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Impacts on the Environment & Human Health

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Dean Chigounis

on 9 April 2014

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Transcript of Impacts on the Environment & Human Health

Transcribed from Miller's Living in the Environment & Barron's AP Environmental Science by C. Chigounis, April 2014
Impacts on the Environment & Human Health
Hazards to Human Health
Cigarette smoke contains over 4,700 chemical compounds including 60 known carcinogens.
No threshold level of exposure to cigarette smoke has been defined.
Long term evidence indicates long-term smoking greatly increases likelihood of developing numerous fatal conditions.
Cigarette smoking associated with 85% of lung cancer cases as well as mouth, pharynx, larynx, esophagus, stomach, pancreas, kidney, bladder, and colon cancers.
Cigarette smoking has also been linked to leukemia, cardiovascular disease, stroke, sudden death, cardiac arrest, peripheral vascular disease, and aortic aneurysms.
Many components of cigarette smoke classified as ciliotoxic material (irritate the lining of respiratory system)

Smoking and Other Preventable Risks
Hazards to Human Health
Risk Analysis
: the weighing of a risk to the related benefits. Overall process that allows one to evaluate and deal with the consequences of events based on probability.
Four
classes of risk:

High risk: smoking, driving while intoxicated, etc.
Low risk: infrequent events with large consequences (earthquake on the East Coast of US)
Very low risk: events that have never been recorded in history (major meteor striking North American continent
Mixed risk: outcomes that increase in frequency against a background of occurrences (cases of cancer beyond the norm).

Understanding how people take risks is associated with their preferences.
Three
types of preferences:
Revealed preferences
: observations on the risks people actually take
Expressed preferences:
measured through public opinion polls
Natural Standards
: risks people have historically taken in the past

Risk Analysis:
divided into risk assessment & risk management.
Risk assessment
is an objective estimation of risk (includes identification of hazards, does-response assessments, exposure assessments, etc.
Risk management
: process of determining what to do about risk (includes risk identification and use of mitigating measures to reduce risk).
Acute & Chronic Effects
Acute health effects
: characterized by sudden & severe exposure and rapid absorption of the substance. Normally, a single large exposure involved. Effects are often reversible ex. CO poisoning

Chronic health effects
: occur over prolonged or repeated exposure over many days, months, or years. Symptoms may not be immediately apparent. Chronic health effects often irreversible. ex. lead or mercury poisoning, asbestosis, or cancer
Dose-Response Relationships
Dose-Response
: describes the impact a chemical, etc. has on a population resulting from differing levels of exposure to that substance.
Observes how various doses impact organisms.
Relationships are used in determining whether various environmental risks are safe or hazardous.
Dose-Response Curve:
graph that relates the amount of drug or toxin given (plotted on x-axis) compared with the response (plotted on y-axis). Area on graph where response first observed is known as "threshold dose". Beyond this point, negative side effects begin to appear
LD50 (lethal dose 50%)
: median lethal dose of a pollutant or drug that
kills
half the tested population within 14 days and is most common indicator of toxicity.
EC50:
the concentration of a compound where 50% of its effect is observed.
Typical Dose-Response Curve
Air Pollutants
Air Toxins
air pollutants known to cause health problems
ex) asbestos, benzene, chloroform, formaldehyde, lead, mercury, nickel, perchloroethylene
Asbestos
exposure in asbestos factories and shipyards known to cause asbestosis.
lungs become scarred with fibrous asbestos.
victims usually exposed to high levels for long period of time.
symptoms (mesothelioma) usually don't appear until 20-30 years post first exposure
Carbon Monoxide
created from incomplete combustion
enters bloodstream via lungs and binds with hemoglobin (molecule that transports oxygen)
results in slowed reflexes, confusion, drowsiness, brain damage, death, etc.
Indoor Air Pollutants
may be acute or chronic
may occur after single exposure or prolonged exposure
typical symptoms: respiratory disease, heart disease, cancer
Lead
exposure via inhalation or ingestion
can lead to seizures, brain & kidney damage, mental retardation, and / or behavioral disorders
children six and under most at risk

