Unit 6 Test

How can humans speed up bioremediation (ie. Get bacteria to consume more toxins)

-Aerate the soils- the more air you can get in to the soils, the greater the rate bacteria can respire and the greater the rate of contaminant degradation. Physical 'turning' also results in physical attrition of contaminants, another benefit in reducing contaminant concentrations. -Balance the nutrients - the main food source is the contamination you're trying to treat, however hydrocarbon degrading bacteria require Nitrogen, Phosphorous, and Potassium (NPK) to be able to degrade contamination. Producing the right balance of nutrients will speed up the remediation process. -Balance moisture- Bacteria require moisture to do their job, too much moisture and you starve them of oxygen, not enough and you don't get the most out of them. -Warm the soils - maintaining a working temperature in the soils can be approached several ways, bioremediating in large piles (bio-piles) gives an insulating effect which keeps the core of the bio-pile warm. Sheeting the pile with 'fleeces' keep the warmth (and the moisture) in the bio-pile. Probably the easiest approach is to do the work in the summer months, and avoiding the freezing winter months. -Add contaminant specific bacteria - I am always a little cautious about this approach, sometimes it works and sometimes it doesn't. Culturing the native bacteria gets results every time. Adding new bacteria can produce great results, assuming they survive. Soil conditions have so many variables including pH, and metal mixtures, and few bacteria can stand up to the test of being introduced to a new soil, so this approach can be hit or miss regarding speeding up the remediation process.

Know whether they are caused by bacteria, virus or protozoa, how you are infected and the general effects they have in the body: Tuberculosis

-Bacteria -Spreads as bacteria multiply; each person with active TB typically infects 10-15 other people -Many infected do not appear to be sick, and about half of them do not know they are infected; can sometimes have a chronic cough

Know whether they are caused by bacteria, virus or protozoa, how you are infected and the general effects they have in the body: Diarrheal diseases (know some examples)

-Bacteria and viruses -Infected by eating foods or drinking liquids contaminated with diarrhea-causing germs, touching surfaces or objects contaminated with the diarrhea-causing germs and then touching their own mouth, nose, or eyes, and sharing personal items such as towels and toothbrushes -Causes you to lose fluids, salts, and minerals that affect the amount of water the body retains -> dehydration

Know whether they are caused by bacteria, virus or protozoa, how you are infected and the general effects they have in the body: Malaria

-Protozoa -Malaria is caused by a parasite that is spread by the bites of certain mosquito species. Four species of protozoan parasites in the genus Plasmodium cause malaria. Most infections occur when an uninfected female of any of about 60 Anopheles mosquito species bites a person (usually at night) who is infected with Plasmodium parasite, ingests blood that contains the parasite, and later bites an uninfected person. Plasmodium parasites then move out of the mosquito and into the human's bloodstream and liver where they multiply. Malaria can also be transmitted by blood transfusions and by drug users sharing needles. The malaria cycle repeats itself until immunity develops, treatment is given, or the victim dies -It infects and destroys red blood cells, causing intense fever, chills, drenching sweats, anemia, severe abdominal pain, headaches, vomiting, extreme weakness, greater susceptibility to other diseases, and is deadly

Know whether they are caused by bacteria, virus or protozoa, how you are infected and the general effects they have in the body: SARS

-Virus -Easily spread from person to person -Causes flu-like symptoms, can quickly turn into life-threatening pneumonia, and is deadly

Know whether they are caused by bacteria, virus or protozoa, how you are infected and the general effects they have in the body: Hepatitis B

-Virus -Like HIV, it is transmitted by unsafe sex, sharing of needles by drug users, infected mothers who pass the virus to their offspring before or during birth, and exposure to infected blood -Damages the liver and is deadly

Know whether they are caused by bacteria, virus or protozoa, how you are infected and the general effects they have in the body: HIV/AIDS

-Virus -The virus is transmitted from one person to another by unsafe sex, sharing of needles by drug users, infected mothers who pass the virus on to their offspring before or during birth, and exposure to infected blood -Effects the immune system and leaves the body vulnerable to infections such as tuberculosis (TB) and rare forms of cancer such as Kaposi's Sarcoma

Know whether they are caused by bacteria, virus or protozoa, how you are infected and the general effects they have in the body: Influenza

-Virus -Transmitted by the body fluids or airborne emissions of an infected person -High fever, cough and muscle aches, usually come on suddenly and are more severe than colds

Know whether they are caused by bacteria, virus or protozoa, how you are infected and the general effects they have in the body: Ebola

-Virus -Transmitted through bodily fluids from an infected person to a non-infected person through passage ways. Not contagious until having symptoms -Attacks the immune system's cells and nuetralizes its responses - allowing the virus to proliferate. Causes high temperature, aching, and sore throat which progress into vomiting, rashes, and diarrhea

Know whether they are caused by bacteria, virus or protozoa, how you are infected and the general effects they have in the body: West Nile virus

-Virus (from mosquitos) -Transmitted to humans by the bite of a common mosquito that becomes infected by feeding on birds that carry the virus -Causes severe illness including encephalitis and meningitis and is deadly

Pandemic

A global epidemic, such as AIDS is called a pandemic.

Epidemic

A large-scale outbreak of an infectious disease in an area or country is called an epidemic.

Nontransmissible disease

A nontransmissible disease is caused by something other than a living organism and does not spread from one person to another. Such diseases tend to develop slowly and have multiple causes. Examples include cardiovascular (heart and blood vessel) diseases, most cancers, asthma, diabetes, and malnutrition. As average life expectancy increases, people are more likely to suffer and die from nontransmissible diseases such as cardiovascular diseases and cancers.

Transmissible disease

A transmissible disease (also called a contagious or communicable disease) is an infectious disease that can be transmitted from one person to another. Examples are flu, HIV, tuberculosis, and measles.

What area of the world is most affected by HIV/ AIDS? What are the consequences to the populations of these countries?

AIDS has reduced the life expectancy of the 750 million people living in sub-Saharan Africa from 62 to 47 years—40 years in the seven countries most severely affected by AIDS. The premature deaths of teachers, health-care workers, soldiers, and other young productive adults in such countries leads to diminished education and health care, decreased food production and economic development, and disintegrating families. This means that countries like Botswana are expected to lose half of their adult populations within a decade. Such death rates drastically alter a country's age structure. AIDS has also left more than 15 million children orphaned—roughly equal to the number of children under age 5 in the United States. Many of these orphans are forced into child labor or the sex trade.

