in the name of god 1 st session: prrinciples of environmental health
TRANSCRIPT
IN THE NAME OF GOD
1st session: PRRINCIPLES OF ENVIRONMENTAL HEALTH
BIRTH, LIFE, DEATH AND ENVIRONMENT
• The life expectancy was short in the beginning, but enough for to survival and reproduction of human beings. They had to cope with:– Constant search for sufficient food and drinking water
while avoiding natural toxins– Infections and parasites– Injuries and animal attacks– Cold and hot temperature, rain, snow, disasters, …
• All of fore mentioned “HAZARDS” occurred in “NATURAL LIVING ENVIRONMENT” but now “MODERN HAZARDS” are emerging and may overtake this “TRADITIONAL HAZARDS” in some societies
BIRTH, LIFE, DEATH AND ENVIRONMENT-continued
INCREASE IN LIFE EXPECTANCY
• Why?–Improvements made in the living
environment,
–Improvements in nutrition,
–Improvements in medical cares,
• Or all of them?
DOMAIN OF ENVIRONMENTAL SCIENCES
• Studying hazards in the environment, their health effects and the variations in sensitivity to exposures within populations
• Development of effective means to protect against hazards in the environment
ECOSYSTEM
• A system of dynamic interdependent relationships among living organisms and their environment
• It has self stabilizing mechanisms and internal balance
• Its capacity to sustain changes and cope with them is limited
HEALTH AND ENVIRONMENT
• Health is: “a state of complete physical, mental and
social well being and not merely the absence of disease or infirmity” WHO
Environment is :“all that is external to the individual human
host. It can be divided into physical, biological, social, cultural, etc., any or all of which can influence health status in populations” last,1995
IMPACTS OF ENVIRONMENT ON HEALTH
• Hundreds of millions of peoples suffer from respiratory diseases associated with indoor and outdoor air pollution
• Half a million people are dying prematurely world-wide from exposure to air pollution, much of it linked to increased car density.
• Hundreds of millions of peoples are exposed to unnecessary physical and chemical hazards in the living environment
• Half of a million die as a result of road accident• Four million infant and children die from diarrhea diseases• …
INTERACTIONS BETWEEN HUMAN ACTIVITIES, HEALTH AND ENVIRONMENT
The scale and nature of human activities
Physical and chemicalenvironment
Biologicalenvironment
Health
SUSTAINABLE DEVELOPMENT
• Development that meets the needs of the present without compromising the ability of future generations to meet their own needs
CONCEPT OF SUPPORTIVE ENVIRONMENT
• How good environment enhance health• Building health housing, promoting healthy life
styles, cleaning up industrial pollution, reducing traffic hazards, reducing tobacco smoking and changing dietary habits
• In poor communities the most important issues may be basic sanitation and water supply, improved maternal and child health care, and control of communicable diseases
BASIC REQUIREMENTS FOR A HEALTTHY ENVIRONMENT
• Clean air
• Safe and sufficient water
• Adequate and safe food
• Safe and peaceful settlement
• Stable global environment
• WHO has published global estimates of burden of disease caused by 25 risk factors in the World Health Report 2002.
• seven of these risk factors are environmental
ENVIRONMENTAL BURDEN OF DISEASE
Ambient air Indoor air Lead Water, sanitation and hygiene Climate change Food safety Selected occupational risks,including:
Injuries , Carcinogens, Selected airborne particulates, Ergonomic stressors, Sharps injuries in health-care workers
ENVIRONMENTAL BURDEN OF DISEASE - SEVEN ENVIRONMENTAL RISK FACTORS
ENVIRONMENTAL BURDEN OF DISEASE - other risk factors
• UV radiation
• Recreational water quality
• Fluoride in drinking water
• Arsenic in drinking water
• Community noise
• Nutrition
ENVIRONMENTAL BURDEN OF DISEASE - METHODOLOGY
Using :
Disability-Adjusted Life Year (DALY) that combines the burden due to death and disability in a single index. Using such an index permits the comparison of the burden due to various environmental risk factors with other risk factors or diseases.
• 25-33% of the global burden of disease can be attributed to environmental risk factors.
• Children under 5 years of age seem to bear the largest environmental burden, and the portion of disease due to environmental risks seems to decrease with economic development.
Kirk R. Smith, Carlos F. Corvalan, and Tord Kjellstrom.Epidemiology 1999;10:573-584
ENVIRONMENTAL BURDEN OF DISEASE
2nd , 3rd session
water
Water Scarcity“Water is life”
Prof Kader Asmal, Chairman, World Commission on Dams
“Whiskey is for drinking, water is for fightin’ over”Mark Twain, commenting on water conflicts in the
American Midwest
“We have one common goal: to provide water security in the 21st Century”Ministerial Declaration of The Hague, World Water
Forum, April 2002
What is Scarcity?
Water shortage, water scarcity, and water stress are three terms used in the discussion of how to meet human water needs
Assuming a minimum need for renewable water per person of 1,000 cubic meters:20 countries, mostly in the Middle East and
North Africa (MENA), are at or below this level now
What is Scarcity?
At 2,000 cubic meters per person:
water is potentially a serious constraint, especially in drought years, and about 40 countries fall in this range, according to the FAO.
While these may be reasonable benchmarks for water shortage, the issue really is one of supply and demand, and so scarcity is a relative term
What is Scarcity?
From a water planning perspective, it is argued that– shortage is absolute– scarcity is relative– stress is a sign of approaching scarcity or
shortage
For example, Tunisia and Kenya both have water availability less than 1000 m3 per capita, but demand is less than supply
What is Scarcity?
Regardless of definition, in most areas:– demand is increasing faster than supply– so scarcity is increasing
Measures of ScarcityStress Level
Description People competing for a million m3 of water
Water availability per capita (1000s m3)
1 Water surplus < 200 >5
2 Water management
problems
200 - 600 1.67 – 5.0
3 Water stress 600 - 1000 1.0 - 1.67
4 Absolute scarcity 1000 - 2000 0.5 – 1.67
5 Beyond water barrier
> 2000 <0.5
Source: Falkenmark, 1989
Measures of Scarcity
Source: UNEP, 2002
Measures of Scarcity
Source: UN/WMO, 1997
Stress Level Description Demand/Supply
1 Low < 0.1 or 10%
2 Moderate 0.1 to 0.2
3 Medium-high 0.2 to 0.4
4 High > 0.4 or 40%
Causes of Scarcity(assuming climate is constant)
• Agriculture
• Domestic water use
• Industrial water use
• Pollution
• Climate change
Causes of Scarcity
Source: Gleick et al., 2001
Pollution
Source: Gleick et al., 2001
Pollution
Percent population without access to adequate sanitation services
Source: Gleick et al., 2001
Morbidity and Mortality from Water-related diseases
Source: Gleick et al., 2001
Morbidity and Mortality from Water-related diseases
Source: Gleick et al., 2001
Types of Scarcity
• First order scarcity– a physical shortage of water
• Second order scarcity– an institutional inability to satisfy demand or
deliver clean water
• None of the maps shown take account of second order scarcity
Drop in Groundwater Level
Impacts of groundwater over-pumping
• Increased costs
• Decreased water quality
• Loss of farmland
• Subsidence
Subsidence
Water files-1-2
Distribution of Precipitation Versus Surface Area of Watersheds
28.00%
47.00%
16.00%
8.00%
1.00%
<100mm/y
100-250mm/y
250-500mm/y
500-1000mm/y
>1000mm/y
An
nu
al P
reci
pit
atio
n,
(mm
/yea
r)
Surface Area of Watersheds(%)
Proportion of Evaporation toTotal Precipitation in Iran
Total Precipitation = 413 Billion Cubic Meter
Evaporation
Effective Precipitation
Effective Precipitation = 28%Quantity = 117 Billion Cubic MeterAverage Precipitation = 70mm/y
Evaporation = 72%
Quantity = 296 Billion Cubic Meter
Urban & Rural Population in Iran
Year
PO
PU
LA
TIO
N
)M
illio
n(
0
10
20
30
40
50
60
70
1966 1991 2005
Urban
Rural
Total
37.87%
2574400057.02%
55837000
67000000
64.9%
Population increase in some dry provinces during 1966-2003
po
pu
lati
on
(m
illi
on
)
Province
0.2
21
0.9
4
0.5
42
1.2
84
2.9
46
6.4
44
0.8
25
2.2
19
1.0
12
2.3
8
0.1
76 0.5
79
0
1
2
3
4
5
6
7
Yazd Hormozgan khorasan Sistan &baluchestan
Kerman Semnan
1966 2004
Water files-2
Population
5.953
9.407
15.855
26.844
36.788
43
13.002
16.382
22.601 23.267 23.5
18.955
25.789
33.709
49.445
60.055
66.5
17.854
0
10
20
30
40
50
60
70
1956 1966 1976 1986 1996 2003
YEAR
Po
pu
lati
on
(M
illio
n)
Urban Population
Rural Population
Total
Available Fresh Water
6203
2025
816
0
1000
2000
3000
4000
5000
6000
7000
1950 1960 1970 1980 1990 2000 2010 2020 2030
Year
Qub
ic M
eter
per
Cap
ita/
Yea
r
Access to Piped Water (Urban)
97.7
98.5
100 100 100
96.5
97
97.5
98
98.5
99
99.5
100
2002 2006 2011 2016 2021
Year
Per
cen
t
Access to Piped Water (Rural)
84
88
95
98100
75
80
85
90
95
100
105
2002 2006 2011 2016 2021
Year
Pe
rce
nt
Access to Sanitary Sewage Disposal Services (Urban)
19
30
45
5560
0
10
20
30
40
50
60
70
2002 2006 2011 2016 2021
Year
Pe
rce
nt
Access to Sanitary Sewage Disposal Services (Rural)
0.5 2
15
25
30
0
5
10
15
20
25
30
35
2002 2006 2011 2016 2021Year
Perc
en
t
Water Loss Through Distribution Network
2725
22.520
18
0
5
10
15
20
25
30
2002 2006 2011 2016 2021Year
Perc
en
t
Wastewater Generation
8
5.2
4
3
4
5
6
7
8
9
1994 1996 1998 2000 2002 2004 2006 2008 2010 2012
Year
Was
tew
ater
Gen
erat
ion
(B
illi
on Q
ubic
Met
er/Y
ear)
Coverage of Collection System (2003)
20%
80%
Collected
Not Collected
Treated & Untreated Sewage (2003)
8%
92%
Treated
untreated
Water Exploitation
47613
3895244638
90000
50171.5
45000
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
100000
Surface Water Ground Water
Water Resource
Wat
er E
xplo
itat
ion
Mil
lio
n Q
ub
ic M
eter
1989
1994
Avalable
Water files-3
Attention: It has PDF file
Water-borne DiseasesBy Ramin Nabizadeh
Diseases Related to Water
Water-borne Diseases
Water-washed Diseases
Water-based Diseases
Water-related Diseases
Water-borne Diseases
Diseases caused by ingestion of water contaminated by human or animal
excrement, which contain pathogenic microorganisms
Include cholera, typhoid, amoebic and bacillary dysentery and other diarrheal
diseases
Diarrheal Diseases
• Giardiasis (Protozoan)
• Cryptosporidiosis (Bacteria)
• Campylobacteriosis (Bacteria)
• Shigellosis (Bacteria)
• Viral Gastroenteritis (Virus)
• Cyclosporiasis (Parasite)
In addition, water-borne disease can be caused by the pollution of water with
chemicals that have an adverse effect on health
• Arsenic
• Flouride
• Nitrates from fertilizers
• Carcinogenic pesticides (DDT)
• Lead (from pipes)
• Heavy Metals
Water-washed Diseases
Diseases caused by poor personal hygiene and skin and eye contact with
contaminated water
These include scabies, trachoma, typhus, and other flea, lice and tick-borne
diseases.
