Unit Ten - The Bio EdgeManagement of Hazardous Waste Friday, March 18, 2011. Solid Waste Friday,...

AP Environmental Science

Unit Ten

Friday, March 18, 2011

Pollution: I. Solid Waste &

Hazardous Materials/Chemicals


Solid and Hazardous Wastes


Overview

Solid Waste Waste Prevention

Reducing the Amount of Waste Reusing Products Recycling Materials

Hazardous Waste Types of Hazardous Waste Management of Hazardous Waste


Solid Waste


Solid Waste

US generates more solid waste per capita than any other country 2.1 kg per person per day

Waste stream- describes the steady production of all waste products that human produce


Types of Solid Waste

Municipal solid waste Solid material discarded by homes, office

buildings, retail stores, schools, etc. Relatively small portion of solid waste

produced Non-municipal solid waste

Solid waste generated by industry, agriculture, and mining


Composition of Municipal Solid


Disposal of Solid Waste

Three methods Sanitary Landfills Incineration Recycling

“open dumps” cheap not compacted not covered dirty, smelly more common in developing countries


Disposal of Solid Waste

United States Landfilling most common method of disposal

Japan Recycling most common method of disposal


Sanitary Landfill


Sanitary Landfill

Considerations for choosing a Landfill local topography and drainage patterns proximity to aquifer recharge zones permeability of underlying rock formations community attitudes


Sanitary Landfill

Compacting and burying waste under a shallow layer of soil

Most common method of disposal Problems

Methane gas production by microorganisms Contamination of surface water & ground

water by leachate Not a long-term remedy Few new facilities being opened Closing a full landfill is very expensive


Special Problem: Tires Made from materials

that cannot be recycled Can be incinerated or

shredded

Sanitary Landfill

Special Problem: Plastic Much of plastic is from packaging Chemically stable and do not readily break

down and decompose


Incineration

Volume of solid waste reduced by 90% Produces heat that can make steam to

generate electricity Produce less carbon emissions than fossil fuel

power plants Byproduct

Bottom ash Fly ash


Incineration Types of Incinerators

Mass burn (below) Modular Refuse-derived


Composting

Municipal Solid Waste Composting Includes: Food scraps, Sewage sludge,

Agricultural manure, Yard waste Reduces yard waste in landfills and total

waste volumes Can be sold or distributed to community


Waste Prevention


Waste Prevention

Three Goals (the three “R’s”) (1) Reduce the amount of waste (2) Reuse products (3) Recycle materials


Reducing Waste

Purchase products with less packaging


Reducing Waste

Source reduction Products designed and manufactured to

decrease the volume of solid waste Pollution Prevention Act (1990) Dematerialization

Progressive decrease in the size and weight of a product as a result of technological improvements


Reusing Products

Refilling glass beverage bottles Heavier glass that costs more

Japan recycles almost all bottles Reused 20 times


Recycling Materials

Recycling involves melting or shredding old products to make new products

Every ton of recycled paper saves: 17 trees 7000 gallons of water 4100 kwatt-hrs of energy 3 cubic yards of landfill space

Recycle Glass bottles, newspapers, steel cans, plastic

bottles, cardboard, office paper


Recycling

Recycling Paper US recycles 50% Many developed

countries are higher

Recycling Glass US recycles 25% Costs less than

new glass (right)


Recycling Recycling Aluminum

Making new can from recycled one costs far less than making a brand new one

49% of aluminum was recycled in 2007 saves: energy, materials (bauxite ores), land