Know the disadvantages to making paper & some alternative ways to make paper

About 55% of the world's industrial tree harvest is used to make paper. The pulp and paper industry is the world's fifth largest energy user and uses more water to produce a metric ton of its product than any other industry. In both Canada and the United States, it is the third-largest industrial energy user and polluter, and paper is the dominant material in the MSW of both countries. Paper (especially newspaper and cardboard) is easy to recycle. Recycling newspaper involves removing its ink, glue, and coating and then reconverting it to pulp, which is pressed into new paper. Making recycled paper uses 64% less energy and produces 35% less water pollution and 74% less air pollution than does making paper from wood, and, of course, no trees are cut down. In 2007, the United States recycled about 56% of its wastepaper (up from 25% in 1989). At least 10 other countries recycle 50-97% of their wastepaper and paperboard, and the global recycling rate is 43%. Paper recycling leaders are Denmark (97%), South Korea (77%), and Germany (72%). Despite a 56% recycling rate, the amount of paper thrown away each year in the United States is more than all of the paper used in China. Also, about 95% of books and magazines produced in the United States are printed on virgin paper. In producing this textbook we strive to use paper with a high percentage of recycled fibers. However, recycled paper of the quality required is often hard to get and costs more than conventional paper, which adds to the price of this book. Being green often involves trade-offs. One problem associated with making paper is the chlorine (Cl2) and chlorine compounds (such as chlorine dioxide, ClO2), used to bleach about 40% of the world's pulp for making paper. These compounds are corrosive to processing equipment, hazardous for workers, hard to recover and reuse, and harmful when released into the environment. A growing number of paper mills (mostly in the European Union) are replacing chlorine-based bleaching chemicals with chemicals such as hydrogen peroxide (H2O2) or oxygen (O2).

List some ways (at least 4) that we can reduce the incidence of AIDS and other infectious diseases.

According to the WHO, a global strategy to slow the spread of AIDS should have six major priorities. First, reduce the number of new infections below the number of deaths. Second, concentrate on the groups in a society that are most likely to spread the disease, such as sex workers, intravenous drug users, and soldiers. Third, provide free HIV testing and pressure people from high-risk groups to get tested. Fourth, implement a mass-advertising and education program geared toward adults and schoolchildren to help prevent the disease, and emphasize abstinence, condom use, and male circumcision (which apparently can reduce the transmission of HIV to men from infected female partners by up to 60%). Fifth, provide free or low-cost drugs to slow the progress of the disease. Sixth, increase funding for research on the development of microbiocides such as a vaginal gel that could help women to protect themselves from getting HIV/AIDS. According to the WHO, the global death rate from infectious diseases decreased by about two-thirds between 1970 and 2000 and is projected to continue dropping. Also, between 1971 and 2000, the percentage of children in developing countries immunized with vaccines to prevent tetanus, measles, diphtheria, typhoid fever, and polio increased from 10% to 84%— saving about 10 million lives each year. It costs about $30 to get a basic package of vaccines to a child—an affordable way to save a child's life for roughly the price of a single night out at the movies in a developed country. Figure 17-10 lists measures promoted by health scientists and public health officials to help prevent or reduce the incidence of infectious diseases—especially in developing countries. An important breakthrough has been the development of simple oral rehydration therapy to help prevent death from dehydration for victims of severe diarrhea, which causes about one-fourth of all deaths of children younger than age 5. It involves administering a simple solution of boiled water, salt, and sugar or rice, at a cost of only a few cents per person. It has been the major factor in reducing the annual number of deaths from diarrhea from 4.6 million in 1980 to 1.9 million in 2006. Few investments have saved so many lives at such a low cost. In 2006, the WHO estimated that implementing the solutions in Figure 17-10 could save the lives of as many as 4 million children younger than age 5 each year. Recall that more than a third of the world's people—2.6 billion—do not have decent bathroom facilities, and more than a billion get their water for drinking, washing, and cooking from sources polluted by animal and human feces. A key to reducing sickness and premature death from infectious disease is to focus on providing people with simple latrines and access to safe drinking water. The U.N. estimates that this could be done for about $20 billion a year—about what rich countries with almost universal access to clean water spend each year on bottled water. Bad news. The WHO estimates that only 10% of global medical research and development money goes toward preventing infectious diseases in developing countries, even though more people worldwide suffer and die from these diseases than from all other diseases combined. Fortunately, the problem is getting more attention. In recent years, philanthropists including Bill and Melinda Gates and Warren E. Buffet have donated billions of dollars to improve global health, with primary emphasis on preventing infectious diseases in developing countries.

Know some ways that we can reduce waste: At home

According to the integrated waste management approach, our efforts should be focused less on disposal and recovery of wastes and more on source reduction of these wastes. There are many ways that individuals can reduce municipal solid waste. Individuals can carry their own shopping bags and buy products in bulk. We can also reduce the use of paper napkins, plates, utensils and towels but using reusable alternatives such as cloth napkins & rags. You can reuse and repurpose items such as washing and reusing plastic or glass food containers. To reduce food waste, individuals can try to waste as little food as possible & compost what's left. You can also borrow items from the library or purchase music or movies digitally

Infectious disease

An infectious disease is caused when a pathogen such as a bacterium, virus, or parasite invades the body and multiplies in its cells and tissues - causes disease. Examples are flu, HIV, malaria, tuberculosis, and measles.

Pathogen

Biological hazards from more than 1,400 pathogens that can infect humans. A pathogen is a living organism that can cause disease in another organism. Examples are bacteria, viruses, parasites, protozoa, and fungi.

What is bioremediation? Phytoremediation?

Biological method to detoxify hazardous waste. Uses organisms to breakdown hazardous waste. Phytoremediation uses plants to breakdown hazardous waste.

Be able to give and explain examples of bioremediation

Bioremediation companies that specialize in soil and groundwater use microbes that feed on the hazardous substances for energy, which results in the breakdown of the targeted contaminant. Examples include junkyards, industrial spills, land development, fertilizer use, and more.

Understand why children & infants are much more susceptible to the effects of toxins than adults

But infants and young children are more susceptible to the effects of toxic substances than are adults for three major reasons. First, children generally breathe more air, drink more water, and eat more food per unit of body weight than do adults. Second, they are exposed to toxins in dust or soil when they put their fingers, toys, or other object in their mouths (as they frequently do). Third, children usually have less welldeveloped immune systems and body detoxification processes than adults have.

Understand how hazardous waste can be detoxified by: Chemical methods

By adding other chemicals that can react with the waste or chemicals that will bind with the harmful substances so they are easier to remove. Chemical reactions can also neutralize some of the toxins, making them less toxic for disposal. Nanomagnets are tiny magnets that can bind with organic pollutants like oil and then be removed by a magnet.

What happened at Love Canal?

CERCLA was partly enacted because of disasters like Love Canal. At Love Canal, a neighborhood in Niagara Falls, New York families were evacuated in 1978 after buried toxic chemicals rose to the surface, contaminating homes and an elementary school. This event got lots of national attention. It turned out that the neighborhood was built on a toxic waste dump site and the residents were never notified of this. There are thousands of former military and industrial waste sites that are contaminated and need to be cleaned up. (Love canal is named after the man who envisioned putting a canal between the Niagara River and Lake Ontario- the canal never was built).

