Environmental Science

WEEK 6-7 / SIM AND PPT BASED

ENVIRONMENTAL HEALTH AND  Epidemics of typhoid fever

TOXICOLOGY  Cholera
 Yellow fever
TOPIC OUTLINE AIDS
1 Global Burden of Diseases  highly treatable disease
2 Emergent Diseases CHRONIC DISEASES
3 Ecological Epidemiology  Account for nearly 60% of the 65.5 million total
4 Ecotoxicology deaths worldwide each year and about half of the global
5 Bioaccumulation and Biomagnification disease burden
6 Persistent Organics Pollutants (POPs) AIDS
7 Chemical Interactions Increasing Toxicity  highly treatable disease
8 Factors Influencing Toxicity
9 Measuring Toxicity EMERGENT DISEASE
1 Risk Assessment  not previously known or that have been absent for at
0 least 20 years
1 Sustainable Agriculture  rapid international travel makes it possible for these new
1 diseases to spread around the world at jet speed
 originated in a non-human animal species
ENVIRONMENTAL HEALTH AND  arise due to stresses in biological systems that upsets
TOXICOLOGY normal ecological relationship

HEALTH  a state of complete physical, FACTORS CONTRIBUTING TO DISEASE

mental, and social being (World EMERGENCE
Health Organization) Microbial  genetic drift
DISEASE  influence by environmental Adaption  genetic shift in Influenza A
factors by impairing physical ang Changing Human  Mass immunocompromising
psychological functions Susceptibility with HIV/AIDS
 impairment of an individual’s Climate and  diseases with zoonotic vectors
being and capacity to function Weather such as West Nile Disease
 mostly attributed to inadequate (transmitted by mosquitoes) are
behavioral and environmental change moving further from the tropics as
FACTORS THAT  Diet and nutrition the climates warm
RESULT IN  Infectious agent Change in human  rapid travel enabled COVID to
MORBIDITY  Hereditary qualities demographics and rapidly propagate around the
(ILLNESS) AND  Poisonous substance trade globe
MORTALITY  Injury Economic  use of antibiotics to increase
(DEATH)  Stress development meat yield of farmed cows leads
ENVIRONMENT  focuses on disease-causing to antibiotic resistance
AL HEALTH external factors, including elements Breakdown of  The current situation in
of the natural, social cultural and public health Zimbabwe
technological worlds Poverty and social  Tuberculosis is primarily a
inequality problem in low-income areas
GLOBAL BURDEN OF DISEASE (GBD) War and famine  Gulf war, Ukraine war
 Comprehensive regional and global research program of Bioterrorism  2001 Anthrax attacks
disease burden
Dam and irrigation  malaria and other mosquito
 Assesses mortality and disability from major diseases,
system borne disease
injuries, and risk factors
construction
 Considers the health, social, political, environmental,
and economic factors
 Mortality data is based on Disability Adjusted Life
Years (DALYs) as a measure of disease burden

SMALLPOX
 completely wiped out in 1997
POLIO
 has been eliminated everywhere in the world except
for few remote villages in northern Nigeria
ECOLOGICAL EPIDEMIOLOGY
RARELY ENCOUNTERED

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Environmental Science
WEEK 6-7 / SIM AND PPT BASED

