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Toxicity
and Bioaccumulation Testing of Zinc from Weathered
Substrates Using Plants and Worms
E.P.H.
Best, U.S. Army Engineer Research and Development Center,
Environmental Laboratory, 3909 Halls Ferry Road,
Vicksburg, MS 39180, Tel: 601-634-4246; Fax: 601-634-3410,
Email: beste@wes.army.mil
K.N. Geter, Analytical Services, Inc., 3532 Manor Drive,
Ste #3, Vicksburg, MS 39180
H.E. Tatem, U.S. Army Engineer Research and Development
Center, Environmental Laboratory, 3909 Halls Ferry Road,
Vicksburg, MS 39180
Contaminants
in soils and sediments can move from substrates into food
webs because of their contact with substrate-colonizing or
–inhabiting plants and animals, and as such cause
unacceptable risks. A study was conducted to evaluate the
(1) Toxicity of metals from metal-contaminated dredged
material to terrestrial plants and worms; (2)
Bioaccumulation of metals from metal-contaminated dredged
material accumulate in terrestrial plants and worms; and
(3) Effects of substrate characteristics other than
metal concentration alone on the biotic responses.
Results
indicated that bermudagrass is a far more sensitive test
organism than earthworms.
A 55d-EC50 of 645 mg total-Zn kg-1
substrate dry weight (DW) was found for plants (bermudagrass),
and a 28-d LC50 >1793 mg total-Zn kg-1
substrate DW for earthworms.
Zinc
accumulated in the plants and worms. Plant tissue-Zn
concentrations associated with normal and phytotoxic
growth were, respectively, 163 and 324 mg Zn kg –1
DW. The Biota
to Soil Accumulation Factor (BAF) for Zn in plants
decreased from 1.25 to 0.42 between 100 and 1500 mg
total-Zn kg-1 substrate DW. The tissue-Zn concentration in worms ranged from 93 to 177 mg
kg-1 DW. The BAF for Zn in worms decreased from
0.93 to 0.10 between 100 and 2000 mg total-Zn kg-1
substrate DW. These BAFs can be used in estimates of
trophic transfer of contaminants from DM in food chains.
Of the substrate characteristics tested other than zinc
concentration, i.e. organic matter content, moisture level
(only in plants), and pH, none significantly affected
biomass production and tissue metal concentration in both
organisms.
Riverbank
Stabilization of Lead Contaminated Soils using Native
Plant Vegetative Caps
JoAnn
M. Camacho, B.S., CHMM, U.S. EPA Environmental Response
Team, 2890 Woodbridge Ave, Bldg 18, Edison, NJ
08837, Tel: 732-906-6916, Fax:732-321-6724
Richard Fetzer, M.P.A., U.S. EPA Region II, 4530 Bath
Pike, Bethlehem, PA 18017-2070,Tel:
610-861-2087, Fax:610-861-2072
Mark Huston, M.S., U.S. Fish and Wildlife Service, 2890
Woodbridge Ave, Bldg 18, Edison, NJ
08837 Tel: 732-321-6609, Fax:732-321-6605
Christopher Gussman, M.S., Lockheed Martin Co., 2890
Woodbridge Ave., Bldg. 209, Edison, NJ 08837, Tel:
732-321-4200, Fax:732-494-4021
Daniel G. Crouse, B.S., P.E., EarthTech, Inc, 7870 Villa
Park Drive, Suite 400, Richmond, VA
23228 Tel: 804-515-8300, Fax: 804-515-8305
Robert Helverson, B.S., Tetra Tech EMI, 709 Chelsea Parkway,
Boothwyn, PA 19061
, Tel:
610-485-6410, Fax: 610-485-8587
Hamburg
is a small borough in Berks County, Pennsylvania. During the 1940s and 1950s, crushed automobile battery
casings, containing high levels of lead, were used as fill
in and around Hamburg.
Several of the fill areas are along the eastern
bank of the Schuylkill River and the Schuylkill River
Canal. In
order to reduce exposure to human and ecological
receptors, the U. S. EPA
initiated removal actions at several of the fill
areas. Removal
actions at three of these fill areas, the Berry Property,
the City Playground, and the Port Clinton Avenue sites,
utilized native plant stabilization and caps.
The
Berry Property consisted of a flat, wooded area adjacent
to the river. The
City Playground consisted of a steep wooded slope between
the river and the parking lot for the community park.