Water-based Diseases
Diseases caused by parasites found in intermediate organisms living in
contaminated water
Includes Schistosomiasis and Dracunculiasis
Water-related Diseases
Water-related diseases are caused by insect vectors, especially mosquitoes, that breed
or feed near contaminated water.
The Problem
• ~80% of infectious diseases • > 5 million people die each year • > 2 million die from water-related diarrhea
alone • Most of those dying are small children
Other Consequences
• Lost work days
• Missed educational opportunities
• Official and unofficial healthcare costs
• Draining of family resources
Control & Prevention
Global
Governments
Communities
Individuals
Education Issues
• Hygiene education
• Good nutrition
• Improvements in habitation and general sanitation
• Higher education training in water-related issues
Global Surveillance
• Public health infrastucture
• Standardized surveillance of water-borne disease outbreaks
• Guidelines must be established for investigating and reporting water-borne diseases
The Future
Even if by the year 2015 the proportion of people who are unable to reach or to afford safe drinking water is halved,
between 34 and 76 million people, mostly children, will die from preventable water-
borne diseases
More Challenges
• Developed countries and chlorine-resistant microbes
• Climate Changes
• Economic barriers for developing countries to sanitize large amounts of water
Climate Change
• Water scarcity compromises hygiene
• Reduced water pressure increases risk of back siphoning of contaminated water
• Floods causing breaching of barriers between sewage and water systems
• Warming/cooling changes distribution of pathogens and vectors
• Increased UV exposure resulting in increased susceptability to disease
• Increased mutation rates with unpredictable effects on ecosystems (pathogen development)
Water files-4
AST324 \ Presentations \ WQ Standards.ppt
80
WATER QUALITY STANDARDS: WHAT ARE THEY GOOD FOR?
• A basis for assessing water quality data
• A "trigger" for initiating action
• An "end point" for terminating action
• A regulatory/ educational tool
Standards are targeted at a particular end use
• Drinking water - human/ livestock
• Fish and Wildlife
• Crop production : irrigation
• Industrial processing
• All standards must be performance based, especially health based standards.
TYPES OF DRINKING WATER STANDARDS
• PRIMARY
– health related
– enforced
TYPES OF DRINKING WATER STANDARDS
• SECONDARY– non-health related contaminants that
affect flavor, odor, color– iron– manganese– sulfate– hydrogen sulfide– chloride– recommended but not enforced
KINDS OF HEALTH RELATED STANDARDS
• Maximum Contamination Levels Goals (MCLG's)– Level at which there are no known or
anticipated adverse health effects.– non-enforceable– set at 0 for known carcinogens
KINDS OF HEALTH RELATED STANDARDS
• Maximum Contamination Level (MCL's)– set as close to the MCLG as is technically
and economically feasible– enforceable
Drinking Water Health Advisories (HA)
• Lifetime HA: The concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects over a lifetime of exposure, with a margin of safety.
Drinking Water Standards (EPA, May 1995)
A. Chemical1. Maximum Contaminant Level (mg/ L) lead .015 mercury .002 nitrate (as N) 10.0 nitrite (as N) 1.0 alachlor (lasso) 0.002 aldicarb 0.007 atrazine 0.003 carbofuran (Furadan) 0.04
Drinking Water Standards (EPA, May 1995)
2. Secondary Maximum Contaminant Level (mg/ L) chloride 250 copper 1 iron 0.3 pH 6.5 to 8.5 sulfate 250 total dissolved solids (TDS) 500
Drinking Water Standards (EPA, May 1995)
B. Physical color 15 color
units odor 3 odor
unitsC. Bacteriological coliform bacteria none
Water files-5
Drinking-Water Standards
History Key Definitions How Standards are Developed Current Issues Confronting
Developers of Standards
Water Quality First Linked to Disease
1854 - Cholera epidemic in London linked to Broad Street Pump
1887 - Typhoid (Lawrence, Mass.) 1892 - Cholera (Hamburg, Germany) 1908 - Jersey City, NJ first community to
disinfect water with chlorine
1854 - Cholera epidemic in London linked to Broad Street Pump
1887 - Typhoid (Lawrence, Mass.) 1892 - Cholera (Hamburg, Germany) 1908 - Jersey City, NJ first community to
disinfect water with chlorine
Drinking Water Standards Development in U.S.
1914 - 1st Federal standards (applied only to interstate carriers)
U.S. Public Health Service Standards (revised 1925, 1946, 1956, 1962)
1974 - Federal Safe Drinking Water Act passed following EPA report of 66 potential carcinogens found in New Orleans water supply (act applies only to public supplies)
1986 - Safe Drinking Water Act Amended
Public skeptical of EPA and water industry Studies showed many systems with one or more
toxic chemicals Congress prescribes rigorous schedule for
establishing standards 83 contaminants named for standards development filtration of surface water supplies mandated EPA directed to establish 25 new standards every
three years
Growth in Number of Drinking Water Standards
22 22 3034
62
87
111
133
158
183
0
20
40
60
80
100
120
140
160
180
200
# C
on
tam
inan
ts R
egu
late
d
Pre
-19
86
19
86
19
87
19
89
19
91
19
92
19
93
19
94
19
97
20
00
Year
Assumes SDWA Reauthorization(failed in 1994)
Definitions Primary drinking water contaminant - health-
related, enforced Secondary drinking water contaminant - non-
health-related, not enforced
Definitions Maximum Contaminant Level Goal (MCLG) - A non-
enforceable regulatory goal designed to prevent adverse human health effects and allow an adequate margin of safety (MCLG = 0 for any carcinogen)
Maximum Contaminant Level (MCL) - maximum permissible level of a contaminant in water delivered to any user of a public water system (set as close to MCLG as is technically and economically feasible)
Lifetime Health Advisory Level (HAL) - non-regulatory concentration of drinking water contaminant that is not expected to cause any adverse effects over a lifetime of exposure.
