Heavy metals and its effects on plants and environmentHaider Ali Malik
Heavy metals are natural constituents of the earth’s crust , but indiscriminate human activities have drastically altered their geochemical cycles and biochemicals balance.
Any toxic metals may be called heavy metals.
Since heavy metals have a propensity to accumulate in selective body organs.
The average safety levels in food or water are often misleading high.
Heavy is any metal or metalloid of environmental concern.
Heavy metals are metallic element that have relatively high density usually greater than 5 g/cm3, or their density is greater than the density of water.
Heavy metals and its effects on plants and environmentHaider Ali Malik
Heavy metals are natural constituents of the earth’s crust , but indiscriminate human activities have drastically altered their geochemical cycles and biochemicals balance.
Any toxic metals may be called heavy metals.
Since heavy metals have a propensity to accumulate in selective body organs.
The average safety levels in food or water are often misleading high.
Heavy is any metal or metalloid of environmental concern.
Heavy metals are metallic element that have relatively high density usually greater than 5 g/cm3, or their density is greater than the density of water.
Analysis of Heavy Metals in fish,water and sediment from Bay of Bengalinventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
The Use Of Pistia stratiotes To Remove Some Heavy Metals From Romi Stream: A ...iosrjce
The study involved a laboratory experiment on the use of Pistia stratiotes in the removal of some
heavy metals from a stream polluted by waste water from Kaduna Refinery and Petrochemical Company. Water
sample was collected from Kaduna Refinery effluent point, Romi up and Romi down. The Bioconcentration
(BCF) and Biotranslocation (BTF) Factors of each metal were determined. The experinmental study showed
that Pistia stratiotes is a suitable candidate for effective removal of heavy metals (Hg, Cd, Mn, Ag, Pb, Zn) from
Romi stream.
The Use Of Ecchornia crassipes To Remove Some Heavy Metals From Romi Stream: ...iosrjce
The study involved a laboratory experiment on the use of Ecchornia crassipes in the removal of
some heavy metals from a stream polluted by waste water from Kaduna Refinery and Petrochemical Company.
Water sample was collected from Kaduna Refinery effluent point, Romi up and Romi down. The
Bioconcentration (BCF) and Biotranslocation (BTF) Factors of each metal were determined. The experinmental
study showed that Ecchornia crassipes is a suitable candidate for effective removal of heavy metals (Hg, Cd,
Mn, Ag, Pb, Zn) from Romi stream.
Removal of heavy metals (Cr, Cd, Ni and Pb) using fresh water algae (Utricula...Innspub Net
A study was conducted to check the efficiency of different fresh water algae for removing heavy metals (Cr, Cd, Ni and Pb) from contaminated water. The three most abundant indigenous algal species namely Ulothrix tenuissima, Oscillatoria tenuis and Zygogonium ericetorum were collected from fresh water channels of Parachinar, Pakistan and brought to the laboratory of Soil and Environmental Sciences Department at the University of Agriculture, Peshawar Pakistan for proper identification. To check the efficiency for removing heavy metals artificial contaminated water was prepared and was inoculated with mix culture of above mentioned algae and incubated for 10 days. After incubation algal species were removed from water through centrifugation and was dried, digested and analyzed for heavy metals. The results showed that the concentration of all heavy metals was substantially reduced in the algal inoculated contaminated water. The analysis of algal biomass showed that considerable amount of metals and other elements were recovered in algae. Among the tested algal species, Zygogonium ericetorum showed maximum removal Ni(99.40ug) and Cr(66.84ug) from contaminated water followed by Oscillatoria tenuis with 84ug(Ni) and 64.83ug(Cr) respectively. However Oscillatoria tenuis showed maximum removal of Cd(41.00ug) than the other algal species. Similarly Zygogonium ericetorum showed maximum removal of Pb (451ug) followed by Ulothrix tenuissima where 441ug was recorded. Highest amount Cd, and Ni were recovered in Zygogonium ericetorum biomass while highest amount of Cr and Pb were recorded in the biomass of Oscillatoria tenuis. Finally it could be concluded that algae have efficiently removed heavy metals from contaminated water. Further research is needed to test other algal species for removal of heavy metal and other elements from the contaminated water.
