discipline: microbial diversity and bioremediation · 2 1. major environmental pollutants • about...
TRANSCRIPT
Discipline:
Microbial Diversity and
Bioremediation
“Heavy Metals” and Persistent Organic
Compounds: Effects and Mechanisms of Toxicity
Professor Luciana Maria Saran
Technology Department
School of Agricultural and Veterinarian Sciences
São Paulo State University
Jaboticabal, SP, Brazil
1
2
1. Major Environmental
Pollutants
• About Pollutant:
“A substance or energy introduced into the
environment having undesired adverse effects and
possibly causing long- or short-term damage by
changing the growth rate of plants or animal species,
or by interfering with human amenities and health is
called pollutant”.
Source: Das, S. et al. Bicrobial Biodegradation and Biorremediation, 2014.
DOI: http://dx.doi.org/10.1016/B978-0-12-800021-2.00002-9
1. Major Environmental
Pollutants
• “Heavy metals”.
• Polyciclic aromatic hydrocarbons (PHAs).
WHY?
• Because their persistent nature and tendency to
spread into ground as well as surface water.
3
4
1. Major Environmental
Pollutants: Sources
Source: Das, S. et al. Bicrobial Biodegradation and Biorremediation, 2014.
DOI: http://dx.doi.org/10.1016/B978-0-12-800021-2.00002-9
5
1. Major Environmental
Pollutants: Generalized View of
the Effects of Toxic Metals and
PHAs on the Human Body
Source: Das, S. et al. Bicrobial Biodegradation and Biorremediation, 2014.
DOI: http://dx.doi.org/10.1016/B978-0-12-800021-2.00002-9
6
1. Major Pollutants in Nature,
Their Source, Route of
Exposure, Level of
Contamination, Health Effects
Compound Source of
Exposure
Major Route
of Exposure
Environmental
Level
Health Effects
Arsenic, As
Food, air,
drinking water
Oral
• Air: 1-3 ng/m3
(rural areas);
20-100 ng/m3
(urban areas).
• Drinking water: 2
µg/L.
• Soil: 0.1-97 mg/kg.
Lung cancer,
cardiovascular
effects, and
encephalopathy
Cadmium, Cd
Food, cigarette,
smoking, drinking
water, and air
Oral, inhalation,
and dermal
• Air: 0.1-5 ng/m3
(rural areas);
2-15 ng/m3 (urban
areas).
• Drinking water:
< 5 µg/L.
• Soil: 0.06-1.1
mg/kg; 0.27 mg/kg
(agricultural).
Glomerular
damage, bone
mineralization, and
emphysema
Source: Das, S. et al. Bicrobial Biodegradation and Biorremediation, 2014.
DOI: http://dx.doi.org/10.1016/B978-0-12-800021-2.00002-9
7
1. Major Pollutants in Nature,
Their Source, Route of
Exposure, Level of
Contamination, Health Effects
Compound Source of
Exposure
Major Route
of Exposure
Environmental
Level
Health Effects
Lead, Pb
Contaminated
food, drinking
water, lead-
based paint
Inhalation
• Air: < 0.05 µg/m3.
• Water: 5-10 µg/L.
• Soil: < 10-30 g/kg.
Elevated blood
pressure, colic in
children,
neuropathy,
reduced fertility
Mercury, Hg
Water, air,
dental
amalgam
fillings, waste
incinerators
Inhalation and
oral
•Air: < 0.9-1.5 ng/m3.
• Water: 0.5-100 ng/L.
• Soil: 6-17 mg/kg.
Diarrhea and/or
abdominal pain,
kidney damage,
and acrodynia
PHAs
Air and food
Inhalation and
oral
•Air: < 0.9-1.5 ng/m3.
• Water: 0.5-100 ng/L.
• Soil: 6-17 mg/kg.
Cancer, mutation,
and skin irritation
Source: Das, S. et al. Bicrobial Biodegradation and Biorremediation, 2014.
DOI: http://dx.doi.org/10.1016/B978-0-12-800021-2.00002-9
2. Major Environmental
Pollutants: “Heavy Metals”
• There are 14 essential metals for human beings: Ca,
K, Na, Mg, Fe, Zn, Cu, Sn, V, Cr, Mn, Mo, Co and Ni.
• Some metals considered toxic at high concentrations,
such as Zn, Cu, Cr and Ni, are fundamental to the
metabolism in low concentrations.
