MPH 6010 Exam 2 Flashcards
Environmental policy
statement by an organization of its intentions & principles in relation to its overall environmental performance-statement by an organization of its intentions & principles in relation to its overall environmental performance
Goal of environmental policy
reduce human risks or environmental damages resulting from pollution
Precautionary principle
preventive, anticipatory measures should be taken when an activity raises threats of some harm to the environment, wildlife, or human health, even if some cause-and-effect relationships are not fully established-Suggests policymakers should err on the side of an ounce of prevention & take protective measures even when full scientific certainty is lacking
Environmental justice
equal treatment of all people in society irrespective of their racial background, country of origin, & SES
*People should have a opportunity to participate in decisions
*The public’s contribution can influence the regulatory agency’s decision
*Their concerns will be considered in the decision-making process
*The decision makers seek out & facilitate the involvement of those potentially affected
Environmental sustainability
strong, just, & wealthy society can be consistent with a clean environment, healthy ecosystems, & a beautiful planet
*Resources should not be depleted faster than they can be regenerated
*There should be no permanent change to the natural environment
3 components of sustainable development
Materials & energy use
Land use
Human development
Polluter-pays principle
the polluter should bear the expenses of carrying out the pollution prevention & control measures introduced by public authorities to ensure that the environment is in an acceptable state
5 phases of the policy cycle
1- problem definition, formulation, & reformulation
2-Agenda setting
3-Policy establishment
4-Policy implementation
5-Policy assessment`
Agenda setting
Set priorities & involve stakeholders
Beware of lack of information on risk & lack of coordination
Problem definition, formulation, & reformulation
Often seen as the most important phase
Define problems & alternatives
Look into research, public opinion, SES factors, & interest groups
Beware of poorly defined problems
Policy establishment
Formally adopt public policy
Legitimization
Beware of inability to coordinate & assess research information
Policy implementation
Put the policy into practice (government agencies doing so)
Beware of lack of government support
Will likely need to use economic incentives
Policy assessment
How effective was the policy
May incorporate environmental objectives
Environmental objectives
Statements of policy intended to be assessed using information from a monitoring program
Epidemiologic studies & policy making
Epidemiologic studies provide important data to policymakers (interface between science & policy development)
Risk assessment & policy making
Risk assessments help balance economic & other costs with health & societal benefits that may accrue through policy alternatives
4 components connected with policy development
Hazard - Relates to the physical & chemical properties
Risk - Probability of exposure
Impacts - Actual effects of exposure
Social costs - Society’s perception of the importance of harm to the environment
Risk assessment for policy development
Participatory procedure in which the different stakeholders are involved early in the risk analysis process to characterize risk, even before they are given a formal assessment
*Occurs at the very beginning
Goal of risk assessment for policy development
Aims to elicit the values & perspectives of the community so that multiple dimensions of risk can be taken into account early on
Risk management for policy development
the adoption of steps to eliminate identified risks or lower them to acceptable levels
EX- Licensing laws, Standard setting laws, Control oriented measures, Monitoring
Licensing laws
Risk management technique
Require licensing & registration for new & existing chemicals & include requirements for toxicity testing
EX- FIFRA
Standard setting laws
Risk management technique
Establish standards of exposure for chemicals used in specific situations
EX- clean air act
Control oriented measures
Risk management technique
Think design of packages so that they are childproof
Environmental impact
any change to the environment, whether beneficial or adverse, wholly or partially resulting from an organization’s activities, products or services
Environmental impact assessment
process that reviews the potential impact of human-related activities with respect to their general environmental consequences
Health impact assessment
method for describing & estimating the effects that a proposed project or policy may have on the health of a population
EX- Large dams, mines, power plants, airports
Development corridors, urban redevelopment
Mission of US EPA
protect human health & the environment
Develops & enforces environmental regulations which bring about cleaner air and purer water and protect the land
Gives grants, studies environmental issues, sponsors partnerships, teaches people about the environment, & publishes information
Government performance & results act of 1993
EPA has a strategic plan that must be updated periodically because of this act to incorporate new strategic goals
Significance of New York Convention & Kyoto Protocol
set forth international policies to reduce the emission of so-called greenhouse gasses into the atmosphere
Lifestyle approach to ID exposure pathways
environmental policies can be directed toward various lifestyle exposure pathways
Built environment