Know the health problems associated with smoking (including secondhand smoke) and why it is hard to quit smoking

Cigarette smoking is the world's most preventable major cause of suffering and premature death among adults. In 2007, the WHO estimated that tobacco use helped to kill 100 million people prematurely during the 20th century and could kill 1 billion people during this century unless governments act now to dramatically reduce smoking. The WHO estimates that each year, tobacco contributes to the premature deaths of at least 5.4 million people (about half from developed and half from developing countries) from 25 illnesses including heart disease, lung cancer, other cancers, bronchitis, emphysema, and stroke. By 2030, the annual death toll from smoking-related diseases is projected to reach more than 8 million—an average of 21,900 preventable deaths per day. About 80% of these deaths are expected to occur in developing countries, especially China, with 30% of the world's smokers, and India with 11% (compared to 4.5% in the United States). According to the CDC, smoking kills about 442,000 Americans per year prematurely—an average of 1,210 deaths per day, or nearly one every minute. This death toll is roughly equivalent to six fully loaded 200-passenger jet planes crashing every day with no survivors! Yet, this ongoing major human tragedy in the United States and throughout the world rarely makes the news. The overwhelming consensus in the scientific community is that the nicotine inhaled in tobacco smoke is highly addictive. Only one in ten people who try to quit smoking succeeds. Smokers suffer about the same relapse rate as do recovering alcoholics and those addicted to heroin or crack cocaine. A British government study showed that adolescents who smoke more than one cigarette have an 85% chance of becoming smokers. Passive smoking, or breathing secondhand smoke, also poses health hazards for children and adults. Children who grow up with smokers are more likely to develop allergies and asthma. Among adults, nonsmoking spouses of smokers have a 30% higher risk of both heart attack and lung cancer than do spouses of nonsmokers. In 2006, the CDC estimated that each year, secondhand smoke causes an estimated 3,000 lung cancer deaths and 46,000 deaths from heart disease in the United States. A 50-year study published in 2004 by Richard Doll and Richard Peto found that cigarette smokers die, on average, 10 years earlier than nonsmokers, but that kicking the habit—even at 50 years old—can cut a person's risk in half. If people quit smoking by the age of 30, they can avoid nearly all the risk of dying prematurely, but again, the longer one smokes, the harder it is to quit.

Know some ways that we can reduce waste: In industry

Companies can redesign products to use a lower amount of materials than in the past. Costs less too. For example milk jugs contain less plastic than they did in the 1970's and disposable water bottles contain less plastic than they did a couple years ago. The weight of cars has been reduced 25% since the 1960s by using lighter materials. Companies can also redesign their manufacturing processes to produce less waste and to produce waste that is less toxic. For example we can replace toxic chemicals with non-toxic or less toxic chemicals such as in dry cleaning. Other companies are able to recycle and reuse parts. The Caterpillar truck company disassembles engines and fixes worn parts which are then as good as new. Consumers can also vote with their dollar for companies that use less packaging and companies that build products to last.

What is composting?

Composting is a form of recycling that mimics nature's recycling of nutrients—one of the four scientific principles of sustainability. It involves allowing decomposer bacteria to recycle yard trimmings, food scraps, and other biodegradable organic wastes. The resulting organic material can be added to soil to supply plant nutrients, slow soil erosion, retain water, and improve crop yields. Homeowners can compost such wastes in simple backyard containers, in composting piles that must be turned over occasionally, or in small composting drums that can be rotated to mix the wastes and to speed up the decomposition process. Over 6 million homes in North America compost their organic wastes and the number is increasing. The United States has about 3,300 municipal composting programs that recycle about 37% of country's yard wastes. This is likely to rise as the number of states (now 20) that ban yard wastes from sanitary landfills increases. The resulting compost can be used as organic soil fertilizer, topsoil, or landfill cover. It can also be used to help restore eroded soil on hillsides and along highways, and on strip-mined land, overgrazed areas, and eroded cropland. To be successful, a large-scale composting program must be located carefully and odors must be controlled, because people do not want to live near a giant compost pile or plant. Some cities in Canada and many European Union countries compost more than 85% of their biodegradable wastes in centralized community facilities. Sometimes composting takes place in huge indoor buildings. In the Canadian city of Edmonton, Alberta, an indoor composting facility the size of eight football fields composts 50% of the city's organic solid waste. Composting programs must also exclude toxic materials that can contaminate the compost and make it unsafe for use as fertilizer.

How does CERCLA/superfund regulate waste?

Comprehensive Environmental Response Compensation and Liability Act (CERCLA) (1980). CERCLA is also known as the Superfund program. CERCLA was partly enacted because of disasters like Love Canal. CERCLA established a federal program to clean up these polluted sites in the US. Experts would identify polluted sites, take action to protect groundwater near these sites, and then clean up the pollution as funds were available. A fund was established from taxes paid by petroleum and chemical companies that would pay the approximately $25 million to clean up each site. Additionally, CERCLA operates on the polluter pays principle, which means that in addition to this fund, the money for clean up came from the polluting company itself. That requires that the government identify the original polluter, which is often difficult. In 1995, the CERCLA fund ran out of money. Now, taxpayers are paying the cost of clean up, but not much clean up is happening due to the lack of funding and difficulty identifying polluters. Under CERCLA companies are required to report storage of toxic chemicals, so citizens can easily find out what toxic chemicals are being stored near them.

Understand the advantages and disadvantages: Deep-well disposal

Deep-well injection is a long-term disposal method. A well is drilled below the groundwater and through an impermeable layer of rock. The well is lined with concrete and then hazardous waste is pumped down the well into the porous rock below. The well is intended to be isolated from groundwater and human contact because it is in a porous layer below an impermeable layer. Nevertheless, the well casings can become corroded or cracked and leak waste into soil and groundwater. Additionally, earthquakes can cause cracks and leaks. Only specific locations.

What is Fresh Kills? What happens to trash from NYC now?

Despite its efforts to limit MSW, New York City was one of the first U.S. cities to run out of landfill space. Until 2001, most of the city's garbage was buried in its Fresh Kills landfill on Staten Island, the world's largest public landfill. At its busiest in 2001, this landfill, a monument to a throwaway society, was deeper than the city's Statue of Liberty is tall. However, after filling up in 2001, it was closed. Now it is being transformed into recreational facilities, restored wetlands, and a large public parkland. Since 2001, the city has been hauling its massive amounts of garbage to landfill sites in New Jersey, Pennsylvania, and Virginia. Each day, some 600 energy-inefficient and polluting tractor trailers, which if lined up would form a convoy nearly 14 kilometers (9 miles) long, haul trash out of New York City to landfills as far as 480 kilometers (300 miles) away. Similarly, in 2002, Canada's largest city Toronto closed its last landfill and, since then, has been shipping all of its garbage to Wayne County, Michigan (USA), for burial. As oil prices rise and concerns over CO2 emissions increase, it may become too expensive at some point for New York (and for other cities) to haul garbage long distances to burial sites. Then what?

