This document summarizes a study on the effects of shear stress and oxygen levels on the toxicity of contaminated sediment and overlying water. Gust chambers were used to subject sediment cores to different shear stresses and oxygen concentrations. Testing found that oxygen had a greater effect than shear stress on the release of metals like copper from sediments. Under oxygenated conditions, more metal sulfides dissolved, releasing metals into the water. While toxicity was low under experimental conditions, substantial metal release occurred even at low shear stresses. The presence of oxygen significantly increased metal release from sediments.
Impact Of Municipal Solid Waste Dump On Ground Water Quality in kattamanchi, ...mahendra v
The present study deals with the physico-chemical characteristics of ground water quality. Such a water samples were collected from different identified bore wells for the purpose of studying the quality of groundwater during May 2014. The bore wells from which the samples were collected are extensively used for drinking purpose. It has been
proved from the present investigation findings that value of few parameters are pH,TDS, Total Hardness, Calcium, Sulphate, Chloride, Salinity, and Iron fall out of the permissible range with reference to WHO guideline levels for drinking water. The most serious pollution threat to groundwater is from TDS, Total Hardness, salinity, Calcium, chloride and Fe, which are associated with sewage and pollution of tannery waste. Hence, suggested to take proper care to avoid contamination of groundwater pollution through periodic monitoring of the water quality.
Impact Of Municipal Solid Waste Dump On Ground Water Quality in kattamanchi, ...mahendra v
The present study deals with the physico-chemical characteristics of ground water quality. Such a water samples were collected from different identified bore wells for the purpose of studying the quality of groundwater during May 2014. The bore wells from which the samples were collected are extensively used for drinking purpose. It has been
proved from the present investigation findings that value of few parameters are pH,TDS, Total Hardness, Calcium, Sulphate, Chloride, Salinity, and Iron fall out of the permissible range with reference to WHO guideline levels for drinking water. The most serious pollution threat to groundwater is from TDS, Total Hardness, salinity, Calcium, chloride and Fe, which are associated with sewage and pollution of tannery waste. Hence, suggested to take proper care to avoid contamination of groundwater pollution through periodic monitoring of the water quality.
Heavy Metals Assessment in Water Reservoirs Reinforced By Służewiecki Stream IJERA Editor
The study concerned copper and cadmium contamination in bottom sediments of selected surface water reservoirs at the urban area. The concentrations of the metals in sediments was up to 20-times higher compared with a geochemical background. Based on ecotoxicological evaluations, the toxic impact of cadmium in tested sediments can occur frequently, while for copper – it can sometimes be observed. The sediments can be classified as heavily polluted and dangerous to water biota, especially for sediment-dwelling organisms. The accumulation of metals migrating with the Służewiecki stream in reinforced reservoirs can result in their anthropopressure- related degradation.
Characterization of expanded austenite developed on AISI 316L stainless steel...Javier García Molleja
Authors: J. García Molleja, L. Nosei, J. Ferrón, E. Bemporad, J. Lesage, D. Chicot, J. Feugeas.
Surface and Coatings Technology 204 (2010) 3750-3759 (August 25th 2010)
Because Elsevier copyright policy only the first page -of ten- is shown. Available at: http://dx.doi.org/10.1016/j.surfcoat.2010.04.036
Biochemical Oxygen Demand and its Industrial SignificanceAdnan Murad Bhayo
BOD is the amount of dissolved oxygen needed by aerobic biological organism in a body of water to breakdown organic material present in a given water sample at certain temperature over a specific time period .
Most of Bacteria in the aquatic columns are aerobic. Escherichia coli, Bacillus subtilis, Vibrio cholera.
Atmosphere contains 21% oxygen (210000 mg/dm3)
Higher the temperature of water higher will be the rate of respiration. So, concentration of oxygen decreases.
Many Animal species can grow and reproduce normally when dissolved oxygen level is ~ 5.0 mg/L.
HYPOXIA: When dissolve oxygen content below 3.0 mg/L. Many Species move elsewhere and immobile species may die
ANOXIA: When dissolve oxygen content below 0.5 mg/L. All aerobic species will die
Fertilizer contains Nitrate contributes to high BOD
Phosphate present in Soap and detergent that enhances the growth of algal blooms. As a result depletion of oxygen occur.
In a body of water with large amount of decaying organic material , the dissolved oxygen level may drop by 90 %, this would represent High BOD
In a body of water with small amount of decaying organic material , the dissolved oxygen level may drop by 10 %, this would represent Low BOD
ANALYSIS OF BOD OF WATER
Use glass bottles having 60 mL or greater capacity. Take samples of water.