urban areas & structures constructed by humans as opposed to undeveloped, rural areas
Policies for design of the built environment have great potential for influencing public health
WHO
major international agency that is responsible for environmental health at the global level
Provides leadership in minimizing adverse environmental health outcomes associated with pollution, industrial development & related issue
Federalism
government structured around a strong central government with specified authorities retained by lower levels of government
US agencies responsible for environmental health
EPA
National Institute for Occupational Safety & Health (NIOSH)
Agency for Toxic Substances & Disease Registry (ATSDR)
National Institute of Environmental Health Sciences (NIEHS)
National Institute for Occupational Safety & Health (NIOSH)
Conducts research & makes suggestions to prevent worker injury & illness
Mission is to develop new knowledge in the field of occupational safety & health & to transfer that knowledge into practice
Established by the Occupational Safety & Health Act of 1970
Agency for Toxic Substances & Disease Registry (ATSDR)
Nation’s public health agency for chemical safety
Mission is to use the best science, take responsive action, & provide trustworthy health information to prevent & mitigate harmful exposures to toxic substances & related disease
Created by the Comprehensive Environmental Response, Compensation & Liability Act of 1980
OVERALL…
Protecting the public from toxic exposures
Increasing knowledge about toxic substances
Delivering health education about toxic chemicals
Maintaining health registries
National Institute of Environmental Health Sciences (NIEHS)
Supports a wide variety of research programs directed toward preventing health problems caused by the environment
Environmental advocacy organizations
help educate people & seek to mold public opinion regarding the organizations’ positions on specific topics
Major environmental health laws adopted by the US
Clean air act
Clean water act
Safe drinking water act
National environmental policy act
Federal insecticide, fungicide & rodenticide act
Toxic substances control act
Comprehensive environmental response, compensation & liability act
Resource conservation & recovery act
Occupational safety & health act
Endangered species act
Principles of environmental policy development
The precautionary principle
Environmental justice
Environmental sustainability
The polluter-pays principle
Clean Air Act of 1970
A comprehensive federal law that regulates air emissions from stationary and mobile sources.
Authorizes EPA to establish National Ambient Air Quality Standards (NAAQS) to protect public health and public welfare and to regulate emissions of hazardous air pollutants.
Clean Water Act
The Federal Water Pollution Control Act of 1948 was the first major U.S. law to address water pollution.
As amended in 1972 and 1977, the law became commonly known as the Clean Water Act (CWA).
Established the basic structure for regulating pollutants discharges into the waters of the United States.
Safe Drinking Water Act of 1974
Established to protect the quality of drinking water in the U.S.
Authorizes EPA to establish minimum standards to protect tap water and requires all owners or operators of public water systems to comply with these primary (health-related) standards.
National Environmental Policy Act of 1969
One of the first laws ever written that establishes the broad national framework for protecting our environment.
NEPA’s basic policy is to assure that all branches of government give proper consideration to the environment prior to undertaking any major federal action that significantly affects the environment.
Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) of 1996
FIFRA provides for federal regulation of pesticide distribution, sale, and use.
All pesticides distributed or sold in the U.S. must be registered (licensed) by EPA.
Before EPA registers a pesticide under FIFRA, the applicant must show that using the pesticide according to specifications ‘will not generally cause unreasonable adverse effects on the environment.’
Toxic Substances Control Act (TSCA) of 1976
Provides EPA with authority to require reporting, record-keeping and testing requirements, and restrictions relating to chemical substances and/or mixtures.
Various sections of TSCA provide authority to maintain the TSCA Inventory, under Section 8, which contains more than 83,000 chemicals.
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) 1980
Provides a Federal “Superfund” to clean up uncontrolled or abandoned hazardous-waste sites as well as accidents, spills, and other emergency releases of pollutants and contaminants into the environment.
EPA was given power to seek out those parties responsible for any release and assure their cooperation in the cleanup.
Resource Conservation and Recovery Act (RCRA) of 1976
EPA controls hazardous waste from the “cradle-to-grave.” This includes the generation, transportation, treatment, storage, and disposal of hazardous waste.
Enabled EPA to address environmental problems that could result from underground tanks storing petroleum and other hazardous substances.
RCRA focuses on waste minimization and phasing out land disposal of hazardous waste as well as corrective action for releases.
Endangered Species Act of 1973
Provides a program for the conservation of threatened and endangered plants and animals and the habitats in which they are found.
The U.S. Fish and Wildlife Service (FWS) maintains a worldwide list of endangered species. Species include birds, insects, fish, reptiles, mammals, crustaceans, flowers, grasses, and trees.