The Port Clinton Avenue site consisted of flat and
sloped wooded and old-field areas between the canal and
Port Clinton Avenue.
At all three sites, some of the contaminated
surface soils were removed and the remainder was
graded and capped. The clean soil cap was then seeded with native and/or
non-invasive grasses, covered with an erosion control mat,
and planted with native shrubs.
At the City Playground and Port Clinton sites the
existing trees were maintained to preserve the slope
stability and the
natural environment.
Great care was taken to ensure community access to
the Playground. The
work was coordinated with the Hamburg Borough Council, the
Schuylkill River Greenway Association, and the
Pennsylvania Department of Environmental Protection.
This
paper will detail the removal actions performed, discuss
some of the problems encountered, and describe the
solutions developed. Some of these issues included maintaining the existing trees,
dealing with invasive species, maintaining the plants
during a drought, channeling storm-water runoff, and
teaming with local entities.
Phosphate-Based
Stabilization of Lead Impacted Soil
Raveendra
Damera, P.E., DEE, General Physics Corp., 6095 Marshalee
Drive, Elkridge, MD 21075,
Tel:
410-379-3622, Fax: 410-540-5305
Dev Murali, P.G., General Physics Corp., 6095 Marshalee
Drive, Elkridge, MD 21075,
Tel:
410-379-3684, Fax: 410-540-5305
Phillina Peete-Tookes, M.B.A., J.D., Goddard Space Flight
Center, Greenbelt, MD 20771,
Tel:
301-286-0509, Fax: 301-286-1745,
Phillip J. Nessler, P.E., C.S.P, Goddard Space Flight
Center, Greenbelt, MD 20771, Tel: 301-286-4693, Fax:
301-286-1745
Total
and toxicity characteristic leaching procedure (TCLP) lead
concentrations as high as 5,055 mg/kg and 447 mg/L were
observed in the backstops of pistol and rifle ranges
located at GSFC, Maryland.
Decision for cleanup of the range soils was driven
by GSFC objectives to reduce worker exposure, facilitate
future expansion, and minimize contaminant migration.
Based on a technology evaluation and treatability
studies, a three-step cleanup process consisting of
in-place inactivation of lead-impacted soil, screening of
stabilized soil to recover recyclable material, and
off-site disposal of the remaining stabilized soil as
non-hazardous waste, was selected.
In-place inactivation of impacted soil was achieved
by mixing soil with a proprietary phosphate-based binder.
A field x-ray fluorescence instrument was used to
delineate the extent of contamination.
In-place inactivation of impacted soil was achieved
by mixing soil with a proprietary phosphate-based binder.
This technology achieved TCLP levels well below the
regulatory TCLP limit of 5.0 mg/L.
Multiple extraction procedure tests were also
performed to determine the long-term leachability
potential of the stabilized material.
Total lead concentration in all ten consecutive
extraction tests together was less than the regulatory
TCLP limit. Stabilized
soil was screened to separate and recycle approximately 25
tons of material consisting of lead slugs/fragments and
ballistic sand. Approximately
700 tons of stabilized soil was disposed of at an off-site
landfill. Use
of in-situ inactivation methodology eliminated the need
for lengthy regulatory approvals and facilitated
completion of the cleanup (including an additional
investigation, feasibility and treatability studies,
design, and implementation) in approximately 6 months.
Heavy
Metal Stabilization and Toxicity Reduction by Interstitial
Mineral Solution Crystalization
Keith
E. Forrester, P.E., Pte., President, FESI, 78 Tracy Way,
Meredith, NH, Tel: 603-279-3407,
Email:
www.fesi@worldpath.net
Mobility
of soluble and fine particle heavy metals under rainwater,
subsurface and surface water flow regimes are often not
properly controlled by stabilization methods designed to
meet batch-based extraction tests. Most batch-based
stabilized wastes remain toxic to humans and animals
though digestion of heavy metals into stomach acid (dilute
hydrochloric acid) and subsequent uptake into blood serum,
substitution in bone calcium apatite, and loading in brain
tissue, liver and other body receptors.
Batch
based stabilization technologies also often fail to
provide for stabilization of heavy metals within the
interstitial material environment, providing only surface
contact during field stabilization while relying on the
batch reactor test to stabilize interstitial metals during
the extraction period prior to filtered aliquot analyses.
