chapter 15: environmental health, pollution and toxicology

Chapter 15: Chapter 15: Environmental Health, Environmental Health, Pollution and ToxicologyPollution and Toxicology

Disease is often due to an imbalance resulting from Disease is often due to an imbalance resulting from poor adjustment between the individual and the poor adjustment between the individual and the environment.environment. Continuum from state of health to diseaseContinuum from state of health to disease Gray zone in-betweenGray zone in-between As a result of exposure to chemicals in the environment As a result of exposure to chemicals in the environment

we may be in the midst of an epidemic of chronic we may be in the midst of an epidemic of chronic disease.disease.

DiseaseDisease

Seldom has a one-cause-one-effect Seldom has a one-cause-one-effect relationship w/ the environmentrelationship w/ the environment

Depends on several factorsDepends on several factors Physical environmentPhysical environment Biological environmentBiological environment LifestyleLifestyle

DiseaseDisease

Chances of experiencing serious Chances of experiencing serious environmental health problems and environmental health problems and disease depends ondisease depends on The water we drinkThe water we drink The air we breatheThe air we breathe The soil we grow crops inThe soil we grow crops in The rocks we build our homes onThe rocks we build our homes on

DiseaseDisease

Natural processes can release harmful Natural processes can release harmful materials into the soil, water or air.materials into the soil, water or air.

Lake Nyos in Cameroon, AfricaLake Nyos in Cameroon, Africa Experienced sudden release of carbon Experienced sudden release of carbon

dioxidedioxide Killed 1,800 people in near by town.Killed 1,800 people in near by town.

DiseaseDisease

Lake Nyos Webquest Questions

1. Where is Lake Nyos located?2. In what chain of volcanos is Lake Nyos situated?3. Describe the Lake Nyos Disaster4. Are there any other lakes where this could or has

happened?5. On the first link below, it is stated that the amount of

gas that can be dissolved in the water is dependent on what two things? What law tells us that this is true?

6. Air is typically comprised of what percent carbon dioxide? What concentration level is considered fatal?

7. What is being done to avert similar disasters in the future? Describe the solution.

Polluted environment Polluted environment impure, dirty, or otherwise unclean. impure, dirty, or otherwise unclean.

PollutionPollution refers to the occurrence of refers to the occurrence of unwanted change in the environment unwanted change in the environment introduction of harmful materials or the production of introduction of harmful materials or the production of

harmful conditions.harmful conditions.

ContaminationContamination similar to that of pollution similar to that of pollution implies making something unfit for a particular use through implies making something unfit for a particular use through

the introduction of undesirable materialsthe introduction of undesirable materials Think of contamination as rendering something polluted.Think of contamination as rendering something polluted.

TerminologyTerminology

ToxicToxic refers to materials (pollutants) that refers to materials (pollutants) that are poisonous to people and other living are poisonous to people and other living things.things. Toxicology is the science that studies chemicals Toxicology is the science that studies chemicals

that are known to be or could be toxic.that are known to be or could be toxic. Carcinogen Carcinogen is a particular kind of toxin that is a particular kind of toxin that

increases the risk of cancer. increases the risk of cancer. Carcinogens are the most feared and regulated Carcinogens are the most feared and regulated

toxins in our society.toxins in our society.


AdditivityAdditivity - A biologic response to exposure to - A biologic response to exposure to multiple substances that equals the sum of responses multiple substances that equals the sum of responses of all the individual substances added together of all the individual substances added together

AntagonismAntagonism – A biologic response to exposure to – A biologic response to exposure to multiple substances that is multiple substances that is lessless than would be than would be expected if the known effects of the individual expected if the known effects of the individual substances were added togethersubstances were added together

SynergismSynergism The interaction of different substances resulting in a The interaction of different substances resulting in a

total effect great than the sum of the effects of the total effect great than the sum of the effects of the separate substances.separate substances.

E.g. sulfur dioxide and coal dustE.g. sulfur dioxide and coal dust


Pollutants may be introduced into the environment Pollutants may be introduced into the environment at:at:

Point sourcesPoint sources, such as smokestacks, pipes , such as smokestacks, pipes discharging into waterways, stream entering the discharging into waterways, stream entering the ocean, or accidental spills. ocean, or accidental spills.

The Clean Water Act specifically defines a "point The Clean Water Act specifically defines a "point source" in section 502(14) of the Act. That source" in section 502(14) of the Act. That definition states: definition states:


The term "point source" means any discernible, The term "point source" means any discernible, confined and discrete conveyance, including but confined and discrete conveyance, including but not limited to any pipe, ditch, channel, tunnel, not limited to any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, or stock, concentrated animal feeding operation, or vessel or other floating craft, from which vessel or other floating craft, from which pollutants are or may be discharged. This term pollutants are or may be discharged. This term does not include agricultural storm water does not include agricultural storm water discharges and return flows from irrigated discharges and return flows from irrigated agriculture.agriculture.


Pollutants may also be introduced into the Pollutants may also be introduced into the environment at:environment at:

Non point sourcesNon point sources (Area sources), which are (Area sources), which are more diffused over the land and include urban more diffused over the land and include urban and agricultural runoff and, orand agricultural runoff and, or

mobile sources mobile sources such as automobile exhaustsuch as automobile exhaust. .