and it reduces pollutants Recycling Metals other than Aluminum

Lead, gold, iron, steel, silver and zinc Metallic composition is often unknown

Makes recycling difficult


Recycling

Recycling Plastic 12% of all plastic was

recycled in 2007 Less expensive to make

from raw materials 37% of PET was

recycled in 2007 Mostly water and soda

bottles


Recycling

Recycling Tires Few products are made from old tires

Playground equipment Trashcans Garden hose Carpet Roofing materials

36% of tires are currently recycled to make other products


Integrated Waste Management


Hazardous Waste


Love Canal Toxic Waste Site

Hazardous Waste Any discarded chemical that threatens

human health or the environment Reactive, Corrosive, Explosive, Mutagenic

(carcinogenic) or Toxic chemicals Types of Hazardous Waste

Dioxins PCBs Radioactive waste

Often measured in ppm parts per million

1 ounce in 1 million ounces


Hazardous Waste


Case-In-Point Hanford Nuclear


Management of Hazardous Waste

Chemical accidents National Response Center notified Typically involves oil, gasoline or other

petroleum spill Current Management Policies

Resource Conservation and Recovery Act (1976, 1984)

Comprehensive Environmental Response, Compensation, and Liability Act (1980) Commonly known as Superfund


Superfund Program

Cleaning up existing hazardous waste: 400,000 waste sites Leaking chemical

storage tanks and drums (right)

Pesticides dumps Piles of mining

wastes Must be cleaned up


Management of Hazardous Waste Superfund National Priorities List

2009: 1,264 sites on the list States with the greatest number of sites

New Jersey (114) California (94) Pennsylvania (94) New York (85) Michigan (65)

Race is the strongest determinant of who is exposed to environmental hazards



Biological Treatment of Hazardous Chemicals Bioremediation - use of bacteria and other

microorganisms to break down hazardous waste into relatively harmless products Time consuming

Phytoremediation - use of plants to absorb and accumulate hazardous materials in the soil Ex: Indian mustard removed heavy metals


Examples of Phytoremediation



(1) Source reduction (2) Conversion to less hazardous materials (3) Long-term storage


Hazardous Waste Landfill


Pollution: II. Human Health &

Environmental Toxicology


Human Health and Environmental Toxicology


Overview

Human Health In developed countries In developing countries

Environmental Pollution and Disease Environmental Contaminants Endocrine Disrupters Pesticides

Determining Health Effects of Pollutants Ecotoxicology Risk Assessment


Human Health


Human Health Two indicators of human health

Life expectancy - how long people are expected to live

Infant mortality - how many children die before age of 1 year

Vary greatly between countries

Developed countries Developing countries


Health in Highly Developed Countries Health is generally good in these countries Average life expectancy

Men = 75 years Women = 80 years

Leading causes of death in US Cardiovascular disease, Cancer, Lung Disease

Premature deaths caused by lifestyle Poor diet, Lack of exercise, Smoking, Obesity


Health in Developing Countries Biggest problems

Malnutrition, unsafe water, poor sanitation Life Expectancy

Overall is 65 years Very poorest developing countries = 45 years

Due to AIDS epidemics

Childhood mortality is high Diarrheal diseases Malnutrition Malaria AIDS/HIV


Emerging and Reemerging Diseases Emerging Disease - not previously observed in humans

Usually jumps from animal host Ex: AIDS, lime disease, West Nile Virus

Reemerging Disease - existed in the past and are recently increasing in incidence Ex: tuberculosis, yellow fever, malaria


Reasons for Emergence/Reemergence Evolution of disease so it transitions to human

host Evolution of antibiotic resistance in disease Urbanization and overcrowding Increased pop. of elderly - susceptible to disease Pollution and environmental degradation Growth in international travel and commerce Poverty and social inequality


Environmental Pollution and

Disease


Environmental Pollution and Disease Pathways of

Pollution Often difficult to

link pollutants to their effects on people Persistence Bioaccumulation

& magnification


Persistence

A characteristic of certain chemicals that are extremely stable and may take many years to be broken down into simpler forms by natural processes Synthetic chemicals (those not found in

nature) Ex: DDT

Natural decomposers (bacteria) have not evolved a way to break it down


Bioaccumulation

The buildup of a persistent toxic substance in an organism’s body, often in fatty tissues Synthetic chemical do not metabolize well They remain in the body for extended periods

of time


Biomagnification The increased

concentration of toxic chemicals in the tissues of organisms that are at higher levels in food webs