In addition, none of the current batch based stabilization
technologies are designed to capture small sub-micron
particles within a crystalline matrix both inside and
outside of material and waste surfaces.
This
paper presents a FESI-BOND™ patent-pending method of
reducing leachability, sub-micron particulate transport
and toxicity of heavy metals via interstitial mineral
formation and particle crystallization. The FESI-BOND™
stabilizers can be used for both RCRA and CERCLA
industrial waste on-site stabilization as well as for in-situ
or ex-situ heavy metal fixation of mining wastes and
contaminated soils.
Study
on Leaching Hexavalent Chromium from Cement Treated Soil
to the Surrounding Ground
Kazushi
Furumoto, Nobuyuki Tsuneoka and Hirotoshi Mori, Public
Works Research Institute, 1-6 Minamihara, Tsukuba-city,
Ibaraki, Japan, Tel +81-(0)29-879-6767, Fax:
+81-(0)029-879-6798
Hexavalent
chromium can be leached from cement treated soil made by
mixing soil with cement. Rainwater seeps through the
shallow cement treated soil layer, leaching its hexavalent
chromium and carrying the leached hexavalent chromium into
the surrounding ground. Numerical analysis simulation
predicts the effects of the hexavalent chromium on the
surrounding ground. This paper reports the results of the
testing of input values and parameters needed to perform
numerical analysis. A column water pass-through test was
performed to find the leaching value of hexavalent
chromium that is a value input to the numerical analysis,
confirming that it is possible to define the relationship
between the leaching value and seepage quantity. As for
the retardation coefficient that is a parameter for the
numerical analysis, the large soil tank test was
performed. A 30cm layer of cement treated soil with
confirmed leached hexavalent chromium was placed above a
90cm thick sandy layer on the tank's bottom. Rain water
was poured on it, seepage water taken from the sandy
ground 20cm and 40cm below the cement treated soil, and
its hexavalent chromium concentration measured. The same
model as in numerical analysis was compared with results
of calculations using a retardation coefficient obtained
from batch testing. The retardation coefficient of the
sandy ground in the soil tank was estimated by identifying
the measurement results from the soil tank test by
numerical analysis. A comparison of the numerical analysis
results and the large soil tank experiment revealed that
the results of both conform closely if the retardation
factors are equal.
Heavy
Metal Content of Soils on Karstic Area in North Hungary
Ilona
Kevei-Bárány, Head of Department of Climatology and
Landcsape Ecology, University of Szeged, P.O. Box
653, 6701 Szeged, Hungary, Tel: (36)-62-544-157, Fax:
(36)-62-544-158
Email:
keveibar@earth.geo.u-szeged.hu
Rita Kaszala, PhD student,
Department of Climatology and landscape Ecology,
University of Szeged, P.O. Box
653 , 6701 Szeged, Hungary, Tel: (36)-62-544-157, Fax:
(36)-62-544-158
Email:
rita@geo.u-szeged.hu
Karst
areas have specific karstecology system and on that system
the soil plays important role in the relationship of the
clime-host rock and the greenery. For this knowing the
state of the soil is indispensable.
The
karst development and karstic frame at the surface and
close to the surface result the interferences the
carbonated rocks and water. The procession takes place
mostly at the surface of the rocks and the aggregation
soil of the burnst which effects shallow soil layer. This
involves that the properties of the soil claim on the
process of the karst development and settle the whole
dynamic of the running.
The
sample area is situated on the Northern part of Hungary,
the South western part of the National Park of Aggtelek.
It is the catchment basin of the Béke-cave. The Northern
part of the area Trias limestone comes up to the surface,
for this called it uncovered karstic area. Get on south,
this Trias limestone goes to the deep, and on this rock
settle sediment in the age of pannon. We can observe this
duality on the developed soil at parent material. The
northern part of the area you can find mainly reddish tone
remained soils which are rich in clay minerals, and brown
forest solis. On the other hand the covered karstic area
we can find bright, yellowish-brown colored soils, contain
loam and sand (remain like terra fusca).
As
the soils which can be found at the area are other types,
as follows that the primal properties are also different.
The organic matter and the clay mineral content of the
soil influent the metal bound capacity. The pH value is
also an important indicator of the state of the soil.
