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Human Population: Wastes - Management and their Health Risks

presentation for the Wastes: Management and Health Risks lesson of the Environmental Science course. Text and diagrams from the AP textbook Environment: The Science behind the Stories.

jeremy haas

on 23 December 2014

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Transcript of Human Population: Wastes - Management and their Health Risks

Environmental Science
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Approaches to Waste Management
Waste Disposal Methods
Reducing Waste
Hazardous Waste
The Superfund
Environmental Health
Risk management
Waste management aims to:
1). Minimize the amount of waste generated. Reducing waste entering the waste stream is the preferred approach.
2). Recover waste materials and recycle/compost them. This is the next best strategy in waste management.
3). Dispose of waste safely and effectively.
Waste management aims to:
1). Minimize the amount of waste generated. Reducing waste entering the waste stream is the preferred approach.
2). Recover waste materials and recycle/compost them. This is the next best strategy in waste management.
3). Dispose of waste safely and effectively.
Waste management aims to:
1). Minimize the amount of waste generated. Reducing waste entering the waste stream is the preferred approach.
2). Recover waste materials and recycle/compost them. This is the next best strategy in waste management.
3). Dispose of waste safely and effectively.
Waste management aims to:
1). Minimize the amount of waste generated. Reducing waste entering the waste stream is the preferred approach.
2). Recover waste materials and recycle/compost them. This is the next best strategy in waste management.
3). Dispose of waste safely and effectively.
Since 1960, U.S. waste generation has increased 2.8 times, or 1 ton/person each year.
Consumption is greatly increasing in developing nations.
In the U.S., paper, yard debris, food scraps, and plastics are the principal components of municipal solid waste. Paper packaging is the largest component.
Open dumping and burning still occur.

However, most industrialized nations bury waste in lined and covered landfills or burn it in incineration facilities.

The goal of waste disposal is to prevent contamination and health threats.
U.S. landfills are regulated and must meet the EPA’s standards.
Landfills have drawbacks. Collecting the liquid waste (leachate) is not required, waste doesn’t decay much, and nobody wants them in their neighborhood.
Waste is partly decomposed by bacteria, compressed under its own weight, and covered with soil layers to reduce odor and speed decomposition.
Closed landfills must be capped and maintained. 1988, the U.S. had 8000 landfills, today there are less than 1800.
Cities have converted closed landfills into public parks.
Landfills can produce gas for energy.
Bacteria decompose waste and produce methane, which can be collected and sold.
Incinerating trash reduces landfill pressure.
Incineration burns garbage at very high temperatures.

The remaining ash must be disposed of in a hazardous waste landfill.

Scrubbers chemically treat the gases produced in combustion.
Waste-to-energy (WTE) facilities use the heat produced by waste combustion to create electricity.
But they take many years to become profitable and require a certain amount of garbage to operate.
This requirement interferes with community efforts to reduce and recycle waste.
Reducing waste is a better option than disposal.

Preventing waste in the first place:

avoids costs of disposal/recycling,

helps conserve resources,

minimizes pollution,


saves consumer/business money.
Strategies to minimize these wastes include:
Use minimal packaging/recyclable packaging.
Use reusable mugs and water bottles.
Some governments restrict plastic shopping bags.
Plastic bags can take centuries to decompose and 100 billion of them are discarded each year in the U.S.
Companies maximize sales by producing short-lived goods.

Choose durable goods, ones that will last for more than one consumer!

Donate items to resale centers.

Consider not buying.
Renting or borrowing items may be the better solution.
Most waste consists of materials used to package goods.
Bottle Bills increase container costs to discourage these wastes from entering the environment.
Composting recovers organic waste.

Home and municipal composting divert food and yard waste from the waste stream, which reduces landfill waste.

Additionally, composting reduces the need for chemical fertilizers.
Reuse is a main strategy to reduce waste.
Recycling is collecting materials that can be broken down and reprocessed to manufacture new items.

Recycling diverted 61 million tons of materials away from incinerators and landfills in 2008.
Recycling consists of three steps:
2). using recyclables to produce new goods. Many products use recycled materials.
1). collection and processing of recyclable materials through curbside recycling or designated locations.
Materials go to facilities where workers and machines sort, clean, shred, and prepare items.
3). Consumers buy goods made from recycled materials. This must occur if recycling is to function, i.e. if the market expands, prices will fall on the goods.
The growth of recycling is “One of the best environmental success stories ….” .