What are zoonotic diseases? Why has the incidence of these diseases increased in the last half century?

Diseases passed on from animals to humans. West Nile and SARS are examples of diseases that move from animals to humans. Zoonotic diseases have increased as more people move into undeveloped areas to settle and interact with wildlife species, buying and selling wild animals internationally, raising livestock on factory farms, consuming bush meat, and clearing forests.

Know how degradation of plastics in the ocean is harmful to marine life

Each year they threaten millions of seabirds, marine mammals, and sea turtles, which can mistake a floating plastic sandwich bag for a jellyfish or get caught in discarded plastic nets. Plastics discarded on beaches or dumped into the ocean from ships can disintegrate into particles the size of sand grains that resemble the prey of a variety of organisms. These particles can fill the stomachs of birds and other sea creatures and cause dehydration, malnutrition, and eventually starvation. Because tiny plastic particles can accumulate as they move through food webs, some level of plastic is found in most of the seafood people eat.

What does the endocrine system do? What are the two types of endocrine disruptors?

Endocrine system regulates function of hormones in body. Endocrine disruptors interfere with hormones/glands (the endocrine system). Two types/categories of disruptors include: can mimic hormones or block their function which will trick the body into thinking it has more or less of the hormone present. Hormone blockers can block hormone receptor sites on cells and trick your body into thinking there is less of a hormone than there really is. Hormone mimics have a similar molecular structure to hormones so can bind to the same receptors as the hormones and trick your body into thinking there is more of a hormone than there really is.

Understand how hazardous waste can be detoxified by: Physical methods

Filtration through charcoal or resins can remove some of the harmful solids in hazardous wastes, concentrating them for disposal. Distillation (separation by boiling point) can separate out harmful liquids from less harmful ones. These harmful liquids can then be disposed of more easily.

What makes recycling plastics difficult? (Three reasons)

First, many plastics are hard to isolate from other wastes because the many different resins used to make them are often difficult to identify, and some plastics are composites of different resins. For example, a plastic ketchup bottle might have as many as six different layers of plastics bonded together. Most plastics also contain stabilizers and other chemicals that must be removed before recycling. Second, recovering individual plastic resins does not yield much material because only small amounts of any given resin are used in each product. Third, the inflation-adjusted price of oil used to produce petrochemicals for making plastic resins is low enough to make the cost of virgin plastic resins much lower than that of recycled resins. An exception is PET (polyethylene terephthalate), used mostly in plastic drink bottles. However, PET collected for recycling must not have other plastics mixed with it; a single PVC (polyvinyl chloride) bottle in a truckload of PET can render it useless for recycling. Despite its economic value, only about 20% of the PET used in plastic containers in the United States is recycled. However, in 2007, Coca-Cola announced a goal of reusing or recycling 100% of the PET bottles it sells in the United States.

Know the main reasons why people are not good at judging risks

Five factors can cause people to see a technology or a product as being more or less risky than experts judge it to be. First is fear. Research going back 3 decades shows that fear causes people to overestimate risks and to worry more about unusual risks than they do about common everyday risks. Studies show that people tend to overestimate the numbers of deaths caused by tornadoes, floods, fires, homicides, cancer, and terrorist attacks, and to underestimate numbers of deaths from flu, diabetes, asthma, stroke, and automobile accidents. Many people also fear a new, unknown product or technology more than they do an older, more familiar one. For example, some people fear genetically modified food and trust food produced by traditional plant-breeding techniques. Most people have a greater fear of nuclear power plants than of more familiar and highly polluting coal-fired power plants. A second factor is the degree of control we have. Most of us have a greater fear of things over which we do not have personal control. For example, some individuals feel safer driving their own cars over long distances and through bad traffic than they do traveling the same distance on a plane. But look at the numbers. The risk of dying in a car accident in the United States while using a seatbelt is 1 in 6,070 whereas the risk of dying in a commercial airliner crash is 1 in 9 million. Third is whether a risk is catastrophic, not chronic. We usually are more frightened by news of a single catastrophic accident such as a plane crash than we are of a cause of death such as smoking, which has an even larger death toll spread out over time. Fourth, some people suffer from optimism bias, the belief that risks that apply to other people do not apply to them. Some people get upset when they see someone driving erratically while talking on a cell phone. But they may believe that their own talking on the cell phone does not impair their driving ability. A fifth factor is that many of the risky things we do are highly pleasurable and give instant gratification, while the potential harm from such activities comes later. Examples are smoking cigarettes, eating lots of ice cream, and getting a tan. There is also concern about the unfair distribution of risks in some cases. For example, citizens are often outraged when government officials decide to put a hazardous waste landfill or incinerator in or near their neighborhood. Even when the decision is based on careful risk analysis, it is usually seen as a political, not a scientific, decision. Residents will not be satisfied by an estimate putting the lifetime risk of cancer death from the facility at no greater than, say, 1 in 100,000. Instead, they point out that living near the facility means that they will have a much higher risk of dying from cancer than will people living farther away.

Where in the world is malaria most prevalent? How could climate change affect the number of cases of malaria worldwide?

Global warming is likely to increase cases of malaria as populations of malaria-carrying mosquitoes spread to warmer areas. Prevalent in sub-Sahara Africa.

Know what e-waste is, why it is harmful and what happens to most US e-waste (p560)

Hazardous waste includes e-waste or electronic waste (cell phones, TVs, computers). These are particularly of concern because they include heavy metals like lead, cadmium, mercury, arsenic, chromium, tin, and copper which can be harmful to human health. These materials are used widely in industry for wiring, electronics, metal plating, pigments, and dyes. They enter the environment when products containing them are disposed of improperly. One of the problems with e-waste is planned obsolescence: Manufacturers design products to become obsolete quickly so consumers will buy another one. Possible Solutions: Companies can build electronics with more modular design, so that parts can be added or replaced to add new features to a device. This can be expensive and difficult in many cases because we do not know what future innovations will occur. Many companies include prepaid recycling envelopes with new gadgets (Virgin Mobile allows customers to mail back any cell phone- not just virgin mobile phones- for proper disposal, Sprint also does this.). Currently only about 1% of phones are recycled in the US Europe has standardized connectors/accessories for cell phones so you do not need to buy a new one each time you buy a new phone. Another suggestion is for companies to give rebates for keeping old devices like phones after a certain amount of time. We can also encourage companies to use recyclable materials/ packaging. Apple is doing this- they have committed to reducing toxins and packaging for their products. Currently about 10-40% of e-waste is shipped to developing countries, such as China, India and poor African nations. Labor is cheap and workers will dismantle the products to remove valuable materials while exposing the air, water, and their bodies to contamination by toxins. The Basel Convention is an international treaty that bans developed countries from shipping hazardous waste to developing countries. It was ratified by over 150 countries, but not the US (although the US does have national laws against this practice). The treaty and laws can be evaded by labeling hazardous waste as "recyclable materials" which can legally be shipped overseas. Basel Action Network (BAN) is a US non-profit that focuses on ending this trade of hazardous materials between countries and enforcing the Basel Convention.