Turn on the constant temperature chamber to allow the
controlled temperature to stabilize at 20°C ±1°C.
Record the DO level (ppm) of one immediately.
Place water sample in an incubator in complete darkness at 20 C for 5 days. Exclude all light to prevent possibility of photosynthetic production of DO
If don't have an incubator, wrap the water sample bottle in aluminum foil or black electrical tape and store in a dark place at room temperature (20o C or 68 °F).
DILUTION OF SAMPLE
Most relatively unpolluted streams have a BOD5 that ranges from 1 to 8 mg/L
Dilution is necessary when the amount of DO consumed by microorganisms is greater than the amount of DO available in the air-saturated.
If the BOD5 value of a sample is less than 7 mg/L, sample dilution is not needed.
The DO concentration after 5 days must be at least 1 mg/L and at least 2 mg/L lower in concentration than the initial DO
(American Public Health Association and others, 1995).
BOD of the dilution water is less than 0.2 mg/L.
Discard dilution water if there is any sign of biological growth.
pH of the dilution water needs to be maintained in a range suitable for bacterial growth
Bacterial growth is very good between 6.5 to 7.5
Sulfuric acid or sodium hydroxide may need to be added to the dilution water to lower or raise the pH, respectively.
CALCULATION:
The general equation for the determination of a BOD5 value is:
BOD = D1-D2/P
Where
D1 = initial DO of the sample,
D2 = final DO of the sample after 5 days, and
P = decimal volumetric fraction of sample used.
If 100 mL of sample a
Heavy Metals Assessment in Water Reservoirs Reinforced By Służewiecki Stream IJERA Editor
The study concerned copper and cadmium contamination in bottom sediments of selected surface water reservoirs at the urban area. The concentrations of the metals in sediments was up to 20-times higher compared with a geochemical background. Based on ecotoxicological evaluations, the toxic impact of cadmium in tested sediments can occur frequently, while for copper – it can sometimes be observed. The sediments can be classified as heavily polluted and dangerous to water biota, especially for sediment-dwelling organisms. The accumulation of metals migrating with the Służewiecki stream in reinforced reservoirs can result in their anthropopressure- related degradation.
Characterization of expanded austenite developed on AISI 316L stainless steel...Javier García Molleja
Authors: J. García Molleja, L. Nosei, J. Ferrón, E. Bemporad, J. Lesage, D. Chicot, J. Feugeas.
Surface and Coatings Technology 204 (2010) 3750-3759 (August 25th 2010)
Because Elsevier copyright policy only the first page -of ten- is shown. Available at: http://dx.doi.org/10.1016/j.surfcoat.2010.04.036
Biochemical Oxygen Demand and its Industrial SignificanceAdnan Murad Bhayo
BOD is the amount of dissolved oxygen needed by aerobic biological organism in a body of water to breakdown organic material present in a given water sample at certain temperature over a specific time period .
Most of Bacteria in the aquatic columns are aerobic. Escherichia coli, Bacillus subtilis, Vibrio cholera.
Atmosphere contains 21% oxygen (210000 mg/dm3)
Higher the temperature of water higher will be the rate of respiration. So, concentration of oxygen decreases.
Many Animal species can grow and reproduce normally when dissolved oxygen level is ~ 5.0 mg/L.
HYPOXIA: When dissolve oxygen content below 3.0 mg/L. Many Species move elsewhere and immobile species may die
ANOXIA: When dissolve oxygen content below 0.5 mg/L. All aerobic species will die
Fertilizer contains Nitrate contributes to high BOD
Phosphate present in Soap and detergent that enhances the growth of algal blooms. As a result depletion of oxygen occur.
In a body of water with large amount of decaying organic material , the dissolved oxygen level may drop by 90 %, this would represent High BOD
In a body of water with small amount of decaying organic material , the dissolved oxygen level may drop by 10 %, this would represent Low BOD
ANALYSIS OF BOD OF WATER
Use glass bottles having 60 mL or greater capacity. Take samples of water.
Turn on the constant temperature chamber to allow the
controlled temperature to stabilize at 20°C ±1°C.
Record the DO level (ppm) of one immediately.
Place water sample in an incubator in complete darkness at 20 C for 5 days. Exclude all light to prevent possibility of photosynthetic production of DO
If don't have an incubator, wrap the water sample bottle in aluminum foil or black electrical tape and store in a dark place at room temperature (20o C or 68 °F).