Spheroid weathering of granite. Spheroidal weathering is a form of chemical weathering. This occurs when concentric shells of decayed rock are successively loosened and separated from a block of rock by water.
This is the decomposition of rocks due to chemical reactions occurring between the minerals in rocks and the environment. The examples below illustrate chemical weathering.
Water
Water, and many chemical compounds found in water, is the main agent of chemical weathering. Feldspar, one of the most abundant rock-forming minerals, chemically reacts with water and water-soluble compounds to form clay.
Acids
Iron precipitation on Fisher Creek stream channel.
Water contains many weak acids such as carbonic acid. This weak, but abundant, acid is formed when carbon dioxide gas from the atmosphere mixes with rainwater. Sulfur dioxide and nitrogen gases create other types of acid rain that act as chemical weathering agents. Some sources of sulfur dioxide are power plants that burn coal; as well as volcanoes and coastal marshes. Sulfur gases react with oxygen and rainwater to form sulfuric acid. Although relatively weak, acid’s abundance and long term effects produce noticeable damage to vegetation, fabrics, paints and rocks.
Oxidation
Oxidation is another kind of chemical weathering that occurs when oxygen combines with another substance and creates compounds called oxides. Rust, for example, is iron oxide. When rocks, particularly those with iron in them, are exposed to air and water, the iron undergoes oxidation, which can weaken the rocks and make them crumble.
HEAVY METALS POLLUTION AND ITS EFFECT ON ENVIRONMENT
Introduction:
In the era of rapid industrialization and urbanization pollution has totally deteriorated the quality and diversity of life and heavy metals contamination are major cause of environment deterioration which persuades severe poisonous effect on all the forms of living being. It poses threat due to its non-biodegradable, bioaccumulation, stability and persistence characteristics. Therefore, disrupt the natural ecosystem.
Definition: Any metallic chemical elements that has a relatively high density and is toxic or poisonous at low concentration.
In metallurgy, Heavy Metals are defined on the basis of density, having density more than 4g/cm3. In physics it is defined on the basis of atomic number having atomic number more than 20, while in chemistry on the basis of chemical behavior. But, modern definition of heavy metals describes as metallic elements and metalloids which are toxic to the environment and human.
• Heavy metal ranges from 3.5g/cm3 to 7 g/cm3 and have specific gravity at least 5 times more than water.
• These are often called ‘trace elements’ as required in small quantity (ppm or ppb)
• Heavy metals can be found in the forms of sulfates, hydroxides, oxides, sulfides, phosphates, and silicates.
• Heavy metal contamination and toxicity: a prominent environmental issue in water, soil/sediments and air.
• Heavy metals can be both beneficial and detrimental (at high concentration) to the environment and life.
• These are natural components of the Earth’s crust. Consumed by life forms via eating food, drinking water and inhaling air.
Physical Properties of heavy metals
• Lustre /shininess
• High melting point
• High density
• Good conductor of heat and electricity
• Non-degradable
• Malleable
• Ductile
Toxicological properties of Heavy Metals
• Persistence –long residual and half life
• Soil residence time is more than 1000years
• Acute toxicity-plants, animals and microorganisms
• Bioaccumulation and biomagnifications through food chain
• Chronic and sub-lethal effects at low concentration
• Synergistic effects
• Teratogenic and carcinogenic properties
heavy metal toxicity and effect on the environment as well as on the humanShahZain73
Heavy metal toxicity refers to the harmful effects that can occur when the body accumulates high levels of certain metals. Heavy metals such as lead, mercury, arsenic, cadmium, and others can be toxic even at low concentrations. These metals can enter the body through various sources like contaminated water, food, air, or exposure in certain occupations.
When these metals build up in the body over time, they can cause serious health issues. Symptoms of heavy metal toxicity can vary depending on the type of metal and the level of exposure but may include fatigue, headaches, nausea, neurological problems, organ damage, and in severe cases, even death.