Nitrogen Dioxide
health effects include coughing, wheezing, shortness of breathe
Even short exposures to nitrogen dioxide can affect lung function and may cause permanent structural changes in lungs
Ozone
damages lung tissue, reduces lung function, sensitizes lungs to other irritants
low concentration exposure over several hours can still induce respiratory inflammation

PM10
coarse particles can aggravate asthma
exposure to fine particles associated with premature death
older people especially sensitive
can increase susceptibility to respiratory infections
Radon
invisible, radioactive gas resulting from radioactive decay of radium found in soil or rock formations
associated with indoor air pollution
radon is heavy gas and accumulates at floor level
especially bad in well-insulated homes
Sulfur Dioxide
high concentrations of sulfur dioxide affect breathing and may aggravate existing respiratory and cardiovascular disease
sensitive people may include asthmatics, individuals with bronchitis or emphysema, children, or elderly
Preventable Risks & Death Rates in the US
Relevant Laws
Federal Hazardous Substances Act (1960):
required that certain hazardous products bear cautionary labels to alert consumers to the potential hazards of these products.
Federal Environmental Pesticides Control Act (1972
): required registration of all pesticides in the US.
Hazardous Materials Transportation Act (HAZMAT) (1975)
: governs the transportation of hazardous materials and wastes. Covers containers, labeling, and marking standards.
Toxic Substance Control Act (1976)
: gives the EPA the ability to track the 75,000 industrial chemicals currently produced in or imported into the US.
Comprehensive Environmental Response, Compensation and Liability (CERCLA) 1980
: established federal authority for emergency response and cleanup of hazardous substances that been been spilled, improperly disposed of, or released into the environment.
Nuclear Waste Policy Act (1982)
: established a study to find a suitable site for disposal of spent fuel from nuclear reactors. Yucca Mountain, Nevada, seems most feasible at this time.
Hazardous Chemicals in the Environment
Hazardous waste:
waste that is dangerous or potentially harmful to human health or environment. Can be liquids, solids, gaseous, or sludge. EPA has separated hazardous wastes into following categories:

Corrosive
: are wastes that are acidic or alkaline and capable of corroding metal containers, such as storage tanks, drums, or barrels. ex) battery acid

Discarded Commercial Products
: commercial chemical products in unused form. Some pesticides and some pharmaceutical products become hazardous wastes when discarded

Ignitable
: wastes that can create fires under certain conditions, are spontaneously combustible, or have a flash point less than 140'F. Examples include waste oils and used solvents.

Mutagens:
physical or chemical agents that changes the genetic material, usually DNA, of an organism thus increasing the frequency of mutations above the natural background level. Many mutations cause cancer, as mutagens are typically also carcinogenic. Examples) nitrous acid, bromine and bromine-containing compounds, sodium azide (as found in car safety air bag systems), and benzene.

Nonspecific Source:
these include wastes from common manufacturing and industrial processes, such as solvents that have been used in cleaning or degreasing operations.

Reactive:
are unstable under normal conditions; can cause explosions, toxic fumes, gases, or vapors when heated, compressed, or mixed with water. Examples) lithium batteries and explosives

Source Specific:
wastes from industries, such as petroleum refining or pesticide manufacturing. Examples( certain sludges and wastewaters from treatment and production processes.