Understand the advantages and disadvantages: Hazardous waste landfills

Hazardous waste landfills have standards that are more strict than those of sanitary landfills. Waste is put into drums and buried in a lined landfill. The groundwater surrounding the landfill is continually monitored for leaks. This is good for waste that cannot be further detoxified or destroyed (like mercury). These drums can also be stored in secure buildings above ground where they can be monitored if the water table is very high and digging cannot occur. This method is the least-used disposal method because it is so expensive.

Know the sources and health effects of the following toxins: Dioxins

If you ate a bowl of cereal with milk, the milk could be contaminated with dioxins. Dioxins are a group of chemicals that are produced as a byproduct of industrial/ manufacturing processes and incomplete waste incineration. Dioxins settle onto the ground and bodies of water and can then enter the food chain. Once in the food chain dioxins biomagnify with each trophic level since it accumulates in fatty tissue, like DDT. Humans are exposed to dioxins by eating animal products like meat, fish and dairy. All people have a background level of dioxins in their bodies (highest in Europe), though the average amount has decreased since the 1970's and 80's because of improved emissions standards and better monitoring of food. At high levels, dioxins can cause impairment of the immune system and liver function. There is some evidence that some dioxins can cause cancer. Evaluating the effects of dioxins is difficult because results vary greatly between species. Also because they are so ubiquitous and because it takes a lot of exposure to cause a disease it is hard to link the exposures to the disease with certainty. If a person develops cancer it is hard to determine if it was caused by dioxin exposure or something else. Nevertheless some dioxins are classified as likely carcinogens.

Know the sources and health effects of the following toxins: Bisphenol-A

If you drink bottled water, your bottle of water will likely contain phthalates and Bisphenol-A (BPA) BPA is a chemical used in many plastics. It can be found in many products such as water bottles, baby bottles, food storage containers, and in the lining of cans. Many studies have shown that BPA can leach out if the plastic is heated or if it is exposed to acid. Studies have shown that BPA can mimic estrogen and can cause a wide variety of effects in animals such as early puberty, reduced sperm counts, diabetes, hyperactivity, prostate disease and others. These findings are controversial: studies by the chemical industry have found no evidence of these effects.

Know the sources and health effects of the following toxins: Mercury

If you have eaten sushi recently, you may have eaten tuna. That tuna could be a source of Mercury or PCBs. Mercury is an element, so it cannot break down. It is naturally occurring and enters the environment through coal-burning power plants, waste incineration and mining. Once it is released, it accumulates in water and sediments and eventually works its way into aquatic food chains. Organisms high on these food chains, like tuna, tend to have higher concentrations due to biomagnification. Humans can be exposed to mercury by breathing it in from the air or by eating contaminated food. Once it is in a person's body, it can cause birth defects to unborn children. In adults it can cause cognitive deficits- people become "mad as a hatter." This makes mercury a teratogen as well as a neurotoxin.

Know the sources and health effects of the following toxins: PCBs

If you have eaten sushi recently, you may have eaten tuna. That tuna could be a source of Mercury or PCBs. PCBs are another chemical that accumulates in fish. They are a group of chemicals that were originally used as insulators in manufacturing. They entered the air, water and soil while they were manufactured and although they were banned in 1977, they still remain in the environment. They are found everywhere, even in people because they are so persistent. Once PCBs are in the environment they get into aquatic food chains, like mercury. They biomagnify up the food chain and enter the bodies of humans when humans ingest contaminated food. They have been shown to cause cancer in animals and can probably cause cancer in humans in high concentrations. They also may cause learning disabilities if children are exposed in the womb. This makes PCBs carcinogens (and possibly teratogens). If you drink bottled water, your bottle of water will likely contain phthalates and Bisphenol-A (BPA)

Why has the leading cause of death in most countries shifted from transmissible to nontransmissible diseases since 1900?

In 1900, infectious disease was the leading cause of death in the world and in the United States. Since then, and especially since 1950, the incidences of infectious diseases and the death rates from such diseases have been greatly reduced. This has been achieved mostly by a combination of better health care, the use of antibiotics to treat infectious diseases caused by bacteria, and the development of vaccines to prevent the spread of some infectious viral diseases. As a result, average life expectancy has increased in most countries, the leading cause of death has shifted to nontransmissible cardiovascular disease, and the percentage of people dying from cancers is increasing in both developed and developing countries.

Know what POPs stand for, what they are, and some examples

In 2000, negotiators agreed to a global treaty that would ban or phase out use of 12 of the most notorious persistent organic pollutants (POPs), also called the dirty dozen. The list includes DDT and eight other persistent pesticides, PCBs, dioxins, and furans. Animal studies have shown that the harmful effects of various POPS include tumors and cancers, birth defects, compromised immune systems, feminization of males and masculinization of females, abnormally functioning thyroid glands, and reproductive failure. There is also concern that some of these chemicals may play a role in malformed penises in boys, increased testicular cancers, and a 50% decline in sperm counts and sperm quality in men in a number of countries. Although such evidence is not clear and is controversial, phasing these chemicals out could be a reasonable precaution. New chemicals will be added to the list when the harm they could potentially cause is seen as outweighing their usefulness. This treaty went into effect in 2004 but has not been ratified and implemented by the United States.

What is the difference between primary and secondary recycling?

In primary or closed-loop recycling, these materials are recycled into new products of the same type—turning used aluminum cans into new aluminum cans, for example. In secondary recycling, waste materials are converted into different products. For example, used tires can be shredded and turned into rubberized road surfacing, newspapers can be reprocessed into cellulose insulation, and plastics can be reprocessed into various items.

Know the advantages and disadvantages of disposing of waste in landfills & incinerators

Landfill advantages: -World's poorest people scavenger for items to salvage and sell -Some landfills capture produced methane and use it to generate energy (methane gas recovery well) Landfill disadvantages: -Open dumps attract birds and other pests because of the exposed trash -Leachate must be monitored during the operational period of the landfill and for some time after it is closed -Very little decomposition occurs *anaerobic -Some methane (flammable and potent greenhouse gas) is produced Incinerator advantages: -Ash collected from MSW being burned in the incinerator is collected and disposed of in the landfill, and takes up much less space than the original MSW -Burning trash can generate enough heat to boil water and turn a turbine -> this can generate electricity to run the plant or add to the grid -No methane or leachate produced Incinerator disadvantages: -Produce air pollution which could contain dioxins or other hazardous chemicals (particularly true if household hazardous waste is improperly included with the MSW) -Still needs to be disposed of in a landfill

Know some ways that we can reduce waste: Through legislation

Local and state goverments can take a number of actions to encourage people to reduce waste. Bag bans are one of these measures. San Jose will be the largest city in the country to ban plastic bags on January 1st. In cities that have similar bans, customers have to bring their own bags and plastic bag pollution has decreased. Another option is a Pay‐as‐you‐throw or Fee‐per‐bag system. This system uses financial incentives to influence consumer behavior. Households only pay for the amount of trash they actually dispose of, but are not charged for extra recyclables. The less waste a house generates the less it is charged for trash collection. A third method of encouraging waste reduction & recycling are Bottle bills. Under these laws consumers receive a refund for returning used bottles at designated locations. Many states pay 5 cents per bottle, but Michigan pays 10 cents. As a result, they have seen even better rates of recycling.

