Introduction to Geo-medicine - PowerPoint Presentation

Slide1

Introduction to Geo-medicineSlide2

Module Name: Introduction to

Geo-medicine

Module Code: MEG 2643

Lecture

Notes

Lecturer: Ms

Mundalamo

Department of Mining and Environmental

Geology

School of Environmental Geology

University of VendaSlide3

Outline

What is

Geomedicine

? Definition and Concept

Periodic table of elements – Revision

Principal chemical constituents of the human body

Essential elements in life systems

Control on elemental intake

Toxic elements

Sources of toxic elements

Bioavailability of toxic elements to

bioreceptors

Pathways of toxic elements in soils , plants and animal systems

Dose-response curves

The changing nature of disease

Health effects of excess/deficiency of selenium, lead. mercury, zinc, cadmium and arsenic

Investigation of casual links between specific diseases and the geological environment

Geogenic sources of atmospheric particulates

Dust emission in mining and mineral processing and the fate of inhaled particles

Chronic Bronchitis

Allergic lung disease

Coal workers pneumoconiosis

Asbestosis

Cancer and mutagens

SilicosisSlide4

Outline

Geological aspects of waste disposal including radioactive waste

Ionization and radon gas

Balneology of peat deposits

Health spas and mineral waters

Geochemical maps in medical geology

Environmental data sources

Medical data sources

Data analysis using Pearson’s correlation

Use of remote sensing and GIS in human health studies

Analytical techniques in environmental Geochemistry

Geochemical Data bases Slide5

Projects

Berylliosis

Group

A

Talcosis Group B

Siderosis Group C

Geophagia Group D

Podoconiosis

and

Kaposis’s

sarcoma

Group

ESlide6

References

Author

Komatina

,

Miomir

M.

Medical geology : effects of geological environments on human health

Publisher Amsterdam, The Netherlands : Elsevier, 2004.

Medical Geology : A

regional Synthesis

Closing

the GapSlide7

What is

Geomedicine

?

-

Geomedicine

, often referred to as Medical Geology, is upcoming discipline that links earth sciences and medicine

.

- It is the science that investigates the effects of the presence or absence of trace elements in organisms

.

- The discipline tries to establish casual links between specific diseases in human, animals and plants and geological processes and human activities in space and time.

-

The study of

geomedicine

includes industrially derived exposure to known toxic elements originating from mining and mineral processing.Slide8

What is

Geomedicine

?

-

Geomedicine

is a multidisciplinary subject, which requires cooperation among geologists, clinicians, epidemiologists, biologists, veterinarians etc.

- The role of geologist is to help isolate geological aspects that might influence the incidence of diseases.

- Medical Geology has acquired its present status due partly to inter–disciplinary approaches in solving scientific problems and partly to advances in analytical methodology, enabling the determination of nutritional trace elements at lower detection levels (

ppm

/ppb)

- Trace elements are important not only for their deficiency, but also for their excess. Besides such elements such as

As

, F, Se,

Pb

, Zn, Fe, Mo can cause severe consequences in circumstances of natural chronic poisoning.Slide9

What is

Geomedicine

?

- Both, Acute and Chronic toxicity have to be considered.

- Deficiencies, excess or imbalances in the supply of inorganic elopements from dietary sources can have an important influence on human and animal health.

- Such situations arise mainly from anomalies in the inorganic elements composition of food chains, which are frequently attributed to the composition of the geochemical environment as modified by the influence of soil composition and bacterial variables. Slide10

Why this new discipline

?

Create

awareness of, and concern for the environment during the exploitation of natural

resources

Develop concepts and skills for assessing and resolving environmental issues, questions and problems related to mining and mineral

processing

Introduce

a firm background in professional expertise and environmental principles in research and development activities in society, leading to improved methodologies and techniques for

mitigation

Promote participation in practical environmental activities

with

a view to enhancing environmental quality in the lives of local communities.Slide11

Why this new discipline?

Improve communication amongst the various disciplines concerned with diseases caused by geological factors which influence the well being of man and minerals

Developed information material for the use of schools, publics and private

organisation

interested in these fields to show the impact of geologic factors on well being of man and animals.

Encourage geological surveys, universities, and geological societies to take a more active role in providing useful information on geologic conditions in

Geoscience

and health problems.

Encourage the development of local working groups of multi-disciplinary

Geomedicine

, Geoscientists, Geo environment and health expect

Encourage research in the area of producing more effective methodologies for the study of geological factors in environment medicineSlide12

Essential elements in life systems

Essential elements are all those elements which are of great importance in life system. That is in plants animals and humans.

These essential elements are further classified into

major elements/macro elements and

trace elements/microelements

.Slide13

Major elements

Are those which are needed most in life system.

More than 99% of human body is made of the six major elements: O, C, H, N, Ca, and P.

Human body is about 60% water. The rest:

protein, fat, carbohydrates containing: O, C, H, N, Ca, and P

Teeth and bone: Ca, O, P, HSlide14

Dissolve salts: K, Na, Mg, Ca,

Cl

, Br, I, C, O, P

Major elements of the human body are obviously critical to life and health.

Thus most part of the

Geomedicine

is the study of the effects of the presence or absence of the trace elements

Major elements Slide15

Trace elements

Trace elements are those found in concentrations of about 10 to 100

ppm

or less.

The essential trace elements are required in small amounts for proper functioning of various enzyme system

These elements can have quite different effects, depending on the concentration in which it occurs or consumed.