8
2. Major Environmental
Pollutants: “Heavy Metals”
• Influence of the metal concentration on the development of
a living being: (a) essential metal and (b) non-essential
metal.
Develo
pm
en
t
Concentration
Deficient Optimum Toxic Letal
(a)
Develo
pm
en
t
Concentration
Toxic Letal Tolerable
(b)
9
2.1 Sources of
“Heavy Metals” in the
Environment
Natural Sources Anthropogenic Sources
• Volcanic eruptions • Mining
• Earthquakes • Energy and Fuel
Production
• Floods • Eletrocplating
• Storms • Waste water sludge
treatment
• Nuclear fuels
• Agricultural wastes
10
Source: Das, S. et al. Bicrobial Biodegradation and Biorremediation, 2014.
DOI: http://dx.doi.org/10.1016/B978-0-12-800021-2.00002-9
2.2 Biogeochemical Cycles
of Heavy Metals in the
Environment
11
Source: Das, S. et al. Bicrobial Biodegradation and Biorremediation, 2014.
DOI: http://dx.doi.org/10.1016/B978-0-12-800021-2.00002-9
2.3 Arsenic, As
• It is one of the most toxic elements.
• It occurs naturally in the earth's
crust.
• Present in the atmosphere, soil,
rocks, freshwater and living
organisms.
12
• In nature: it exists in various chemical forms (organic
and inorganic species).
• Oxidation states: As5+, As3+, As0 e As3-
2.3 Arsenic, As: Main
Species Reported
in the Literature
Source: Souza, J.M.O. Quim. Nova, 2014. 38(1), 118-127. 13
Inorganic Species
Organic Species
2.3 Arsenic, As: Main
Species Reported
in the literature
Source: Souza, J.M.O. et al. Quim. Nova, 2014. 38(1), 118-127. 14
Organic Species
2.3 Arsenic, As: Main
Species Reported
in the Literature
Species that may occur in water:
• In natural water arsenite, As(III); arsenate, As(V);
monomethylarsonic ion (MMA) and dimethylarsinic
ion (DMA).
• In ground water arsenite, As(III) and arsenate,
As(V) .
• In sea water, ponds, lakes and where there is
possibility of biomethylation: arsenite, As(III) and
arsenate, As(V) occur together with MMA and DMA.
Source: Barra, C.M. et al. Quim. Nova, 2000. 23(1), 58-70. 15
2.3 Arsenic, As:
Main Anthropic Sources
• Mining activity.
• Use of fossil fuels.
• Herbicides, insecticides and defoliants containing As
and used in agriculture.
• As is used in the manufacture of some glass,
semiconductor materials and photoconductors.
• As is used as a feed additive for poultry and cattle.
Sources: Barra, C.M. et al. Quim. Nova, 2000. 23(1), 58-70.
Montoya, E.A.R. et al. Terra Latinoamericana , 2015. 33(2), 103-118.
16
2.3 Arsenic, As: Cycle
Source: Langdon, C.J. et al. Environmental Pollution , 2003.124(3), 361-373. 17
2.3 Arsenic, As:
Toxicological Aspects
• Inorganic compounds are 100 times more toxic than
the partially methylated forms (monomethylarsonic
acid, MMA or MMAA and dimethylarsinic acid, DMA or
DMAA).
Source: Farias, J.S.F et al. Quim. Nova, 2012. 35(7), 1401-1406.
18
• As(III) and As(V): most toxic
species.
• As(III) is 60 times more toxic than
As(V).
2.3 Arsenic, As:
Toxicological Aspects
• Order of toxicity of arsenic compounds:
organic compounds of As5+
organic compounds of As3+
inorganic compounds of As5+
inorganic compounds of As3+
To
xic
ity In
cre
as
ing
Ord
er
Source: Farias, J.S.F et al. Quim. Nova, 2012. 35(7), 1401-1406.
19
2.3 Arsenic, As:
Toxicological Aspects
• Absorption of arsenic compounds oral via and
inhalation.
• It can also occur by dermal via.
• Main route of elimination by the human body urine.
• Inorganic arsenic methylation in the human body is a
detoxification process that occurs in the kidneys:
As(V) As(III) MMA(V) MMA(III) DMA(V)
Source: Barra, C.M. et al. Quim. Nova, 2000. 23(1), 58-70. 20
2.3 Arsenic, As:
Toxicological Aspects
• Exposure to arsenic may lead to:
# Cardiovascular problems (hypertension and
arrhythmias).