Diagram (right) is example of biomagnification of DDT


Endocrine Disrupters A chemical that mimics, interferes with or

disrupts the normal hormone functions in humans and wildlife Hormones-chemical messengers

Examples include: PCBs, Dioxins Heavy metals - lead and mercury DDT

Animals exposed to these chemicals have altered reproductive development and are often sterile


Endocrine Disrupters Case Study: 1980 chemical spill into Lake

Apopka, FL Male alligators began to exhibit low

testosterone levels and high estrogen levels


Endocrine Disrupters and Humans Infertility and hormonally related cancers

are increasing Breast cancer and testicular cancer

Phthalates have been implicated as potential endocrine disrupters Common ingredient in: cosmetics, fragrances,

nail polish, medication, toys, food packaging


Cancer Cancer- uncontrolled cell growth

benign tumor-mass of cells not life threatening

malignant tumor-mass of cells that impede the functions of other cells (life threatening)

Mutagens compounds that cause mutations in DNA

Carcinogens compounds that cause mutations that lead to

cancer Not all mutagens are carcinogens but all

carcinogens are mutagensFriday, March 18, 2011

Pesticides


What is a Pesticide Broad spectrum pesticide

A pesticide that kills a variety of organisms, not just the targeted organisms


First generation pesticide Inorganic compounds (minerals)

lead, mercury, arsenic not used much today because they are

highly toxic and remain in soil for a long time

Botanicals (organic): plant derived pesticides nicotine, rototene, pyrethrin (from

chrysanthemum flowers seen on previous slide)

highly toxic BUT biodegradable and they will not persist in soil for long

What is a Pesticide


What is a Pesticide

Second generation pesticide Synthetic organic poisons 20,000+ are registered currently Ex: DDT


Major Groups of Insecticides Largest group of pesticides are insecticides

Chlorinated Hydrocarbons (example: DDT) Organic compound containing Chlorine Slow to degrade and persist in the environment Banned or largely restricted low toxicity towards humans

Organophosphates Cabamates


Major Groups of Insecticides Organophosphates

Organic compounds that contain phosphorus Most poisonous insecticide Do not persist as long as chlorinated hydrocarbons

(low persistence explained shortly) low bioaccumulation also explained shortly

Cabamates Broad spectrum; derived from cabamic acid Do not persist as long as chlorinated hydrocarbons

(low persistence explained shortly) low bioaccumulation also explained shortly


Problems with Pesticides

Evolution of Genetic Resistance Pest populations

are evolving resistance to pesticides (right)


Pesticide Resistance

Pesticide Treadmill Cost of applying pesticide increases While their effectiveness decreases

Resistance Management Strategies for managing genetic resistance in

order to maximize the period in which a pesticide is useful


Problems with Pesticides Imbalances the

Ecosystem Spraying to kill

insects can affect birds, rabbits, etc.

Despite 33-fold increase in pesticides since the 1940s, crop loss has not decreased much


Problems with Pesticides Creation of New Pests

Infestation of red scale insects on lemons after DDT sprayed to control another pest



Persistence, Bioaccumulation Biological Magnification



Persistence - trait of certain chemicals that are stable and take a long time to be biodegraded can cycle through environment for years

Bioaccumulation - The buildup of a persistent pesticide or other toxic substance in an organism’s body cells selectively absorb and store molecules

Biological magnification - Increased concentration of toxic chemicals in tissues of organisms at higher trophic levels in food webs



Mobility in the Environment Do not stay where they are applied


Mild: nausea, vomiting, headaches

Severe: damage to nervous system,

Risk of Pesticides to Human Health Short-term Effects of Pesticides

Handling food with pesticide residue


Risk of Pesticides to Human Health Long-term Effects of Pesticides

Cancer - lymphoma Breast cancer Sterility Miscarriage Birth defects Decreases body’s ability to fight infection Potential connection to Parkinson’s disease