DILUTION OF SAMPLE
Most relatively unpolluted streams have a BOD5 that ranges from 1 to 8 mg/L
Dilution is necessary when the amount of DO consumed by microorganisms is greater than the amount of DO available in the air-saturated.
If the BOD5 value of a sample is less than 7 mg/L, sample dilution is not needed.
The DO concentration after 5 days must be at least 1 mg/L and at least 2 mg/L lower in concentration than the initial DO
(American Public Health Association and others, 1995).
BOD of the dilution water is less than 0.2 mg/L.
Discard dilution water if there is any sign of biological growth.
pH of the dilution water needs to be maintained in a range suitable for bacterial growth
Bacterial growth is very good between 6.5 to 7.5
Sulfuric acid or sodium hydroxide may need to be added to the dilution water to lower or raise the pH, respectively.
CALCULATION:
The general equation for the determination of a BOD5 value is:
BOD = D1-D2/P
Where
D1 = initial DO of the sample,
D2 = final DO of the sample after 5 days, and
P = decimal volumetric fraction of sample used.
If 100 mL of sample a
Isotherm Modeling and Thermodynamic Study of the Adsorption of Toxic Metal by...CrimsonpublishersEAES
Isotherm Modeling and Thermodynamic Study of the Adsorption of Toxic Metal by the Apricot Stone by Moussa Abbas*, Tounsia Aksil and Mohamed Trari in Environmental Analysis & Ecology Studies
The synthesis and characterization of three new metal chalcogenide aerogels, Chalcogels,
AFe3Zn3S17 (A= Na, K, or Rb) is described. Alkali metal polychalcogenides (Na2S5, K2S5, or Rb2S5)
reactwith metal acetate like Fe(OAc)2 and Zn(OAc)2in formamide solutionforming extended polymeric
frameworks by gelation. Chalcogels obtained aftersupercritical drying have BET surface areas of
430, 444, and 435 m
2
/g for NaFe3Zn3S17, KFe3Zn3S17, and RbFe3Zn3S17, respectively. The effect of the
counter ions (K, Na, and Rb) wasstudied by examined the adsorption capacities of the resulting
chalcogels toward different gases and volatile organic compounds. The measurements showed that
CO2 and toluene adsorption capacities increase with the polarizability of the surface atoms in the
following order: Rb chalcogel> K chalcogel> Na chalcogel.This finding reveals a trend based on
cation size and acid–base surface properties that might have a significant impact on altering
adsorptive properties of chalcogels by using more polarizable counter ions.
Study of the Sediments Metallic Contamination in Oum Er-Rbia EstuaryIOSRJAC
This work fits in the framework of a program of study and monitoring of the Impact of natural and anthropogenic Factors on the quality of surface waters of the river Oum Er-Rabia (Morocco); it focuses on the analysis and evaluation of the metal contamination of the sediments of this stream using an index of contamination (IC) and the index of polymetallic contamination (ICP). The spatial and temporal variations of the sediment content in Fe, Mn, Cd, Zn, Cu, Pb, Cr and Co reveal the presence of an important metal contamination, dominated mostly by Pb, Cd, Cr, Zn and Co however at the level of the mouth where the metal concentrations are very low. From this fact situation does not pose a concern for the ecosystem in the vicinity of the downstream of the estuary, this finding is related can be the size and the fraction of the mouthpiece sediments.
Chemical Oceanography is fundamentally interdisciplinary. The chemistry of the ocean is closely tied to ocean circulation, climate, the plants and animals that live in the ocean, and the exchange of material with the atmosphere, cryosphere, continents, and mantle
I) What is ArsenicArsenic is a widely distributed element in .docxsleeperharwell
I) What is Arsenic?
Arsenic is a widely distributed element in the earth's crust and is recognized as a toxic and carcinogenic substance. Arsenic is widely used as a pesticide, herbicide, wood preservative, semiconductor material, and feed additive. These anthropogenic pathways have introduced large amounts of arsenic into the environment, increasing the concentration and distribution of arsenic in environmental water bodies. In recent years, in some countries, especially Bangladesh, China, and Mongolia drinking water sources are found in concentrations that can lead to acute and chronic human poisoning of arsenic. Therefore, the arsenic in drinking water has caused great concern. Given the great danger of arsenic to human health and the increasing severity of arsenic pollution, in 1993, the WHO took the lead in the indicator value of arsenic in drinking water from 50 μg / L to 10 μg / L. Subsequently, the European Union, Japan, the United States, respectively, their drinking water arsenic standards for 10 μg / L.
