Exam 1 Flashcards
contaminant
anything added to the environment that causes a deviation from the average composition that a particular phase of environment would have in the absence of human activity
air pollution
the excessive concentration of foreign material in the air which adversely affects the well being of humans, plants, or animals or causes damage to property
1) personal (indoor): cigarettes, pipes, household sprays
2) occupational: workplace (in or outdoor)
3) Community: ambient or outdoor
pollutants for us
we call contaminants pollutants when they adversely affect something we value, and is present in high enough concentration to do so
which contaminants are called pollutants is changeable: at one point soot was the only air pollutant, now there are hundreds
1970 US clean air act
air quality criteria documents (books)
contained a summary of what is known about:
sulfur oxides, particulates, oxidants, carbon monoxide, hydrocarbons, nitrogen oxides
Carbon Dioxide
until 25 years ago the goal was to breakdown pollutants to CO2 - it was not a pollutant
NOW because it is a greenhouse gas and global warming, it is our most concerning pollutant because of climate change
climate change crisis means energy crisis
Meuse valley, Belgium 1930
first modern air pollution disaster
river valley, densely populated, highly industrialized
it was winter and there was high barometric pressure and thermal temperature inversion
63 people, mostly elderly died
symptoms: shortness of breath, cough, nausea, vomiting
because SO2 mixed with H2O making SO4 sulfuric acid mist
cattle, birds and rats died
Donora Pennsylvania 1948
Monogahela river surrounded by mountains and the valley between the mountains and a set of railroad tracks is a natural trap for pollutants
industrial town-steel mill, sulfuric acid plant,
small population- 14000
there was a temperature inversion- warm air trapped cold air near the ground and there was a fog that lasted 4.5 days
the fog then turned into very thick smoke that made it hard to see through
air started smelling of sulfur dioxide (pollutnat was SULFUR DIOXIDE AND PARTICULTES-so turned into ACID SMOG since coal burning, industry and urbanization)
6000 people became sick, 20 died
U.S Public health service was called in- first time air pollution officially recognized as health problem
sulfur gas+particulates=sulfuric acid mist
calls for help suddenly stopped even though the dense fog remained, maybe since the fog droplets had gotten so big they couldnt get into lungs
C. Poza Rico, Mexico 1950
single source of pollution- high sulfur crude oil- Hydrogen sulfide (H2S)
inversion in valley, 22 sudden deaths, 320 hospitalized of all ages
1952 Great London smog
londoners burned soft coal in factories and power plants
temperature inversion
5 days of the worst smog the city had ever seen
“pea soup”- public transportation stopped, indoor concerts had to be stopped because no one could see the stage
people died a lot in a short time frame
causes were bronchitis, coronary disease pneumonia
high deaths correlated with high smoke concentrations
new analysis showed that small particles were found deep in the victim’s lungs and that pollution levels during the episode were 5 times above current regulatory standards
(pollutnat was SULFUR DIOXIDE AND PARTICULTES- so turned into ACID SMOG since coal burning, industry and urbanization)
world-wide air pollution episode
nov 27- dec 10, 1962
thousands of excess deaths in many cities including NYC, London, Boston, Paris
Seveso, Italy
a valve broke at the Insudtrie Chimiche something something chemical plant
cloud of 2,3,7,8 tetrachlorodibenzopara-dioxin (TCDD) (or just Dioxin) traveled southwest through Seveso toward Milan and it was a contaminant of herbicide
it is a selective killer of leafed weed (was used in agent orange)
4% of farm animals died and the rest had to be killed
Italian government tried to cover it up
TCDD (Dioxin)
caused nacrosis of liver, GI tract bleeding, stomach ulcers
was used in agent orange
is a selective killed of leafed weeds
Bhopal India 1984
pesticide plant leak killed up to 2000 with upto 350,000 injured and 100,000 permanent disabilities
due to Methyl isocyanate (MIC)
carbon monoxide combined with chlorine to form phosgene, phosgene combine with methylamin to form MIC
MIC is an irritant to the lungs- causes edema, fluid (causes of death, bronchospasms, corneal opacity
felt like breathing fire
“worst industrial accident in history”
Similarities among disasters in history
winter months dense populations heavy industrialization often a valley temperature inversion stagnant air accident, or a mixture created from non-accidents
African lakes
2 west african lakes killed more than 1700 people because of a gas buildup of CO2 to toxic levels that erupted
how was inorganic mercury taken up into the foodchain
the inorganic mercury was methylated by microorganisms in the anaerobic sludge lying at the bottom of the bay and so became more soluble in fatty tissue and was easily taken up into living organisms
risk assessment
the use of a base of scientific research to define the probability of some harm coming to an individual or a population as a result of exposure to a substance or situation
risk management
is the public process of deciding what to do where risk has been determined to exist
it includes integrating risk assessment with considerations of engineering deasibility and figuring out how to exercise our imperitice to reduce risk in the light of social, economic and political factors
PCBs
mixture od 209 individual chlorinated compounds
are fat-soluble, water insoluble hydrocarbons
have no smell or taste, are colorless to light yellow
extremely stable
fire resistant and an electrical insulator
workers exposed to high doses develop certain kinds of cancers including liver and biliary tract cancer
EPA and International agency for research on cancer have determined them to be carcinogenic to humans
what are the health risk assessment components
hazard identification, dose-response assessment and exposure assessment are used to characterize risk
exposure assessment for chemicals formula
C= Q/(LxDxW)
C= exposed person's concentration Q= amount released L= Distance D= Dispersion W=wind speed
epidemiology