Reducing Pesticides in Your Life Reducing pesticides residues in your diet

peel fruits & veggies when possible cook foods that you believe have residue buy organic wash fruits & veggies before eating

Reducing pesticide exposure use other insects like lady bugs to protect

your garden plants wash aphid infested veggies with water accept slightly blemished fruits & veggies keep wood piles away from the house


Laws Controlling Pesticide Use

Food, Drug, and Cosmetics Act (1938) Pesticide Chemicals Amendment (1954) Delaney Cause (1958) Federal Insecticide, Fungicide, and

Rodenticide Act (1947, updated most recently in 2008)

Food Quality Protection Act (1996)


Toxicology


Determining Health Effects of Pollutants Toxicology is the study of the effect of

toxicants on the human body Toxicant - chemical with adverse human

health effects Nearly anything can be toxic at some level! example caffeine


Determining Health Effects of Pollutants Toxicity measured by dose and response

Dose: amount that enters that body of an exposed organism

Response: the amount of damage caused by a specific dose

Detection of Toxic Chemicals depends on sensitivity of measuring

techniques how much/many chemicals are present


Toxicology

Acute toxicity Adverse effects occur within a short period

after exposure to toxin Chronic toxicity

Adverse effects occur some time after exposure, or after prolonged exposure to toxin


Toxicity

LD50 Lethal dose to

50% of the test organisms

Smaller the LD50, the more lethal the chemical

Determined for all new synthetic chemicals


Toxicity

ED50 Effective dose to 50% of the test organisms ED50 causes 50% of the population to exhibit

whatever effect is under study Dose-Response Curve

Illustrates the effect of different doses on a population

Threshold Level Maximum dose with no measurable effects


Toxicity: ED50


Toxicity: Dose Response Curve


Children and Chemical Exposure Children more susceptible to chemicals

Weigh less than adults Bodies are still developing Play on floors and lawns Put things into their mouths

Diagram (right) Children in foothills not exposed to pesticides Children in valley were exposed


Identifying Cancer Causing Substances Toxicologist

Dose rats with varying levels of chemicals to see if they develop cancer

Difficult to extrapolate results to humans Epidemiologists

Look at historical exposure of groups of humans

See if exposed group have increased cancer rate


Review Cancer Cancer- uncontrolled cell growth Mutagens

compounds that cause mutations in DNA Carcinogens

compounds that cause mutations that lead to cancer Not all mutagens are carcinogens but all

carcinogens are mutagens

Cancer is a chronic effect of pesticides on humans


Chemical Mixtures Most studies look at one chemical, but

humans tend to be exposed to chemical mixtures Ex: automobile exhaust

Chemical Mixtures interact by Additivity-expected interaction 1=1=2 Synergy-greater than expected 1+1=3 Antagonism-less than expected 1+1=1.5

These studies are expensive and take a while to complete


Ecotoxicology Dilution Paradigm is not valid

“Dilution is the solution to pollution” Boomerang Paradigm is accepted

“What you throw away can come back and hurt you”

Ecotoxicology The study of contaminants in the biosphere

and their harmful effects on ecosystems Helps policy makers determine costs and

benefits of industrial and technological “advances”


Case Study: The Ocean

Land based nutrient and pollution runoff into ocean is affecting microorganisms

Ex: Red Tide Red pigmented

poisonous algal blooms Toxins kill off fish and

make humans sick


Risk Assessment Risk- probability that a particular adverse

effect will result from some exposure or condition

We assess risk daily with four steps Hazard identification Dose response assessment Exposure assessment Risk characterization

As a society we tend to focus money and attention on health risks that most well publicized and scary


Risk Assessment


Ecological Risk Assessment

Difficult to assess because effect occur at wide range of scales Individual plants and animals Ecological communities over wide regions

Human-induced environmental stressors also range greatly

There is a need to quantify risks to the environment


Unit Ten - The Bio EdgeManagement of Hazardous Waste Friday, March 18, 2011. Solid Waste Friday,...

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