That is effects such as acute or chronic toxicity.Slide16

Toxic elements

Elements which have effects at very low concentration

These elements often replace trace elements in the body, but get stuck where they are and shut down the essential function

Example:

Cd

, Hg: replace Zn, C u

Sr

,

Ba

: replace Ca

As,

Sb

: replace P

Se, Te replace S

W replace Cr, MoSlide17

Non essential elements

These elements can be added to the body to produce a beneficial effect

The warning is that small amount is beneficial, but too much is dangerous and can lead to toxicity Slide18

Heavy metals/Trace elements

Harmful elements known to have adverse physiological significance at relatively low levels include heavy metals such as

- As,

Cd

, Cr, Pd, Zn and Hg and

- also include the radioactive elements such as

U,Ra

,

Rn

, Th, Es

All trace elements are toxic if ingested or inhaled at sufficiently high levels for long enough periods of timeSlide19

TOXICITY

Toxicity is the degree at which chemical substances have ability to induce biochemical harmful effects to bio-receptors (living organisms- plants, human, animals)

Three categories of toxicity

Acute toxicity

Accelerated toxicity

Chronic toxicity Slide20

Acute toxicity

-is the effect of toxic when one massive dose of toxic element is taken from a single exposure or from multiple exposure in a short period of time

-Mainly occurs at less than 24 hours

-But still can be up to 14 days from the days of taking the substances

Slide21

Accelerated toxicity

-it is the intermediate stage of toxic effect after single or multiple exposure in an intermediate period of time

- Mainly occurs after exposed to acute toxicity when no treatment had encountered

Slide22

Chronic toxicity

– effects of exposure to small doses over a long period of time

Progressive effect of toxic elements

Mainly effect becomes permanent and can not be cured Slide23

Sources of toxic elements

Natural and

Anthropogenic SourcesSlide24

Natural Sources

Accumulation of heavy metals due to natural sources is through:

Chemical and physical weathering of rocks

Decomposition of plants, animals detritus

Precipitation

Volcanic activity

Wind erosion

Forest fire smoke

Oceanic spray

Floods

Earth quakes Slide25

Anthropogenic activities

Accumulation of heavy metals due to anthropogenic activities include activities such as:

metalliferous

mining and smelting

Agricultural and Horticultural materials

Sewage

sludges

Fossils fuel combustion

metallurgical industries, manufacture, use and disposal of metals commodities

electronics

waste deposal

metal, smelting ,

corrosion of metals in use,

forestry,

agriculture,

sports and leisure activities.Slide26

Natural sources:

The

movement of chemical compounds among various path through the lithosphere,

hydrosphere, Atmosphere

and biosphere

These constitute

the Geochemical

circleSlide27

Geochemical

CircleSlide28

The most common natural origin of trace elements is the Geochemical origin- chemical constituents from geological environment.

Trace elements occurs as trace constituents of primary minerals in igneous rocks – crystallized magma

They become incorporated into these minerals by

isomorphously

substitution which is governed by ionic charge, ionic radius and

electronegativity

of the major elements and trace element .Slide29

Trace constituent of rock forming minerals

:

Mineral

Trace

constituents

susceptibility to weatheringOlivine Ni, Co,

Mn

, Li, Zn, Cu, Mo easily weathered

Hornblende

Ni,

Co,

Mn

, Li, V Zn Cu

Ga

Biotite

Rb

,

Ba

, Ni, Co, Zn, Cu

,

Garnet

Mn

, Cr,

Ga

moderately

stable

Orthoclase

Rb

,

Ba

,

Sr

, Cu,

Ga

Muscovite

F

,

Rb

,

Ba

,

Sr

, Cu, V

Magnetite

Zn

Co, Ni, Cr,

V

Quarts -

Very

resistantSlide30

Weathering of rocks will contribute on soils contamination through processes such as

hydrolysis,

hydration,

dissolution,

oxidation

and reduction

,

ion exchange and carbonationThe trace element concentrations in sedimentary rocks are depended upon the mineralogy and adsorptive properties of the sedimentary materials.Slide31

Mean

heavy metal contents of major rock types:Slide32

Bioavailability of toxic elements

Slide33

This explains the FORM in which elements are available for

bioreceptors

.

The form in which the element might have

negative or positive

impacts on the environment

The property of a substance that makes its chemical uptake biota Slide34

This can be defined as

Element Speciation

Distribution of an element among defined chemical species in a system

Speciation – species distribution

Chemical species - chemical elements : specific form of an element defined by its isotopic composition

Speciation analysis – analytical activities in analytical chemistry of identifying and or measuring the quantities of one or more individual chemical species in a sample

This can be denoted as

oxidation state

and or

complex molecular

structures.Slide35

Which then influences the

bioavailabity

of toxic elements

OXIDATION STATE

examples

As

As (III) and As (IV) are toxic

Cr

Cr (III) -- essential

Cr (VI) – highly toxic and cancer promotingSlide36

Cu

Ionic Cu (II)is toxic in aquatic systems

It is the normal oxidation state for soluble aqueous complexes

It is stable at aqueous complexesSlide37

C(III)

Unstable in aqueous solution

Cu+ is classified as soft acid and forms complexes with typical soft base metalsSlide38

Fe

Fe (II) – less toxic

Absorption capacity is lower compared to Fe(III)

Only Fe (II) is effective against deficiency

Important for supplementation

But Fe (III) toxicSlide39

Hg

Inorganic mercury salts are less dangerous than

methylated

forms

These are more toxic than inorganic mercurySlide40

Inorganic

Compounds &

Complexes

These are readily consumed in either liquid or gas, especially water

The distribution of an element among different compounds affects its transport and bioavailability by determining properties as charge, solubility and diffusion coefficient.Slide41

;EXAMPLES 1 (Ni)

Ni salts of

NIcl

or Ni(SO4) are water soluble and of low oral toxicity

Ni oxides or

sulphur

are highly insoluble in water, but their bioavailability may be influenced by biological

legands

. (A legands is a group of ions or molecule coordinated to a central atom or a molecule in a complex);Trinickel disulphide (Ni3S2) is an important carcinogen in animals. Slide42