 Study of the ecology of infectious diseases fatigue

includes population and community level studies of IMMUNE SYSTEM DEPRESSANTS
the interactions between hosts and their pathogens and  suppress the immunes system
parasites and covers diseases of both humans and
wildlife The following are the suspected of disrupting the
immune system and making it susceptible to a variety of
Examples opportunities infections of dead animals:
 Ebola hemorrhagic fever  high levels of pesticides residue
 Chronic wasting disease (CWD)  polychlorinated biphenyis (PCBs)
 Tropical disease: malaria, cholera, yellow fever,  other contaminants
and dengue fever ENDOCRINE DISRUPTORS
 chemicals that disrupt the natural activity of
Resistance to Drugs, Antibiotics, and Pesticides hormones
Protozoan parasite
 causes malaria HORMONES
 resistant to most drugs  chemical released by cells into the
 mosquitoes transmit it have developed resistance to bloodstreams in one part of the body to regulate
many insecticides the function and development of tissues and
organs in the body
Reasons for antibiotic resistance to develop
 antibiotics doesn’t work against certain diseases
harmful effects of persistent chemicals are that they
e.g., viral infections
interfere with healthy growth, development, and
 given to person who could fully recovered
physiology of a variety of animals and humans at
without them
shallow doses
 starting and not finishing prescription
 widespread use of antibiotics in animal
agriculture Hormone  have similar shapes to natural
mimics hormones and amply their effects
Example:
.
(1) BPA (Bisperol A)
 used for plastic products ranging
ECOTOXICOLOGY
from water bottles to tooth-
 study of toxins (poisons) and their effects
protecting sealants
 many substances are known to be poisonous
Hormone  prevent natural hormones from
 toxin’s damage or kill living organisms because they
blockers attaching to their target organ
react with cellular components to disrupt metabolic
Example:
functions
(1) Endocrine disruption
 billionths/millionths of gram can cause irreversible
 linked to increased risk of breast
damage
cancer, develop mental and
reproductive toxicity, allergies, and
EFFECTS OF TOXINS
immune-toxicity.
ALLERGENS
 immune-activating agents
 some acts directly antigens like white blood cells and
NEUROTOXINS
indirectly antigens
 class of metabolic poisons that individually attack
 direct antigens recognize them as foreign and
nerve cells (neurons)
stimulate the production of specific antibodies
 most neurotoxins are both fast-acting and highly
 indirect antigens linking and modifying the
toxic
composition of foreign materials and become antigenic
Types:
and induce immune system to the response
Heavy metals
EXAMPLE (1) Formaldehyde
S  widely used chemical that is potent  lead and mercury
sensitizer of the immune system  causes permanent brain damage
 directly allergenic and can trigger Organophosphates (Malathion, Parathion)
reactions to other substances Carbamates (carbaryl, zineb, maneb)
 commonly used in plastics, wood  inhibit acetylcholinesterase – the
products, insulation, glue, and fabrics enzymes that control the transfer of signals
between nerve cells and the tissue or organs
*sick build syndrome they innervate
 headaches, allergies, and chronic Anesthetics (ether, chloroform, halothane)

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Environmental Science
WEEK 6-7 / SIM AND PPT BASED

Chlorinated hydrocarbons (D.D.T., Dieldrin, disruptors, and have linked to

Aldrin) reproductive abnormalities and
 disrupt nerve cell membranes needed for decreased fertility
nerve action Perchlorate  a waterborne contaminant
leftover of fuel utilized by rockets
TERATOGENS and from propellants
 chemical substance or other factors which cause  includes the cause of pollution
different abnormalities during embryonic growth and in our waters, especially in waters
development used for irrigation.
 ex. rocket/missile propellants,
Alcohol munitions, explosives, fireworks,
 most popular teratogens airbag initiators, and road flares
 can lead to fetal alcohol syndrome during Bisphenol A  widely used in various products
pregnancy (B. P. A.) such as bottled water and tooth-
protecting sealants
 vital component in the creation
CARCINOGENS of polycarbonate plastics
 substance that causes cancer, invasive, and out-of-  an environmental estrogen and
control cell growth resulting in malignant tumors may alter sexual development in
 cancer is the second leading cause of death both males and females
Atrazine  a substance applied to crops
BIOACCUMULATION AND such as corn, cereal grains,
BIOMAGNIFICATION sugarcanes, and Christmas trees
 increase concentrations of toxins as herbicide in the United States
of America
BIOACCUMULATION
 cell performs a selective absorption and storage of
CHEMICAL INTERACTION INCREASING
variation of molecules
TOXICITY
 accumulate nutrients and essential minerals
 may absorb and store harmful substances
SYNERGISM
BIOMAGNIFICATION
 interaction in which one substance intensifies the
 when organisms ingest other organisms making
impact of another material
toxins accumulated from the base and concentrated in
 an important concept that considers pollution at the
the highest tropical level
same time
 interaction of different materials, which results in a
PERSISTENT ORGANIC POLLUTANTS (POPs)
total effect more significant than the added impact of
 are toxic chemicals that adversely affect human health
separate substances
and the environment around the world
 extremely widespread
 found from tropics to the Arctic
 long-living top predators are where it frequently
accumulates
MOST SIGNIFICANT CONCERNS
Polybrominated  known as flame retardants
diphenyl ethers  used in textiles and plastics
(PBDE) found in computers and appliances
 now found in humans and other
species globally

Perfluoro octane  widely used as nonstick,

sulfonate (PFOS) waterproof stain-resistant product
and  ex. Teflon, Gortex,
perfluorooctanoic Scotchguard, and Stainmaster
(PFOA or C8)
Phthalates  present in products such as
(pronounced deodorants, plastics, and cosmetics
thalates)  present in products used for
children's toys, medical
equipment, and packaging for food
 act as endocrine hormone

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Environmental Science
WEEK 6-7 / SIM AND PPT BASED