The
poster shows some result of experiment which search the
relationship between the soluble and the complexed heavy
metal content of the soil and the pH value together with
the amount of the macro- and microelements which can get
into the greenery.
Soil
Pollution by Heavy Metals from Transport Systems in
Lithuania
Evelina
Kliaugiene, Vilnius Gediminas Technical University,
Department of Environmental Protection, Sauletekio al. 11,
Vilnius, LT-2040 Lithuania, Tel: +37052744725, Fax:
+37052744731
Pranas Baltrenas, Vilnius Gediminas Technical University,
Department of Environmental Protection, Sauletekio al. 11,
Vilnius, LT-2040 Lithuania, Tel: +37052744723, Fax:
+37052744731
The
main objectives of this research are investigations of the
environmental impact of pollution caused by the transport
sector in Lithuania; evaluation of environmental impact of
transport sector on soil; preparation recommendations for
the reduction of impact on soil. The object of this
research is the environmental impact of the Transport
system (motor and railway transport sectors) on soil. The
motor and railway transport sectors are the main sources
of pollutants in Lithuania. Therefore these two sectors
are under the more detailed research than the other two
– air and water transport sectors. The main goals of
this research are the environmental impact of motor and
railway transport sectors on soil (topsoil). The most
important thing in this program is to set the sample net
and to choose the right method of collecting the soil
samples. The whole territory of Lithuania was divided into
the areas where the environmental impact of motor and
railway transport sectors on soil is the most intensive.
Some other areas were selected where the pollution impact
is the lowest, for the purposes to compare polluted and
not polluted areas. For evaluation of pollution caused by
the motor and railway transport, the soil samples were
collected across the road or railway, and each profile of
samples contained about 12-14 samples depending on the
relief. One sample was composed of five sub-samples
collected according to the “envelope” principle. After
transportation of the topsoil samples to the laboratory
the following analytical method was used AAS. Heavy metals
(Zn, Co, Cr, Ni, Cu, Pb, Mn) were analyzed for the
purposes to evaluate the composition of contaminants in
the topsoil. Following conclusions could be made after the
interpretation of the results. Some of them are:
substances emitted are exposed to various aerodynamic and
gravitation forces resulting in their separation and,
depending on their physical and chemical properties, they
settle selectively on the soil surface at different
distances from the road surface. The main amount of heavy
metals is settling on the soil surface in the narrow
limited zone of the highway itself, its slopes and
ditches. On the railways, the heavy metals are settling in
the narrow zone next to the tracks depending on relief
conditions.
The
Biosolids Digestion Treatment Reduces Potentially Toxic
Elements Availability in Soils and Maize Uptake
Raúl
S. Lavado, Facultad de Agronomía, Universidad de Buenos
Aires, Av. San Martín 4453, 1417 Buenos Aires. Argentina,
Tel: 54
11 4524-8022, Fax: 54 11 4524-8076, Email:
lavado@agro.uba.ar
Mónica
Rodríguez, Facultad de Agronomía, Universidad de Buenos
Aires, Av. San Martín 4453, 1417 Buenos Aires. Argentina
Miguel
A. Taboada, Facultad
de Agronomía, Universidad de Buenos Aires, Av. San Martín
4453, 1417 Buenos Aires. Argentina
Sewage
sludge could be applied without any previous treatment
(non digested biosolids - ND) to soils or applied after it
has been subjected to physical, biological and even
chemical treatments (digested biosolids - DB). Due to a
few interactions
among elements with organic and inorganic surfaces, we
hypothesized that ND have more potentially toxic elements
(PTE) available than DB. Our objective was to quantify the
soil availability of 6 PTE, and its uptake by a crop in a
soil applied with digested and non digested biosolids. Six
field experiments were carried out on farms located in the
north of Buenos Aires province, Argentina. The crop was
maize and the soils were Typic Argiudolls. The treatments
were ND and DB. Cadmium (Cd), Chromium (Cr), Copper (Cu),
nickel (Ni), lead (Pb) and zinc (Zn) were determined in
biosolids, in soils (EDTA extractable and total contents),
and in maize (aerial biomass -leaves and shoots- and
grains). The PTE were determined with ICP. No
biosolid sample exceeded the regulations for agricultural
usage.
Concentrations
of Cd,
Cu, Pb and Zn were similar in both
biosolids but ND have higher concentrations of Cr and Ni.