Exposures are seldom to a single species of Ni. For example, in various refining operations workers may encounter N3S2,

NiO

, Ni, Ni-Cu oxides, Ni-Fe oxides, NiSO4, Nicl2 and NiCO3

Inmost natural waters (ph 5-9) the free dominant Ni species are either the free Ni2+, NiCO3, Ni(OH)2, NiSO4, Nicl2 and Ni (HN4)2.Slide43

Under the reducing conditions the low solubility of Ni

sulphide

may limit dissolved nickel

concouter

EXAMPLE 2 (Cu

In contrast to Ni, Cu can form stable compounds in more than one oxidation state

Cu(ii) is the normal oxidation state for soluble aqueous complexes, Slide44

Although insoluble complexes of Cu(

i

) are also stable.

Cu(iii) complexes are relatively few in numbers and are unstable in aqueous media.

Cu(

i

) is classified as a soft acid and forms complexes with typical soft bases-

iotides

sulphur thiosulphates etc. It is only stable at vary low equilibrium concentration. Slide45

Stable insoluble Cu(

i

) compounds includes

CuCN

,

Cucl

, Cu2S. The

Cucl

and Cu-cyanide are even more stable in water than Cu(ii) complexes The relative stabilities of Cu(i) and Cu(ii) species in soluble values considerably depending upon the nature of the ligands presentSlide46

EXAMPLE 3 (Zn)

Zn has only one oxidation state, Zn(ii) that is stable.

In terms of its reactions with

ligands

, it is intermediate between the

hard

and soft acids

It has greater solubility and generally higher concentrations than most metals.

However the widespread use of Zn makes contamination

a real problemSlide47

Concentrations are generally low for wider drainage; 0.00002-0.0018

mg/liter

But concentration in rivers are relatively high up to 0.0156

mg/liter

or more in cases of anthropogenic pollution. For example,

giltrale

fraction of water drainage

In normal

pH range waters;Free Zn-ion is the predominant form.Then CO32- and (OH)- are the dominant speciesSlide48

EXAMPLE 4 (Pb)

A member of group IV (C, Si,

Ce

,

Sn

)

Like Cu and Zn it is intermediate between hard and soft acids.

It has more

than

one oxidation state. Background concentration of Pb; 0.000006-0.000050 mg/L, measured in remote streams in the U.S.A. Slide49

Concentrations

of rivers affected by mining are generally up to 0.065-1.11

mg/L

It is the low oxidation state, Pb(ii), which is the most stable under normal

oxidising

conditions.

Below

pH 7.1; Pb(ii) is present as free ion and for pH >7.1 it exists as a carbonate (PbCO3) and hydroxideSlide50

Adsorption plays a major role in controlling concentration in solution.Slide51

Organic Complexes

Organometallic

Compounds

Organometallic

compounds are compounds containing a covalent bond between a carbon atom and a metal.

Toxicity often results from bioaccumulation of

fatty

tissues and penetrations of membrane barriersSlide52

EXAMPLE

Ionic Hg(ii) is toxic to the mammalian kidney and corrosive at sides of mucosal absorptions

CH3Hg+ Crosses the

blood-brain

barrier, acting as

teratogen

(any substance that interferes with the normal embryonic development

)

and central nervous system toxin.Metals that undergo biomethylation-Hg, Ce & Sn

Slide53

Biomethylation

of metals is generally restricted to microorganisms in sediments and soils with the exception of Co in Vitamin B12

Note;

Methylation

of metals generally increases their toxicity,

Methylation

of

As &

Se contributes to their detoxificationSlide54

Manufactured

organometallic

also find their way into the environment through deliberate addition to treat seed grains

eg

(Phenyl)

Sn

as a fungicide and CH3As(

ONa

)2 as a herbicides or as (CH3)4 Pb and (C2H5)4 Pb during gasoline.Slide55

In the environment, binding to

polyamons

such as

humic

and

solic

acids and to colloidal particles contributes to the patterns of transport or availability of elements

e.g.

Cd ,Cn & PbSlide56

Pathways of toxic elements is soils animals and plants Slide57

For identification of environmental impact,

conceptual model

of pollution can be used as a flow chart in order to follow the chain in determination of the pathways of toxic materials to

bioreceptorsSlide58

Conceptual model

Elements emitted from sources are dispersed in the environment (air, in water and soils) through several transport agents

Wind transportation- metal rich dust and particulates

Rainwater and flood – flows into rivers and lakes

Gravity – movement of particles down the sides of heaps into rivers or onto soil

Land , air or sea—anthropogenic transportation

Placement – direct tipping of materialSlide59

During transportation, some heavy metals are deposited in soils that are taken by biota

and some are absorbed by humans and follows the route of chemical absorptionSlide60

ABSORPTION

Mouth, Lungs skin

GI Tract

DISTRIBUTION

Blood and Lymph System

EXCRETION

Feces, Urine, Expired Air,

secretion

RETENTION

Soft tissue, bones, Fat

Ingestion Inhalation Dermal contact

Key routs of chemical absorption, distribution and ExcretionSlide61

Absorption, where toxic materials might be ingested through the mouth, or inhaled through the lungs or through dermal contact with the skin

Distribution, this where these toxic chemicals will be distributed through the blood and the lymph system

Excretion, toxic materials will then be excreted as feces, urine, expired air

Retention, when the toxic materials are not excreted then they are retained in the body such as in soft tissue, bones or as fat Slide62

In plants absorption of heavy metals are taken up by roots system from soil solution, which can be by:

Passive (non-metabolic) uptake, involving diffusion of ions in the soil solution into the root endodermis