# Conjunctivitis.
# Hyperkeratosis.
# Hyperpigmentation and gangrene in the limbs.
# Cancer (lung, skin, bladder and kidney) in humans
may be caused by As inorganic species.
21
2.4 Mercury, Hg
• It occurs in nature in three oxidation states: Hg0, Hg2+
(mercury ion) and Hg2+ (mercuric ion).
22 So
urc
es
: M
icaro
ni, R
.C.C
.M.
et
al. Q
uim
. N
ova
, 2
00
0. 2
3(4
), 4
87
-49
5.
Bis
ino
ti, M
.C;
Ja
rdim
, W
.F. Q
uim
. N
ova
, 2
00
4. 2
7(4
), 5
93
-60
0.
• Hg0 is a liquid metal and argent
at room temperature.
• In nature it is associated with
other elements (HgS).
• Hg0 is obtained by heating the HgS followed by
condensation.
2.4 Mercury, Hg:
Main Sources
• Natural sources:
. Volcanic eruptions;
. Natural evaporation and mercury mines.
23
2.4 Mercury, Hg:
Main Sources
• Anthropogenic Sources:
. Fossil fuel burning;
. Electrolytic production of chloro-soda;
. Acetaldeído production;
. Waste incinerators;
. Paper pulp production;
. Inks;
. Pesticides;
. Fungicides.
24
So
urc
es
: M
icaro
ni, R
.C.C
.M.
et
al. Q
uim
. N
ova
, 2
00
0. 2
3(4
), 4
87
-49
5.
Bis
ino
ti, M
.C;
Ja
rdim
, W
.F. Q
uim
. N
ova
, 2
00
4. 2
7(4
), 5
93
-60
0.
2.4 Mercury, Hg:
Chemical Species
• Inorganic species: elementary Hg (Hg0); mercury ion
(Hg22+), little stable in environmental systems and
mercuric ion (Hg2+).
• Organic species (alkylmercury compounds):
methylmercury (CH3Hg+) and dimethylmercury
[(CH3)2Hg)] are the most commun.
• Increasing order of solubility in water of some
mercury compounds: Hg0, Hg2Cl2, Hg(CH3)2 and
HgCl2.
25 Sources: Micaroni, R.C.C.M. et al. Quim. Nova, 2000. 23(4), 487-495.
Bisinoti, M.C; Jardim, W.F. Quim. Nova, 2004. 27(4), 593-600.
2.4 Mercury, Hg:
Global Cycle
26
27
2.4 Mercury, Hg:
Global Cycle
• Hg2+ conversion to organic forms:
Hg2+ + organic matter CH3Hg+ and (CH3)2Hg
H2O, bacteria
Hg2+ HgS Hg2SO4 CH3Hg+
H2S
Eutropic condition
aeration
Less
soluble
More
Soluble
Source: Duruibe, J.O.; Ogwuegbu, M.O.C; Egwurugwu, J.N. International Journal of Physical Sciences, 2007. 2(5), 112-118.
2.4 Mercury, Hg:
Toxicological Aspects
• Occupational exposure to mercury human
contamination occurs through the respiratory tract.
• Occupational contamination Hg0 and mercury salts
are mainly responsible.
• Environmental contamination caused by ingestion
of fish (from freshwater or salt water), affects the
bloodstream and causes problems in the central
nervous system.
• Organic mercury compounds, mainly methylmercury,
are responsible for environmental contamination. 28
So
urc
es
: M
icaro
ni, R
.C.C
.M.
et
al. Q
uim
. N
ova
, 2
00
0. 2
3(4
), 4
87
-49
5.
Bis
ino
ti, M
.C;
Ja
rdim
, W
.F. Q
uim
. N
ova
, 2
00
4. 2
7(4
), 5
93
-60
0.
2.4 Mercury, Hg:
Toxicological Aspects
Mercury bioaccumulation
or biomagnification
29
2.4 Mercury, Hg:
Toxicological Aspects
• Toxic effects of Hg0 occur after oxidation of this
specie.
• Due to the high affinity of Hg for sulfhydryl groups of
proteins and for phosphoryl, amide and amine
groups.
• It interferes with cell metabolic functions, causes
damage to the cell membrane and in the transport
through the membrane.