1. Chemical properties of arsenic in water bodies
In the aqueous environment, the two common oxidation states of arsenic are As(V) and As (III). (As(V) is oxygenated surface water and As (III)is the main form of arsenic in groundwater, while As(III) is the form of arsenic in anoxic groundwater. When the pH was in the neutral range, As(III) was mainly present in the form of H3 AsO3, while As(V) was present in the form of H2 AsO4 – and HAsSO4 2-. Therefore, in the typical pH range of water (pH = 5 to 8), As(V) exists in the form of anions, while As (III) exists in the form of neutral molecules. Therefore, the drinking water arsenic removal technology will involve the removal of arsenic in 2 different
vale nice states and the presence of forms.
2. Research progress of the arsenic removal process
2.1 Coagulation and flocculation method
Coagulation and precipitation method because of its easy to use, easy to grasp, and accept and become the most widely used, the most widely used arsenic drinking water treatment method. The most common coagulants are iron salts and aluminum salts. Many studies have shown that the coagulation and precipitation method in addition to the arsenic effect and the oxidation state of arsenic in water, the initial concentration of arsenic, the type and dose of coagulant, water quality conditions, and other factors. as (Ⅲ) removal effect is poor As (V) removal rate is higher. The oxidation of As (Ⅲ) to As (V) can improve the removal rate of arsenic. When the initial concentration of As (Ⅲ) <0∙8 mg/L, sodium hypochlorite 1∙25 mg/L can effectively oxidize As (Ⅲ) into As (V) to achieve the same removal effect as As (V). (1) If the use of perchlorate coagulant, it can replace the sodium hypochlorite and iron salt 2 reagents to simplify the treatment method and perchlorate oxidation capacity than sodium hypochlorite, potassium permanganate, etc. stronger, in the oxidation process will not produce secondary p.
1. SHEAR STRESSES AND
OXYGEN LEVELS ON
CONTAMINATED SEDIMENT
AND OVERLYING WATER
TOXICITY
Alejandro Vega
Northwestern University
SROP
7/13/2013
2. Metals are dispersed in
the overlying water as
cations or solid particles
As some metals go deeper they
react with several compounds
and as a result of sulfate
reduction, the heavy metals
become metal sulfides.
The metal sulfides
become stable and
can last a very long
time in the sediment
even after original
source of
contamination is
removed.
Some contaminants can be very persistent
and remain for long periods of time in
sediment
3. The resuspension of sediment
puts metal sulfides in the
oxygenated water. Storms and
human activities can cause large
resuspensions.
Although the metal
sulfides are stable in the
sediment, they dissolve
when put in contact with
oxygen.
The metal sulfides are
oxidized and
dissolved, causing an
ongoing release of
metal into the
overlying water.
The persistent metals in the sediment can
cause an ongoing release of metal into marine
and fresh water environments
4. Portsmouth Naval Shipyard
First established in 1800 and
during WWI it specialized in the
construction of submarines.
It built submarines until 1969
and today it supplies the U.S.
Navy submarine fleet with
refueling and modernization
work.
Wetlands bordering Seavey
island are contaminated with
hazardous substances that are
attributed to PNSY.
Sediment in this area is very
fine grained with 76% of
particles having a diameter
5. Gust Chambers (GC) were used
to test contaminated sediment
The gust chamber (GC) is
a 45 cm long tube with a
diameter of 9.5 cm. It was
filled 10cm high with
sediment and seawater. A
small spinner at the top
provided the shear stress
acting on interface.
The GC provides
controlled flow conditions
on sediment cores.
6. Conditions for Gust Chambers
Each GC had one parameter that was changed,
with three shear stresses being tested as well
as one chamber with deoxygenated water.
Each shear stress was a certain percentage of
the critical shear stress
7. There were two main procedures
used to test the sediment.
The first part: Daily water
samples tested turbidity,
conductivity, dissolved
oxygen (DO), temperature,
pH. Part of the sample was
stored for later tests with
Atomic Absorption
Spectrometer in which
element concentrations
were detected.
The second part: Sediment
cores from the gust
chambers were cut every
half cm for the first two
cms and then every 1cm
from 2-10cm.
8. N2, H2S
Sediment sample, 6M HCl
N2
N2
Reactio
n Flask H2S
Tra
p
Gas Outlet
SEM/AVS analysis was used to test
sediment samples (2nd Part)
Acid Volatile Sulfide (AVS) measures the portion of solid phase sulfide
that reacts with metal. The NaOH purged with the H2S was diluted and
had absorbance measured.
Simultaneously extracted metals (SEM) were also detected by diluting
the contents in the round flask and filtering them. After they were
analyzed using ICP-AES which determines what elements are present
in sample.