Active (metabolic) uptake which takes place against the concentration gradient but requires metabolic energy and can therefore be inhibited by toxinsSlide63

Relative difference in the uptake of the ions is due to several factors such as surface area of the root, rate of

evapotranspiration

and roots exudates

General order of transfer coefficient for most of biologically controlled heavy metals were deduced as indicated in tabled below, which is the metal concentration in plant tissue above ground divided by total metal concentration in the soil

 Slide64

Element

Soil-Plant Transfer coefficient (SPTC)

As

0.01 – 0.1

Cr

0.01 -0,1

Cu

0.1 – 10

Pb

0.01 – 0.1

Zn

1 – 10

Soil-plants transfer coefficients of heavy metals Slide65

Dose Response CurveSlide66

Slide67

Dose-response curve

is a simple X-Y graph relating the magnitude of a stressor

(e.g. concentration of a pollutant, amount of a drug, temperature, intensity of radiation)

to the response of the receptor (e.g. organism under study)

The response may be a physiological or biochemical response, or even death (mortality)Slide68

The measured dose (milligram, micrograms, or grams per kilogram of body-weight) is generally plotted on the X axis

and the response is plotted on the Y axis

the curve is typically sigmoidal , with the steepest portion in the middle

It usually illustrate the dose of the essential elements

Simply relates the exposure dose and the measurable biological effectSlide69

It should be realised that dose-response relationships will generally depend on the

exposure time; quantifying the response after a different exposure time leads to a different relationship and possibly different conclusions on the effects of the stressor under consideration. Slide70

90 natural occurring elements

73 are trace elements in the body

18 of 73 are essential trace elements Slide71

Element

Mass%

element

Mass%

Oxygen

65

Calcium

1.4

Carbon

18

Phosphorus

1

Hydrogen

10

Magnesium

0.50

Nitrogen

3

Potasium

0.34

Sulfur

0.26

Sodium

0.14

Chlorine

0.14

Abundance by mass % of major and minor elements in the human bodySlide72

Abundance of some trace elements in the human body

element

Mass%

element

Mass%

Arsenic

0.26

Manganese

0.17

Bromine

2.9

Molybdenum

0.08

Cobalt

0.021

Nickel

0.14

Chromium

0.094

Selenium

0.11

Copper

1

Silicon

260

Fluoride

37

Tin

0.24

Iron

60

Tungsten

0.008

Iodine

0.19

Vanadium

0.11

lithium

0.009

Zinc

33Slide73

If an essential trace element is completely withdrawn from the diet ,

signs and symptoms of deficiency should occur ,

such as growth retardation and loss of hair

supplementation should alleviate the symptoms and reverse the deficiency stateSlide74

Changing nature of diseases Slide75

Toxicity

This can be explained by toxicity

Toxicity/Poisoning - chemical injury to body organs or a chemically induced disturbance of the functions in biological systems

Such toxic effects may follow the exposure to exogenous (environmental) substances

Substances that normally are considered as harmless may also, if the dose is big enough, cause deleterious effects and thereby act as poisons

Examples of this are sodium chloride, oxygen and water. Slide76

The science devoted to the study of the structures, effects and fate of poisonous substances is called toxicology

Clinical toxicology deals with problems related to poisonings in humans and their treatment

Poisoning may be acute, accelerated or chronicSlide77

In acute poisoning the body is exposed to the toxic substance in a high dose, on one occasion and during a short period of time

Symptoms of poisoning develop in close relation to the exposure

Examples of acute poisonings are massive drug overdoses, poisonings after mushroom meals, alcohol poisonings, and bites or stings

Acute ToxicitySlide78

Acute poisoning just means 1 big dose of a poison that kills something or someone all at once

So, death by lethal injection is acute poisoning

The circumstances around an acute poisoning are often obvious and easy to detect

Mainly occurs at less than 24hours

But still can be up to 14 days from the days of taking the substancesSlide79

Chronic Toxicity

In chronic poisoning the organism is on the contrary exposed repeatedly to toxic agents during a long period,

but every exposure means that just a low dose of the poison is entering the body

Normally no symptoms develop in relation to each exposure, although that may happen (e.g. in chronic exposure to solvents)

Instead the patient gradually becomes ill after a period of months or years Slide80

In chronic poisoning the toxic substance may accumulate in body tissues or cause a small irreversible damage at each exposure

After a long time, enough poison has been accumulated in the body, or the damage has become significant enough, to cause clinical symptoms

Examples of typical chronic poisonings are long-term exposure to heavy metals like lead, mercury or cadmium, inhalation of organic solvents in the occupational context, and exposure to pesticides. Slide81

chronic poisoning is a buildup of toxic chemicals over time

the slow and insidious onset of a chronic poisoning may cause considerable diagnostic difficulties. Slide82

Accelerated toxicity

Is intermediate between chronic and acute toxicity

Develops after 5 -10 years of heavy exposure to toxic elements

It is the late stage of acute toxicity and early stage of chronic effect

Symptoms of chronic diseases starts to show off.Slide83

Sources , pathways and effects of excess/deficiency

of :

Selenium, lead, mercury, zinc,

and cadmiumSlide84

Selenium

Selenium is a non metallic chemical element.

In chemical activity and physical properties it resembles sulfur and tellurium

Selenium appears in a number of allotropic forms: the most popular are a red amorphous powder, a red crystalline material, and a gray crystalline metal like form called

metallic

selenium. Slide85

Se

Selenium burns in air and is unaffected by water, but dissolves in concentrated nitric acid and alkalis

Low levels of selenium can end up in soils or water through weathering of rocks

It will

then

be taken up by plants or end up in air when it is adsorbed on fine dust particles.