• Causes mental deterioration in highly contaminated
individuals. 30
So
urc
es
: M
icaro
ni, R
.C.C
.M.
et
al. Q
uim
. N
ova
, 2
00
0. 2
3(4
), 4
87
-49
5.
Bis
ino
ti, M
.C;
Ja
rdim
, W
.F. Q
uim
. N
ova
, 2
00
4. 2
7(4
), 5
93
-60
0.
31
2.5 Chromium, Cr
• It´s found in trace amount in most rocks and soils.
• In nature it is found in a higly insoluble form.
• All the common soluble forms due to the
contamination of industrial effluents.
• Cr(VI) is carcinogenic.
Source: Kotás, J.; Stasicka, Z. Environmental Pollution, 2000. 107, 263-283.
32
2.5 Chromium, Cr:
Chemical Species
• Cr can exist in several chemical forms displaying
oxidation numbers from 0 to VI.
• Cr(III) and Cr(VI) are stable enough to ocurr in the
environment.
• In natural waters: Cr exists in its two stable oxidation
states, Cr(III) and Cr(VI).
• Under anoxic or suboxic conditions, Cr(III) should be
the only form.
Source: Kotás, J.; Stasicka, Z. Environmental Pollution, 2000. 107, 263-283.
33
2.5 Chromium, Cr:
Chemical Species
• In soils: Cr is present mostly as insoluble Cr(OH)3 or
as Cr(III) adsorbed to soil components.
• In neutral-to-alkaline soils: Cr(VI) exists monstly in
soluble (e.g. Na2CrO4) but also in moderately-to-
sparingly soluble chromates (e.g. CaCrO4, BaCrO4,
PbCrO4).
• In more acid soils (pH < 6): HCrO4- becomes a
dominant form.
Source: Kotás, J.; Stasicka, Z. Environmental Pollution, 2000. 107, 263-283.
34
2.5 Chromium, Cr in
Waters: Sources
• Natural sources:
- Weathering of rock constituents;
- Wet precipitation;
- Dry fallout from the atmosphere;
- Run-off from the terristrial systems.
Source: Kotás, J.; Stasicka, Z. Environmental Pollution, 2000. 107, 263-283.
35
2.5 Chromium, Cr in
Waters: Sources
• Anthropic sources:
- Discharge of wastewater from the metallurgical
industry;
- Electroplating and tanning industries;
- From sanitary landfill leaching;
- Water cooling towers;
- Tanning industries.
Source: Kotás, J.; Stasicka, Z. Environmental Pollution, 2000. 107, 263-283.
36
2.5 Chromium, Cr in Soil
Systems: Sources
• Main sources of Cr in natural soils: weathering of their
parent materials.
• An increase in local concentration in soils originates
from:
- fallout and washout of atmospheric Cr-containing
particles;
- refuse from industrial activity.
Source: Kotás, J.; Stasicka, Z. Environmental Pollution, 2000. 107, 263-283.
37
2.5 Chromium, Cr in
Atmospheric Systems:
Sources
• Natural sources:
- Volcanic eruptions;
- Erosion of soils and rocks;
Souce: Kotás, J.; Stasicka, Z. Environmental Pollution, 2000. 107, 263-283.
38
2.5 Chromium, Cr in
Atmospheric Systems:
Sources
• Anthropic sources:
- Metallurgical industries;
- Refractory brick prodution;
- Eletroplating;
- Combustion of fuels;
- Production of Cr chemicals (chromates, dichromates,
pigments, Cr trioxide and Cr salts).
Source: Kotás, J.; Stasicka, Z. Environmental Pollution, 2000. 107, 263-283.
39
2.5 Chromium, Cr:
Toxicological Aspects
• Inhalation and retention of Cr(VI)-containing materials
can cause perforation of the nasal septum, asthma,
bronchits, pneumonitis, inflamation of the larynx and
liver and increase incidence of bronchogenic
carcinoma.
• Skin contact of Cr(VI) compounds can induce skin
allergies, dermatitis, dermal necrosis and dermal
corrosion.
Source: Kotás, J.; Stasicka, Z. Environmental Pollution, 2000. 107, 263-283.
40
2.5 Chromium, Cr:
Toxicological Aspects
• Toxic properties of Cr(VI) arise from:
- the possibility of free difusion across cell
membranes;
- strong oxidative potential;
- formation of free radicals during the reduction of
Cr(VI) to Cr(III) occurring inside the cell Cr(III) in a
significant concetration cause adverse effects.