Medical advances towards controlling infectious diseases include
Immunizations
Antibiotics
Declines in mortality
Eradication of smallpox
Public health achievements that contributed to controlling infectious diseases include
Improved environmental sanitation
Disinfection of drinking water
Innovations in methods of food storage
Zoonosis
an infection or infectious disease transmissible under natural conditions from vertebrate animals to humans
Can be a disease-causing pathogen that maintains an infection cycle in a host that is independent from humans, who can become inadvertent hosts
Think organisms who can infect both humans & animals during their life cycles
Modes of transmission for zoonotic pathogens
Contact with the skin
Bite or scratch of an animal
Inhalation
Ingestion
Bite of an arthropod vector
Vector
an insect or any living carrier that transports an infectious agent from an infected individual or its wastes to a susceptible individual or its food or immediate surrounding
Rodents & arthropods
Part of the chain of transmission of infectious diseases
Vector-borne infection
several classes of vector-borne infections each with epidemiological features determined by the interaction between the infectious agent & the human host on the one hand and the vector on the other- environmental factors influence the epidemiologic pattern by virtue of their effects on the vector & its habits
How are vector borne infections spread
Spread by biological transmission
Examples of vector-borne infections
Examples include malaria, leishmaniasis, plague, lyme disease, & rocky mountain spotted fever
Malaria
Found in more than 100 countries
-More than 40% of the world’s population at risk
Endemic regions
-Central and South America
-Africa, Middle East
-India, Southeast Asia
-Oceania
Annual death toll: more than 1 million persons
Infectious Agents of Malaria
Plasmodium falciparum
Most deadly
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
Cost of Malaria
Estimated global direct economic costs: $12 billion US annually
Direct costs
-Treatment (e.g., hospitalization, medicine)
-Disease prevention (e.g., medicine, pesticide use)
Other costs
-Lost productivity
-Lost earnings
-Negative impact on tourism and agricultural labor
Malaria Transmission
Involves complex life cycle of mosquitoes (the vector) and human hosts (with human liver and human blood stages)
Transmitted through the bite of an infected mosquito of the anopheles type
What Can Be Done to Control Malaria?
Use of DDT and synthetic antimalaria drugs found to be efficacious in mid-20th century
DDT use opposed by many developed nations, especially the US
-Thought to be harmful to wildlife
South Africa has used annual spraying of DDT inside of homes
Leishmaniasis
The reservoir for the cutaneous form of leishmaniasis includes wild rodents, human beings, and carnivores (e.g., domestic dogs).
Transmitted from the reservoir to the human host by a sand fly (phlebotomus fly)
Endemic in 82 countries
Cutaneous leishmaniasis is transmitted by the bite of an infected sand fly
Environmental Factors Associated with Observed Increases in Leishmaniasis
Movement of the human population into endemic areas
Increasing urbanization
Extension of agricultural projects into endemic areas
Climate change due to global warming
Plague infectious agent
bacterium Yersinia pestis
-Infects both animals and humans
Plague transmission
bite of a flea harbored by rodents (direct contact) then airborne transmission from person to person
Black death
a devastating global epidemic of bubonic plague that struck Europe and Asia in the mid-1300s.
Lyme Disease causative agent
the bacterium Borrelia burgdorferi
Lyme Disease transmission
via black-legged ticks (Ixodes scapularis)- Ingest blood by puncturing the skin of the host
Rocky Mountain Spotted Fever causative agent
Rickettsia rickettsii (rickettsial agent)
Case fatality rate: up to 25% among untreated patients
Rocky Mountain Spotted Fever transmission
bite of an infected tick
Viral Hemorrhagic Fevers (VHF)
Causative viruses require an animal host or insect host (arthropod vector) as a natural reservoir.
Rodents: cotton rat, deer mouse, house mouse
Viruses limited to geographic areas where the host species reside
Arthropod-Borne Viral Diseases
Also known as arboviral diseases
Group of viral diseases that can be acquired through bite of blood-feeding arthropod vector
Vectors that transmit arboviruses
-Ticks
-Sand flies
-Biting midges
-Mosquitoes
Four Main Clinical Symptoms of Arboviral Disease
Acute central nervous system (CNS) illness
Acute self-limited fevers, with and without exanthem (rash)
Hemorrhagic fevers
Polyarthritis and rash, with or without fever and of variable duration
Arboviral Encephalitis
Caused by a virus that produces an acute inflammation of:
-Sections of the brain
-Spinal cord
-Meninges
Etiologic agents include viruses associated with many forms of encephalitis.