Standards for Non-Carcinogens Based on Dose/Response Studies Assume a response “threshold” can be
identified Uses a “Safety Factor” approach to
calculate the standard
Dose/Response Testing
Threshold or NOAEL(no observed adverse affect level)
Dose
Res
po
nse
Definitions Reference Dose (RfD) - the daily exposure
without deleterious effects over a lifetime Drinking Water Equivalent Level (DWEL) -
drinking water concentration assuming RfD for 70 kg adult is dissolved in 2 liters of water assumed to be consumed daily
Lifetime Health Advisory (HAL) - determined by applying relative source factor (generally 20% for organics, 10% for inorganics) to the DWEL
Calculating Reference Dose RfD(mg/kg/day) = NOAEL(mg/kg/day) /
Safety Factor Safety factor of 100 usually used
factor of 10 for human/animal response differences
factor of 10 for inter-individual response differences
additional safety factor of 10 applied if data are questionable
Calculating DWEL & HAL
HAL(mg/L) = DWEL(mg/L) X RSC
Relative Source Factor
Daily Water Consumption (2 L)DWEL(mg/L)=
RfD(mg/kg/day) X Body Wt (kg)
20% for organics10% for inorganics
Example Calculation
NOAEL for Aldicarb = 0.125 mg/kg/day RfD = NOAEL/Safety Factor = 0.125/100 = 0.00125 mg/kg/day
DWEL = [RfD X Body Wt.] / 2 Liters = [0.001 mg/kg/day X 70 kg] / 2 L = 0.035 mg/L
Lifetime HAL = DWEL X Source Factor = 0.035 mg/L X 0.2 = 0.007 mg/L
Drinking Water Standards for Carcinogens
5 EPA Cancer Groups A - Known human carcinogens B - Probable human carcinogens C - Possible human carcinogens D - Not classifiable E - No evidence of human carcinogenicity
Drinking Water Standards for Carcinogens
Based on Dose/Response Studies But assume that NO response threshold
can be identified (ie any dose poses some risk)
Use mathematical models to extrapolate animal D/R data to the low risk levels considered acceptable for humans
Why Assume No Theshold for
Carcinogens? High natural incidence of tumors in all species
makes threshold hard to define (requires large number of animal studies)
Practical doses that lead to identifiable numbers of excess tumors in small animal populations are much higher than doses of interest in minimizing cancer risk to humans
D/R Modeling for Carcinogens Several math models have been
proposed...risk estimates from different models can vary by as much as 1,000,000 fold
Model Lifetime Risk@ dose = 1 mg/kg/day
One - hit 6.0 X 10 -5
Linear Multistage(used by EPA)
6.0 X 10 -6
Multihit 4.4 X 10 -7
Weibull 1.7 X 10 -8
Probit 1.9 X 10 -10
Drinking Water Standards for Carcinogens
D/R relationship generally treated as linear risk = dose X constant so if dose increases 10-fold ... risk also
increases 10-fold EPA sets lifetime health advisories at 1 in 1-
million risk level, but MCL’s often set at higher risk level due to technical or economic considerations
Current Scientific Issues in Drinking Water Standards Development
Can cancer “thresholds” be identified? How to set “standards” for mixtures of
contaminants Highly sensitive (and inexpensive) new water
testing methods (ELISA) making pesticide testing more affordable
Establishing standards for new chemicals and chemical metabolites
Water files- 6
DRINKING WATER TREATMENT PLANT
HOW DOES IT WORK?HOW DOES IT WORK?
Typical Water Treatment PlantTypical Water Treatment Plant
WaterWater
sourcesource
Rapid MixRapid Mix FlocculatorsFlocculators
Sedimentation basinSedimentation basin
FilterFilter
ClearwellClearwell
WATER SOURCE
– GROUND WATER
• WATER WELLS
– SURFACE WATER
• RIVERS
• LAKES
• SPRINGS
– GROUND WATER
• WATER WELLS
– SURFACE WATER
• RIVERS
• LAKES
• SPRINGS
Rapid MixRapid Mix
• Also called a flash mix.• Basin or tank where chemicals are added to
the water.– Chemicals promoted coagulation and
disinfection.– Some chemicals are chlorine, potassium
permanganate, activated carbon, etc…
• Water stays in basin a maximum of 60 seconds.
Rapid Mix ExampleRapid Mix Example
CoagulantsCoagulants
Disinfectant - ChlorineDisinfectant - Chlorine
Oxidizing AgentsOxidizing Agents
Taste and odor control Taste and odor control (Carbon)(Carbon)
Raw water coming Raw water coming from river, lake, from river, lake, reservoir, or well.reservoir, or well.
Water goes Water goes to flocculator.to flocculator.
Coagulation and FlocculationCoagulation and Flocculation
• Water sources, polluted by man and nature are likely to contain suspended particles such as organic and inorganic materials.
leavesleavesbacteriabacteriavirusesvirusesinsectsinsectssilt or mudsilt or mud
Coagulation and Flocculation (cont.)Coagulation and Flocculation (cont.)
• Coagulation and flocculation are used to remove materials, especially non-settleable solids, and color from water.
• Chemicals cause the particles to clump together forming floc. When pieces of floc clump together with the use of flocculators (ex. rotating paddles), they form larger, heavier floc which settle out.
Flocculation ExampleFlocculation Example
Water coming from Water coming from rapid mix.rapid mix. Water goes to sedimentationWater goes to sedimentation
basin.basin.
SedimentationSedimentation
• Sedimentation allows water containing heavy floc to move across a basin at a much slower velocity.
• Because of gravity, the heavy floc particles will move (settle) toward the bottom of the sedimentation basin.
• After the particles ‘settle out’ the sludge is then removed from the bottom of the basin.
Sedimentation Basin ExampleSedimentation Basin Example
Water coming from flocculation basin.
Water goes to filter.
Settling TubesSettling Tubes
FiltrationFiltration
• Filtration removes particles and floc that were not completely settled out during the sedimentation process.
• Water passes through materials such as a bed of fine sand, coal, or other granular substance. Particles will be removed through adsorption, absorption, and straining.
Filter ExampleFilter ExampleWater coming from sedimentation basin.
Fine Sand
Coarse Sand
Gravel
Water going to clearwell.
ClearwellClearwell
• Filtered water (also called finished water) is stored in the clearwell.
• Disinfectant (usually chlorine) is added to kill disease-carrying organisms which may not have been removed.
• Usually, the clearwell is baffled to provide a longer amount of time for disinfectant to have contact with the water.
Clearwell ExampleClearwell Example
Water coming from filter.
Watergoing tocustomer.
Water is Recycled
• Water is taken from the source, treated, then sent to the customer for consumption.
• After the water is used, it goes to the wastewater plant for treatment and is discharged back to the river.
Wastewater ProblomMPH-1386
Ramin Nabizadeh
4th sessionwaste water
Wastewater Characteristics
• Wastewater Composition– Key design issues:
• Solids: density, particle size, level of Volatile Suspended Solids
• Biochemical Oxygen Demand• Micro-organism (Pathogens)• Ammonia• Nutrient (Nitrogen & Phosphorus
WATERBORNE DISEASE
• The global availability of clean drinking water is the primary water pollution problem today
• Many serious human diseases and epidemics are caused by waterborne pathogens.
.
Sewage
You could become ill by coming into contact with micro-organisms present in the sewage -
• Bacteria• Viruses• Parasites
How you become infected
eating, drinking, smoking, wiping the face with contaminated gloves
cuts, scratches or wounds and some organisms enter the body through the eyes
either as dust or mist
• Hand-to-mouth contact
• Skin contact
• Breathing
WATERBORNE DISEASE
B. FECAL COLIFORM BACTERIA• A fecal coliform bacteria count is the standard
measure of microbial pollution and disease potential in a source of drinking water.
• Though not themselves pathogenic, the presence of fecal coliform bacteria indicates that water is contaminated with human and/or animal waste that may carry pathogens.
BIOCHEMICAL OXYGEN DEMAND (BOD)
• The biochemical oxygen demand (BOD) is the amount of oxygen required for the bacterial decomposition of organic matter in water.
• Natural sources, agricultural runoff, and human sewage contribute to the BOD of bodies of water.
• An excessive BOD causes water’s dissolved oxygen content to fall below the level needed to support the entire biological community.
BIOCHEMICAL OXYGEN DEMAND (BOD)
• A sudden discharge of organic matter, such as raw sewage, into a waterway produces three zones: a pollution zone, an active decomposition zone, and a recovery zone.
• Streams are naturally able to degrade organic waste; however, when this capacity is exceeded, the stream’s recovery may be delayed and many organisms destroyed.
© 2003 John Wiley and Sons Publishers
Fig 21.3 Relationship between dissolved oxygen and biochemical oxygen demand (BOD) for a stream following the input of sewage.
NUTRIENTS
• Excessive levels of nutrients, particularly nitrogen and phosphorus, can lead to serious water pollution problems such as eutrophication.
A. MEDICAL LAKE: AN EXAMPLE• While not directly harmful to aquatic life,
excess nutrients can severely disrupt and damage an aquatic ecosystem
NUTRIENTS
B. EUTROPHICATION• Eutrophication is the process by which
excess nutrients stimulate the growth of aquatic plants, which then decompose; this bacterial decomposition raises the BOD and may lead to a die-off of many aquatic species.
• Eutrophication may be a natural process or cultural in origin.
© 2
003
John
Wil
ey a
nd S
ons
Pub
lish
ers
Fig 21.7 The eutrophication of a lake.
SEDIMENT
• Sediment, tiny rock and mineral particles carried by water, is our greatest (in volume and mass) water pollutant.
• Excessive sedimentation of waterways not only reduces water quality but also represents loss of soil at the point of origin
SURFACE-WATER POLLUTION
• Surface waters become polluted when their capacity to dilute, remove, or convert a harmful substance to tolerable levels is exceeded.
