonal dynamics of a number of elements (Mn, Mo, Ag, Cd) is characterized by a mean two- or threefold increase in concentration from spring  till fall, this resulting mostly from the water volume decrease. Zn and Pb contents are high and relatively stable.

 The qualitative and quantitative series of geochemical stream is as follows: Cu₍₆₉₎ – Zn₍₆₈₎ - Pb₍₅₆₎ - Ag_(6.4) - Cr_(5.4)-Ni₍₂₎. The comparative analysis shows that in 2003 Cu, Zn, Pb concentration coefficient (CC) (the background exceed) increased 5.7, 9.7, 12.4 times respectively, Ag CC was relatively stable and Cr CC decreased by 1.7. Such results are explained by the change in pollution specificity due to the development or collapse of some industrial branches under condition of unstable economy. While conducted investigations, especially high concentrations of Pb, Cd, Zn were established. Mean Pb, Cd, Zn contents in water exceed Maximum Permissible Concentration (MPC) 12, 3-4, 4 times respectively. Most of HM precipitate to Yerevan lake as exclusively toxic constituent of bottom  sediments.

Biogens.  The contents of nitrates, phosphates and ammonium nitrogen make 8.1, 0.4, 0.27 mg/L respectively. The given values exceed the background: nitrates – 6-7, ammonium nitrogen –3-4, phosphates – 1.5-2 times.

The investigations allowed establishing significant man-made pollution of River Hrazdan water, the basic reasons of such pollution being insufficient level of wastewater cleanup and uncontrolled wastewater discharge into sewage network.          

Treatment of Heavy Metals in Stormwater Using Wet Pond and Wetland Mesocosms

Swarna Muthukrishnan, Ph.D., ORISE Post Doctoral Fellow, Urban Watershed Management Branch, Water Supply & Water Resources Division, National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 2890 Woodbridge Avenue, Edison, NJ 08837, Tel: 732-321-4436, Fax: 732-321-6640, Email: muthukrishnan.swarna@epa.gov

Urban stormwater runoff is a significant source of suspended sediments and associated contaminants, including heavy metals, to receiving waterways.  These metals are either dissolved or bound to particulates (coarse - >75 µm; fine particulates - <75 - 1 µm; colloids - <1 µm).   Information on the particulate association of heavy metals in stormwater is a critical requirement prior to using pond and wetland best management practices (BMPs) as stormwater treatment controls.  Heavy metals in stormwater are primarily removed by sedimentation in structural BMPs, and these sediments may be toxic to benthic invertebrates and aquatic microorganisms.  The proposed research will be conducted at U.S. EPA’s Urban Watershed Research Facility (UWRF) in Edison, NJ to evaluate the effectiveness of pond and wetland BMP mesocosms to remove heavy metals from stormwater runoff.  The runoff draining from roofs and parking lots of the adjacent county college will be investigated.  Seven heavy metals (Cu, Zn, Pb, Cr, Fe, Al, and Mn) will be investigated based on results from an earlier screening procedure (August 2004) on stormwater runoff in the same location.  The research objectives include: (i) characterizing the association of heavy metals with fine particulates (20 to 0.4 µm) in stormwater runoff; (ii) evaluating the relative removal of particulate-bound as well as dissolved heavy metals in wet pond and cattail wetland mesocosms; and (iii) investigating the solid-phase chemical associations of heavy metals in cattail wetland sediments by selective sequential extraction procedures and thereby assessing the potential for sediment toxicity and heavy metal bioavailability.  The project will commence in March 2005, and two actual rain events per season (winter, spring, summer, and fall) will be sampled in order to determine any seasonal variability in stormwater heavy metal-particulate associations.  Wetland sediments will be sampled twice; at the start and after the completion of the stormwater sampling events.

Effects of Class B Sewage Sludge Applications on Agricultural Fields in Northwest Ohio

Jennifer E. Rader, The University of Toledo, Department of Geography and Planning, 2801 West Bancroft Street, Mail Stop 932, UH 4390, Toledo, OH 43606, Tel: 419-308-4152, Fax: 419-530-7919, Email: jennifer.rader@utoledo.edu
Kevin Czajkowski, The University of Toledo, Department of Geography and Planning, 2801 West Bancroft Street, Mail Stop 932, UH 4580, Toledo, OH 43606, Tel: 419-530-4274, Fax: 419-530-7919, Email: kcajko@pop3.utoledo.edu
Alison Spongberg, The University of Toledo, Department of Earth, Ecological and Environmental Sciences, 2801 West Bancroft Street, Mail Stop 604, BO 3086, Toledo, OH 43606 Tel: 419-530-4091, Fax: 419-530-4421, Email: alison.spongberg@utoledo.edu
Theresa Benko, The University of Toledo, Department of Geography and Planning, 2801 West Bancroft Street, Mail Stop 932, UH 4420A, Toledo, OH 43606, Tel: 419-530-4313, Fax: 419-530-7919, Email: tbenko@utnet.utoledo.edu
David Czajkowski, The University of Toledo, Department of Geography and Planning, 2801 West Bancroft Street, Mail Stop 932, UH 4390, Toledo, OH 43606, Tel: 419-530-2545, Fax: 419-530-7919, Email: david.czajkowksi@utoledo.edu
Alycia Pittenger, The University of Toledo, Department of Earth, Ecological and Environmental Sciences, 2801 West Bancroft Street, Mail Stop 604, Toledo, OH 43606 Tel: 419-530-2009, Fax: 419-530-4421, Email: alycia.pittenger@utoledo.edu
Justin Pitts, The University of Toledo, Department of Earth, Ecological and Environmental Sciences, 2801 West Bancroft Street, Mail Stop 604, Toledo, OH 43606 Tel: 419-530-2009, Fax: 419-530-4421, Email: justin.pitts@utoledo.edu