Teratogens:
substances that cause birth defects; examples include drinking alcohol (ethanol), radioactive compounds, dioxin, certain pharmaceuticals (dilantin, lithium, mercury, tetracycline, ethers, tabacco, and excessive caffeine.
Treatment, Disposal, & Cleanup of Contaminated Sites
Strategies to cleanup hazardous waste:
producing less
converting hazardous material to less hazardous substances
placing toxic material into perpetual storage

Produce less waste:
recycle: collect hazardous waste and use them as raw material for new products
reduce or eliminate toxicity: substitute for hazardous chemicals. ex) puron for freon
Conversion to less hazardous or nonhazardous substances
:

chemical, physical, & biological treatment
: bioremediation uses bacteria to break down hazardous material. Phytoremediation involves rhizofiltration (using sunflowers to absorb radioactive wastes), phytostabilization (using willow and poplar trees to absorb organic contaminants), phytodegradation (using poplars to absorb and break down contaminants), and phytoextraction (using Indian mustard and brake ferns to absorb metal contaminants).
Pros
: inexpensive, low energy, little to no air pollution, easy to build
Cons
: slow, effective only as far down as roots will reach, some toxins can evaporate through plants, plants can be toxic and need to be disposed of properly, chemical methods involve cyclodextrin.
Incineration:
can release air pollutants and toxic ash (such as lead, mercury, and dioxins)

Thermal Treatment:
Plasma arcs. Pros: small, mobile, no toxic ash. Cons: expensive and can release particulates, chlorine gas, toxic metals, and radioactive wastes

Arid Region Unsaturated Zone:
unsaturated zone is the subsurface between the land surface and underlying aquifers; includes sites in the arid western US that are being relied upon to isolate significant portions of the nation's radioactive and other hazardous wastes for thousands of years
Capping:
often used in combination with other cleanup methods, covers buried wastes to prevent contaminants from spreading; spreading or mitigation of buried wastes can be caused by surface water moving through site or by wind blowing dust off site; primary purpose of cap is to minimize contact between rain and surface water and the buried waste.
Caps: a) minimize water movements through the wastes by using drainage, b) resist damage caused by settling, c) prevent standing water by funneling away as much water as the underlying filter or soils can handle.
Capping is used when the underground contaminants is so expensive that excavating and removing it isn't practical or when removal would pose more threats to human health. Wells are often used to monitor groundwater where a cap has been installed.
Landfill:
Pros: inexpensive
Cons: groundwater seepage and contamination

Salt Formations:
toxic wastes deposited in deep salt formations. Absence of flowing water within natural salt formations prevents dissolution and subsequent spreading of waste products. Rooms and caverns in salt can be sealed, thus isolating waste from biosphere.

Surface Impoundments:
excavated ponds, pits, lagoons. Pros: low cost, low operating cost, built quickly, wastes can be retrieved and, if lined, can be stored for long periods. Cons: groundwater contamination, VOC pollution, overflow occurs, earthquakes, promotes waste production
Underground Injection:
Pros: low cost, wastes can be retrieved, simple technology. Cons: leaks, earthquakes, groundwater contamination

Waste Piles:
storage of toxic materials in drums, underground vaults, or above-ground buildings. Pros: easy to identify leaks. Cons: shipping of materials to facilities results in accidents.
Case Study
First synthesized chlorinated pesticide was DDT. It appeared to have low toxicity and was broad spectrum. It did not break down, so it did not have to be reapplied often. Crop production increased and mosquitoes decreased. In 1962, Rachel Carson published Silent Spring, which made the connection between DDT and nontarget organisms by direct and indirect toxicity. DDT persisted in the environment through bioaccumulation (and increase up the food chain) and biomagnificaiton (concentration in tissue). DDT was found to decrease eggshell thickness in several species of birds, nearly wiping out bald eagles and peregrine falcons. DDT was beginning to show up in the native people of the Arctic, seals, and human breast milk. It was pulled off US market and now being manufactured in Indonesia.
Bioaccumulation
Bioaccumulation:
the increase in concentration of a pollutant from the environment in an organism or part of an organism.

Involves biological sequestering of substances that enter the organism through respiration, food intake, or epidermal (skin) contact with the substance.