• Point sources of water pollutants are distinct, discrete outlets such as pipes or wells.
• Nonpoint sources of pollution are diffuse and intermittent and may be influenced by a variety of natural and human land-use factors; these sources include urban runoff, agriculture, mining, and forestry.
SURFACE-WATER POLLUTION
• Because of their diffuse nature, nonpoint sources are generally more difficult to monitor and control than are point sources.
• Water pollution can be addressed by source reduction or treating polluted water to remove or convert pollutants.
• Running water such as in rivers and streams generally responds more quickly and completely to cleanup efforts than does still water such as in lakes and ponds.
GROUNDWATER POLLUTION
• Groundwater, a vital source of drinking water in the IRAN, can be contaminated by any number of toxins as a result of land-use and waste disposal practices.
• Bacterial breakdown of pollutants does not generally occur in the anaerobic environment of groundwater.
• Because groundwater (versus surface water) moves slowly, pollutants that reach it may remain concentrated for long periods.
GROUNDWATER POLLUTION
• A. PRINCIPLES OF GROUNDWATER POLLUTION: AN EXAMPLE
• The cleanup of groundwater contaminated by leaking underground storage tanks illustrates the complexity of remediation efforts.
WATER REUSE
• Water reuse is the use of wastewater after treatment.
• Reuse may be inadvertent, in which case risks may be present; indirect, with several planned intermediate stages between use and reuse; or, direct, when treated wastewater is piped directly to a user.
© 2003 John Wiley and Sons Publishers
Fig 21.23 Components of a resource recovery wastewater treatment plant.
© 2003 John Wiley and Sons Publishers
Fig 21.22 The wastewater renovation and conservation cycle.
© 2003 John Wiley and Sons Publishers
Fig 21.20 Septic-tank sewage disposal system and location of the absorption field with respect to the house and well.
WASTEWATER TREATMENT
B. WASTEWATER TREATMENT PLANTS
• In urban or more densely developed rural areas, sewage is collected through pipes and sent to a wastewater treatment plant, where treatment proceeds through primary, secondary, and sometimes advanced stages.
FOUR STAGES IN THE TREATMENT OF SEWAGE Preliminary treatment Involves screening for large objects, maceration and the separation of storm flows.Primary treatment (sedimentation)Suspended solids are separated out as sludge.Secondary (biological) treatmentDissolved and colloidal organics are oxidised in the presence of micro organisms.Tertiary treatmentWhen a high quality effluent is required. It may involve the removal of further BOD, bacteria, suspended solids, specific toxic compounds or nutrients.
PRELIMINARY TREATMENT
•Screening – physical removal of relatively large or heavy solid e.g. rags.
•Achieved by passing through 75-100 mm screens.
•No real reduction in BOD.
1. Preliminary treatment
•Solids removal
•Grit settling
•Flow rate control
WASTEWATER TREATMENT
1. Primary Treatment
• Primary sewage treatment mechanically removes up to 40% of wastewater pollutants through use of screens and settling (sedimentation) tanks.
PRIMARY TREATMENT
• Slowing the sewage flow down.
•Sewage is ‘kept’ in a chamber.
•~ 60 % SS removed and 30-50 % of BOD removed.
2. Primary settlement
•Solid particles settle out by gravity
•Settling tank
•Horizontal flow
•Upward flow
•Radial flow
WASTEWATER TREATMENT
2. Secondary Treatment
• Effluent from primary treatment enters secondary treatment, usually consisting of activated sludge chambers where the wastewater is mixed with bacteria and oxygen, promoting bacterial digestion of nutrients.
• After secondary treatment, which removes up to 90% of the wastewater’s original pollution, the effluent is disinfected, then discharged into a receiving waterway; sludge is digested, dried, and landfilled or used as a soil conditioner.
3. Secondary treatment
1. Fixed film systems - (trickling filter)
2. Suspended film systems (activated sludge)
3. Lagoon systems
Trickling filter
SECONDARY TREATMENT
Trickling filter
Activated Sludge
Both biological treatments as they depend on microbes breaking down organic material to CO2 and H2O.
Secondary Treatment
• Utilizes the biological removal of dissolved organics
– About 90-95% reduction in BOD
– Several options are available• Aerobic treatment
– Produce cells
– CO2
• Anaerobic Treatement– Sludge– Fermentations– Acetate generation– Methane generation
Secondary Treatment
• Aerobic treatment– Activated Sludge
• A portion of the active biomass is returned to the system• Microorganisms are acclimated to the environment
Mixers for Aeration
Clarifier
Activated Sludge Return
Water fromPreliminary Treatment
Activated sludge
Secondary Treatment• Aerobic treatment
– Trickling Filter• Support material serves as the platform for attached growth• Organisms form Biofilms• Organics consumed as they pass
• Time to form biomass on the support media• Low food concentrations to high cells number and demand
Support MaterialMicrobial Growth
Secondary Treatment• Aerobic treatment
– Extended Aeration• Microbes degrade the dissolved organics• High oxygen requirement• Less sludge produced
Mixers for Aeration
Water fromPreliminary Treatment
Microbes degradeOrganics
Lyses of the Bacterial Cells
Released Nutrients
ACTIVATED SLUDGE PROCESS
•Primary effluent is mixed with a flocculent suspension of microbes and aerated in a tank (5-10 hours).
•Slime-forming bacteria including Zoogloea ramigera form flocs. Associated with the flocs protozoa and invertebrates.
•Secondary effluent then settled in a tank.
© 2003 John Wiley and Sons Publishers
Fig 21.21 Diagram of sewage treatment processes.
5. Sludge treatment
•Expensive-up to 50% of sewage treatment cost
•Type of treatment depends on disposal route
•In EU most is spread on farmland or sent to landfill
•In UK anaerobic digestions plants are common
SLUDGE
•Sludge is generated at both primary and secondary stages – decomposed anaerobically.•Sludge consists of protein, fats and polysaccharides.Two stages:First stage – digestion in closed tanks at 27 – 35 oC for 7-30 days, methane and CO2 produced.Second stage – sludge settles and thickens in open tanks for 20-60 days.
Secondary Treatment• Sludge treatment
– Anaerobic Digestors• Process the excessive amounts of biomass produceded• Fermentations
– Organics» Butyrate» Propionate» Lactate
• Acetogenic RXN– Butyrate, Propionate, Lactate, etc.
» Acetate» H2
» CO2
• Methanogenic– Acetate, H2, HCO3
-
– Methane
– This Sludge is returned to the start of the Secondary Treatment
SLUDGE DISPOSAL
• Dumping at sea banned in 1998 in the UK.
•Land use – fertilizer, restricted by heavy metal content and transport costs.
•Landfill – holes are running out/cost rising.
•Incineration - a popular option!
Anaerobic digestion
Aim: Optimisation of biological processes for maximum energy production
Organic matter + water CO2 + CH4 + NH4 + H2S
Requirements:
•Oxygen free
•No inhibiting salts
•6.5 < pH < 7.5
•Alkalinity 1500-7500 mg/l
•Nutrients eg. phosphorous, nitrogen
•Steady temperature
•Constant solids loading
3 stage process:
•Acidogenesis
•Acetogenesis
•Methane production
1. Hydrolysis and acidogenesis
In hydrolysis and acidogenesis (Fig. 4-1; Stage 1), sugars, ammo acids, and fatty acids produced by microbial degradation of biopolymers are successively metabolised by groups of bacteria and are primarily fermented to acetate, propionate, butyrate, lactate, ethanol, carbon dioxide, and hydrogen.
Digester types
1. Upflow anaerobic sludge blanket (UASB)
2. Upflow anaerobic filter process (UAFP)
3. Anaerobic fluidized bed process
4. Two phase methane fermentation process
SkimmerAnaerobic digesters
Methane collection
WASTEWATER TREATMENT
3. Advanced Wastewater Treatment
• Advanced wastewater treatment methods include use of filters and chemicals to remove remaining nutrients, heavy metals, and organic pollutants; this level of treatment is called for when the wastewater discharge must meet stringent quality standards
WASTEWATER TREATMENT
4. Chlorine Treatment
• The most common disinfectant for treated wastewater is chlorine; recent studies have raised concerns about its effect on aquatic life and on human health
TERTIARY TREATMENT
Refers to any or all of the following:
Further removal of BOD and SS.
Further removal of nitrates and phosphates.
Further removal of pathogenic microbes.
SEWAGE TREATMENT - SUMMARY
Three objectives in the treatment of sewage: • To convert sewage into suitable end products.• To produce a satisfactory effluent which can be discharged into a local watercourse.• To produce sludge which can be disposed.