Application of sewage sludge, or biosolids, on agricultural fields has been considered by many to be a cost-effective means of waste disposal while simultaneously acting as a cheap, productive fertilizer.  However, the effects of such application are not fully known.  Our study investigates three main areas of concern regarding this practice in Northwest Ohio: heavy metals, nitrates and total organic carbon.   The study is being conducted on an agricultural field in Oregon, Ohio that receives Class B sewage sludge from a nearby sewage treatment facility.  Samples were collected at three depths from forty-seven sampling locations throughout the field prior to sludge application and at intervals following application.  The effects of application over time, at the different depths and during different seasonal conditions will be evaluated.  A control field possessing similar soils and crop rotation activities but no history of sludge application has also been included. Samples are currently being analyzed.  Spectral readings have been collected and will be compared with Landsat-7 imagery to assess whether remote sensing can be utilized as a tool with regards to the application of sewage sludge. Results from the first year of the study will be presented.  A “sister” study is being conducted by Dr. Robert Vincent at Bowling Green State University for comparison. 

Revealing Risk Groups Under Condition of Pollution of Cities with Heavy Metals

A.Saghatelyan, L Sahakyan, Center for Ecological-Noosphere Studies of NAS RA. Abovian Str. 68, Yerevan, 375025, Armenia, Tel: (374-1) 56-93-31, Email: ecocentr@sci.am, svlilit@yahoo.com

Heavy metals are attributed to stable environmental pollutants. Special attention paid to them when assessing ecological state of territories is conditioned by their specific impact upon human organism.

In cities, reappearance of processed substances in the environment and their re-involvement in natural cycles have acquired a of large-scale character, this resulting in formation of man-made geochemical associations of heavy metals on urbanized sites.                      

The picture of heavy metal pollution of territories is identified through geochemical mapping of soils. The relevant maps show pollution sources and structure, and based on them territory zoning is carried out by level of pollution with separate elements or their associations. Environmental risk assessment in such zones is based on geo-ecological principle regarding data spatial and temporal timing and reflection on specialized maps.

Thus, treating the territory as objectifying factor we may collate geochemical and other ecologically significant factors with medical and biological indices of the populace. In particular, we have established the increase in occurrence rate of perinatal mortality in the zones of intense lead and copper anomalies.

Geochemical maps may easily be transformed to sanitary-hygienic ones, this making it possible to operatively reveal groups exposed to top risk and requiring thorough examination.

Under condition of social and economic crisis, a new large risk group has been formed among urban population: a so-called “urban home-gardeners” who - to survive- have to grow agricultural crops on small plots of land within the bounds of the city.

Biogeochemical mapping of vegetation and studying mobile forms of metals in soils allowed contouring the areas where agricultural crops polluted with heavy metals are grown and revealing risk groups with whom preventive work should be conducted so as to rise their awareness.            

Lead and Reactive Sulfide Stabilization in Soil: Lessons Learned

Christen Clarke Sardano, Shaw Environmental and Infrastructure, 100 Technology Center Drive Stoughton, MA 02072-4705, Tel: 617-589-7261, Fax: 617-589-2160, Email: christen.sardano@shawgrp.com
Ronald Richards, Shaw Environmental and Infrastructure, 100 Technology Center Drive Stoughton, MA 02072-4705, Tel: 617-589-5499, Fax: 617-589-2160, Email: ronald.richards@shawgrp.com

A Site in greater Boston with a variety of contaminants of concern (including polycyclic aromatic hydrocarbons, mercury, lead and petroleum hydrocarbons) was undergoing redevelopment.  To complete construction, large quantities of soil needed to be removed from the site and disposed of or reused in accordance with state and federal regulations.  Two contaminants of concern, lead and reactive sulfide, were particularly of concern for on-site stabilization prior to disposal, due to the large cost differential between disposal as a hazardous waste and on-site treatment with off-site disposal subsequent to treatment.  The paper details the subcontractor process of on-site soil stabilization for soils that originally had concentrations of TCLP Lead greater than 5 milligrams per liter (mg/L) and reactive sulfide concentrations above 500 milligrams per kilogram (mg/kg).  The process of characterization of this site is described, which allowed for soil segregation allowing soil not requiring treatment being transported off-site through a load and go operation and the soil to be stabilized using on-site stockpiling with subsequent treatment in accordance with the Massachusetts Department of Environmental Protection (MADEP) and United States Environmental Protection Agency (EPA) regulations.  The treatment process is detailed including an overview of the chemistry of both the lead stabilization and the neutralization of the reactive sulfide and comparison results provided.  The paper discusses how the use of on-site stabilization leads to significant cost savings.  In addition, lessons learned are described along with recommendations for developing work plans for this type of work.