Soils which
received ND
showed higher contents of extractable Zn and Cu and total
Cr, Zn and Cu. Maize aerial biomass exhibited higher
concentrations of Cd, Cr, Cu and Zn. In maize grains only
Cd was significantly higher. Pb showed no differences in
any soil or crop component. The
results
obtained partially support the proposed hypothesis: The
concentration of Cu and Zn was higher in soils and maize
plants, and that of Cd in grains, when plots received ND.
Study
on Chromium Contaminated Soils and Waters around a
Chromate Factory
Yilian
Li, Wuhan University, Wuhan City, China 430072, Tel:
86-(0)27-87481050, Fax:
86-(0)27-87801763, Email: yl.li@cug.edu.cn
Yanxin Wang, China University of Geosciences, Wuhan City,
China 430074
This
study was conducted to find how the soils and waters,
including suface water and ground water, have been
seriously contaminated by chromium which comes from a
chromate factory. Survey on the contamination of chromium
shows that the soils around the dichromate-producing
factory can not grow vegetables and fruit trees, the
highest chromium VI in soil reachs 115mg per 1 kg soil. In
surface water, the chromium VI ranges from o.1 mg/L to
1500 mg/L. And the chromium can reach up to 5 mg/L even in
groundwater. Detailed investigation was carried out on
terrain and hydrogeological conditions and source of
contaminant in the site of chromate factory and shows that
the leaching of chromate tailing caused by weathering and
rain was carried to the adjacent soils
and surface water around the site of factory. The
character of hydrogeology of the factory site indicates
that the groundwater is highly vulnerable to chromate
contamination. What’s more, a tailing was placed at a
mountain valley that chromium easily entries into a large
aquifer and make it contaminated. At the same time, the
authors attempt to mitigate chromium pollution of
continuous runoff and leak of tailing by designing an
annular barrier to surround the factory. The materials of
barrier, such as iron, zeolite, coal gangue and organic
materials, were tested to remove chromium from dichromate
water. Experiments show that a sequence these materials
could be a good method to prevent chromium pervading to
soils waters and much cheaper than any others.
Modified
In Vitro Method for the Determination of Lead and
Arsenic Bioaccessibility
James F. Occhialini, James C.
Todaro and Joseph Clements, Alpha Analytical Labs, Eight
Walkup Drive, Westborough, MA 01581, Tel: 508-898-9220
The authors present and discuss the analytical
results obtained using a modification of the Solubility/Bioavailabilty
Research Consortium’s In
Vitro Method for Determination of Lead and Arsenic
Bioaccessibility. Method modifications are described together with an overview
of the observed reproducibility and sensitivity of the
modified procedure. An
extended series of sample replicates are analyzed for both
total and bioaccessable lead and arsenic, with conclusions
and additional recommendations presented.
Peculiarities
of the Heavy Metals Speciation in the Background and
Polluted Soils of Russian Plane
Leonid
V. Perelomov, Tula State University, Department of Biology
and Medicine, 300600, Lenin Avenue, 92, Tel:
007-0872-35-57-57, Fax: 007-0872-33-13-05, Email:
perelomov@rambler.ru
The heavy metals speciation has
been studied by sequential extraction procedure of Tessier
et al. (1979) in the background and polluted acidic soils
as well as in the model experiments with addition of the
soluble salts of lead and zinc. The method parts metals
into five fractions: exchangeable, bound to carbonate (or
specifically adsorbed ions bound to other acid-soluble
phases), bound to Fe-Mn oxides, bound to organic matter
and residual. The exchangeable fraction is considered to
be the most mobility and bioavailability, and
residual fraction the least, with the other fractions
having intermediate degrees of mobility. Grain size and
chemical composition of parent rocks and participation of
elements in the biogeochemical cycles determine fractional
composition of the heavy metals in the unpolluted soils.
The dominant forms of Mn and Pb are Fe-Mn oxides; the
greater part of Zn is accumulated in the structure of
primary and clay minerals of residual fraction. There is
equilibrium between different forms of the metals in the
background soils. The fractional composition of the heavy
metals in the polluted soils is contrasted with unpolluted
soils. Anthropogenic combination of the metals is
thermodynamically instability and their transformation
proceeds through soluble phase. Therefore Mn, Zn and Pb
are accumulated in the mobile fractions in the
high-polluted soils. Sequential extractions demonstrated
that after 1, 3 and 12 month of treatments of high
concentrations of lead and zinc (500-1000 mg/kg) the
majority of metal is accumulated in the exchangeable
fraction. The increase of the phyto-available exchangeable
fraction has been the cause of toxic levels of metals in
the plant tissues. Thus anthropogenic combinations of
heavy metals are accumulated in the mobile forms in the
high-polluted acidic soils and are able to remain in the
mobile forms for months and years.