-St. Louis encephalitis
-Western equine encephalitis
-LaCrosse encephalitis
Cost
approximately $150 million, including vector control and surveillance activities
Transmission of Arboviral Encephalitis
bite of an arthropod vector (primarily mosquitoes)
Reservoirs for Arboviral Encephalitis
nonhuman vertebrate hosts (e.g., wild birds and small animals)
West Nile Virus
Mosquito-borne arboviral fever
-Mosquitoes become carriers after feeding on infected birds
Etiologic agent: Flavivirus
Factors Associated with the Rise of Emerging Zoonoses
Ecological changes resulting from agricultural practices
-Deforestation
-Conversion of grasslands
-irrigation
Other factors
-Changes in the human population and human behavior (e.g., wars, migration, and urbanization)
Hantavirus Pulmonary Syndrome (HPS) causative agent
hantavirus (Bunyaviridae family)
Hantavirus Pulmonary Syndrome (HPS) transmission
inhalation of aerosolized (airborne) urine and droppings from infected rodents
Primary vectors: four species of rodents
-Cotton rat, rice rat, white-footed mouse, and deer mouse
Dengue Fever
Causative agent: flaviviruses
Mortality rate: Dengue hemorrhagic fever (DHF) is life-threatening.
Affected areas: primarily tropical and subtropical areas of the world
Transmission: bite of Aedes aegypti mosquito
Chlamydia psittaci
a type of bacteria that often infects birds. Less commonly, these bacteria can infect people and cause a disease called psittacosis. Psittacosis can cause mild illness or pneumonia (lung infection). To help prevent this illness, follow good precautions when handling and cleaning birds and cages.
Control of Mosquito-Borne Diseases
Use sentinel chickens and birds to monitor for presence of viruses.
Drain standing water.
Introduce mosquito-eating fish into ponds.
Wear repellents and protective clothing.
Repair window screens.
Toxic Metals
Heavy metals (e.g., lead, mercury, nickel)
Other metallic compounds (e.g., aluminum, iron, tin)
Featured in the CERCLA Priority List of Hazardous Substances
CERCLA Priority Listof Hazardous Substances
The Agency for Toxic Substances and Disease Registry (ATSDR) has identified a list of rank-ordered hazardous substances, known as the CERCLA Priority List of Hazardous Substances.
This list is revised and published on a 2-year basis, with a yearly informal review and revision
Characteristics of Hazardous Substances on the CERCLA Priority List
Pose the most significant potential threat to human health because they have:
-Known or suspected toxicity and
-Potential for human exposure at NPL sites
It is possible for substances with low toxicity but high NPL frequency of occurrence and exposure to be of the priority list.
Examples of Hazardous Substances from the 2007 CERCLA Priority List of Hazardous Substances
Arsenic
Lead
Mercury
Benzene
Cadmium
DDT, p, p’-
National Priorities List (NPL)
This is “EPA’s list of the most serious uncontrolled or abandoned hazardous waste sites in the United States identified for possible long-term remedial action under Superfund.”
Sites are scored based on the Hazard Ranking System and updated at least once a year.
Heavy Metals
A heavy metal has a high atomic weight with a specific gravity that exceeds the specific gravity of water by five or more times
Classification of Toxic Effects of Metals
Major toxic metals with multiple effects
Essential metals with potential for toxicity
Metals related to medical therapy
Minor toxic metals
Bioaccumulation
Toxic substances such as heavy metals become more concentrated and potentially more harmful as they move up the food chain
Modes of Exposure
Lungs (through inhalation of dusts, metal fumes, and vapors)
Skin (through contact with dusts)
Mouth (by ingestion)
High- Level Contacts
Contact with high concentrations of toxic metals is most likely to occur in an occupational setting, e.g., among persons who work with metals
Low- Level Contacts
Lower-level exposures may result from contact with the ambient environment (e.g., children may ingest toxic metals present in paint).
Acute Toxic Metal Poisoning
The symptoms of acute poisoning from exposure to metals generally have rapid onset—from a few minutes to approximately one hour.
Depending upon portal of entry, symptoms may consist of gastrointestinal effects (vomiting and stomach pain) and neurological effects (headaches, suppression of normal breathing, and convulsions).