WASTEWATER TREATMENT
Sludge Treatment
Primary Treatment Secondary Treatment
Coarse SolidsRemoval
Suspended SolidsRemoval
Soluble OrganicRemoval
NitrogenRemoval
PhosphorousRemoval
Coagulation & Sedimentation
Denitrification
Sedimentation
Flotation
Tricklingfilter
AeratedLagoon
Anaerobictreatment
Stabilizationbasins
ActivatedSludge
Aerobic orAnaerobicdigestion
Screening
Water pollution
Overview
• Definitions
• Surface Water Pollution
• Pollutants
• Groundwater Pollution
• Wastewater Treatment
Water Pollution
• 1.2 billion people worldwide do not have
access to clean water• Each day almost 10,000 children <5 years old
in Third World countries die as a result of illnesses contracted by use of impure water
Water Pollution
• Water Pollution = degradation of water quality
(biological, chemical, or physical)– Judged according to the use of the water
• Pollutant = any substance that in excess
is known to be harmful to life
Surface-Water Pollution & Treatment
• Point Source = specific, confined pollution– On-site clean-up; regulated by permit
Image: EPA
Groundwater Pollution
White lines of overlay is the surface
street layout
Zones of color show regions of
increasing groundwater
pollution(red = highest pollution; light blue = lowest)
Wastewater Treatment
• Septic systems used by 30% U.S. population• Failure may = surface or groundwater pollution
• Stability affected by geology:– Soil type– Depth to water
table– Depth to bedrock– Topography
Wastewater Treatment
"When the well "When the well is dry, we learn is dry, we learn the worth of the worth of water"water"- Benjamin Franklin- Benjamin Franklin
5th sessionglobal enviroment
Attention: it has WORD files
What is Acid Rain and What Causes It?
How Do We Measure Acid Rain?
What Are Acid Rain's Effects?
• Surface waters (e.g., lakes and streams) and animals living in them
• Forests
• Automotive Coatings (e.g., car paint)
• Materials
• Visibility
• Human Health
Where Does Acid Rain Affect Lakes and Streams? How Does Acid Rain Affect Fish and Other Aquatic Organisms? How Does Acid Rain Affect Ecosystems? What is the Role of Nitrogen in Acid Rain and other Environmental Problems? How is the Acid Rain Program Addressing These Issues?
Effects of Acid Rain: Lakes & Streams
• Where Does Acid Rain Affect Lakes and Streams?
• How Does Acid Rain Affect Fish and Other Aquatic Organisms?
• How Does Acid Rain Affect Ecosystems? • What is the Role of Nitrogen in Acid Rain and
other Environmental Problems? • How is the Acid Rain Program Addressing
These Issues?
How Does Acid Rain Affect Fish and Other Aquatic Organisms?
What Society Can Do About Acid Deposition
• Understand acid deposition's causes and effects
• Clean up smokestacks and exhaust pipes
• Use alternative energy sources
• Restore a damaged environment
• Look to the future
• Take action as individuals
Ozone Layer
• What Is Stratospheric Ozone?
• Ozone Depletion
• What Is Being Done?
• How Ozone Depletion Affects UV Levels?
Health Effect of UV Radiation
• Skin Cancer and Other Skin disorders
– Melanoma
– Nonmelanoma Skin cancer
– Actinic Kratosis
– Premature Skin Ageing
• Cataracts and Other Eyes Damage
• Immune Suppression
UV Levels Depend on :
• Stratospheric Ozone
• Time Of Day
• Time of Year
• Latitude
• Altitude
• Weather Condition
UV Index Number Exposure Level
0 to 2 Minimal
3 to 4 Low
5 to 6 Moderate
7 to 9 High
10+Very High
What is the UV Index?
Action Steps
• Limit Time in the Midday Sun• Seek Shade• Always Use Sunscreen• Wear a Hat• Cover Up• Wear Sunglasses that Block 99-100% of UV
Radiation• Avoid Sunlamps and Tanning Parlors• Watch for the UV Index
Global Warming
6th session
AIR POLLUTION EPIDEMIOLOGY
DEFINITION
• Emission into the air of hazardous substances at a rate that exceeds the capacity of the natural processes in the atmosphere to :– convert them
– precipitate them
– dilute them
IMPORTANCE
• Human
• Plants
• Animals
• Metals
• Buildings
• 1 billion urban dwellers suffer from SO2
IMPORTANCE
• 100 million tones SO2
• 68 million tones of NOX
• 57 million tones of SPM
• 177 million tones of CO
Are released in one year as a result of human activities
PHYSICAL FORMS
• Aerosols
• Liquids
• gassesThe constituents of this phase changes with
location, season, traffic, meteorological factors, industrial activities,...
AEROSOLS
• Size and composition are the most important characteristics from the health point of view
• Size predicts how the particle travels in the airways : the smaller, the more penetration
• Composition predicts what happens when it deposited
(Particulate = small particle)
AEROSOLS- ctd• Aerodynamic diameter:
the diameter of a sphere that would settle at the same velocity as the particle in question.
• Although larger particles carry much more substances, they are much less likely to cause an effect to human body, because they don’t penetrate to lower respiratory tract, and their composition are less hazardous than smaller ones
AEROSOLS- ctd• >100 = irritation of nose, eyes & ...• <100 = inhalable fraction :
• 20 - 100 =URT fraction• > 10 coarse• < 10 fine (PM10) can penetrate alveoli • <2.5 = the most important portion (PM2.5)• <0.5 = ultrafine (PM0.5)• <0.1 tend to not precipitate and go in and out
• although not considered in size measurement, shape is very important too.
LIQUID PHASE
• Liquid phase :– droplet– associated with solid phase
• the latter are always water based
• they are very dependent on atmosphere humidity and with increasing humidity both the droplets and adsorbed components increase
LIQUID PHASE• mist: cloud or dense collection of droplets
• adsorption: the process of attraction of liquid and gaseous pollutants to the surface of the particles
• fog : aerosols of liquid water droplets that form from condensation in an atmosphere saturated with water vapour
• acid rain: rain and snow that precipitate particles and dissolved gasses with acidic properties
GAS PHASE
• Two important properties:– solubility– chemical reactivity
• relatively soluble : sulphates, nitrates, SO2
• relatively insoluble: oxides of nitrogen, ozone
• the role of solubility of gaseous pollutants is like of size for particles
COMMON HEALTH EFFECTS
• Respiratory tract
• Cardiovascular system
• Nervous system
• Cancer
RESPIRATORY TRACT(the most common health effect of all pollutants)
• Cough
• Nose , throat and eye irritation
• Shortness of breath
• Exacerbation of allergic symptoms
• Worsening of asthma and COPD
• Respiratory tract infections
CARDIOVASCULAR SYSTEM
Reduction of oxygen deliveryAggravation of atherosclerosisSecondary to lung diseases
NERVOUS SYSTEM• Neurotoxicity of lead
• Learning difficulties in children
CANCER
There Is not clear and consistent evidences regarding air pollution and cancers except for hazardous air pollutants (e.g. VOC)
MECHANISM TARGET ORGAN POLLUTANT
AGGRAVATION OF RESPONSE TO
OTHER POLLUTANTS
RESPIRATORY SPM
INFLAMATION
SYSTEMIC TOXICATION
RESPIRATORY
OTHER ORGANS
LEAD
BRONCHITIS AIRWAYS SO2
BRONCHITIS AIRWAYS NO2
CARBOXY HB BLOOD & CELLS CO
INFLAMMATION, FIBROSIS, INFECTION
TERMINAL AIRWAYS O3
POLLUTANT MAXIMUM ALLOWED*
PM10 yearly : 50
PM2.5 yearly : 15
24 hr. :45
LEAD Quarterly : 115
SO2 Yearly : 80
24 hr. : 365
NO2 Yearly : 100
CO One hour :40
8 hour : 10
OZONE One hour : 235
8 hour : 155
*US EPA- 1999
3.4583 227.7500 75.159709 30.102211
3.3636 486.1083 103.6379 60.020793
1.8167 288.9667 60.031910 39.105351
1.6500 844.3000 101.8410 119.651867
1.6500 30.0292 10.774571 4.252010
.6958 44.4750 9.527455 7.786194
12.2667 719.6875 95.275074 42.341018
POLLUTANTSO2
NO
NO2
NOX
CO
OZONE
PM10
Minimum Maximum Mean Std. Deviation
DESCRIPTION OF TEHRAN POLLUTANTS (1376- 80)
Is it important to separate health effects of each
pollutant?