The level at which a given substance is bioaccumulated depends upon:
rate of uptake
mode of uptake (gills, ingested along with food, contact with skin, etc.)
rate the substance is eliminated from organism
transformation of the substance by metabolic processes
lipid (fat) content of organism
environmental factors
Biomagnification
Biomagnification
: the increase in concentration of a pollutant from one link in the food chain to another.

In order for biomagnification to occur, the pollutant must be long-lived, mobile, soluble in fats, and biologically active.
If a pollutant is short-lived, it will be broken down before it can become dangerous.
If it is not mobile, it will stay in one place and be less likely to be taken up by many organisms.
If the pollutant is soluble in water, it will be excreted by the organism.
Pollutants that dissolve in fats, however may be retained for long periods of time. It is traditional to measure the amount of pollutants in fatty tissues of organisms such as fish. In mammals, milk produced by females is often tested since milk is high in fat and because the young are often more susceptible to damage from toxins.
Bioaccumulation vs. Biomagnification
Example: methylmercury is taken up by bacteria and phytoplankton. Small fish eat the bacteria and phytoplankton and
accumulate
the mercury. The small fish in turn are eaten by larger fish, which can become food for humans and animals resulting in the buildup (
biomagnification
) of large concentrations of mercury in human and animal tissue. As a general rule, the more fat-like a substance is, the more likely it is to bioaccumulate in organisms, such as fish.
Economic Impacts
Cost Benefit Analysis
: technique for deciding whether to make a change. One adds up the benefits of an action and subtracts the costs associated with it.

Costs can be one time or ongoing.
Benefits are most often received over time.
Time is factored into a cost benefit analysis by calculating pay-back period - the time for the benefits of change to repay its costs.
Carried out using only financial costa and benefits
ex) cost-benefit analysis of new road would entail cost of building the road subtracted from the economic benefits of improving transport links. Simple cost-benefit analysis would NOT measure either the cost of environmental damage or the benefit of quicker and easier travel to work. More sophisticated approach is to attempt to put a financial value on intangible costs and benefits, which is highly subjective.

Cost benefit analysis applies to
THREE
economic situations:
can help determine whether public service provided by private sector is adequate.
can be used to judge and assess market failures in private sector and their impact on health, safety, and environmental needs of country.
helps to address social needs in cost-effective manner in areas that only the government can address.
Economic Impacts
Cost-benefit analysis can be used for evaluating policy alternatives, shaping regulatory strategies, & evaluating specific regulations.

A cost-benefit analysis requires:
1. gathering all information and data about a public issue, including history and background
2) defining the possible solutions to solving the issue
3) brainstorming the possible environmental and societal consequences of the altneratives
4) quantifying the benefits and costs
5) making decisions and balancing concerns
External Costs
External Cost:
occurs when products or activities of one group has negative impact on another group and when the impact is
NOT FULLY ACCOUNTED, COMPENSATED FOR
in the price of production.

ex) power station generates emissions of SO2 causing damage to buildings and human health. In this case, the cost to the owners of the building and to those who suffer from respiratory issues is not taken into account in the cost of electricity production. In this example, the environmental costs are "external" because, although they are real, they are not costs to society. The owner of the power plant is NOT taking them into consideration when setting the price of electricity.

The
total cost
of a good society (called the social cost) includes the cost incurred by the industry as well as the external costs.

One way to account for external costs is through the use of "
eco-taxes
" - taxing damaging fuels, etc. in proportion to their external costs. Another is through
subsidizing
of cleaner technology
Eco-taxes (Green Taxes)
Ecotaxes:
intended to promote ecological sustainability by providing economic incentives; can complement or reduce need for regulatory approaches; ecotax may attempt to maintain overall tax revenue by proportionately reducing other taxes (green tax shift).