Selenium is most likely to enter the air through coal and oil combustion, as selenium dioxide. Slide86

Se

This substance will be converted into selenium acid in water or sweat

Selenium substances in air are usually broken down to selenium and water fairly quickly, so that they are not dangerous to the health of organisms

Selenium can accumulate in the body tissues of organisms and can

then

be passed up through the food chain Slide87

Se

Usually this bio magnification of selenium starts when animals eat a lot of plants that have been absorbing large amounts of selenium, prior to digestion

Due to irrigation run-off concentrations of selenium tend to be very high in aquatic organisms in many areas

When animals absorb or accumulate extremely high concentrations of selenium it can cause reproductive failure and birth defectsSlide88

Se

- Selenium exposure takes place either through food or water, or when we come in contact with soil or air that contains high concentrations of selenium.

-This is not very surprising, because selenium occurs naturally in the environment extensively and it is very widespread.

-The exposure to selenium mainly takes place through food, because selenium is naturally present in grains, cereals and meat.

- Selenium uptake through food may be higher than usual in many cases, because in the past many selenium-rich fertilizers have been applied on farmland.Slide89

Se

People that live near hazardous waste-sites will experience a higher exposure through soil and air

Selenium from hazardous waste-sites and from farmland will end up in groundwater or surface water through irrigation

This phenomenon causes selenium to end up in local drinking water, so that exposure to selenium through water will be temporarily increased.Slide90

Se

People that work in metal industries, selenium-recovery industries and paint industries also tend to experience a higher selenium exposure, mainly through breathing

Selenium is released to air through coal

combustion

People that eat a lot of grains that grow near industrial sites may experience a higher exposure to selenium through food

Exposure to selenium through drinking water may be increased when selenium from hazardous waste disposals ends up in water wells.Slide91

Se

Exposure to selenium through air

can

cause dizziness, fatigue and irritations of the mucous membranes

When the exposure is extremely high, collection of fluid in the lungs and bronchitis may occur.

Selenium uptake through food is usually high enough to meet human needs; shortages rarely occur. When shortages occur people may experience heart and muscle problems.

When selenium uptake is too high health effects will be likely to come about. Slide92

Se

The seriousness of these effects depends upon the concentrations of selenium in the food and how often this food is eaten.

The health effects of various forms of selenium can vary from brittle hair and deformed nails, to rashes, heat, swelling of the skin and severe pains

When selenium ends up in the eyes people experience burning, irritation and tearing.

Selenium poisoning may become so severe in some cases that it can even cause death.Slide93

Se

Overexposure of selenium fumes may produce accumulation of fluid in the lungs, garlic breath, bronchitis,

pneumonitis

, bronchial asthma, nausea,

fever

, headache, sore throat, shortness of breath, conjunctivitis, vomiting, abdominal pain, diarrhea and enlarged liver

Selenium is an eye and upper respiratory irritant and a sensitizer. Overexposure may result in red staining of the nails, teeth and hairSlide94

Se

Selenium deficiency causes rare endemic diseases where there is low level of Se in soil

Keshan cardiomyopathy

and

Kashin

– Beck diseases, which are deforming arthritis (China)

Mild deficiency of Se causes heart and cancer (Europe)Slide95

Lead

-Lead is a soft, malleable poor metal, also considered to be one of the heavy metals

-Pb is mainly light blue in colour which is soft and resistance to corrosion

-It was mainly used in petrol (gasoline), but is being phased out on environmental grounds

-Used in manufacturing car battries, electrodes, in the glass of computer and television screens, bullets, Slide96

Pb

Native lead is rare to find in nature, but naturally is found in zinc, silver and copper ores and it is extracted together with these metals

Metallic lead does occur in nature, but it is rare.

Lead is usually found in ore with zinc, silver and (most abundantly) copper, and is extracted together with these metals.

The main lead mineral is galena (PbS), which contains 86.6% lead. Slide97

Pb

Other common varieties are cerussite (PbCO3) and anglesite (PbSO4).

Besides occurring naturally more concentrations found in the environment are a result of anthropogenic activities

Example is Pb from petrol - Chlorines bromines and oxides pollute the environment- through the exhausts of cars

Larger particles pollute soils or surface waters, the smaller particles will travel long distances through air and remain in the atmosphereSlide98

Pb

Its main pathways are through uptake of food, (70%), water (20%) and air (10%).

Example of Foods staff include fruit, vegetables, meats, grains, seafood, soft drinks and wine may contain significant amounts of lead

Cigarette smoke also contains small amounts of lead

Lead can enter (drinking) water through corrosion of pipes especially when water is highly acidicSlide99

Pb

Effects of Pb include:

Brain damage, Miscarriages, anaemia, blood pressure, Kidney damage, Infertility of men, Lowering IQ of children, hyperactivity and damage to the nervous system and the brains of unborn children.

Other anthropogenic activities include not fuel combustion, industrial processes and solid waste combustion

Lead can end up in water and soils through corrosion of leaded pipelines in a water transporting system and through corrosion of leaded paints. Slide100

Pb

It cannot be broken down; it can only converted to other forms.

Lead accumulates in the bodies of water organisms and soil organisms. --Fish can take place even when only very small concentrations of lead are present.

Body functions of phytoplankton (O) can be disturbed when lead interferes.