How can governments discourage people from smoking?

Many health experts urge that a $3-5 federal tax be added to the price of a pack of cigarettes in the United States (and in other countries). Then users of tobacco products—not the rest of society—would pay a much greater share of the $158 billion per year (an average of $301,000 per minute) in health, economic, and social costs associated with smoking in the United States. Analysts also call for classifying and regulating the use of nicotine as an addictive and dangerous drug under the U.S. Food and Drug Administration, eliminating all federal subsidies and tax breaks to tobacco farmers and tobacco companies, and using cigarette tax revenues to finance an aggressive antitobacco advertising and education program. After a rally one day in 2005, activists left 1,210 pairs of empty shoes in front of the U.S. capital to remind lawmakers that each day tobacco kills that many people in the United States. So far, Congress has not enacted such reforms. Some other countries are enacting smoking bans. In 2004, Ireland, Norway, and Scotland enacted bans on smoking in all indoor workplaces, bars, and restaurants. And in 2004, India banned smoking in public places, as well as tobacco advertising in the mass media and tobacco sales to minors. Studies had shown that smoking was killing 2,200 people a day in India. In 2006, France banned smoking in public facilities, and Great Britain did so in 2007.

Know what LD-50 is and how to obtain this value by looking at a graph

One approach is to determine the lethal dose—the amount needed to kill an animal. A chemical's median lethal dose (LD50) is the dose that can kill 50% of the animals (usually rats and mice) in a test population within an 18-day period.

What is meant by planned obsolescence? How can it contribute to increased waste?

One of the problems with e-waste is planned obsolescence: Manufacturers design products to become obsolete quickly so consumers will buy another one.

How does RCRA regulate waste?

One way the the government encourages companies to use the methods we've just discussed is through the Resource Conservation & Recovery Act. RCRA sets standards for sanitary landfills but it also regulates some hazardous waste. It sets standards for managing some types of hazardous waste. It also allows the government to issue permits for companies that allow them to produce and dispose of certain amounts of waste in safe ways. Large generators of hazardous waste must be tracked "from cradle to grave." This means that companies are responsible for disposing of the hazardous waste they produce and then they need to submit proof to EPA that they have done so. The idea behind this is that the high costs of disposal will incentivize companies to invest in reducing their hazardous waste. *Also in solid waste disposal and reduction lecture

What are MRFs? What is source separation? Why do experts prefer it over MRFs?

One way to recycle is to send mixed urban wastes to centralized materials-recovery facilities (MRFs or "murfs"). There, machines or workers separate the mixed waste to recover valuable materials for sale to manufacturers as raw materials. The remaining paper, plastics, and other combustible wastes are recycled or burned to produce steam or electricity to run the recovery plant or to sell to nearby industries or homes. Such plants are expensive to build, operate, and maintain. If not operated properly, they can emit CO2 and toxic air pollutants, and they produce a toxic ash that must be disposed of safely, usually in landfills. Because MRFs require a steady diet of garbage to make them financially successful, their owners have a vested interest in increasing the throughput of matter and energy resources to produce more trash—the reverse of what prominent scientists believe we should be doing. To many experts, it makes more environmental and economic sense for households and businesses to separate their trash into recyclable categories such as glass, paper, metals, certain types of plastics, and compostable materials. This source separation approach produces much less air and water pollution and costs less to implement than MRFs cost. It also saves more energy, provides more jobs per unit of material, and yields cleaner and usually more valuable recyclables. In addition, sorting material educates people about the need for recycling.

What type of material makes up the largest percentage of municipal solid waste?

Paper and cardboard (37%), yard waste (12%), food waste (11%), plastics (11%), and metals (8%).

Know the sources and health effects of the following toxins: Phthalates

Phthalates are used to soften plastics (like PVC). They are used in many soft plastics like baby toys and IV bags. They are also used in many cosmetic products like lotions, deodorants, nail polishes, shampoos and even in medicines. Phthalates are implicated as causes of many conditions though most of them are still being tested. There is evidence that they disrupt hormones which can lead to breast cancer. They also may cause metabolic effects that lead to obesity.

Understand how hazardous waste can be detoxified by: Plasma arc torch

Plasma arc torch uses very high temperature plasma (created by passing an electric current through a gas) to break compounds into atoms and ions. Byproducts can be used to make fuel. This takes a lot of energy, but can be very effective. It is not a common method, but it is in use at a few locations worldwide.

Know the top three diseases that kill the most people each year

Pneumonia and flu, HIV/AIDS, and diarrheal diseases

What is the precautionary principle?

Pollution prevention is a strategy for implementing the precautionary principle. According to this principle, when there is reasonable but incomplete scientific evidence of significant or irreversible harm to humans or to the environment from a proposed or existing chemical or technology, we should take action to prevent or reduce the risk instead of waiting for more conclusive evidence. Note that the precautionary principle is a general guideline that does not specify what should trigger action, or what specific action should be taken. There is controversy over how far we should go in implementing pollution prevention based on the precautionary principle. If we applied it strictly, those proposing to introduce a new chemical or technology would bear the burden of establishing its safety. This would require two major changes in the way we evaluate risks. First, new chemicals and technologies would be assumed to be harmful until scientific studies could show otherwise. Second, existing chemicals and technologies that appear to have a strong chance of causing significant harm would be removed from the market until their safety could be established. For example, after decades of research revealed the harmful effects of lead, especially in children, lead-based paints and leaded gasoline were phased out in most developed countries. Some movement is being made in this direction, especially in the European Union. In 2000, negotiators agreed to a global treaty that would ban or phase out use of 12 of the most notorious persistent organic pollutants (POPs), also called the dirty dozen. The list includes DDT and eight other persistent pesticides, PCBs, dioxins, and furans. Animal studies have shown that the harmful effects of various POPS include tumors and cancers, birth defects, compromised immune systems, feminization of males and masculinization of females, abnormally functioning thyroid glands, and reproductive failure. There is also concern that some of these chemicals may play a role in malformed penises in boys, increased testicular cancers, and a 50% decline in sperm counts and sperm quality in men in a number of countries. Although such evidence is not clear and is controversial, phasing these chemicals out could be a reasonable precaution. New chemicals will be added to the list when the harm they could potentially cause is seen as outweighing their usefulness. This treaty went into effect in 2004 but has not been ratified and implemented by the United States. In 2006, the European Union enacted new regulations that require the registration of 30,000 untested and unregulated potentially harmful chemicals. The most hazardous substances will no longer be approved for use if safer alternatives exist. And when there is no alternative, producers must present a research plan aimed at finding one. Many environmental scientists applaud this use of pollution prevention to implement the precautionary principle, but some say that the regulation does not go far enough and has too many loopholes. Manufacturers and businesses contend that widespread application of this approach would make it too expensive and almost impossible to introduce any new chemical or technology. They argue that we can never have a risk-free society. Proponents of increased reliance on pollution prevention agree that we can go too far, but argue we have an ethical responsibility to reduce known or potentially serious threats to human health and to our life support system. They also point out that using the precautionary principle focuses the efforts and creativity of scientists, engineers, and businesses on finding solutions to pollution problems based on prevention rather than on cleanup. This in turn reduces health risks for employees and society, frees businesses from having to deal with pollution regulations, reduces the threat of lawsuits from harmed parties, increases profits, in some cases, from sales of safer products and innovative technologies, and improves the public image of businesses operating in this manner.