Modeling the Competitive Effect of Phosphate, Sulfate, Silicate and Tungstate on the Adsorption of Molybdate onto Goethite

Nan Xu, Center for Environmental Systems, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA, Tel: 201-216-5329, Fax: 201-216-8303, Email: nxu@stevens.edu
Washington Braida, Center for Environmental Systems, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA, Tel: 201-216-5329, Fax: 201-216-8303, Email: wbraida@stevens.edu
Dimitris Dermatas, Center for Environmental Systems, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA, Tel: 201-216-5329, Fax: 201-216-8303, Email: ddermata@stevens.edu
Christos Christodoulatos, Center for Environmental Systems, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA, Tel: 201-216-5329, Fax: 201-216-8303, Email: christod@stevens.edu

Competitive adsorption amongst anions affects the partitioning and transport of anionic solutes in subsurface and surface waters. To enable the prediction of molybdenum distribution within natural anoxic environments, binary competitive batch sorption experiments were performed using MoO₄^2- and goethite suspensions in 0.1M NaCl under anoxic conditions.  The competitive anions studied were phosphate, sulfate, silicate and tungstate.  The pH range covered was from 3 to 10 and all experiments were performed at 25^oC.  Molybdate adsorption onto goethite was reversible as shown by the overlapping of sorption and desorption isotherms.  The competitive adsorption results showed that the anions which form inner-sphere complexes inhibit the formation of outer-sphere complexes. Tungstate and phosphate strongly competed with molybdate during the adsorption process. Furthermore, tungstate and phosphate show competitive displacement of adsorbed molybdate. The CD-MUSIC (Charge Distribution MUlti SIte Complexation) model was used to describe the anionic adsorption envelopes and isotherms on goethite.  The competitive adsorption envelope predicted by the CD-MUSIC model provided a satisfactory fit for the experimental adsorption data of molybdate over the whole pH range tested. Furthermore, CD-MUSIC prediction of the molybdate adsorption isotherm strongly agrees with the experimental isotherm. Experimental and modeling results strongly suggest that molybdate partition behavior under anoxic conditions strongly depends on the competitive interactions of other anions such as phosphate, silicate and tungstate.

Metal Ions Binding onto Lignocellulosic Substrate Extracted from Coconut Husk

Kishore K. Krishnani, Centre for Environmental Engineering, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, 07030, NJ
Xioaguang Meng, Centre for Environmental Engineering, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, 07030, NJ
Veera M. Boddu, US Army Construction Engineering Research Laboratories, Champaign, IL
Christos Christodoulatos, Centre for Environmental Engineering, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, 07030, NJ

The presence of heavy metals in the aquatic environment has been of great concern because of their toxicity and non biodegradable nature. Chromium and cadmium are toxic and relatively widespread in the environment. These metals are used in a wide variety of industries such as electroplating, metal finishing, leather tanning, chrome preparation and battery and find their way to the aquatic environment through wastewater discharges. Therefore a systematic study on the removal of chromium and cadmium from wastewater is of considerable significance from an environmental point of view. In the present study, natural and eco-friendly product has been prepared from coconut husk for the removal of cadmium and chromium. The maximum adsorption capacity and pH dependence has been investigated. X-ray photo electron spectroscopy (XPS) was used to characterize sorbed metal ions. Scanning Electron Microscope (SEM) images of the substrate were also obtained.

Preparation of Eco-friendly Product from Wheat corns for the Removal of Mercuric and Lead IP Ions

Kishore K. Krishnani, Centre for Environmental Engineering, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, 07030, NJ
L. Dupont, GRECI, UFR Sciences Exactes et Naturelles, Universite’ de Reims Champagne-Ardenne, BP 1039, 51687, Reims Cedex 2 France
Xioaguang Meng, Centre for Environmental Engineering, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, 07030, NJ

Natural waters have been found to be contaminated with several heavy metals arising mostly from mining wastes and industrial discharges. Currently used water treatment technologies involving chemical precipitation, evaporation and electrochemical treatment and the use of ion exchange resins are expensive and sometimes ineffective especially, when metals are present in solution at very low concentrations. In recent years, a promising alternative method for removal of metal ions employs certain plants which possess the natural ability to uptake heavy metals for the remediation of environment. In the present studies, an inexpensive and effective adsorbent has been prepared from wheat corns for the removal of mercuric and lead ions from water. The maximum adsorption capacity and removal mechanisms of metal ions onto the substrate has also been studied. In order to estimate functional groups, non aqueous potentiometric titrations were performed on the substrate. Product has been imaged by scannining electron microscopes.

Top