-Soil functions are disturbed by lead intervention, especially near highways and farmlands, where extreme concentrations may be present. Slide101

Mercury (Hg)

It is heavy , silver metal

Liquid at room temp. but

solidifies at - 40

°C

Boils at 355 °C

High specific gravity – 13.6 g.cm

-3

Alloy with other metals

Part finder of cinnabarMain ore of Hg

Rhombohedral crystal structure

t can be extracted by heating cinnibar in a current of air Slide102

Hg

It occurs in two oxidation state Hg (I) and Hg (II)

It exists in the form of inorganic and organic mercury

Methylation of inorganic mercury into organic mercury occurs in the microorganisms under anaerobic conditions e.g in underwater sediments

Organic mercury is highly poisonous and it is easily absorbed by the gastric and intestinal organs

It is then carried by blood into the brain , liver and kidneySlide103

Natural sources Hg

Extremely rare native element on Earth crust

Also found in cinnibar and also in other minerals such as corderite and livingstonite

Mercury ore generally occurs in belts where rocks of high density are forced to the crust of the earth

Often in hot spring or other volcanic regions

Natural source such as volcanic eruption is responsible of almost half of the atmospheric Hg emissionsSlide104

Release in the environment

anthropogenic sources

The rest of % is mainly released by human –generated activities which include:

Emission of stationary coal combustion and oil combustion

Gold production

Cement production

Waste disposal- municipal and hazardous waste and sewage sluge

From steel production

Mercury production for batteriesSlide105

Applications

Cosmetics – manufacturing of mascara

Production of chlorine and caustic soda – Cl is produced from NaCl using electrolytes to separate Na from Cl

Caustic soda is produced by dissolving salt in water and brine is produced with byproduct being NaOH

Dentistry – main ingredients in dental amalgams

Slide106

Hg in Gold mining

For century Hg has been used for amalgamation of gold

It is estimated that about 1.32 kg of Hg is lost for every 1 kg of Au produced

About 40% of this loss occur during the initial concentration and amalgamation stage of Au

The lost is released directly into the soil, streams and rivers, initially as inorganic Hg, which later converts into organic HgSlide107

Hg in Gold mining

This is taken into the food chain, mainly by fish and other aquatic life

The remaining 60% Hg is released directly into the air when the Hg is released directly into the air when Hg – Au amalgam is heated during the purification process and is often inhaled

Hg is a very volatile element, thus dangerous levels are readily obtained in air

Safety standards require that Hg vapour should not exceed 0.1 mg/m3 in airSlide108

Hg in Gold mining

Hg once taken in, is accumulated into the human body and attacks the central nervous system, resulting in:

numbness and unsteadiness in the legs and hands,

awkward movements,

tiredness,

ringing in the ears,

narrowing of the field of vision,

los of hearing,

slurred speech,

loss of sense of smell and taste and forgetnessSlide109

Hg in Gold mining

Hg poisoning may lead to disease known as minamata

Minamata disease was first detected in 1956 in Minamata Bay –Japan

It was caused by eating large quantities of fish or shell fish contaminated by industrial discharges of Hg compounds in Minamata Basin

200mg/L of Hg in blood and 50mg/g in hair are the provisionally established standards and any higher concentration is considered to be at risk of poisoning

The allowable level of methyl Hg in fish is 0.3ppmSlide110

Zinc

Zinc, is a bluish-white, lustrous metal. It is less dense than iron and has a hexagonal crystal structure.

The metal is hard and brittle at most temperatures. Zinc is a fair conductor of electricity.

It has relatively low melting (420 °C) and boiling points (900 °C).

Metals long known to form binary alloys with zinc are Aluminium, antimony, bismuth, gold, iron, lead, mercury, silver, tin, magnesium, cobalt, nickel, tellurium and sodium.

Zinc makes up about 75 ppm (0.007%) of the Earth crust, making it the 24th most abundant element there. Slide111

Zn

Soil contains an average of 64 ppm, but actual soils have 5–770 ppm zinc.

Seawater has only 30 ppb zinc and the atmosphere contains 0.1 to 4 µg/m3.

The element is normally found in association with other base metals such as copper and lead in ores.

Zinc is a chalcophile ("sulfur loving"), meaning the element has a low affinity for oxygen and prefers to bond with sulfur in highly insoluble sulfides. Slide112

Zn

Other minerals from which zinc is extracted include smithsonite (zinc carbonate), hemimorphite (zinc silicate), wurtzite (zinc sulfide), and sometimes hydrozincite (basic zinc carbonate).

With the exception of wurtzite, all these other minerals were formed as a result of weathering processes.

Exploitable reserves of zinc exceed 100 million tonnes, with large deposits in Australia, Canada and the United States.

Zinc deficiency occurs where insufficient zinc is available for metabolic needs. Slide113

Zn

It is usually nutritional, but can be associated with malabsorption, acrodermatitis enterropathica, chronic liver disease, chronic renal disease, diabetes, malignancy, and other chronic illnesses.

Diets rich in foods that contain a lot of phytic acid, such as cereals and legumes, decrease zinc absorption into the body.

Zinc supplements are important and help prevent disease and reduce mortality, especially among children with low-birth weight or stunted growth. Slide114

Zn

Symptoms of chronic zinc deficiency are stunted growth and retarded sexual development.

Plants that grow in soils that are zinc-deficient are more susceptible to disease.

Even though zinc is an essential requirement for a healthy body, excess zinc can be harmful.

Excessive absorption of zinc suppresses copper and iron absorption. Slide115

Zn

The free zinc ion in solution is highly toxic to plants, invertebrates, and even vertebrate fish.

Stomach acid with HCl, will cause metallic zinc to dissolves readily to give corrosive zinc chloride.

Levels of zinc in excess of 500 ppm in soil interferes with the ability of plants to absorb other essential metals, such as iron and manganese.

-Chronic ingestion of over 1 kg of zinc results in death due to gastrointestinal bacterial and fungal infections.Slide116

Zn

Ingestion of about 12 grams of zinc, only shows lethargy and ataxia (gross lack of coordination of muscle movements)

Pennies and other small coins are sometimes ingested by dogs, resulting in the need for medical treatment to remove the foreign body.