Health-ecological
Investigation of Soil Pollution with Heavy Metals and
Arsenic in a Metallurgical and Ore Output Region
Al
Spasov, National Center of
Hygiene, Medical Ecology and Nutrition, 15, Dimitar
Nestorov Str., Sofia, Bulgaria, Tel/Fax: 003592594120
M. Sidjimov, National Center of Hygiene, Medical Ecology
and Nutrition, 15, imitar Nestorov Str., Sofia, Bulgaria,
Tel: 0035998866785
The
investigation is executed in a central Bulgarian region
with both well developed agricultural and metallurgical
activities. The agricultural land is approximately 38700
decares. Geographically the region is estimated as closed
valley with dominating winds into south-west and
south-east direction. The survey of the heavy metal soil
pollution is executed in the south-west part of the
valley, characterized with high density of ore-dressing
factories and landfills for industrial hazardous wastes.
Executed is collection of soil samples and analysis of
probes from 4500 decares including agricultural land and
three living areas, two of the last situated 1000m to the
north-east (Chavdar village) and south (Benkovski village)
from the landfill for industrial wastes. Determined are
the following average concentrations for heavy metals:
lead - 110mg/kg soil; copper – 280mg/kg; zinc –
130mg/kg; cadmium – 0,75mg/kg; arsenic – 18mg/kg.
Studied is also the heavy metals content in plants.
The
soil and plant pollution in the region is realized mainly
through the aerosol pathway. Proved is the existence of
possibilities for dispersion of dust particles, coming
from the landfill for industrial wastes. Analysing the
morbidity rate for the region for groups of the population
(children and adults), found are respiratory and allergic
disturbances to be with higher frequency rate compared
with the average data for the country.
The
general conclusion of the achieved results proves that the
pollution of the soils comes primarily from the found 12
km in east direction non-ferrous ore-dressing and
metallurgical plant. The correlation between the soil
pollution and the morbidity of the population allows the
creation of prophylactic programs including change in the
land used for agricultural purposes, sowing only definite
plant cultures and some other measures aiming at
limitation of the health risk.
Remediation
of Lead Contaminated Soil Using Physicochemical and
Phytoremediation Technique: Experience from South West
Nigeria
M. K. C. Sridhar, M.Sc.,
Ph.D., J. O. Etaghene, B.Sc., MPH, 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
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 remediating the soil using
physico-chemical 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. 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 a feasible in
remediating the lead contaminated soil.
Continuous
Biosorption of Pb, Cu and Cd by Phanerochaete
chrysosporium in a Packed Column Reactor
K.Pakshirajan
and T.Swaminathan, Department of Chemical Engineering,
Indian Institute of Technology Madras, Chennai, Tel.:
091-44-22578222, Fax.: 091-44-22570509, Email:
tswami@che.iitm.ac.in
The
wide spread use of metals and chemicals in the processing
industries has resulted in the discharge of aqueous
effluents in large quantities. These very often contain
high levels of heavy metals, which also pose serious
environmental problems. Apart from metal processing
industries, mining, coal-fire powered generation plants
and extractive metallurgical operations generate huge
volumes of toxic liquid wastes. The conventional physico-chemical
methods such as chemical precipitation, ion exchange or
reverse osmosis for controlling heavy metal discharge into
the environment can be both expensive and sometimes not
very effective. Biosorption, however seems to be a good
alternative both in terms of reducing the cost of the
process and also in meeting the discharge limits.
The
dynamic removal of lead, copper and cadmium in a single
component system by Phanerochaete
chrysosporium was studied in packed column reactors.