SOME OF MORE IMPORTANT POLLUTANTS
• Particulate
• Sulphur dioxide
• Nitrogen oxides
• Ozone
• Carbon monoxide
• VOCs
• Trace metals
PARTICULATES
• Small particulate have more liquid and gaseous components and thus are more toxic
• PM2.5 tends to be uniformly distributed throughout the urban region when it is produced
• health effects of PM2.5, Ozone and Sulphates are not easily separable
SULPHUR DIOXIDE
• Is a major constituent of ultrafine particles
• Was one of the major component of London fog (December 5 1952)
• Airway irritation and bronchoconstriction
NITROGEN OXIDES
• NO: a product of combustion
• NO2 : a secondary pollutant or a product of high temp combustion
• Irritation of airways and exacerbation of asthma
Ozone
• Secondary pollutant:– volatile hydrocarbons + Nitrogen oxides +
Sun shine + Stagnant weather condition
• URT: – nasal discharge, throat irritation
• LRT:– cough, wheeze, chest pain, infections
• Non respiratory symptoms:– headache, fatigue
CARBON MONOXIDE
• Incomplete burning of fossil fuels(e.g. cars) and biomass fuels
• Binding haemoglobin an affinity that Is 200 to 300 times greater than O2
• Atherosclerosis
VOLATILE ORGANIC COMPOUNDS
• Benzene, chloroform, methanol, carbon tetrachloride, formaldehyde, …
• Indirect effects:
– helping in ozone production
• direct effects:
– respiratory irritation, headache, nervous system, cancers
TRACE METALS
• Cadmium, mercury, zinc, copper, lead, …
• Lead is the most famous trace metal from the health point of view and can cause:
– nerve damage
– learning and behavioral abnormalities in children
– many other organs damage
INDOOR AIR OPLLUTION• Developed countries :airtight buildings• Developing countries: open fires• It has been identified as one of the
foremost global environmental problems• Exposes more people worldwide to
important air pollutant than outdoor source• Rural people in developing countries may
receive as much as two third of global exposure to particulates
INDOOR AIR OPLLUTION SOURCES
• Tobacco smoke
• Radon decay products
• Formaldehyde
• Asbestos fibers
• Combustion products
• other household chemicals
• Fungi, viruses, bacteria, …
INDUSTRAI AIR POLLUTION
• Emission of pollutants into the atmosphere due to industrial activities that may travel
long distances
TYPES OF INDUSTRIAL POLLUTIONS
• Reducing:– Sulphur dioxide, particulates
• Photochemical:– Ozone, NOx, Aldehydes & Organic nitrites
• Point source:– Lead near a smelter
INDUSTRIAL ACCIDENTS
• Belgium 1930 (Meuse valley)
• USA 1948 (Pensilvania)
• Mexico 1950 (Poza rica)
• England 1952 &19662 (London)
• India 1984 (Bhopal)
Air Quality Index
• The AQI is an index for reporting daily air quality. It tells you how clean or polluted your air is, and what associated health effects might be a concern for you.
• The AQI focuses on health effects you may experience within a few hours or days after breathing polluted air.
• http://www.epa.gov/airnow/aqibroch/aqi.html
Air Quality Index(AQI) Values
Levels of Health Concern Colors
When the AQIis in this range:
...air quality conditions are:
...as symbolizedby this color:
0 to 50 Good Green
51 to 100 Moderate Yellow
101 to 150 Unhealthy for Sensitive Groups
Orange
151 to 200 Unhealthy Red
201 to 300 Very Unhealthy Purple
301 to 500 Hazardous Maroon
Air Quality Index (AQI): Particle Pollution
IndexValues
Levelsof HealthConcern
Cautionary Statements
0-50 Good None
51-100* ModerateUnusually sensitive people should
consider reducing prolonged or heavy exertion.
101-150 Unhealthy for Sensitive GroupsPeople with heart or lung disease, older
adults, and children should reduce prolonged or heavy exertion.
151-200 Unhealthy
People with heart or lung disease, older adults, and children should avoid
prolonged or heavy exertion. Everyone else should reduce prolonged or heavy exertion.
201-300 Very Unhealthy
People with heart or lung disease, older adults, and children should avoid all physical activity outdoors. Everyone
else should avoid prolonged or heavy exertion.
301-500 Hazardous
People with heart or lung disease, older adults, and children should remain
indoors and keep activity levels low. Everyone else should avoid all
physical activity outdoors.
Air Quality Index (AQI): Carbon Monoxide (CO)
IndexValues
Levelsof HealthConcern
Cautionary Statements
0-50 Good None
51-100* Moderate None
101-150 Unhealthy for Sensitive Groups
People with heart disease, such as angina, should reduce heavy exertion and avoid sources of
CO, such as heavy traffic .
151-200 Unhealthy
People with heart disease, such as angina, should reduce
moderate exertion and avoid sources of CO, such as heavy
traffic .
201-300 Very Unhealthy
People with heart disease, such as angina, should avoid exertion and sources of CO, such as
heavy traffic .
301-500 Hazardous
People with heart disease, such as angina, should avoid exertion and sources of CO, such as heavy traffic. Everyone else should reduce heavy exertion .
يبسمه تعال
طرح جامع ارزيابي اقتصادي خسارات وارده بر سالمتي حاصل از آلودگي هواي شهر
– گزارش کميته سالمت در برآورد حد تهران هواي منتسب به آلودگياقل عوارض بهداشت
مطالعهيهدف از اجرا از ي برخي اقتصاديبه کميت در آوردن و ارزش گذار•
ي هوا بر سالمت شهروندان تهرانياثرات آلودگ محدوديت هايبرخ•
، . . . و ي، فرهنگي، کشاورزيع اثرات صنعتيف وسيط– هواي آلودگيبهداشت
در به يت روش شناسي و محدوديت اثرات بهداشتيماه–ت در آوردن آنهايکم جهت ي عفونيهايمارينسل اول مطالعات: تشابه با ب•
هوايد آلودگيش شدين اثرات افزاييتعي مکانيسه هاينسل دوم: مقا•ن يي تعيک مکان براي در ي زمانيسه هاينسل سوم: مقا•
هواياثرات نوسان آلودگ
روش مطالعه
در اين مطالعه عوارض در سه دسته عمده در قالب •سه مطالعه مجزا بررسي شدند:
مرگ هاي منتسب به آلودگي هوا•بستري هاي منتسب به آلودگي هوا • منتسب به آلودگي هوا ) symptoms(شكايات •
بدين ترتيب چهار نوع داده جمع آوري شد: داده هاي آلودگي هوا و داده هاي مربوط به هر يك از سه دسته
عارضه فوق.
داده هاي آلودگي هوا
داده هاي مربوط به آلودگي هوا طي فاصله زماني •با استفاده از 1380 /29/12 لغايت 1/1/1376
يت هوايفيدستگاههاي زير و توسط شرکت کنترل کتهران سنجش و ثبت شده اند:
•CO: Thermo Model :48•NOX: Thermo Model :42•PM10: Rupprecht & Patashnick Model•O3: Thermo Model :49•SO2: Rotrok Model: 477
داده هاي مرگ و مير
داده هاي مربوط به سن، جنس، علت و تاريخ •فوت کليه متوفياني که طي فاصله زماني
در شهر 1380 /29/12 لغايت 1/1/1376تهران بزرگ فوت نموده بوده اند از کامپيوتر
بهشت زهرا استخراج گرديد.
هاي بيمارستاني داده
ستخراجداده هاي مربوط به سن، جنس، تشخيص و • 1/1/1376تاريخ بستري كليه بيماراني كه در فاصله
: به علل29/12/1380لغايتپر فشاري خون، سکته قلبي، آنژين قلبي، •
کورپولمونال، آريتمي قلبي، نارسايي قلبي، سکته مغزي، عفونت دستگاه تنفس تحتاني، بيماري انسداد ريوي، شوک، کوما و سنکوپ
سيستم كدگذاري شهر تهران واجد بيمارستان 25 در• نفر 23ي) بستري شده بودند توسط عمدتا̈ آموزش(
كارشناس مدارك پزشكي آموزش ديده
داده هاي مربوط به شكايات و عاليم ناخوشي
شماره تلفن به صورت 160 باروزانهتماس • منازل ين کل شماره هاي از بتصادفي ساده
پزسشگر 8 شهر تهران توسط يمسکونيده علوم اجتماعيآموزش د
ات:يست شکايل•درد قفسه تهوع، کارائي،، حوصله•
سوزش چشم، تنگي نفس، سينه،خلط، سردرد، طپش قلب، سوزش گلو،
سرفه
پايش جمع آوري داده ها
داده هاي مربوط به بيماران بستري شده در •:بيمارستانها
، )sensitivity( حساسيت LQASبا استفاده از روش – positive( ارزش اخباري مثبتو )specificity(ويژگي
predictivevalue ( سيستم جمع آوري داده ها تعيين گرديد.