Source: Kotás, J.; Stasicka, Z. Environmental Pollution, 2000. 107, 263-283.
41
2.5 Chromium, Cr:
Toxicological Aspects
Cr(III)
Capability to coordinate
various organic compounds
Resulting in inhibition
of ome metallo-enzyme
systems
Source: Kotás, J.; Stasicka, Z. Environmental Pollution, 2000. 107, 263-283.
42
2.6 Cadmium, Cd
• Cd is a naturally occurring metal, usually being found
as an impurity in Zn or lead (Pb) deposits.
• It generally exists as divalent cation (Cd2+),
complexed with other elements (e.g. CdCl2);
• Comercially, Cd is used in televisions screens, lasers,
batteries, paint pgiments, cosmetic, in galvanizing
steel, and as barrier in nuclear fission.
43
2.6 Cadmium, Cd
44
2.6 Cadmium, Cd
• Natural activities: volcanic activity, weathering and
erosion.
• Human activities: tobacco smoking, mining, smelting
and refining of non-ferrous metals, fossil fuel
combustion, incineration of municipal waste
(especially cadmium-containing batteries and
plastics) and manufacture of phosphate fertilizers.
• Application of municipal sludge to agricultural soil
can be a significant source of cadmium.
45
2.6 Cadmium, Cd
• Cd exposure occurs from ingestion of contaminated
food.
• Cd exposure from drinking-water is relatively
unimportant compared with exposure from the diet.
• Smoking tobacco is an important source of exposure.
46
2.6 Cadmium, Cd
• The kidney is the critical target organ. Cd
accumulates primarily in the kidneys and this
accumulation may led to renal dysfunction.
• High intake of Cd can lead to disturbances in Ca
metabolism and the formation of kidney stones.
• High inhalation exposure to cadmium oxide fume
results in peneuminitis.
• It can contribute to the development of lung, kidney
and prostate cancer.
47
2.7 “Heavy Metals”:
Biochemistry of Toxicity
• “Heavy Metals” when ingested, in the acid medium
of the stomach, they are convertes to their stable
oxidation states (Pb2+, Cd2+, As2+, As3+, Hg2+).
• “They combine with the body´s biomolecules such as
proteins and enzymes to form strong and stable
chemical bonds”.
Source: Duruibe, J.O.; Ogwuegbu, M.O.C; Egwurugwu, J.N. International Journal of Physical Sciences, 2007. 2(5), 112-118.
48
2.7 “Heavy Metals”:
Biochemistry of Toxicity
• Heavy Metals´ reactions during bond formation with
the sulphydryl groups (-SH) of cysteine and sulphur
atoms of methionine (-SCH3):
Source: Duruibe, J.O.; Ogwuegbu, M.O.C; Egwurugwu, J.N. International Journal of Physical Sciences, 2007. 2(5), 112-118.
49
2.7 “Heavy Metals”:
Biochemistry of Toxicity
• “Heavy Metals” can induce enzymatic inhibition for
example, toxic As3+ occurs in herbicide, fungicides
and inseticides and can attack –SH groups in
enzymes to inhibit their bioactivities.
Source: Duruibe, J.O.; Ogwuegbu, M.O.C; Egwurugwu, J.N. International Journal of Physical Sciences, 2007. 2(5), 112-118.
50
2.8 “Heavy Metals” in
Drinking Water
Heavy metal Portaria MS N.
2.914/2011 (mg L-1)
WHO
(mg L-1)
Arsenic, As 0.01 0.01
Barium, Ba 0.7 1.3
Cadmium, Cd 0.005 0.003
Lead, Pb 0.01 0.01
Copper, Cu 2 2
Chromium, Cr 0.05 0.05
Mercury, Hg 0.001 0.006
Nickel, Ni 0.07 0.07
Selenium, Se 0.01 0.04
51
2.9 “Heavy Metals” in
Freshwater
Heavy metal CONAMA N. 357/2005
Classes 1 e 2 (mg L-1)
CONAMA N. 357/2005
Classe 3 (mg L-1)
Arsenic, As 0.01 0.033
Barium, Ba 0.7 1.0
Cadmium, Cd 0.001 0.01
Lead, Pb 0.01 0.033
Copper, Cu 0.009 0.013
Chromium, Cr 0.05 0.05
Mercury, Hg 0.0002 0.002
Nickel, Ni 0.025 0.025
Selenium, Se 0.01 0.05
52
2.10 “Heavy Metals” in
Wastewater
Heavy metal CONAMA N. 430/2011
(mg L-1)
Arsenic, As 0.5
Barium, Ba 5.0
Cadmium, Cd 0.2
Lead, Pb 0.5
Copper, Cu 1.0
Chromium, Cr 0.1 (Cr6+); 1.0 (Cr3+)
Mercury, Hg 0.01
Nickel, Ni 2.0
Selenium, Se 0.3
53
2.11 “Heavy Metals”
in Soil
• See CONAMA Resolution N. 420, December 28, 2009.