The packed column consisted of biomass of P.chrysosporium
immobilized on polyurethane foam cubes. The performances
of packed columns were described through the concept of
breakthrough and the values of column parameters predicted
as a function of bed depth. The column biosorption data
were evaluated in terms of maximum (equilibrium) capacity
of the column, the amount of metal loading and the yield
of the process. The maximum capacities for lead, copper
and cadmium were 70.7, 43.7 and 70.8 mg respectively and
their yields were 39.2, 40.6 and 41 % respectively. The
kinetic and mass transfer aspects of the dynamic removal
of the three metals were studied using several
mathematical models commonly used to describe the column
performance in adsorption processes. Column studies showed
good agreement between the experimental data and the
simulated breakthrough curves obtained with Adams-Bohart
or the Wolborska model and the Clark model. While the
initial segment of the breakthrough curve was defined by
the Adams-Bohart and Wolborska models, the whole
breakthrough curve was well predicted by the Clark model
for all the three metals studied.
Centrifuge
Modeling of Zinc Sorption in Clay
Maria
Antonia Tanchuling and Osamu Kusakabe, Tokyo Institute of
Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8552 Japan,
Tel: 81-3-5734-2798, Fax: 81-3-5734-3578
Sorption
is an important contaminant transport process with special
significance in retarding contaminants. Determination of
the capability of a clay liner’s ability to attenuate
contamination is necessary for the proper design of waste
containment sites. Centrifuge tests are able to replicate
in situ stresses and thus would be able to simulate field
conditions more closely than 1g column and batch
equilibrium conditions. Using a drum centrifuge, the
process of sorption was simulated by allowing zinc nitrate
solution to leach unto the clay layer.The clay layer was
first normally consolidated using the centrifuge. The
concentration of the solution draining out of the clay
layer was analyzed for zinc concentration. After the
leaching tests, sorbed zinc in different layers were also
measured. Breakthrough curves were plotted and the
partitioning coefficient was determined. Column tests and
batch equilibrium tests were also conducted. Partitioning
coefficients were obtained and compared with the results
from the centrifuge tests. Results show that partitioning
coefficients from batch equilibrium tests are higher, thus
overestimating the attenuation capability of the clay
liner.
Removal
of Heavy Metals from Sewage Sludge used as Soil Fertilizer
Marian
Turek, Silesian University of Technology, ul.
B. Krzywoustego 6, 44-100 Gliwice, Poland, Tel:
+48 32 2372735, Fax: +48 32 2372277
Teofil Korolewicz, Silesian University of Technology, ul.
B. Krzywoustego 6, 44-100 Gliwice, Poland
, Tel: +48 32 2372533, Fax: +48 32 2372277
Jerzy Ciba, Silesian University of Technology, ul.
B. Krzywoustego 6, 44-100 Gliwice, Poland, Tel:
+48 32 2371021, Fax: +48 32 2372277
The
sewage sludge with heavy metals contents as follows
(mg/kg): Cd-3.43; Co-5.25; Cu-131; Fe-51300; Mn-177;
Ni-37.5; Pb-104; Zn-3300 was examined. Metals speciation
by sequential extraction according to Tessier and Rudd and
procedure recommended by European Community Bureau of
Reference (BCR) as well as analysis of chemical forms of
metals were carried out. It was found that Zn content only
is higher than the value permissible in sewage sludge for
agricultural application (2500 mg/kg). The good
agreement of results obtained by Tessier and BCR
procedures was observed. Comparison of sequential analysis
and analysis of chemical forms of metals indicates that
the sum of metals contents in the exchangeable, carbonate
and bound to Fe/Mn oxyhydroxides forms of metals (found by
Tessier and BCR analysis) corresponds to the sum of
sulfate, oxide, metallic and siliceous forms. From the
other hand the content of form bound to organic matter or
sulfides corresponds to sulfide form while the residual
corresponds to ferrate form. Preparatory extraction of
metals from the sewage sludge using sodium salt of
ethylenediaminetetraacetic acid, sodium pyrophosphate(V)
and ammonia water has also been investigated.
As far as the examined leaching agents are concerned EDTA-Na
appeared to be the best. Single leaching with this agent
results in metals contents as follows (mg/kg): Cd-1.1;
Co-2.1; Cu-105; Fe-17700; Mn-28.3; Ni-12.8; Pb-44;
Zn-1200. These contents meet requirement of sewage sludge
used as soil fertilizer
according to Polish regulations.