Treatment for heavy metal toxicity usually involves removing the source of exposure, chelation therapy to remove metals from the body, and supportive care to manage symptoms. It's essential to be aware of potential sources of heavy metals and take precautions to minimize exposure to protect your health.
Analysis of Heavy Metals in fish,water and sediment from Bay of Bengalinventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
The Use Of Pistia stratiotes To Remove Some Heavy Metals From Romi Stream: A ...iosrjce
The study involved a laboratory experiment on the use of Pistia stratiotes in the removal of some
heavy metals from a stream polluted by waste water from Kaduna Refinery and Petrochemical Company. Water
sample was collected from Kaduna Refinery effluent point, Romi up and Romi down. The Bioconcentration
(BCF) and Biotranslocation (BTF) Factors of each metal were determined. The experinmental study showed
that Pistia stratiotes is a suitable candidate for effective removal of heavy metals (Hg, Cd, Mn, Ag, Pb, Zn) from
Romi stream.
The Use Of Ecchornia crassipes To Remove Some Heavy Metals From Romi Stream: ...iosrjce
The study involved a laboratory experiment on the use of Ecchornia crassipes in the removal of
some heavy metals from a stream polluted by waste water from Kaduna Refinery and Petrochemical Company.
Water sample was collected from Kaduna Refinery effluent point, Romi up and Romi down. The
Bioconcentration (BCF) and Biotranslocation (BTF) Factors of each metal were determined. The experinmental
study showed that Ecchornia crassipes is a suitable candidate for effective removal of heavy metals (Hg, Cd,
Mn, Ag, Pb, Zn) from Romi stream.
Removal of heavy metals (Cr, Cd, Ni and Pb) using fresh water algae (Utricula...Innspub Net
A study was conducted to check the efficiency of different fresh water algae for removing heavy metals (Cr, Cd, Ni and Pb) from contaminated water. The three most abundant indigenous algal species namely Ulothrix tenuissima, Oscillatoria tenuis and Zygogonium ericetorum were collected from fresh water channels of Parachinar, Pakistan and brought to the laboratory of Soil and Environmental Sciences Department at the University of Agriculture, Peshawar Pakistan for proper identification. To check the efficiency for removing heavy metals artificial contaminated water was prepared and was inoculated with mix culture of above mentioned algae and incubated for 10 days. After incubation algal species were removed from water through centrifugation and was dried, digested and analyzed for heavy metals. The results showed that the concentration of all heavy metals was substantially reduced in the algal inoculated contaminated water. The analysis of algal biomass showed that considerable amount of metals and other elements were recovered in algae. Among the tested algal species, Zygogonium ericetorum showed maximum removal Ni(99.40ug) and Cr(66.84ug) from contaminated water followed by Oscillatoria tenuis with 84ug(Ni) and 64.83ug(Cr) respectively. However Oscillatoria tenuis showed maximum removal of Cd(41.00ug) than the other algal species. Similarly Zygogonium ericetorum showed maximum removal of Pb (451ug) followed by Ulothrix tenuissima where 441ug was recorded. Highest amount Cd, and Ni were recovered in Zygogonium ericetorum biomass while highest amount of Cr and Pb were recorded in the biomass of Oscillatoria tenuis. Finally it could be concluded that algae have efficiently removed heavy metals from contaminated water. Further research is needed to test other algal species for removal of heavy metal and other elements from the contaminated water.
Spheroid weathering of granite. Spheroidal weathering is a form of chemical weathering. This occurs when concentric shells of decayed rock are successively loosened and separated from a block of rock by water.
This is the decomposition of rocks due to chemical reactions occurring between the minerals in rocks and the environment. The examples below illustrate chemical weathering.
Water
Water, and many chemical compounds found in water, is the main agent of chemical weathering. Feldspar, one of the most abundant rock-forming minerals, chemically reacts with water and water-soluble compounds to form clay.
Acids
Iron precipitation on Fisher Creek stream channel.
Water contains many weak acids such as carbonic acid. This weak, but abundant, acid is formed when carbon dioxide gas from the atmosphere mixes with rainwater. Sulfur dioxide and nitrogen gases create other types of acid rain that act as chemical weathering agents. Some sources of sulfur dioxide are power plants that burn coal; as well as volcanoes and coastal marshes. Sulfur gases react with oxygen and rainwater to form sulfuric acid. Although relatively weak, acid’s abundance and long term effects produce noticeable damage to vegetation, fabrics, paints and rocks.