This resolution provides guiding values of quality
soil for the presence of chemical substances and
establishes guidelines for the environmental
management of areas contaminated by these
substances due to anthropic activities.
54
2.12 United State Environmental
Protection Agency (USEPA) Maximum
Contamination Levels for Heavy Metal
concentration in Air, Soil and Water
Source: Duruibe, J.O.; Ogwuegbu, M.O.C; Egwurugwu, J.N. International Journal of Physical Sciences, 2007. 2(5), 112-118.
55
3. Persistent Organic
Compounds
56
3.1 Polyciclic Aromatic
Hydrocarbons (PHAs)
• PHAs are a large group of compounds formed during
incomplete combustion organic mater.
• PHAs highly hydrophobic in nature and tend to
adsorb into the surface of soil (or sediments in marine
environment).
• 16 PHAs have been listed as a toxic pollutants by the
US EPA (Environmental Protection Agency).
• Potent carcinogens and mutagenic. Source: Das, S. et al. Bicrobial Biodegradation and Biorremediation, 2014.
DOI: http://dx.doi.org/10.1016/B978-0-12-800021-2.00002-9
3.1 Polyciclic Aromatic
Hydrocarbons (PHAs)
57
58
Biogeochemical Cycles of PHAs
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59
3.2 Polyclorinated
Biphenyls (PCBs)
• They are produced by chemical synthesis.
• There is no natural processes can generate PCBs.
• PCBs good insulators.
60
3.2 Polyclorinated
Biphenyls (PCBs)
61
3.2 Polyclorinated
Biphenyls (PCBs): Sources
• Transformers, capacitors, and others eletrical
equipments PCBs have been used as coolants and
lubrificants.
• Control formulations of dedusting agents and in used
oil for dust supression.
• Burning of PCB-containing products.
62
3.3 Nitroaromatic
Compounds (NACs)
• NACs are recalcitrant due to the presence of the nitro
group.
63
3.3 Nitroaromatic
Compounds (NACs)
• They are introduced to the environment from
anthropogenic sources and synthesis.
• They are used as dyes, pesticides, explosives, and
fharmaceusticals.
• Vast aplication of them has led to the environmental
contamination of soil, ground water, and freshwater.
64
3.4 Phtalates
• They are used as plasticizers and
used to make plastic flexible and
resilient.
• They are in products like automobile
parts, toys, cosmetics, and food
packing.
• Phthalates cause developmental and reprodutive
toxicity. Chronic exposure to them causes cancer.
65
3.4 Polybrominated
Biphenyls (PBBs)
• PBBs are artificial chemicals.
• Persistent environmental pollutants.
• They are used as plastic additives to make products
like televisions, plastic foams, computer monitors, etc.
66
References
• Barra, C.M. et al. Quim. Nova, 2000. 23(1), 58-70.
• Bisinoti, M.C; Jardim, W.F. Quim. Nova, 2004. 27(4), 593-600.
• Das, S. et al. Bicrobial Biodegradation and Biorremediation, 2014.
DOI: http://dx.doi.org/10.1016/B978-0-12-800021-2.00002-9.
• Duruibe, J.O.; Ogwuegbu, M.O.C; Egwurugwu, J.N. International Journal of Physical
Sciences, 2007. 2(5), 112-118.
• Farias, J.S.F et al. Quim. Nova, 2012. 35(7), 1401-1406.
• Kotás, J.; Stasicka, Z. Environmental Pollution, 2000. 107, 263-283.
• Langdon, C.J. et al. Environmental Pollution , 2003.124(3), 361-373.
• Micaroni, R.C.C.M. et al. Quim. Nova, 2000. 23(4), 487-495.
• Montoya, E.A.R. et al. Terra Latinoamericana , 2015. 33(2), 103-118.
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