Reactio
n Flask
9. Total Reduced Inorganic Sulfur
(2nd Part)
• AVS represents a small portion of the amount of
sulfide in the sediment so this second analysis was
also performed.
• TRIS is the sum of the elemental sulfur, AVS and
pyrite
• Reduced sulfur species were decomposed to H2S in a
hot acidic CrCI2 solution. N2, H2S
Sediment sample, Chromium, 95% Ethanol, 6M HCl
N2
N2
H2S
Tra
p
Gas Outlet
Condens
er
Heated
Reactio
n Flask
10. AVS Results and Discussion
The AVS were
relatively close to
each other deeper in
the sediment but
PNS6, 7, and 8 are
significantly lower at
the surface.
The oxygen
concentration in the
overlying water had a
greater effect on the
AVS than the shear
stress.
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 10 20 30 40
Depth(cm)
AVS (μmol/g dw)
PNS5_Deoxy_3%
PNS6_Oxy_3%
PNS7_Oxy_50%
PNS8_Oxy_70%
11. TRIS Results
TRIS shows
approximately 10x
more of sulfur content
in the sample.
The shear stress had a
larger effect on the
TRIS than the differing
oxygen levels in the
GC.
The GC differed most
at the surface like the
AVS.
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 50 100 150 200
Depth(cm)
TRIS (μmol/g dw)
PNS5_Deoxy_3
%
PNS6_Oxy_3%
PNS7_Oxy_50%
PNS8_Oxy_70%
12. The SEM/AVS ratio is important
when determining toxicity.
SEM/AVS < 1toxicity potential is lowSEM/AVS > 1toxicity potential is high
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0.0 0.2 0.4 0.6 0.8 1.0
Depth(cm)
ΣSEM/AVS
PNS5_Deoxy_3%
PNS6_Oxy_3%
PNS7_Oxy_50%
PNS8_Oxy_70%
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0.0 0.2 0.4 0.6 0.8
Depth(cm)
SEM Cu/AVS
PNS5_Deoxy_3
%
PNS6_Oxy_3%
PNS7_Oxy_50%
PNS8_Oxy_70%
13. The difference in the release of metal was
substantial when oxygen levels were
changed
There was a greater
release of copper into the
oxygenated overlying
water.
The total Cu in the
overlying water includes
all dissolved species of
copper as well as copper
bounded to sediment
particles.
The oxygen in the water
was able to oxidize more
of the metal sulfides and
release free metal
0.0
2.0
4.0
6.0
8.0
0 2 4 6 8 10 12 14
TotalCuinOW(μg/L)
Time (days)
PNS6_Oxy
PNS5_Deoxy
0.0
2.0
4.0
6.0
8.0
0 2 4 6 8 10 12 14
DissolvedCuinOW
(μg/L)
Time (days)
14. Problems in the experiment
The water was deoxygenated by pumping N2
gas into the beaker, while the gas did push out
most of the oxygen it also pushed out CO2.
Due to this error there was an increase of
CaCO3 particles in the gust chamber.
These particles lowered the amount of
dissolved copper species in the overlying
water.
15. Conclusion
Although the likeliness of toxicity was low,
there was a substantial release of metal into
the overlying water even at low shear stresses.
Oxygen also has a large effect on the release
of metal, areas of the harbor that experience
anoxic conditions can have very little release
of metal since less metal sulfides are
dissolved.
This experiment focused on copper because,
in large amounts, it can lead to dangerous
ecological effects.
16. Thank You for your Attention
I also want to thank Dr. Aaron Packman,
Minwei Xie, Andrea Salus, the SROP
mentors and SROP program.
17. Sources
Allen, H. E., Fu, G. 1991 Draft Analytical method for determination of acid volatile sulfide
in sediment. Environmental Protection Agency. 13-14
Eggleton, J. Thomas, K. V. 2003 A review of factors affecting the release and
bioavilability of contaminants during sediment disturbance events. Environment
International. 974-976
Carbonaro, R. F. Mahony, J. D. Walter, A. D. Halper, E. B. Di Toro, D. M. (2005),
Experimental
and Modeling Investigation of Metal Release From Metal- Spiked Sediments, 3007
Lee, J. S. Lee B. G. 2000 Influence of Acid Volatile Sulfides and Metal Concentrations
on Metal Partitioning in Contaminated Sediments. Department of Oceanography,
Seoul national University, 4512-4513
McGarth, J. A. Paquin, P. R. Di Toro, D. M. (1990) Use of The SEM And AVS Approach
in Predicting Metal Toxicity in Sediments, 3