ات:يم و شکايعالداده هاي • يتماس ها% از 10 روزانه شيم و پاينظارت مستق–
همان روز
روش تجزيه و تحليل داده ها
بررسي رابطه مرگ ومير و نيز بستري در بيمارستان •:با آلودگي هوا
با )time series(روش هاي سري زماني – و)poisson(ي رگرسيون پواسونهامدلاستفاده از
)linear regression(خطي هوا: يات و سمپتوم ها با آلودگي رابطه شکابررسي•
)logistic regression(رگرسيون لوجستيك –
جينتا
•SO2 ميکرومتر به طور 10 و ذرات معلق کوچکتر از معني داري با مرگ رابطه داشتند بطوريکه با افزايش
نفر 0.028هر واحد از هر يک از اين آالينده ها به ترتيب نفر به تعداد مرگ هاي روزانه افزوده ميگشت0.046و
از بيماريهاي تحت مطالعه ، آنژين قلبي، نامنظمي •ضربان قلب (آريتمي)، سکته مغزي و بيماري انسداد
مزمن ريوي با آلودگي هوا رابطه نشان داد در مورد شکايات و سمپتوم ها بين ذرات معلق کوچکتر •
ميکرومتر با کاهش کارايي، سوزش چشم و 10از با تهوع، سوزش چشم و سردرد – و SO2سردرد -
NO2 با خارش گلو ، سرفه و خلط رابطه معني دار مشاهده شد
Estimation upon Maximum 10 Percent of Days over Standard Level of Japan
GroupEffect group
PollutantMean daily effect/unit
Mean Annual Effect
Minimum Annual Effect
Maximum Annual Effect
Death*
All Death Pm10 0.028 420.59388 105.14847 736.03929
All Death SO2 0.046 87.4759 30.4264 144.5254
30-65 CO 0.113 230.188345 46.852495 415.56126
30-65 SO2 0.016 30.4264 5.70495 55.14785
Over 65 Pm10 0.016 240.33936 60.08484 420.59388
Hospitalization
Angina CO 0.68 1385.2042 521.48864 2220.40085
Arrhythmia
Pm10 0.027 405.57267 129.182406 690.97566
CVA NO2 0.017 292.44165 39.565635 516.0735
COPD CO 0.29 590.74885 122.2239 1059.2738
Telephone Survey
Efficacy Pm10 2580 38754721.8 18325876.2 59483991.6
Nausea SO2 575 1093448.75 359411.85 1829387.3
Eye SO2 915 1740009.75 384133.3 3099689.5
Eye Pm10 1940 29141147.4 8772386.64 49569993
Headache SO2 1430 2719359.5 899480.45 4544943.5
Headache Pm10 4040 60685688.4 28239874.8 93281714.1
Sputum NO2 961 16531554.45 5315557.05 27695944.5
Cough NO2 946 16273517.7 3354477.75 29244165
Estimation upon Maximum 5 Percent of Days over Standard Level of Japan
GroupEffect group
PollutantMean daily effect/unit
Mean Annual Effect
Minimum Annual Effect
Maximum Annual Effect
Death*
All Death Pm10 0.028 547.3832 136.8458 957.9206
All Death SO2 0.046 136.3348 47.4208 225.2488
30-65 CO 0.113 288.30255 58.68105 520.4754
30-65 SO2 0.016 47.4208 8.8914 85.9502
Over 65 Pm10 0.016 312.7904 78.1976 547.3832
Hospitalization
Angina CO 0.68 1734.918 653.1456 2780.9715
Arrhythmia Pm10 0.027 527.8338 168.12484 899.2724
CVA NO2 0.017 314.77965 42.587835 555.4935
COPD CO 0.29 739.8915 153.081 1326.702
Telephone Survey
Efficacy Pm10 2580 50437452 23850268 77415624
Nausea SO2 575 1704185 560158.2 2851175.6
Eye SO2 915 2711877 598687.6 4830994
Eye Pm10 1940 37925836 11416849.6 64513020
Headache SO2 1430 4238234 1401877.4 7083482
Headache Pm10 4040 78979576 36752872 121401774
Sputum NO2 961 17794308.45 5721583.05 29811484.5
Cough NO2 946 17516561.7 3610707.75 31477965
Estimation upon Maximum 1 Percent of Days over Standard Level of Japan
GroupEffect group
PollutantMean daily effect/unit
Mean Annual Effect
Minimum Annual Effect
Maximum Annual Effect
Death*
All Death Pm10 0.028 786.8378 196.70945 1376.96615
All Death SO2 0.046 228.6798 79.5408 377.8188
30-65 CO 0.113 397.6018 80.9278 717.7944
30-65 SO2 0.016 79.5408 14.9139 144.1677
Over 65 Pm10 0.016 449.6216 112.4054 786.8378
Hospitalization
Angina CO 0.68 2392.648 900.7616 3835.274
Arrhythmia Pm10 0.027 758.73645 241.67161 1292.6621
CVA NO2 0.017 356.97365 48.296435 629.9535
COPD CO 0.29 1020.394 211.116 1829.672
Telephone Survey
Efficacy Pm10 2580 72501483 34283647 111281346
Nausea SO2 575 2858497.5 939575.7 4782390.6
Eye SO2 915 4548739.5 1004202.6 8103219
Eye Pm10 1940 54516619 16411188.4 92734455
Headache SO2 1430 7108959 2351424.9 11881407
Headache Pm10 4040 113529454 52830538 174509383.5
Sputum NO2 961 20179510.45 6488521.05 33807504.5
Cough NO2 946 19864533.7 4094697.75 35697365
Estimation upon Maximum 1 Percent of Days over Standard Level of Japan
Effect group PollutantMean daily
effect/unit
Mean Annual Effect
Minimum Annual Effect
Maximum Annual Effect
All Death
Pm10 0.028 787 200 1377
All Death
SO2 0.046 229 80 378
30-65 CO 0.113 398 81 718
30-65 SO2 0.016 80 15 144
Over 65 Pm10 0.016 450 112 787
Estimation upon Maximum 1 Percent of Days over Standard Level of Japan cont.
Effect group PollutantMean daily
effect/unit
Mean Annual Effect
Minimum Annual Effect
Maximum Annual Effect
Angina CO 0.68 2392 901 3835
Arrhythmia
Pm10
0.027 759 242 1293
CVA NO2 0.017 357 48 630
COPD CO 0.29 1020 211 1830
Estimation upon Maximum 1 Percent of Days over Standard Level of Japan cont.
Effect groupPollutan
tMean daily effect/unit
Mean Annual Effect (10 6)
Minimum Annual Effect
)10 6(
Maximum Annual Effect
(10 6)
Efficacy Pm10 2580 72 34 111
Nausea SO2 575 2.9 0.94 4.8
Eye SO2 915 4.6 1 8.1
Eye Pm10 1940 54.5 16.4 92.7
Headache SO2 1430 7.1 2.35 11.9
Headache Pm10 4040 113.5 52.8 174.5
Sputum NO2 961 20.2 6.5 33.8
Cough NO2 946 19.9 4 35.7
بحث و نتيجه گيري
مورد استفاده در اين مطالعه (که رايج ترين روش يمتدولوژ•آناليز اينگونه مطالعات است) فقط قادر به نشان دادن عوارض
، بروز سردرد و يا تشديد ي هوا (نظير مرگ ناگهانيحاد آلودگ نشان دادن عوارض مزمن (نظير ي) ميباشد و براي قلبيبيمار
) بايد از مطالعه کوهورت که ي قلبيبروز سرطان ها و بيماريها کشور يبسيار زمان بر و گران قيمت بوده و در شرايط فعل
انجام صحيح آن دور از ذهن است و يا از مقايسه شيوع عوارض مختلف که بسيار تحت تاثير مخدوش کننده ها قرار يدر شهر ها
دارد و از طرف ديگر سنجش آالينده با کيفيت مطلوب در شهر . هوا انجام نميشود استفاده کردي بدون مشکل آلودگيها
هوا در يع منتسب به آلودگي وقاي کم شماري برايمنابع متعدد•ن دست مطالعات) وجود دارد که ي اين مطالعه (و بطور کلياد به آنها توجه شود.يبا
7th session
ENVIRONMENTAL EPIDEMIOLOGY
References:1. Picciotto IH. Environmental Epidemiology. in :Rothman KJ & Greenland
S. Modern Epidemiology. Phyladelphia: lippincott-Raven, 1998: 555 – 583
2. Morgenetern H. Ecologic Studies. In: Rothman KJ & Greenland S. Modern Epidemiology. Phyladelphia: lippincott-Raven, 1998: 459 - 480
ENVIRONMENTAL EPIDEMIOLOGY
Study of distribution of health related states or events in specified populations in relation to determinants/hazards in the living environment of these populations, and the application of this study to control of such hazards
NEW DOMAINS IN ENVIRONMENTAL EPIDEMIOLOGY
• Shifting from biologic factors to chemical and physical agents (such as :VOC , Metals , Hormones added to Foods , Pesticides and Radiation) and psychological and social factors.
• Evaluating patterns of disease in populations struck by disasters
LINKAGE BETWEEN OCCUPATIONAL AND ENVIRONMENTAL EPIDEMIOLOGY
• Observing higher rates of diseases in occupational (high dose) settings, increases the suspicion of producing such effects at environmental (low dose) settings.
FIELD OF ENVIRONMENTAL EPIDEMIOLOGY
• To characterize the health effects of a known exposure
• To uncover the responsible agent for an observed disease with unknown causal explanation
CENTRAL ISSUE IN BOTH SCENARIOS IS THE QUALITY OF EXPOSURE
ASSESSMENT
RISK ASSESSMENT &
RISK MANAGEMENT
DEFINITION OF RISK
• Risk is , at minimum, a two dimensional concept involving :
• The possibility of an adverse outcome
and
• Uncertainty over the occurrence, timing, or magnitude of the adverse outcome
ASSESSING HUMAN HEALTH RISKS
• Risk: The likelihood of undesirable effects resulting from exposure to a hazard
• Safety: The practical certainty that adverse effects will not result when a substance is used in the quantity and in the manner proposed for its use
METHODS FOR ASSESSING HUMAN HEALTH RISKS
• Human studies– Controlled studies are rare – Are mainly epidemiologic studies
• Laboratory animal studies
SOME TERMS AND INDICES COMMONLY USED
• Threshold: the concentration or dose above which detectable adverse effects may occur under defined conditions of exposure.
• NOAEL (No Observed Adverse Effect Level): the greatest concentration or dose of a chemical which produces no observed adverse effects in the test population.
• LOAEL (Lowest Observed Adverse Effect Level): the lowest dos eor concentration of a chemical that causes an adverse effect in an organism . . .