Gender and Age Differences and Heavy Metal Exposure Effects
The health effects of exposure to heavy metals (e.g., nickel, cadmium, lead, and mercury) are different for women than they are for men
For children, heavy metals are known to present serious hazards, which can include
-impairment of physical and mental development
-damage to internal organs and the nervous system
-some forms of cancer
-mortality
-Nervous system damage
-Memory impairment
-Difficulty in learning
-Range of behavioral problems, such as hyperactivity syndrome and overt aggressiveness
**CAN cross placental barrier
Major Toxic Metals with Multiple Effects
Arsenic
Beryllium
Cadmium
Chromium
Mercury
Lead
Nickel
Arsenic
Varies in toxicity depending upon its chemical form
Byproduct of refining gold and other metals
Used in pesticides, wood preservatives, and in manufacturing processes
Exposure can come from ingestion and inhalation
Standards for Arsenic
10 µg of arsenic per liter of drinking water in 2001
Potential Health Effects of Arsenic Exposure
Skin, bladder, kidney, and liver cancer when ingested
Lung cancer when inhaled
Peripheral vascular disease
Cerebrovascular disease
Cardiovascular disease, e.g., hypertensive heart disease
Diabetes (long-term exposure)
Adverse pregnancy outcomes–spontaneous abortions, stillbirths, and preterm births
Beryllium
Used widely in industry because of its special properties (lighter than aluminum and stronger than steel)
Employees in the metal processing industry most likely to be exposed
Inhalation one of the most common methods of exposure
Class A carcinogen
Cadmium exposure
-cigarette smoke and dietary cadmium-think shellfish and mushrooms
-Occupational exposure to cadmium comes from the production of nickel cadmium batteries, zinc smelting, manufacture of paint pigments, soldering, and from employment in metal factories.
Effects of Cadmium Exposure
Osteoporosis in women
Height loss in men
Kidney damage
Elevated blood pressure
Cardiovascular diseases
“Itai-Itai” disease
Chromium
Naturally occurring element in the earth’s crust
Most common forms are:
-chromium(0)
-chromium(III): an essential nutrient
-chromium(VI): classified as a carcinogen
Effects of Hexavalent Chromium(VI) Exposure
Digestive problems and damage to organs such as the kidney and liver when ingested.
Produces skin ulcers when applied to the skin.
Inhaling chromium(VI) in high concentrations may cause respiratory problems, for example, nose bleeds, perforation of the nasal septum, and runny nose.
Erin Brockovich
Advocated for residents of Hinkley, California, against a power company accused of polluting the town’s water with chromium (VI)
Mercury
Naturally occurring metal that is highly toxic
Released into the environment as a by-product of industrial processes
Even at low levels, mercury deposited in bodies of water represents a potential hazard to human health
Methylation
microorganisms convert elemental mercury into methyl mercury.
The process of bioaccumulation causes mercury levels to become more concentrated in aquatic invertebrates
Minamata disease
In 1956, an environmental catastrophe occurred in Minamata Bay, Japan, where approximately 3,000 cases of neurologic disease resulted among people who ate fish contaminated with methyl mercury. The neurologic condition, which became known as Minamata disease , was characterized by numbness of the extremities, deafness, poor vision, and drowsiness
New almaden mine
mercury contamination from this former mining operation poses a continuing hazard to fish and aquatic life in the affected geographic area; signs have been posted to warn persons not to consume fish caught in nearby streams and lakes due to potentially toxic levels of mercury.
Lead exposure methods
Sources of environmental lead include leaded gasoline, tap water from soldered pipes, and painted surfaces in older buildings.
Another common source of household lead exposure is imported pottery that is used in food service
Effects of Lead Exposure
Serious central nervous system effects and other adverse health consequences occur even when ingested at low levels
Lead poisoning
one of the most common environmental pediatric health problems in the United States
Nickel
Classified as a heavy metal, nickel is one of the constituents of the earth’s crust.
Human exposure to low levels of nickel is probably universal and unavoidable.
Employed in the production of many of the appliances and tools that are used in everyday life, such as nickel cadmium batteries.
Effects of Nickel Exposure
One of the common reactions to skin contact with nickel is nickel allergy, manifested as contact dermatitis.
Cardiovascular-related and renal diseases as well as fibrosis of the lungs
Potential carcinogenic action
Essential Metals with Potential for Toxicity
Copper, zinc, and iron are essential for human nutrition but can be toxic if ingested in excessive amounts.
An optimal range of these essential metals is necessary to maintain health
Copper and the Environment
in electrical wires, pipes, in combination with other metals to form alloys, as a mildew inhibitor, and as a wood and leather preservative
Exposure to Copper
inhalation, ingestion of copper-containing foods and water, and direct contact with the skin
tap water from copper piping
Effects of Copper Exposure
respiratory and gastrointestinal disturbances
Very high levels are known to cause liver damage, renal damage, and death
Zinc
Used commercially as a coating for rust inhibition, as a component of batteries, and in combination with other metals to make brass, bronze, and other alloys
A nutritional element that is important for maintaining health
in earth’s crust
Negative Effects of Excessive Amounts of Zinc
gastrointestinal problems such as stomach cramps, nausea, and vomiting
anemia and damage to the pancreas
Breathing high concentrations of zinc in the workplace causes a disease known as metal fume fever. This condition appears to be an immune-mediated response that originates in the lungs
Iron
Vital to human health, iron is important to the growth of cells and the transport of oxygen within the circulatory system
in earth’s crust
Iron Toxicity
Acute iron intoxication (accidental iron poisoning) is among the most common childhood poisonings.