Examples include:
taxes on use of fossil fuels by greenhouse gases produced
duties on imported good produced by ecologically unsound methods
taxes on mineral, energy, and forestry products that were produced by ecologically unsound methods
fees for camping, hiking, fishing, and hunting
taxes on technologies and products, which are associated with substantial negative externalities
waste disposal taxes
taxes on effluents, pollution, and other hazardous wastes
Cap & Trade
Cap & Trade
: aka "emissions trading", is a market approach to control pollution by providing economic incentives for achieving reductions in emissions of pollutants.

How it works:
the government sets a limit or "cap" on the amount of a pollutant that can be emitted.
companies and other groups are then issued emission permits and are required to hold an equivalent number of allowances or credits, which represent the right to emit a specific amount of a pollutant.
the total amount of allowances and credits cannot exceed the cap, limiting total emissions to that level.
companies that need to increase their emission allowance must then buy credits from those who pollute less.
the transfer of allowances is referred to as a "trade".
basically, the buyer is paying a charge for polluting, while the seller is being rewarded for having reduced emissions by more than was needed.
therefore, those who reduce emissions more cheaply will do so, achieving pollution reduction at the lowest cost to society.
Sustainability
Sustainability
: the continuity of the economic, social, and institutional aspects of human society while simultaneously preserving biodiversity the environment.
Sustainable activities seek to provide the best outcome for both human societies and natural ecosystems.

Several issues are common to both interests:

consideration of risk, uncertainty, and irreversibility
ensuring appropriate valuation, appreciation, and restoration of nature
integration of environmental, social, and economical goals
equal opportunity and community participation
conservation of biodiversity and ecological integrity
a commitment to best practices
no net loss to either human or natural capital
continuous improvement
need for good governance

Unlimited economic and population growth puts many demands on natural resources. Its effects on pollution and carrying capacity of Earth are factors that impact sustainability. These are all analyzed using life cycle assessments and ecological footprint analysis.
Ecological Footprint
Ecological Footprint:
measure of human demand on the Earth's ecosystems. It's a standardized measure of demand for natural capital that may be contrasted with the planet's ecological capacity to regenerate and r
epresents the amount of biologically productive land and sea area necessary to supply the resources a human population consumes, and to assimilate associated waste
.
Currently, humanity uses ecological services, 1.5 times as fast as Earth can renew them.

The "
Carbon Footprint
" is the
amount of carbon being emitted by an activity or organization
. The carbon component of the ecological footprint converts the amount of carbon dioxide being released into the amount of productive land and sea area required to sequester it and tells the demand on the Earth that results from burning fossil fuels. The carbon footprint is 54% of the ecological footprint and its most rapidly-growing component having increased 11-fold since 1961.
Quick Review Checklist
HAZARDS TO HUMAN HEALTH
types of risks
risk management strategies
acute and chronic effects
dose-response relationships
LD50
EC50
dose-response curves
AIR POLLUTION & EFFECTS ON HUMAN HEALTH
air toxins
asbestos
carbon monoxide
indoor air pollutants
lead
nitrogen dioxide
ozone
PM10
sulfur dioxide
smoking
HAZARDOUS CHEMICALS IN THE ENVIRONMENT
corrosive
discarded commercial products
ignitable
nonspecific sources
reactive
sources specific
toxic
TREATMENT, DISPOSAL & CLEANUP OF CONTAINMENT SITES
conversion techniques
chemical, physical, or biological treatment
incineration
thermal treatment
perpetual storage
arid region unsaturated zone
landfill
salt formations
surface impoundments
underground injection
waste piles
CASE STUDY - DDT
RELEVANT LAWS
Federal Hazardous Substances Act (1960)
Federal Environmental Pesticides Control Act (1972)
HAZMAT (1975)
Toxic Substances Control Act (1976)
CERCLA & Superfund ( 1980)
Nuclear Waste Policy Act (1982)
Biomagnification
Cost-Benefit Analysis
Externalities
Marginal Costs
Sustainability
The Shadow of Thalidomide
Biomagnification
The "Story of Stuff"- the Critique
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