the study of the distribution and causes of health and illness in human populations
environmental epidemiology
determines whether a given exposure of a chemical hazardous to human health
toxicology
The study of the harmful actions of chemicals on biologic tissue
The study of poisons
Measuring risk
measuring risk is calculating the probability and severity of public health harm; it is a empirical scientific activity
judging safety
judging the safety of risks, is a normative, political and value laden activity
de minimus
there is an acceptable small amount of each substance (may be different for each substance but not zero)
there is no such thing as zero risk: there is always some small acceptable level of risk
reasons given for not protecting the environemtn
we need more study it would hurt the economy it would cost jobs the risk is exaggerated the damage is trivial you can't keep changing the rules trust us to handle it ourselves we can't afford to accept liability you've got to make hard choices if you've seen one tree, you've seen them all
the precautionary principle
when an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically
has 4 components:
-taking preventive action in the face of uncertainty
-shifting the burden of proof to the proponents of an activity
-exploring a wide range of alternative to possibly harmful actions
-increasing the public participation in decision making
epidemiology
the study of the distribution and causes of health and illness in human populations
or
the study of how disease is distributed in populations and the factors that influence or determine this distribution
disease occurence or its outcome is NOT random, but can vary depending on a variety of characteristics and predisposing factors.
natural history of infectious disease
pathological onset/infection-> incubation period->1st symptoms-?clinical disease during which diagnosis occurs->outcome
incubation period
time between exposure to an infectious agent and onset of symptoms
typical for each infectious disease but variable depending on dose, route, replication rate, host responses
same as the latent period in non-infectious diseases such as cancer, heart disease
latent period
is for non-infectious diseases such as cancer, heart disease
same as the incubation period
take years or decades before illness is apparent (long)
no multiplication of causative agent is involved
multiple low-dose exposures (some chemicals)
some conditions evolve subsequent to chronic conditions or high risk states such as obesity, smoking, diabetes and high blood cholesterol
epidemic
the occurence in a community or region of cases of an illnes or health-related event clearly in excess of normal expectancy
prevalence rate per 1000
number of cases of disease present in the population at a specified time/number of persons in the population at that specified time x1,000
incidence rate per 1000
=number of new cases of a disease in a population during a specific period/ number of persons exposed to risk of developing the disease during that time x 1,000
ebola outbreak
graph showing increasing cases and deaths
one case could lead to man others
always treated as an epidemic - even one case
the changing contribution of chronic and infectious to total mortality in the U.S
the 11 major infectious conditions are decreasing while the 3 major chronic conditions- heart disease, cancer, stroke are increasing
(deaths by accidents also increasing)
trend in cancer over the years
lung and bronchus cancer were increasing but now slowly decreasing- still more cases than before
stomach cancer has decreased over the years
same for men and women except men have higher rate of lung and bronchus
tumor
is a disorder of cells
abnormal growth of cells
a neoplasm is the autonomous growth of tissue that have escaped the normal restraints on cell proliferation (apoptosis-normal cell death, and often exhibit non-differentiation)
neoplams
a neoplasm is the autonomous growth of tissue that have escaped the normal restraints on cell proliferation (apoptosis-normal cell death, and often exhibit non-differentiation)
are irreversible, and their growth is mostly autonomous (self-governing)
cancer
is malignant unrestrained proliferation of somatic cells
invasion
malignant tumors-cancer- are capable of invasion-spread of the neoplasm into adjacent structures
metastasis
malignant tumors are capable of metastasis- implantation of the neoplams into noncontiguous sites (not next to each other, don’t touch each other)
possible reasons for changes in mortality trends of disease
A. artifcatual
1) errors in the numerator die to:
changes in the recognition of disease
changes in rules and procedures for classification of causes of death
changes in accuracy of reporting age at death
2) errors in the denominator due to:
errors in the enumeration of the population
B. real
1) changes in age distribution of th epopulation
2) changes in survivorship
3) changes in incidence of disease: the result of genetic factors or environmental factors
trends males vs females
males die at higher rate at every age than females
women live longer than men
while women live longer than men, they have more `medical conditions or are sicker
retrospective study
select cases and controls, then look for past exposure to a factor to study cause
prospective study
select cohort, classif as to exposure to factor, then follow over time to see if disease develops
historical perspective
identify cohort defined in the past->on basis of existing record classify individuals in cohort as to past exposure to factor -> determine whether disease has developed
indirect epidemiology studies in environmental risk assessment
these studies comapre groups not individuals weakness of these studies: possibility of indirect association interpretation of negative results often look at agents one at a time comparibility of data by place and time mobility problem
air pollution
Air pollution may be defined as the presence in the air (outdoor atmosphere) of one or more contaminants or combinations thereof in such quantities and of such durations as may be or tend to be injurious to human, animal or plant life, or property, or which unreasonably interferes with the comfortable enjoyment of life or property or conduct of business.