Know the difference between recycling and reuse. What are the benefits of each? What materials can be recycled?

Reuse involves cleaning and using materials over and over and thus increasing the typical life span of a product. This form of waste reduction decreases the use of matter and energy resources, cuts pollution, creates local jobs, and saves money. Recycling involves reprocessing discarded solid materials into new, useful products. In addition to saving resources and reducing solid waste and pollution, recycling also reduces unsightly and environmentally harmful litter. Households and workplaces produce five major types of materials that can be recycled: paper products, glass, aluminum, steel, and some plastics.

Understand what a dose-response curve is and how to interpret it

Scientists estimate the toxicity of a chemical by determining the effects of various doses of the chemical on test organisms and then by plotting the results in a dose-response curve.

Why has the incidence of TB increased in recent years?

Several factors account for the recent increase in TB incidence. One is that there are too few TB screening and control programs, especially in developing countries, where 95% of the new cases occur. A second problem is that most strains of the TB bacterium have developed genetic resistance to the majority of the effective antibiotics. Also, population growth, urbanization, and air travel have greatly increased person-to-person contacts, and TB has spread, especially in areas where large numbers of poor people crowd together. In addition, AIDS greatly weakens its victims' immune systems, which allows TB bacteria to multiply in AIDS victims.

How has the amount of trash generated in the US changed since the 1960s? How has the per capita waste generation changed?

Since 1990, the average annual production of MSW by weight per American has leveled off, mostly because of increased recycling and the use of lighter products. Historical analysis reveals some surprises about U.S. waste production.

Understand the advantages and disadvantages: Surface impoundment

Surface impoundments are shallow depressions are lined with plastic and clay. Water containing waste is placed in the impoundment and is left to evaporate. As the water evaporates, the residue of solid hazardous waste is left behind and collected to be transported elsewhere. There are a number of drawbacks to this method. The underlying clay layer can crack and leak waste, and rainstorms cause overflow, contaminating nearby areas. The EPA did a study of these impoundments and found that 70% of surface impoundments were found to have no liners at all. They also estimated as a result of the study that all liners will probably leak eventually.

Know the sources and health effects of the following toxins: Atrazine

Tap water can be contaminated with the pesticide Atrazine. Atrazine is a commonly used herbicide, particularly on farms that use low-till or no-till methods. Because no-till agriculture does not turn up the soil and kill weeds each season, these farms will need to use more herbicide to control weeds. Atrazine has been shown to contaminate groundwater, which is how it gets into drinking water. It was for this reason that the EU banned Atrazine in 2004. Atrazine is still used widely in the US and the EPA has set allowable levels in drinking water. There is some evidence that these levels should be lowered. Atrazine does not cause cancer, but is suspected to be a teratogen. Studies have shown that Atrazine can act like estrogen in frogs causing male frogs to become hermaphrodites. The maker of the chemical is refuting these findings. This makes Atrazine an endocrine disruptor.

How does Basel Convention regulate waste?

The Basel Convention is an international treaty that bans developed countries from shipping hazardous waste to developing countries. It was ratified by over 150 countries, but not the US (although the US does have national laws against this practice). The treaty and laws can be evaded by labeling hazardous waste as "recyclable materials" which can legally be shipped overseas. Basel Action Network (BAN) is a US non-profit that focuses on ending this trade of hazardous materials between countries and enforcing the Basel Convention.

How much MSW does the US recycle? How much do experts think we should recycle?

The United States recycles about 25% of its MSW—up from 6.4% in 1960. This increase has gotten a boost by almost 9,000 curbside pickup recycling programs, which serve about half of the U.S. population. In 2007, the United States recycled about 60% of its steel, 56% of its aluminum cans, 56% of its paper and cardboard, 36% of its tires, 22% of its glass, and 5% of its plastics. Experts say that with education and proper incentives, the United States could recycle 60-70% of these and many other forms of solid waste, in keeping with one of the four scientific principles of sustainability.

Know the sources and health effects of the following toxins: Glyphosate

The cereal itself may contain small amounts of glyphosate, a pesticide (herbicide) also known as Round Up. It is used as a weed killer and will not work its way into groundwater. Additionally, it degrades fairly rapidly (in a matter of months) in the soil, but residues can remain on crops. There is evidence that this pesticide can cause cancer. For those applying the pesticide, such as farm workers, it can cause other adverse effects such as irritation to the eyes, throat or skin. Glyphosate is controversial; the World Health Organization and the state of California consider it to be carcinogenic. The EPA does not. The EPA has set a safe level of glyphosate that is allowed in food. However, the Environmental Working Group, a nonprofit group, believes the level should be much lower. They have found that many food products, particularly those containing oats, exceed their safe level, though they do not exceed the EPA's safe level.

What is the difference between chronic & acute effects?

The damage to health resulting from exposure to a chemical is called the response. An acute effect is an immediate or rapid harmful reaction to an exposure— ranging from dizziness and nausea to death. A chronic effect is a permanent or long-lasting consequence (kidney or liver damage, for example) of exposure to a single dose or to repeated lower doses of a harmful substance.

Know what a bioassay is

The purpose of a bioassay is to determine the LD-50 of a substance (refer to bioassay lab)

What is toxicology? Why is it difficult to definitively determine the health consequences of many toxins?

The study of how toxins impact living things. The study of these chemicals and their effects is called toxicology. These toxins can be split into a few different categories. Most toxins fall into 5 categories. Evaluating the effects of dioxins is difficult because results vary greatly between species. Also because they are so ubiquitous and because it takes a lot of exposure to cause a disease it is hard to link the exposures to the disease with certainty. If a person develops cancer it is hard to determine if it was caused by dioxin exposure or something else. Phthalates are implicated as causes of many conditions though most of them are still being tested.