Oxidation
Oxidation is another kind of chemical weathering that occurs when oxygen combines with another substance and creates compounds called oxides. Rust, for example, is iron oxide. When rocks, particularly those with iron in them, are exposed to air and water, the iron undergoes oxidation, which can weaken the rocks and make them crumble.
HEAVY METALS POLLUTION AND ITS EFFECT ON ENVIRONMENT
Introduction:
In the era of rapid industrialization and urbanization pollution has totally deteriorated the quality and diversity of life and heavy metals contamination are major cause of environment deterioration which persuades severe poisonous effect on all the forms of living being. It poses threat due to its non-biodegradable, bioaccumulation, stability and persistence characteristics. Therefore, disrupt the natural ecosystem.
Definition: Any metallic chemical elements that has a relatively high density and is toxic or poisonous at low concentration.
In metallurgy, Heavy Metals are defined on the basis of density, having density more than 4g/cm3. In physics it is defined on the basis of atomic number having atomic number more than 20, while in chemistry on the basis of chemical behavior. But, modern definition of heavy metals describes as metallic elements and metalloids which are toxic to the environment and human.
• Heavy metal ranges from 3.5g/cm3 to 7 g/cm3 and have specific gravity at least 5 times more than water.
• These are often called ‘trace elements’ as required in small quantity (ppm or ppb)
• Heavy metals can be found in the forms of sulfates, hydroxides, oxides, sulfides, phosphates, and silicates.
• Heavy metal contamination and toxicity: a prominent environmental issue in water, soil/sediments and air.
• Heavy metals can be both beneficial and detrimental (at high concentration) to the environment and life.
• These are natural components of the Earth’s crust. Consumed by life forms via eating food, drinking water and inhaling air.
Physical Properties of heavy metals
• Lustre /shininess
• High melting point
• High density
• Good conductor of heat and electricity
• Non-degradable
• Malleable
• Ductile
Toxicological properties of Heavy Metals
• Persistence –long residual and half life
• Soil residence time is more than 1000years
• Acute toxicity-plants, animals and microorganisms
• Bioaccumulation and biomagnifications through food chain
• Chronic and sub-lethal effects at low concentration
• Synergistic effects
• Teratogenic and carcinogenic properties
heavy metal toxicity and effect on the environment as well as on the humanShahZain73
Heavy metal toxicity refers to the harmful effects that can occur when the body accumulates high levels of certain metals. Heavy metals such as lead, mercury, arsenic, cadmium, and others can be toxic even at low concentrations. These metals can enter the body through various sources like contaminated water, food, air, or exposure in certain occupations.
When these metals build up in the body over time, they can cause serious health issues. Symptoms of heavy metal toxicity can vary depending on the type of metal and the level of exposure but may include fatigue, headaches, nausea, neurological problems, organ damage, and in severe cases, even death.
Treatment for heavy metal toxicity usually involves removing the source of exposure, chelation therapy to remove metals from the body, and supportive care to manage symptoms. It's essential to be aware of potential sources of heavy metals and take precautions to minimize exposure to protect your health.
The metals, which are required in a very minute amount and are considered toxic, are
termed as heavy metals. Researchers have widely investigated and studied these metals
due to their dangerous and harmful influence on health and the environment. Due to their
ability to accumulate and toxic nature these are addressed to be a vital source of environmental
contamination. Heavy metals have critically polluted the environment and its components.
This has severely damaged its abilities to promote life and provide its intrinsic
values. These are naturally available compounds and because of their anthropogenic origin
they are commonly found in various environmental domain. This results in deterioration of
the environment competence to support life and health of human, animals and plants
becomes threatened. This takes place because of bioaccumulation of these heavy metals in
the food chain which is a direct consequence of nondegradable state of the heavy metals.
The surroundings within which the human life exists is referred as the environment. It basically
comprises of the water, land, microorganisms, animal and plant life and the atmosphere
of the earth.