Other groups at risk from iron overload (iron toxicity) include adult men and postmenopausal women
Metals Used in Medical Therapies
Aluminum
Bismuth
Gold
Lithium
Aluminum
used widely in food and beverage containers, in pots and pans, and in construction sites
ingredient in various medicines and cosmetics, for example, buffered aspirin and antiperspirants
Concern about possible association with Alzheimer’s disease
Aromatic Compound
Organic molecule that contains a benzene ring
Examples: benzene and toluene
Hydrocarbon
Organic compound containing only carbon and hydrogen
Examples: acetylene, benzene, and butane
Often occur in petroleum, natural gas, coal, and bitumens
Organic Chemical
Naturally occurring (animal or plant-produced or synthetic) substances containing mainly carbon, hydrogen, nitrogen, and oxygen.
Example: table sugar
Persistent Organic Pollutants (POPs)
Toxic chemicals that adversely affect human health and the environment around the world
Can be transported by wind and water
Most affect people and wildlife far from where they are used and released
Example POP: the pesticide DDT
Polycyclic Aromatic Hydrocarbons (PAHs)
over 100 different chemicals that are formed during the incomplete burning of coal, oil and gas, garbage, or other organic substances like tobacco or charbroiled meat
Volatile Organic Compounds (VOCs)
Organic compounds that evaporate readily into the air
Examples: benzene, toluene, methylene chloride, and methyl chloroform
Pesticide
“Any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating pests. Pests can be insects, rodents, weeds, and a host of other unwanted organisms.”
Insecticide
Compound specifically used to kill or prevent the growth of insects
Herbicide
Chemical pesticide designed to control or destroy plants, weeds, or grasses
Fungicide
Pesticide that is used to control fungi
Nematocide
Chemical agent that is destructive to nematodes
Rodenticide
Agent used to destroy rats and other rodent pests or to prevent them from damaging food, crops, etc
Four Major Classes of Pesticides and Insecticides Derived from Organic Chemicals
Organophosphates (OPs)
Organocarbamates (also called carbamates)
Organochlorides (also called organochlorines)
Pyrethroids (from the class of pyrethrins)
Organophosphate Pesticides (Anticholinesterases)
Inexpensive in comparison to alternatives
Can be used to control a wide range of insects
Have not been weakened by the resistance of insects
Tend not to persist in the environment
Are a frequent cause of fatal poisonings
Effects of Organophosphate Poisoning
Acute effects
-Anticholinesterase activity
-Causes impairment of the neural impulse transfer mechanism
Long-term effects
-Organophosphate-induced delayed polyneuropathy
-Manifested by numbness, loss of sensory abilities, and weakness
Diazinon, malathion, methyl parathion, and parathion
-Sprays, baits, indoor foggers/bombs, flea collars, pet shampoos, powders, animal dips, and granules
Examples of Organophosphate Pesticides
Carbamates
Close relatives of the organophosphate pesticides
Dissipate quickly from the environment as a result of breaking down into other substances
Some approved for controlling garden pests (e.g., wasps, hornets, snails)
An ingredient in some products applied to furry pets to control ticks and fleas
Carbyl (Sevin)
Aldicarb
Fenoxycarb
Propoxur
Metam sodium
Examples of Carbamates
Methyl Isocyanate (MIC)
Intermediate chemical used for the manufacture of carbamate pesticides
Acute exposure extremely toxic to life forms (e.g., human beings, aquatic organisms, and plants)
MIC Release in Bhopal, India
A notorious incident was the accidental release of MIC during a 1984 industrial accident in Bhopal, India.
More than 3,800 people were killed
Organochlorines
Derived from chlorinated hydrocarbons
-Chemical compounds that contain chlorine, carbon, and hydrogen
Characteristically stable and fat-soluble
-Persist in the environment
-Bioaccumulate in the food chain
Associated with suppression of the immune system and cancer
DDT
Lindane
Chlordane
Mirex
Hexachlorobenzene
Methoxychlor
Examples of Organochlorine Pesticides
DDT History
Beginning of widespread use: early 1940s
Maximum use: 1960s
Use in US prohibited: 1972 due to concerns about the possible adverse effects on the health of humans and wildlife
Current status- most developed nations have banned DDT.