Growth is a result of municipalities’ desire to reduce waste, and the public’s satisfaction in recycling.
Recycling rates vary by the product and by the state.
Recycling may not be profitable.

It is expensive to collect, sort, and process materials.
There are enormous energy and material savings.
But market forces do not take into account the health and environmental effects of not recycling.
Some materials are worth recycling from landfills.
Sources of hazardous waste:
1). Industry produces the largest amount of hazardous waste.Materials must be tracked “from cradle to grave”. This is intended to prevent illegal dumping. Illegal dumping creates health risks and high costs for cleanup.

2). Households are the largest source of unregulated hazardous waste, i.e. paint, batteries, solvents, cleaners, pesticides.

3). Mining, small businesses, agriculture, utilities, and building demolition all produce hazardous wastes.
Types of Hazardous Wastes

1). Organic compounds (found in plastics, tires, pesticides, solvents) are particularly hazardous because, they are persistent (slow decay). and they are easily absorbed through the skin.

2). Heavy metals include lead, chromium, mercury, arsenic, cadmium, tin, and copper, are used widely in industry for wiring, electronics, metal fabrication. Heavy metals often attach to fat tissues and accumulate during the lifetime of an organism.
Americans discard 400 million devices/year, and 67% are still in working order.
Electronic waste (“e-waste”) comes from electronic devices.
They are put in landfills, but should be treated as hazardous waste.
Disposing of hazardous waste does not lessen the hazards of the substances, but they help keep the substance isolated from people, wildlife, and ecosystems.
Surface impoundments are shallow depressions, lined with plastic and clay, to store liquid hazardous waste.

The water evaporates and the residue of solid hazardous waste is transported elsewhere.

Problems include cracked liners and rainstorms, which cause overflow.
Deep-well injections are beneath the water table, isolated from groundwater and humans.
The Waste Isolation Pilot Plant (1999) is the first underground repository for waste from nuclear weapons development.

The caverns are 655 m (2,150 ft) below ground in a huge salt formation thought to be geologically stable.
Radioactive waste is very dangerous and persistent.
Environmental health assesses environmental factors that influence human health and quality of life, including natural and human-caused hazards.
The four types of environmental hazards:
Physical hazards occur naturally in our environment.
We increase our vulnerability by deforesting slopes (landslides), channelizing rivers (flooding).
Chemical hazards include pharmaceuticals, disinfectants, pesticides and natural chemicals (venom).
Biological hazards are infectious disease caused by viruses, bacteria, and other pathogens. We can’t avoid infection but we can restrict how it spreads.
Cultural hazards result from where we live, our socioeconomic status, our occupation, our behavioral choices. Examples include: smoking, drug use, nutrition, crime, mode of transportation.
Radon - It can build up in basements. Carcinogenic.

Asbestos - a mineral that insulates and resists fire. Carcinogenic.

Lead - Exposure to lead pipes & paint.
Causes learning problems, behavior abnormalities.

Polybrominated diphenyl ethers (PBDEs) - used in computers, plastics, and furniture.
Affect thyroid hormones, nervous system development.
Indoor environmental health hazards:
The EPA administers a federal program called Superfund that cleans up U.S. sites polluted with hazardous waste.

Dealing with these messes is difficult, time consuming, and expensive.

It is part of Comprehensive Environmental Response Compensation and Liability Act (CERCLA) of 1980.
1). Experts identify polluted sites and determines if the site threatens drinking water supplies, and rank the level of risk to human health.

2). The EPA must hold public hearings to inform area residents of its findings and to receive feedback.