air pollutant
It is a substance or effect dwelling temporarily or permanently in the air , which adversely alters the environment by interfering with the health, the comfort, or the food chain, or by interfering with the property values of people.
A pollutant can be solid (large or sub-molecular), liquid or gas .
It may originate from a natural or anthropogenic source (or both).
It is estimated that anthropogenic sources have changed the composition of global air by less than 0.01%.
However, it is widely accepted that even a small change can have a significant adverse effect on the climate, ecosystem and species on the planet.
Examples of these are acid rain, ozone in the lower atmosphere, and photochemical smog.
pollutants
can be:
particles: solids or liquids suspended in air
gases (vapors)
radioactive
Particles
can be solid or liquid suspended in air
1) dust-man made or natural
2) fumes-oxides of metal formed by combustion of metal
3) mist- fine liquid droplets
4) smoke-gases and solids-product of combustion, or soot
L.A photochemical or oxidizing smog composition
NOx and hydrocarbons (VOC volatile organic chemicals)= ozone precursors+ sunlight
in the atmosphere-chemical reactions that result in 03 and other oxidants such as PAN (eye irritant)
fossil fuels complete and incomplete combustion
complete combustion results in CO2 and H2O
incomplete combustion results in CO, soot, organics (in the air) and NOx
lead trends
lead based paint peaked in the 1920s and then gradually died out
as lead based paint use was decreasing, leaded gasoline was increasing
both sources contributed to the problem of lead in the environment
absorption of lead
lead goes down the iron or calcium pathway
lead absorption is enriched if diet is poor in iron or calcium
children absorb lead well orally, adults poorly
children also have more hand to mouth activity
Pica (an eating disorder typically defined as the persistent ingestion of nonnutritive substances for at least 1 month at an age for which this behavior is developmentally inappropriate) is one of the worst risk factors
lead can be inhaled
tetraethyle lead can be absorbed via skin
leads to IQ and developmental problems in children
distribution of lead
goes into bones
binds into matrix
released during osteolysis (the pathological destruction or disappearance of bone tissue as you get older)
4% in brain, liver, kidneys
1% in blood
crosses the placental and foetal and can be absorbed by the fetus through the mother
health effects of lead
concentration related
IQ/delinquicy related to toal dosage in childhood
can cause IQ/hearing growth problems, interfere with brain cell development, cause premature births, reduced birth weight, difficulty maintaining steady posture, interferes in ability to make red blood cells, decreases ability to use Vitamin D, decreases ability to make red blood cells, stomach ache/cramps, frank anemia, kidney damage, coma/seizures (at higher levels) and can also cause death at very high levels
specturm of biological response to pollutant exposure such as lead
large number of population affected, but only a small percentage feels adverse health affects from the pollutant
effects of lead on children
neurobehavioral: decreased intelligence, developmental delays, behavioral distrubances, seizure and coma (at very high levels)
growth: decreased stature
endocrinologic: altered vitamin D metabolism
hematologic: elevated erythrocyte protoporphyrin levels, anemia
on the fetus: decreased gestational (the process of carrying or being carried in the womb between conception and birth) weight, decreased gestational age, miscarriage and still birth (at very high levels)
exposure in childhood leads to reading disabilities in young adulthood and a failure to complete high school
also high agression, high delinqunecy
no safe level of lead
trends in lead absorption based on race/male and females
in all ages, black people had higher lead in their blood than hispanics or whites
in most ages hispanics had more blood than whites but less than blacks
males had more lead in their blood across all ages than females