Facts about DDT
-Not regarded as a highly toxic pesticide
-Formerly employed worldwide to control insects and harmful mosquitoes that carry malaria
-Was credited at one time with saving millions of people from death due to malaria
-Concentrates in the adipose (fatty) tissues of the body
-Has estimated half-life of approximately 10 years
-All living organisms on earth contain some level of this pesticide.
Human Health Effects of DDT
Linked to
Cancer (pancreatic, non-Hodgkin’s lymphoma, and breast)
Reproductive effects
Impaired lactation
Falling sperm counts
Impaired neurologic function (irritability, dizziness, and numbness)
Pyrethrins
Derived from natural sources
-Certain varieties of chrysanthemum flowers
Have great ability to paralyze and kill flying insects
Interfere with transmission of neural impulses via action on sodium channels
Use of Pyrethrin Insecticides
Generally have low concentrations of the active ingredient
Used inside the home in aerosol cans, insecticide bombs, insecticidal pet shampoos, treatments for lice applied directly to humans, and mosquito repellents
May be inhaled as a result of spraying and may be ingested in foods
Atrazine
Paraquat
Agent Orange (2,4-D and 2,4,5-T)
Herbicides/Defoliants
Agent Orange
Used during the Vietnam War
-Operation Ranch Hand (1962–1971)
Approximately 19 million gallons of defoliants sprayed on 3.6 million acres in Vietnam and Laos
Contained small amount of dioxins
Health Effects of Agent Orange
Soft tissue sarcoma
Non-Hodgkin’s lymphoma
Hodgkin’s disease
Chronic lymphocytic leukemia
Dioxins
A family of chemical compounds that are unintentional byproducts of certain industrial, non-industrial and natural processes, usually involving combustion
-419 known compounds exist.
-Only about 30 are considered the most poisonous.
-Stable, persistent, and bioaccumulate within the food chain
Biopesticides
Pesticides derived from natural materials such as animals, plants, bacteria, and certain minerals
Examples
-Microbial pesticides
-Plant-incorporated protectants
-Biochemical pesticides
What Natural EventsProduce Dioxins?
Forest fires and volcanic eruptions - creates natural background dioxins
What Human Activities Produce Dioxins?
Incineration of industrial and municipal wastes
Burning of some fuels
Bleaching of wood pulp for paper manufacturing process
Manufacture and application of some herbicides
Tobacco combustion
Minute amounts of dioxin in cigarette smoke
Health Effects of Exposure to Dioxin
Chloracne
Skin rashes
Skin discoloration
Growth of excessive body hair
Liver damage
Possible cancer risks
Endocrine effects
Reproductive and developmental effects
Polychlorinated Biphenyls (PCBs)
present in the environment tend to bioaccumulate in fish and other animals used for food and, in turn, affect human health
Common uses before no longer made
-Insulating fluid in transformers and capacitors
-Lubricant
PCB Contamination
Known to be present at as many as 500 sites
Denoted on the 1,598 sites that the EPA has provided on the National Priorities List
Manufacturing terminated in 1977
Health Effects of PCBs
Causes cancer in animals
Designated as probable human carcinogen
May impact the immune system, reproductive system, and children’s intellectual development
May limit the development of immune responses to the Epstein-Barr virus and other viral and bacterial infections
Organic Solvents
Liquid substance capable of dissolving other substances; ‘the solvent does not change in forming a solution’
Solvents: Modes of Exposure
Breathing vapors directly
Ingesting in foods and water
Using foods and cosmetics packed in certain types of plastics
Smoking cigarettes
Working in a factory: chronic exposure
Inhaling vapors released by industrial facilities
Drinking solvent-contaminated groundwater
Tetrachloroethylene
Trichloroethane
Trichloroethylene (TCE)
Toluene
Acetone
Benzene
Examples of Solvents
Styrene
Uses
-Used for the manufacture of polystyrene resins, which are components of many types of plastics
Effects of short-term inhalation
-Central nervous system effects, such as muscle weakness, and problems concentrating on tasks
-Irritation of the respiratory tract
-Possibly carcinogenic
Vinyl Chloride
Mainly for the manufacture of polyvinyl chloride, which is an ingredient in plastic products such as pipes, vinyl siding for houses, plastic coatings, and upholstery
Classified as a human carcinogen
Environmental Estrogens
organic chemicals with estrogenic activity
Sometimes DDT (and its metabolites) is called an endocrine disruptor, meaning that it acts as an antagonist to androgen