What is a pay-as-you-throw (fee-per-bag) system? What are bottle bills? How do they encourage recycling? How else can governments encourage recycling?

To promote separation of wastes for recycling, more than 4,000 communities in the United States use a pay as-you-throw or fee-per-bag waste collection system. It charges households and businesses for the amount of mixed waste picked up, but does not charge for pickup of materials separated for recycling or reuse. Parts of Canada and 11 U.S. states have bottle laws that place a deposit fee on all beverage containers. Retailers must accept the used containers and pass them on for recycling or reuse. Large beverage industries have used their political and financial clout to keep most U.S. states from passing bottle laws, arguing that they lead to a loss of jobs and higher beverage costs for consumers. But experience in Canada and U.S. states with bottle bills shows that more jobs are gained than lost, costs to consumers have not risen, resources are saved, and roadside litter decreases. Some analysts call for a national bottle bill in the United States, while others would ban all beverage containers that cannot be reused, as Denmark, Finland, and Canada's Prince Edward Island have done. Ecuador levies a refundable beverage container deposit fee that amounts to 50% of the cost of the drink. In Finland, 95% of the soft drink, beer, wine, and spirits containers are refillable. How can we encourage reuse and recycling? Proponents say that leveling the economic playing field is the best way to start. Governments can increase subsidies and tax breaks for reusing and recycling materials (the carrot) and decrease subsidies and tax breaks for making items from virgin resources (the stick). Other strategies are to greatly increase use of the fee-per-bag waste collection system and to encourage or require government purchases of recycled products to help increase demand and lower prices. Governments can also pass laws requiring companies to take back and recycle or reuse packaging and electronic waste discarded by consumers, as is done in Japan and some European Union countries. Citizens can pressure governments to require labels on all products listing recycled content and the types and amounts of any hazardous materials they contain. This would help consumers to be better informed about the environmental consequences of buying certain products. One reason for the popularity of recycling is that it helps to soothe people's consciences in a throwaway society. Many people think that recycling their newspapers and aluminum cans is all they need do to meet their environmental responsibilities. Recycling is important, but reducing resource consumption and reusing resources are more effective ways to reduce the flow and waste of resources.

How is Ebola transmitted from person to person? How is Ebola connected to the consumption of bushmeat?

Transmitted through bodily fluids from an infected person to a non-infected person through passage ways. Not contagious until having symptoms. Butchering and eating some forms of bush meat has helped to spread fatal diseases such as HIV/AIDS and the Ebola virus to humans.

Know why genetic resistance to antibiotics is becoming more common and how this relates to MRSA

We risk falling behind in our efforts to prevent infectious bacterial diseases because of the astounding reproductive rate of bacteria, some of which can produce well over 16 million offspring in 24 hours. This allows bacteria to become genetically resistant to an increasing number of antibiotics through natural selection. In addition, some drug-resistant bacteria can quickly transfer their resistance to nonresistant bacteria by exchanging genetic material. Other factors play a key role in fostering such genetic resistance. One is the spread of bacteria (some beneficial and some harmful) around the globe by human travel and international trade. Another is the overuse of pesticides, which increases populations of pesticide-resistant insects and other carriers of bacterial diseases. Yet another factor is overuse of antibiotics. According to a 2000 study by Richard Wenzel and Michael Edward, at least half of all antibiotics used to treat humans are prescribed unnecessarily. In many countries, antibiotics are available without a prescription, which promotes unnecessary use. Resistance to some antibiotics has increased because of their widespread use in livestock and dairy animals to control disease and to promote growth. Also, the growing use of antibacterial hand soaps and other cleansers is probably promoting genetic resistance. As a result of these factors acting together, every major disease-causing bacterium now has strains that resist at least one of the roughly 160 antibiotics used to treat bacterial infections such as tuberculosis. Each year, genetic resistance to antibiotics plays a role in the deaths of at least 90,000 of the 2 million people who pick up mostly preventable infections while they are in U.S. hospitals, according to the U.S. Centers for Disease Control and Prevention. This serious problem is much worse in hospitals in many other countries. A bacterium known as methicillin-resistant staphylococcus aureus, or MRSA, has become resistant to most common antibiotics. This staph infection first appears on the skin as a red, swollen pimple or boil that may be painful and have pus. Many victims think they have a spider bite that will not heal. MRSA can cause a vicious type of pneumonia, flesheating wounds, and a quick death if it gets into the bloodstream. This staph germ typically thrives on the body (mostly on the skin and in the nose) in health care settings where people have open wounds and tubes. But in recent years, it has been increasingly found in the general population. It can be picked up on playgrounds, in meeting rooms, and in gyms. It can spread through skin contact, tattoo needles, and contact with poorly laundered clothing items or shared items such as towels. In 2005, MRSA infections contributed to the premature deaths of 18,650 people in the United States (more than the 17,000 who died from AIDS). Ways to reduce the chances of infection from MRSA include frequent, thorough washing of hands; careful cleansing of even superficial wounds with soap and water; covering all wounds with a clean, dry bandage; and not sharing towels or other linens. Most antibiotics work by crippling key proteins inside bacteria. But bacteria often develop immunity to such chemicals by modifying their protein receptor sites in ways that prevent the antibiotic molecules from entering their cells. In 2008, University of Pennsylvania scientists developed a compound that mimics molecules they identified in frog skin that essentially stab staph bacteria to death. This has inspired a new approach toward killing harmful bacteria by poking thousands of tiny holes in the bacterium's membranes. Ironically, at a time when chemical knowledge gained by studying amphibians could save millions of human lives, our activities are threatening many of the world's amphibian species.

Why is bioaccumulation of toxins bad?

When toxins gets absorbed at a higher rate than the body can get rid of it, the organism is at risk of chronic poisoning. Even if the environment doesn't have a high amount of toxin in it, accumulation through the food chain can be devastating for organisms.

Know definitions for the 5 classes of chemicals that we discussed: carcinogens

cause cancer

Know definitions for the 5 classes of chemicals that we discussed: Teratogens

cause harm to embryo/a fetus (but may not harm the mother) (ie alcohol)

Know definitions for the 5 classes of chemicals that we discussed: Mutagens

cause mutations (modifications to DNA); examples are UV rays (radiation), gamma radiation, the chemicals in tobacco

Know definitions for the 5 classes of chemicals that we discussed: Neurotoxins

damages the nervous system. Cause damage to the brain or nervous system. Effects of a neurotoxin include behavioral changes, learning disabilities and retardation.

Know definitions for the 5 classes of chemicals that we discussed: Endocrine disruptors

disrupt the functions of hormones in the body. Endocrine disruptors interfere with hormones/glands (the endocrine system). Two types/categories of disruptors.

Study units 1-5 study guides

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