SOME TERMS AND INDICES COMMONLY USED-ctd
• VSD (virtually safe dose): that dose of an otherwise hazardous chemical which is so low that it is not considered to pose a risk to human even with daily lifetime exposure.
• TDI (tolerable daily intake): an estimate of the daily intake of a chemical that can occur over a lifetime without appreciable health risk. (no useful intended function, e.g.. Lead, mercury, . . .)
• ADI (acceptable daily intake): an estimate of the daily maximum intake of intake of a substance over a lifetime without appreciable health risk at any stage in human life (useful food production purposes)
SOME TERMS AND INDICES COMMONLY USED-ctd
• Uncertainty factor: a number (equal or greater than one) used to divide NOAEL or LOAEL values derived from measurements in animals or small groups of humans, in order to estimate a NOAEL value for the whole human population; also called margin of safety
• It usually ranges from 1 to 10000:– Inter species variation: 1 – 10– Intra species variation: 1 – 10– Adequacy of studies: 1 – 10– Nature and severity of effect: 1 – 10
• Risk assessment:A systematic process for describing and
quantifying the risk associated with hazardous substances, processes, action or events
• Risk management:The process of evaluating alternative
regulatory actions and selecting among them
WHAT ARE COMPONENTS OF RISK ASSESSMENT?
• Hazard identification
• Dose - response evaluation
• Human exposure evaluation
• Risk characterization
HAZARD IDENTIFICATION
• The determination of whether a particular chemical or agent is or is not causally linked to a particular health effect
1- Carcinogenic to humans
IARC OVERAL EVALUATION OF CARCINOGENICITY TO HUMANS
2A - Probably carcinogenic
2B - Possibly carcinogenic
3 - Not classifiable
4 - probably not carcinogenic
Weight of evidence
DOSE - RESPONSE EVALUATION
• The determination of the relation between the magnitude of the exposure and the probability of the occurrence of the health effect in question
DOSE - RESPONSE , DOSE - EFFECT
• Dose - response:– The relation between the proportion of
individuals in an exposed group that demonstrate a defined effect, and the dose
• Dose - effect:– The relation between the severity of health
effect and the dose
HUMAN EXPOSURE EVALUATION
• How many people will be exposed?
• Through which routes?
• Who is exposed?
• What is the magnitude, duration and the timing of the exposure?
RISK CHARACTERIZATION
The description of the nature and often the magnitude of human
risk, including attendant uncertainty
RISK ASSESSMENT
HAZARD IDENTIFICATION
DOSE - RESPONSE EVALUATION
HUMAN EXPOSURE EVALUATION
RISK CHARACTERIZATION
HAZARD IDENT IFICATION
DOSE - RESPONSE EVALUATION
HUMAN EXPOSURE EVALUATION
RISK CHARACT ERIZATION
Regulatory Decisions
Control Options
Risk Assessment Risk Management
RISK MANAGEMENT
• Selection of an appropriate course of action using:
• Risk assessment
• Statutory and legal requirements
• Economic effects
• Social considerations
• Informed judgments
DRIVING FORCES IN RISK MANAGEMENT
• Politics• Press• Public perception• Bureaucratic imperatives• Law• Economics• Science• Ethics
Dimensions of risk management
• Risk perception• Risk communication• Risk control
– Structural change– Reduce exposure– Reduce potential loss or liability
• Risk anticipation• Risk comparison
Risk perception• Public view of risk may not match that of
experts• People tend to estimate risk best in the
middle of the range• Risk perception is laden with values
learned in society and the family• Risk perception is culturally determined• Risk is perceived as good in many
contexts
Seven cardinal rules of risk communication
• Accept and involve the public as a partner• Plan carefully and evaluate your efforts • Listen to the public’s specific concerns• Be honest, frank and open• Work with other credible sources• Meet the needs of the media• Speak clearly and with the compassion
Risk anticipation
• New idea, in evolution
• Anticipate risk before it becomes a management problem
• Requires internal culture of skepticism
Conventional disaster plan 21st century integrated disaster planning and management
reactive
emergency and crisis management
countermeasure manual approach
predetermined planning
sectoral countermeasure approach
proactive
risk mitigation + preparedness
anticipatory/precautionary approach
adaptive management
comprehensive policy-bundle approach
Conventional and 21st century disaster plan
FRAMEWORK FOR RISK MANAGEMENT
• Define the problem and put it into the context• Analyse the risk associated with the problem in
context • Examine the options for addressing the risks• Make decisions about which options to
implement• Take actions to implement the decisions• Conduct the evaluation of the actions’ results
Risks
Options
Evaluation
Actions
Decisions
Problem/Context
Engage Stakeholders
ECOLOLOGIC STUDIES
Comparison of groups rather than individuals
NEW VISIONS
• Before 1980, was regarded as simple descriptive study
• Now emphasis is on inference and its difficulties
• Although easily and inexpensively conducted, interpretations are often difficult to interpret
WHY CONDUCT ECOLOGIC STUDY
• It is easy, quick and inexpensive• Data on the individual level are not always
available (at least with available resources)• Design limitation (when exposure varies little
within area)• Interest in ecological effects (does increasing
taxes on tobacco decreases its consumption?)• Simplicity of analysis (even individual data in
large surveys sometimes analyzed ecologically)
LEVEL OF MEASUREMENT
• Aggregate measure: summaries of observations derived from individuals (mean, proportion,…)
• Environmental measure: characteristics of place in which members live (air pollution)
• Global measures: attributes of groups etc, that there isn’t analogue at the individual level (population density, total area of green space, a specific law, …)
LEVEL OF ANALYSISlevel for which the data on all variables are
reduced and analyzed
• Individual (all variables are measured and analyzed at individual level)
• Partially ecologic (some variables are measured individually and some at group level)
• Pure ecological (all variables are measured and analyzed at group level)
LEVELS OF INFERENCE
• Biologic (or behavioral):– Measurement of effects on individual risks
• Ecologic :– Measurement of effect on group rates
The target level of causal inference does not always match the level of analysis
10.2 34.5 28.5 12.2 45.6 17.5 19.8
12.5 32.5 24.3 10.0 14.3 38 26.4
28.7 30.2 13.5 23.5 10.8 22.7 20.5
A : mean = 23.9 incidence = 4/7 = 57%
B : mean = 22.4 incidence = 3/7 = 43%
C : mean = 21.1 incidence = 2/7 = 29%
proportion protestant
0
5
10
15
20
25
30
0 0.2 0.4 0.6 0.8 1
suicide rate
Linear (suicide rate)
8th Session
Air Pollution 1:Nature, sources and effects on
ecosystems
Sources of air pollutants
• Industry – Fossil fuel combustion, smelting
• Transport– Fossil fuel combustion
• Agriculture– Animal effluent, fertilizers, – biomass burning
• Domestic– Fossil fuel combustion
Point and Diffuse sources
Types of air pollutants
• Primary pollutants– Emitted directly into the atmosphere
• Secondary pollutants– Generated over time in the atmosphere from
chemical reactions involving primary pollutants, e.g. ozone, acidic aerosols
Pollutants can be further subdivided into gaseous or particulate (aerosol)
forms
Size and composition of particulate air pollution
From:
Turco, 1997, p.164
Radiation for comparison
Major air pollutantsSO2 Gas Fossil fuel combustion, natural
NOx Gases Fossil fuel combustion, natural
CO Gas Fossil fuel combustion
VOCs Gases Cars, organic solvents, natural
NH3 Gas Agriculture, natural
TSP Particulate Oxidation, fossil fuel burning, dust – e.g. PM10
Heavy metals
Particulate Metal processing, fossil fuel burning
Acidic aerosols
Particulate Secondary - reactions of pollutants from fossil fuel burning
Ozone Gas Secondary – from reaction of NOx and VOCs under sunlight
8th session
Air Quality Index
Attention: it has PDF file
Criteria Pollutants
• O3 (ppm) 8-hr 1-hr For Conc.> 0.374 ppm
• PM10 (micro-gr/m3) 24-hr
• CO (ppm) 8-hr
• SO2 (ppm) 24-hr
• NO2 1-hr
Air Quality Index
Air Quality Index (AQI): Ozone
Air Quality Index (AQI): Particulate Matter (PM)
Air Quality Index (AQI): Carbon Monoxide (CO)
Air Quality Index (AQI): Sulfur Dioxide (SO2)
Air Quality Index (AQI): Nitrogen Dioxide (NO2)
How To Calculate AQI?
• Determine the Concentration of Criteria Pollutant
• Use Break Point Table To Convert Conc. Level To AQI
• Find The Maximum AQI
• Consider Maximum AQI for Management Purposes in MONITORING Program.
How to Convert Conc. Level To AQI?
BPIBPI
CBPCBP
I
IBPCBPBPIII
LOLO
HIHI
PLO
PHI
P
LOLOPLOHI
LOHIP
toingcorrespond valueAQI The
toingcorrespond valueAQI The
toequalor than Less is that Breakpoint The
toequalor an Greater th is that Breakpoint The
pPollutant for Index The
)(
9th sessionIt has 2 word files
10th 11th sessionsIt has one PDF file