A
Bioprocess for the Removal of Heavy Metals and Other
Inorganics from Various Waters
Brad
Wahlquist, Applied Biosciences Corporation, 265 Crossroads
Square, Salt Lake City, UT
84115,
Email: bwahlquist@applied-biosciences.com
Tim Pickett, Applied Biosciences Corporation, 265
Crossroads Square, Salt Lake City, UT
84115
, Email:
tpickett@applied-biosciences.com
D. Jack Adams, Applied Biosciences Corporation, 265
Crossroads Square, Salt Lake City, UT
84115, Email:
djadams@applied-biosciences.com
Applied
Biosciences has developed the ABMet™ microbial
bioprocess for the removal of metals and inorganics from
industrial and other waters.
The ABMet™ process uses short retention times and
site-optimized microbial cultures and nutrient blends and
has demonstrated removal of As, Se, Cu, Ni, Zn, Hg, Cd,
Cr, Te, NO3, CN, and NH3.
These bioprocesses can be implemented in pump and
treat and semi-passive systems.
Biological processes result in 1,000 to 10,000
times less sludge than conventional chemical treatments.
Current biological treatment systems range from 2
gal/min to 30 gal/min at pilot scale to over 300 gal/min
at full scale. Larger
treatment systems are also practical – treatment systems
up to 10 million gal/day are currently under evaluation.
Bioprocess retention times depend on contaminant
levels and water chemistry, but range in time from 4 to 24
hours for contaminant removal to below detection. The ABMet™ bioprocess uses low-cost, balanced nutrients
that range in cost from $0.12 to $0.52 per 1,000 gallons
treated, at full-scale.
These metal and inorganic removal bioprocess
technologies have been validated through various pilot and
full-scale implementations and through the EPA’s Mine
Waste Technology Program.
Case studies present quantity and quality of water
treated, reagents used, minimal pretreatment requirements,
water quality inputs, discharge water quality, process
costs, and process benefits.
Metals
Remediation Compound (MRC™):
A New Slow-Release Product for In
Situ Metals Remediation
Anna Willett, Regenesis, 1011
Calle Sombra, San Clemente, CA
92672, Tel: 949-366-8000,
Fax: 949-366-8090, Email:
anna@regenesis.com
Stephen S. Koenigsberg, Ph.D., Regenesis, 1011 Calle
Sombra, San Clemente, CA
92672, Tel: 949-366-8000, Fax:
(949) 366-8090, Email:
steve@regenesis.com
Contamination of groundwater by metals has not been
widely addressed by engineered in
situ remediation technologies, despite the
documentation of metals contamination at greater than 50%
of sites from the National Priorities List and at
Department of Defense and Department of Energy locations.
Metals Remediation Compound (MRC™) is
a slow-release metals remediation product that removes
dissolved metals from groundwater via in
situ immobilization (precipitation and/or sorption to
soil particles). The
immobilized metals are stable under reducing conditions
and may be stable under oxidizing conditions, depending on
the identity of the metal.
MRC is an ester of an organosulfur compound with a
carbon backbone compound.
The organosulfur compound is slowly released when
MRC’s ester bonds are cleaved upon injection into an
aquifer via hydrolysis and/or microbial enzymatic
action. The
organosulfur moiety interacts with metal cations or anions
forms, either to complex them or to reduce them and
complex them sequentially.
These complexes are adsorbed onto soil, filter
media, or other solid supports.
The release rate of the organosulfur compound from
MRC is similar to the release rate of lactic acid, an
electron donor and carbon source for reductive
dechlorination, from polylactate polymers like Hydrogen
Release Compound (HRC®).
This characteristic makes MRC an excellent compound
for use with HRC at sites where chlorinated solvents and
metals exist as co-contaminants.
MRC was tested for removal of
arsenic as arsenate (As in the +5 oxidation state),
chromium as chromate (Cr in the +6 oxidation state), and
copper (Cu) mixtures from groundwater in horizontal soil
column experiments. Additional
experiments were performed with cadmium (Cd), mercury
(Hg), and lead (Pb).
For both mixtures, dissolved metal concentrations
were reduced from input concentrations (4 to 100 mg/L) to
non-detect (10 to 100 μg/L) within 6 days for Cd, Hg,
Pb, and Cu; 13 days for Cr; and 30 days for As.
After 27 days of operation, three pore volumes of
water exposed to oxygen were flushed through the ASV for
30 days, and no metals were remobilized to the aqueous
phase.
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