THE MECHANISMS FOR MINIMIZING TOXIC

EFFECTS MOBILITY, DISTRIBUTION, AND FATE

FACTORS IN ENVIRONMENTAL TOXICITY

Factors Related to Toxic agent
1 Chemical composition and reactivity
2 Physical characteristics (such as solubility, state)
3 Presence of impurities or contaminants
Stability and storage characteristics of a toxic
4
agent
Availability of vehicle (such as the solvent) to
5
carry agent
Movement of the agent through the environment
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and into cells

FACTORS RELATED TO EXPOSURE

1 Dose (concentration and volume of exposure)
2 Route, rate, and site of exposure
3 Duration and frequency of exposure
4 Time of exposure (day, season, year)

RELATED FACTORS TO ORGANISM

Storage, cell permeability of agent and resistance
1
to ingestion
Ability to metabolize, inactivate, sequester, or
2
eliminate the agent
The tendency to activate or alter nontoxic
3
substances, so they become toxic
Concurrent infections or physical or chemical
4
stress
5 Species and genetic characteristics of an organism
6 Nutritional status of the subject
Sex, body weight, age, maturity, and
7
immunological status

Solubility  essential characteristics in determining

how, where, and when a toxic material will
move through the environment
Exposure There are many sources of toxins in our
environment, there are many routes for entry
of dangerous substances into our bodies
• Airborne toxins generally cause
REPAIR MECHANISMS more ill-health compared to other
 Our body performs a damage repair function caused sources.
by the exposure to regular wear-and-tear or toxic or
hazardous materials
 allows individual cells to have enzymes to help repair
the damage in the Deoxyribonucleic acid (D.N.A.) and
protein at the molecular level, organs, and tissues

MEASURING TOXICITY

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Environmental Science
WEEK 6-7 / SIM AND PPT BASED

ACUTE AND CHRONIC DOSES

Acute  the effects of most toxics
Effects  caused by single exposure to the toxin and TOLERANCE
result in an immediate crisis Tolerance  the ability to resist or withstand stress
Chronic  if acute effect became permanent from exposure to a pollutant or harmful
Effect condition
Behavioral  results from changes in the behavior;
Tolerance for example, mice learn to avoid traps
The  a result when the body of an individual
physiological adjusts to tolerate a higher level of
tolerance pollutant

SUSTAINABLE AGRICULTURE
 agriculture is a science and art of growing plants and
other crops, and the raising of animals for food, other
human needs, or economic gain.

NEGATIVE IMPACTS OF AGRICULTURE ON

ENVIRONMENT
RISK ASSESSMENT Land  use of land to yield goods and
Risk  possibility or results of suffering harm Transformation services
or loss by hazard and an indication of the Land  long-term decline in ecosystem
severe damage Degradation function and productivity such as soil
Risk  scientific process of estimating the erosion, soil exhaustion, soil
Assessment threat that hazards pose to human health salinization, overgrazing, frequent
(R.A.)  overall process of hazard identification, burning, and loss of soil biodiversity
risk analysis, and risk evaluation due to use of agrochemicals like
 collection and analysis of site data, pesticides
development of exposure and risk
calculations, and preparation of human TYPES OF PESTICIDES
health and ecological impact reports Organophosphates  most abundantly used synthetic
pesticides
Exposure Assessment Chlorinated  also known as organochlorines
 the process of estimating, measuring, characterizing, hydrocarbons Highly toxic and persistent to
and modeling of the following: sensitive organisms
 Magnitude Fumigants  generally small molecular
 Frequency compounds, like ethylene
 Duration dibromide, methylene bromide, and
 Route of exposure to a possible toxin carbon tetrachloride
Inorganic pesticides  compound made from toxic
elements, like sulfur, copper,
arsenic, and mercury
Natural organic  also known as botanicals
pesticides  extract from plants

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Environmental Science
WEEK 6-7 / SIM AND PPT BASED

Microbial agents  use living organisms or toxins

and biological extracted from them that are used
controls instead of pesticides
 Bacillusthuringiensis
 natural soil bacterium
one of the chief pest
control agents allowed in
organic farming

IMPACTS OF ENVIRONMENT ON AGRICULTURE

1 Global warming
2 Heavy rainfall
3 Flood
4 Acid rain
5 Wind erosion
6 Landslide

ADVANTAGES OF SUSTAINABLE AGRICULTURE

1 Contributes to environmental conservation
2 Prevents pollution
3 Reduces costs
4 Keeps biodiversity
5 Respects the environment
6 Profits farmers economically
7 Preserves social equity

DRAWBACKS OF SUSTAINABLE AGRICULTURE

1 Limited use of lands
2 Takes more work
3 Shorter shelf life
4 Less fertile lands
5 Lower income