The zinc content of some coins can also cause zinc toxicity, which is commonly fatal in dogs, where it causes a severe anemia, also liver or kidney damage; vomiting and diarrhea are possible symptoms.

Storing fruit juices in galvanized cans has resulted in mass poisonings of zincSlide117

Cd

Cd

is a Lustrous, silver –white , ductile, very malleable metal

Its surface has a bluish tinge and the metal is soft enough to be cut with a knife, but it tarnishes in air

It is soluble in acids but not in alkalis

It is similar in many respects to zinc but it forms more complex compoundsSlide118

Cd

in the environment

Natural Sources

Cd

can mainly

be found in the earth’s crust

It always occurs in combination with zinc

Naturally a very large amount of cadmium is released into the environment, about 25 000 tons a year

About half of this cadmium is released into the air through forest fires and volcanoesThe rest of the cadmium is released through human activities, such as manufacturingSlide119

Natural Sources

Mostly

Cd

ore is not mined for the metal, because more than enough is produced as a

byprolduct

of the smelting of zinc from its ore,

sphelarite

(

ZnS

), in which CdS is a significant impurity, making up as much as 3%Thus the main mining areas are those associated with zinc World production is around 14.000 tons pre year, the main producing country is Canada, with the USA, Australia, Mexico, Japan and Peru also being the major suppliers Slide120

Anthropogenic

Cd

also available in the industries as an inevitable by-product of zinc, lead, and copper extraction

After being applied it enters the environment mainly through the ground and pesticides

Also produced during

metalliferous

mining and smeltingSlide121

Pathways

Cd

waste streams from the industries mainly end up in soils

The causes of these waste streams are for instance zinc production, phosphate ore implication and bio industrial manure

Cd

waste stream may also enter the air through (household) waste combustion and burning of fossils fuels

Because of regulations only little cadmium now enters the water through disposal of waste water from households or industries

Another important source of cadmium emission is the production of artificial phosphate fertilizersSlide122

Pathways

Part of the

Cd

ends up in the soil after the fertilizers is applied on farmland and the

restg

of the cadmium ends up in surface waters when waste from fertilizers productions is dumped by production companies

Cd

can be transported over great distances when it is absorbed by sludge. This

Cd

rich sludge can pollute surface water as well as soilsWhen Cd is present in soils it can be extremely dangerous, as the uptake through food will increase Soils that are acidified enhance the Cd uptake by plants

This is a potential danger to the animals that are dependent upon the plants for survivalSlide123

Pathways

Animal eating or drinking cadmium sometimes get high blood pressure, liver diseased and nerve or brain damage

The susceptibility to

Cd

can vary greatly between aquatic organisms

Salt water organisms are known to be more resistant to

Cd

poisoning than fresh water organismsSlide124

Pathways

Cd

can accumulate in their bodies, especially when they eat multiple plants

Cows may have large amounts of

Cd

in their kidneys due to this earthworms and other essential soil organisms are extremely susceptive to

Cd

poisoning

They can die at very low concentrations and this has consequences for he soil structure

When Cd concentrations in soils are high they can influence soil processes of microorganisms and threat the whole soil ecosystemIn aquatuic ecosystem Cd can bio accumulate in muscles, shrimps, lobsters and fishSalt water organisms are known to be resistant to

Cd

poisoning than fresh water organismsSlide125

Health effect of

Cd

Human uptake of

Cd

takes place mainly through food chain

Foodstuffs that are rich in

Cd

can greatly increased the

Cd

concentration in human bodiesExamples are liver, mushroom, shellfish, and dried seaweedAn exposure significantly higher Cd levels occurs when people smokeTobacco smoke transport Cd into the lungs Blood will transport it through the rest of the body where it can increase effects by potential Cd

that is already present from

Cd

-rich foodSlide126

Health Effects of

Cd

This may even cause death

Cd

is

firstg

transported to the liver

thropugh

the blood

It is then bounded to proteins to form complexes that are transported to the kidneysCd accumulates in kidneys, where it damages filtering mechanismsThis causes the excretion of essential proteins and sugar from the body and further kidney damageIt takes a very long time before cadmium that has accumulates in kidneys is excreted from a human bodySlide127

Health effects of

Cd

Other exposures can occur with people who live near

harzadeous

waste sites or factories that releases

Cd

into the air and people that work in the metal refinery industry

When people breathe in cadmium it can severely damage the lungsSlide128

Health effects of

Cd

Other health effects that can be caused by

Cd

are

Diarrhea, stomach pains and severe vomiting

Bone fracture

Reproductive failure and possibly even infertility

Damage to the central

nevours systemDamage to the immune systemPsychological disordersPossibly DNA damage or cancer developmentSlide129

Dust emission in mining and mineral processing and the fate of inhaled particles

Silicosis

Asbestosis

Coal workers pneumoconiosisSlide130

Silicosis

Silica is like asbestos, can result in the development of fibrotic lundg disese and results into a disease known as Silicosis

Natural Sources: Rock , sand and soil

The most common of crystaline silica is known as quarts

Inhailation of air born dust, that contain crystalline silica can occur in a wide variety of settings:

- mining, quarrying and stone cutting, founry operations, paint-blasting and sand blasting, glass manufacturing and etching and some types construction workingsSlide131

Three types of Silicosis

Chronic, acute and accelerated silicosis

Chronic silicosisA progressive lung disease, characterized by the development of

fibrotic tissue in response of inhalation of quarts particles in the size of 0.5 – 0.7 micrometer

Heart and respiratory failure is the consequences of these type of silicosisSlide132

Acute silicosis

In workers exposed to exceptionally high concentrations of fine particles of silica, usually quarts dust

The lungs are often heavy and rigid as the air spaces are filled a finely granular substancesSlide133