Hydrological Cycle
the movement of water in the environment (solar powered)
consists of evaporation, condensation, transportation, evapo-transpiration, precipitation, and runoff
Effects of Environmental Estrogens
May have abnormal influences on the reproductive systems of exposed humans and animals
May act as cancer promoters by having an influence on the onset of female cancers that are thought to be caused by estrogenic activity
Facts about water
freshwater is a limited resource
Hydrological cycle and groundwater depletion- water is both renewable and nonrenewable
Water Pollution
the impairment of water for any of its beneficial uses by anthropogenic alterations of water quality
Water Pollutants
Toxicants
Thermal
Suspended Solids
Organic Matter
Eutrophication
Pathogens
Objective of Drinking Water Treatment
Provide a potable water supply
Safe for human consumption (pathogens)
Aesthetically acceptable
-Turbidity (Cloudy)
-Color
-Tastes
-Odors
Sources of Drinking Water
Groundwater
-Wells
Surface water
-Rivers
-Lakes
-Reservoirs
Groundwater
Uniform Quality
low turbidity
low color
low or no DO
Undesirable minerals
high Fe, Mn
high hardness
Surface water
Variable Quality
high turbidity
colored
DO present
low hardness
taste and odor
4 stages of water treatment
-Coagulation
-Sedimentation
-Filtration
(first 3=clarification)
-Disinfection
Coagulation
removes suspended material using aluminum sulfate
Rapid Mix and Flocculation
-Paddle units rotate slowly, (1 – 2 rpm).
-Causes collisions of colloidal particles in solution
-Results in growth of flocs to sizes that are easily removed by settling or filtration
Coagulant Characteristics
Non-toxic and relatively inexpensive
Insoluble in neutral pH range - do not want high concentrations of metals left in treated water
Alum: Al2(SO4)3.14H2O
Ferric chloride: FeCl3
Ferric sulfate: FeSO4
Examples of coagulants
Sedimentation
The removal of particles from solution by gravity
As the flocs formed, they are removed using settling
To achieve settling, water containing flocs is passed to settling basins
At least 3 hours for flocs to settle on the bottom
Filtration
Designed to remove particles that are too small to be removed during sedimentation
Types of Filters
Single media: sand
Dual media: anthracite coal and sand
Multimedia: anthracite coal, sand and garnet (silicates)
Disinfection
Final stage of treatment
Chlorine gas is the most common disinfectant
Goal of “Disinfection”
-Remove pathogens by killing them
-Provide chlorine residual
-Prevent growth of organisms in distribution system
-Kill pathogens that enter via infiltration and cross contaminations
Disinfection by-products (DBPs)
Concerns
-THMs linked to gastrointestinal cancers
-THM levels regulated
-80ppb as annual average (as total THMs)
Trihalomethanes (THMs)
-CHCl3, CHCl2Br, CHClBr2 and CHBr3
Examples of Disinfection by-products (DBPs)
Hypochlorite salts: NaOCl and Ca(OCl)2 as disinfectants
-more expensive
-more common for small supplies
–Pools
–Small community systems
Chloramines (NH2Cl, NHCl2, NCl3) as disinfectants
longer contact time is required
Chlorine dioxide (ClO2) as disinfectants
very effective
must be produced on site
Ultraviolet radiation as disinfectants
Pros:
-effective bactericide and viricide
Cons:
-water must be free of turbidity and lamps free of slime and precipitates
-no residual protection
Ozone (O3) as disinfectants
Pros:
-very effective – kills cysts
-no taste and odor problems
-widely used in Europe
Cons:
-no residual
-produced on site
-energy requirements make it more expensive than chlorine
Advanced Treatment Processes- Activated Carbon adsorption
Remove synthetic organic chemicals, THMs, taste and odor compounds
Bacteria will grow on activated carbon
Reasons americans drink bottled water
aesthetic reasons: the taste, smell, and appearance of the water
How is tap water treated
with chlorine which can leave an aftertaste
How is bottled water treated
ozonation or reverse osmosis for no aftertaste
Bottled Water Regulations
Considered a food/product.
The U.S. Food and Drug Administration (FDA) regulates bottled water, but there is no standard as to what constitutes bottled water
Is EPA responsible for safety of bottled water?
NO- just safety from public water systems
Is Bottled Water Safer?
No- potential bacterial growth in the water
Trihalomethanes (THMs)
by-products by the practice of public water suppliers of adding chlorine to drinking water to remove bacteria which have been linked to bladder and rectal cancers
REASON FOR BOTTLED WATER