Bioremediation of heavy metals using Fe(III),SULPHATE AND SULPHUR reducing ba...KAVYA K N
Bioremediation of heavy metals with the help of Fe(III),Sulfate AND Sulfur reducing bacteria bacteria,environmental clean up process using geobacter and desulfuromonas species.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
2. Logam berat
•
•
•
•
Yang termasuk dalam logam
berat antara lain:
Hg, Pb, Cd, Cr, As, Cu, Cr, Ni,
Co, Mg
Tersebar merata
Toksisitas tinggi
Nondegradable
Densitasnya lebih tinggi jika
dibandingkan dengan logam lain
Tabel: apakah semua logam berat bersifat
toksik?
4. Apa itu Logam Berat?
Yang termasuk dalam Logam Berat.
5. • Heavy metals are chemical elements that have a specific
gravity (a measure of density) at least five times that of
water.
• generally interpreted to include those metals from periodic
table groups IIA through VIA
• Heavy metals are natural constituents of the Earth's crust
and are present in varying concentrations in all ecosystems
• Metals differ from other toxic substances in that they are
neither created nor destroyed by humans. Therefore, they
tend to accumulate in the soils, seawater, freshwater, and
sediments.
6. Introduction
Although we commonly think of heavy metals as water
pollutants, they are for the most part transported from place
to place via the air, either as gases or as species absorbed
on, or absorbed in, suspended particulate matter. (Baird,
2011)
7. • Metals are probably the oldest toxins known to
humans. Lead usage may have begun prior to 2000
BC in the smelting of silver. Arsenic was obtained
during the melting of copper and tin, and an early
use was for decoration in Egyptian tombs/
8. Mercury illuminated by incandescent
and UV light
Speciation and Toxicity
•
•
Unsur bebas bersifat tidak toksis (kecuali uap Hg)
Bersifat toksis sebagai kation
Putnam, 1972
11. • Mercury is a contaminant of our water ways.
Humans are exposed to mercury in the fish they
eat as well as in the amalgam fillings in their
teeth.
• Arsenic is found naturally in high concentration
in drinking water in various parts of the world.
Cadmium has been classified as a known human
carcinogen.
12. CHEMICAL AND PHYSICAL
PROPERTIES
CHEMICAL AND PHYSICAL PROPERTIES
• 1. Physical states - solids, liquids, gases
aerosols
• 2. Elements - indestructible
• 3. Electrophyllic cations - react with ligands
reversible complexes molecular mimicry
• 4. Oxidation States affects toxicity
• 5. Organometallic compounds differ from
inorganic
• 6. Essential versus non-essential
13. • Heavy metals (HM) exert their toxic effects by
combining with one or more reactive groups
(ligands) essential for normal physiological
functions.
• Heavy metal antagonists (HMA) - chelating
agents are designed specifically to compete with
these groups for the metals, and thereby
prevent or reverse toxic effects and enhance
excretion of metals.
14. Sources of heavy metal pollution
ATMOSPHERIC
Metals can be transferred by the atmosphere in gas or particle
form (aerosol)
• Particles can fall from the atmosphere onto the land or sea = dry
deposition
• Also precipitation can carry particles or dissolved gases = wet
deposition
• Gaseous state elements (Boron, Mercury, Selenium) can also dissolve at the
surface of water bodies (gaseous exchange)
• Bubbles breaking the surface of the sea can release salt particles
containing metals
– can travels from sea to atmosphere as well as atmosphere to sea
15. Sources of heavy metal pollution
RIVERS
• Erosion of rocks containing metals
• Surface runoff sweeps up naturally formed and
anthropogenic metal particles
Metals often bind with sediments and are deposited
on the seabed
– but these can enter the marine environment again is
there is:
– Dredging
– Trawling
– Severe weather
16. Sources of heavy metal pollution
GROUNDWATER SEEPAGE
• Dissolved substances are carried via ground
water movement – contamination in soil may
be picked up by the moving waters
DELIBERATE DISCHARGE
• Contaminated waste dumping
• Industrial discharges
• Sewage