Accelerated silicosis

Is intermediate between chronic and acute silicosis

Develops after 5 -10 years of heavy exposure to silica dust grater than 1.0 micrometer of almost pure quarts

They show no clinical abnormalities other than breathlessness

Death by cardiopulmonary failure within ten years of onset of symptoms is often the outcome of this form of silicosisSlide134

Asbestos

Asbestos is the name of a group of highly fibrous minerals

Separable, long and thin fibers

Fibers are strong enough and flexible enough to be woven

Asbestos fibers are heat resistant, making them useful for may industrial purposes

Because of their durability, asbestos fibers that get into lung tissue will remain for long periods of timeSlide135

Types of Asbestos

Amphibolite

– fibers stay in lthe

lungs longer than

chrysolite

– this tendency may account for their increased toxicity

Example; Brittle crystalline fibers amphibole minerals (

actinolite

,

tremolite, anthophylite, crocidolite and amosite asbestos)Chryssolite – less toxic , e.g. serpentine mineral with long and flexible fibersSlide136

Exposure to Asbestos

We are all exposed to low levels of asbestos in the air

Much more concentrated levels of exposure are known to cause health effects in humansSlide137

Anthropogenic exposure

Anthropogenic exposures asbestos product

manufacturing (insulation, roofing, building materials)

Automotive rep air (breaks and clutches)

Minig

operations

Railroads

Sand or abrasive manufactures

Shipyards/ships/

Steel millsSlide138

Amphibole exposure

Mining activities:

Exposure to tremolite

asbestos can occur in workers involved in mining . Milling, and handling of other ores and rocks containing

tremolite

asbestos (such as

vermuculite

or talc)

Residence who live near milling, milling or manufacturing sitesSlide139

Amphibole Asbestos exposure

Insulation and building materials – amphibole asbestos can be found in a variety of building materials such as insulation, ceiling boards, , floor tiles and cement pipes

Occurs in some

vermuciulite

sources used as home and building

insilationSlide140

Amphibole asbestos exposure

Consumer Products –

Vermuculite

was also commonly sold in gardening and hardware stores

It was used as to improve soil quality or fertilizers carrier

Small amounts of amphibole asbestos have been found in some talc containing crayons

Manufactures of these crayons agreed to eliminate talc from their productsSlide141

Health effects

Significant exposure to any type of asbestos will increase the risk of lung cancer,

mesothelioma

and

nonmaligmant

lung and pleural

dissorders

,

This include asbestosis, pleural plaques, pleural thickening, and pleural effusions (5 to 1,200

fiberyear/mL)Such exposure will result from 40 years of occupational exposure to air concentrations of 0.125 to 30 fiber/mL diseases from asbestos exposure takes a long time to developMost cases of lung cancer or asbestosis in asbestos workers occur 15 or more years after initial exposure to asbestosSlide142

Health Effects

Tobacco smokers are at far greater risk-than non-smokers who has been exposed to asbestos

Diagnosis of

mesothelioma

from exposure to asbestos commonly has been 30 years or moreSlide143

Asbestos Facts

When asbestos fibers are inhaled, most fibers are expelled, but some can be lodged in the lungs and remain there throughout life. Fibers can accumulate and cause scaring and

inflamation

Inhaling longer, more durable asbestos fibers ( such as

tremolite

and other amphiboles) contributes to the severity of asbestos-related disorders

Exposure to asbestos, including

tremolite

,

camincrease the likelihood of lung cancer, mesothelioma, ond nonmalignant lung conditions such as asbestosisSlide144

Fluorosis

Acid Mine DrainageSlide145

Fluorosis

A form of enamel hypomineralization leading to discoloration due to excessive ingestion of fluoride during the development of the teeth

It is caused by over exposure to fluorides from all sources ;

Fluoridated water, Fluoride toothpaste, Mouth rinses, tablets, gels, sealants,

Foodstuffs: tea, medicines, anaetsthetic, pesticides, , herbicides, polluted air/dust/fumes

This condition can manifest in the form of skeletal fluorosis and dental fluorosis

The damage caused by fluorosis is permanent

Prevention is crucialSlide146

Asbestos Facts

Changes in the lining of the lungs (pleural) such as thickening , plaques, calcification, and fluid around the lungs (pleural effusion) may be early signs of asbestos exposure

These changes can affect breathing

Pleural effusion can be an early warning sign for

mesothelioma

(cancer of the lining of the lungs)Slide147

Asbestos Facts

Most cases of asbestos or lung cancer in workers occurred 15 years or more after the person was first exposed to asbestos

Most cases of

mesothelioma

are diagnosed 30 years or more after the first exposure to asbestos

Mesothelioma

has been diagnosed in

asbesos

workers family members, and residents who live close to asbestos mines

Health effects from asbestos exposure may continue to progress even after exposure is stoppedSmoking or cigarette smoke, together with exposure to asbestos, greatly increases the likelihood of lung cancerSlide148

Dental Fluorosis

It is sometimes called enamel fluorosis

It starts with small marks and sports on teethMild transparency of the tooth enamel

If allowed to progress the teeth will become pitted, cracked and brittle

Dental fluorosis usually appears before skeletal fluorosisSlide149

Skeletal fluorosis

Fluoride attacks the bones of the body

It causes brittle bones and joint painTricky to identify as other diseases may cause the same symptoms

In regions where it is endemic it is easily detected

Some tomes x-ray might be done to visualize the bonesSlide150

Importance of fluoride

It is an important dietary

Effective in cavity preventionThe fact that fluorosis exists , is not a reason to stop using fluoride in dental care

But just to be careful

Fluoride filters can be used to reduce the content of fluoride in fluoridated waterSlide151

Acid mine drainage Slide152

Geological aspects of waste disposal including radioactive waste Slide153

Uranium

Geogenic sources of uranium