3). Cleanup goes on a site-by-site basis as funds are available.
Charge polluting parties for cleanup.
A trust fund was established by a federal tax on petroleum and chemical industries. The fund is bankrupt and Congress has not restored it.
Taxpayers now pay all costs of cleanup and fewer cleanups are being completed.
1,279 sites remain, and only 341 have been cleaned up.
The Superfund Process:
Despite our technology, disease kills most of us. Disease has a genetic and environmental basis, i.e. cancer, heart disease, respiratory disorders.
Disease is a major focus of environmental health.
Infectious diseases account for half of all deaths in developing countries. Food security, sanitation, clean drinking water, health clinics, immunizations, and natal care all reduce illness.
Poverty and poor hygiene foster illnesses.
Environmental toxicology is the study of toxic (poisonous) substances in the environment and their effect on humans and other organisms.
Toxicity is the degree of harm a toxin can inflict, and depends on the combined effect of the chemical and its quantity.
Rachel Carson’s book Silent Spring (1962) showed DDT’s risks to people, wildlife, and ecosystems. DDT was banned in the U.S. in 1973, but is still made in the U.S. and exported to help control mosquitoes.
Every one of us carries traces of hundreds of industrial chemicals in our bodies.
Babies are born “pre-polluted” – 232 chemicals were in umbilical cords of babies tested. Unfortunately, very few of the 100,000 chemicals on the market have been tested.
carcinogens and mutagens cause cancer.

teratogens cause birth defects.

neurotoxins assault the nervous system.

allergens over activate the immune system.

endocrine disruptors affect the endocrine (hormone) system.
Types of toxins:
Many products mimic female hormones, for example:
Bisphenol A (BPA) binds to estrogen receptors.
Runoff carries toxins from land to surface water. Aquatic organisms (fish, frogs, invertebrates) are good pollution indicators.
Chemicals can travel by air and water and their effects can occur far from their source.
Chemicals enter organisms through drinking or absorption.
Bioaccumulation is the build up of toxins in the fat tissues of an organism during its lifetime.
Biomagnification occurs when predators eat toxic prey and the toxins become more concentrate in their own tissues.

This has caused the near extinction of peregrine falcons and bald eagles.
Epidemiology studies are large-scale/long-range comparisons between diseased organisms and unexposed groups.

What is measured is the association between a health hazard and a disease – but not necessarily the cause of the disease.
New techniques with cell cultures may replace live-animal testing.
Animal testing involves experiments to show if a toxin or infectious agent causes a disease.
Some people object to animal tests but medical advances would be far more difficult without them.
LD50 (lethal dose 50%) is the amount of toxin required to kill/affect 50% of the subjects.
A high number indicates low toxicity.
Dose-response experiments:
The type of exposure affects the response:

Acute exposure is high exposure to a hazard for short periods of time. Examples include ingestion, oil spills, nuclear accident.

Chronic exposure is low exposure for long periods of time. These are more common but harder to detect because the affect is gradual. i.e. lung cancer, liver damage.
Risk is the probability that some harmful outcome will result from an event or substance.

Risk management is done by our federal agencies:
1). Centers for Disease Control (CDC) manages infectious diseases.

2). The Food and Drug Administration (FDA)
monitors food, cosmetics, drugs, medical devices.

3). The EPA regulates pesticides
and industrial chemicals.
Only 10% of chemicals have been tested for toxicity and only five have been restricted.
The U.S. uses the innocent-until-proven-guilty approach, where hazardous chemicals are approved if economic benefits outweigh hazards.
Europe incorporates the precautionary principle, which helps industries research and develop safer products.
The Stockholm Convention on Persistent Organic Pollutants (POPs) was enacted in 2004 and ratified by over 150 nations.
The plan is to phase out the 12 most dangerous POPs.
Case Study: Transforming New York’s Fresh Kills Landfill
The largest landfill in the world closed in 2001.

Staten Island residents viewed the landfill as a civic blemish.

It was briefly reopened to bury rubble from the World Trade Center after the 9/11 attack.

It will take 30 years to turn it into a world-class public park.
Edmonton, Alberta has one of the most advanced waste management programs.

Waste: 40% is landfilled,
15% is recycled, 45% is composted

90% of the people participate in curbside recycling

It produces 80,000 tons/year in its composting plant

The facility handles 30,000–40,000 tons of waste annually
A Canadian city showcases reduction and recycling
It is in hundreds of products, but in extremely low doses, including: cans, utensils, baby bottles, laptops, and toys.

93% of Americans have it in their bodies.
BPA mimics estrogen, a female hormone, and causes cancer, nerve damage, and miscarriages.
Case Study: Poison in the bottle: is bisphenol A (BPA) safe?
Researchers, doctors, and consumer advocates want regulation.

The chemical industry insists it is safe.

Some countries and states have banned it.

Many companies are removing it voluntarily.
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