Nonpoint source (NPS) pollution, unlike pollution Nonpoint source (NPS) pollution, unlike pollution from industrial and sewage treatment plants, from industrial and sewage treatment plants, comes from many diffuse sources. NPS pollution comes from many diffuse sources. NPS pollution is caused by rainfall or snowmelt moving over is caused by rainfall or snowmelt moving over and through the ground. As the runoff moves, it and through the ground. As the runoff moves, it picks up and carries away natural and human-picks up and carries away natural and human-made pollutants, finally depositing them into made pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters, and even lakes, rivers, wetlands, coastal waters, and even our underground sources of drinking water. our underground sources of drinking water.

Nonpoint Source Nonpoint Source PollutionPollution

Nonpoint sources include:Nonpoint sources include: Excess fertilizers, herbicides, and insecticides from Excess fertilizers, herbicides, and insecticides from

agricultural lands and residential areas;agricultural lands and residential areas; Oil, grease, and toxic chemicals from urban runoff Oil, grease, and toxic chemicals from urban runoff

and energy production;and energy production; Sediment from improperly managed construction Sediment from improperly managed construction

sites, crop and forest lands, and eroding sites, crop and forest lands, and eroding streambanks;streambanks;

Salt from irrigation practices and acid drainage Salt from irrigation practices and acid drainage from abandoned mines;from abandoned mines;

Bacteria and nutrients from livestock, pet wastes, Bacteria and nutrients from livestock, pet wastes, and faulty septic systems;and faulty septic systems;

Atmospheric deposition and hydromodification are Atmospheric deposition and hydromodification are also sources of nonpoint source pollution.also sources of nonpoint source pollution.

Nonpoint Source Nonpoint Source PollutionPollution

Point Source or Nonpoint Source? Why?

How the amount or concentration of a How the amount or concentration of a particular pollutant or toxin present in the particular pollutant or toxin present in the environment is reported varies widely.environment is reported varies widely. waste water pollution reported in millions of gallonswaste water pollution reported in millions of gallons Emissions of nitrogen oxides reported in tons per yearEmissions of nitrogen oxides reported in tons per year Others given by a volume, mass or weightOthers given by a volume, mass or weight

Ppm (parts per million), ppb parts per billion), mg/kg or %Ppm (parts per million), ppb parts per billion), mg/kg or %

Measuring the Amount of Measuring the Amount of PollutionPollution

Suppose 17 grams of sucrose is dissolved in 183 Suppose 17 grams of sucrose is dissolved in 183 grams of water. What is the concentration of sucrose grams of water. What is the concentration of sucrose in ppm?in ppm?

PracticePractice

(17 / 200) x 1,000,000 = 85,000 ppm

The solubility of AgCl is 0.008 grams/100 grams of water. What is this concentration in ppm?

0.008 X 1000000 = 80 ppm 100

Infectious disease Infectious disease Spread from the interactions between Spread from the interactions between

individuals and food, water, air or soil.individuals and food, water, air or soil. Can travel globally via airplanesCan travel globally via airplanes New diseases emerging and previous ones New diseases emerging and previous ones

reemergingreemerging Diseases that can be controlled by Diseases that can be controlled by

manipulating the environment manipulating the environment classified as environmental health concernsclassified as environmental health concerns

Infectious AgentsInfectious Agents

LegionellosisLegionellosis Occurs where air-conditioning systems have Occurs where air-conditioning systems have

been contaminated by disease-causing been contaminated by disease-causing organisms.organisms.

GiardiasisGiardiasis a protozoan infection of the small intestine a protozoan infection of the small intestine

spread via food, water, or person-to-person spread via food, water, or person-to-person contact.contact.

SalmonellaSalmonella a food-poisoning bacterial infection spread via a food-poisoning bacterial infection spread via

water or food.water or food.

Environmentally Environmentally Transmitted Infectious Transmitted Infectious DiseasesDiseases

MalariaMalaria a protozoan infection transmitted by a protozoan infection transmitted by

mosquitoes.mosquitoes. Lyme diseaseLyme disease

Transmitted by ticks.Transmitted by ticks. CryptosporidosisCryptosporidosis

a protozoan infection transmitted via water or a protozoan infection transmitted via water or person-to-person contact.person-to-person contact.

AnthraxAnthrax Bacterial infection spread by terrorist activity.Bacterial infection spread by terrorist activity.

Environmentally Environmentally Transmitted Infectious Transmitted Infectious DiseasesDiseases

The major heavy metals that pose health The major heavy metals that pose health hazards to people and ecosystems include:hazards to people and ecosystems include: mercury, lead, cadmium, nickel, gold, mercury, lead, cadmium, nickel, gold,

platinum, silver, bismuth, arsenic, selenium, platinum, silver, bismuth, arsenic, selenium, vanadium, chromium, and thallium.vanadium, chromium, and thallium.

Each may be found in soil and water not Each may be found in soil and water not contaminated by humans.contaminated by humans.

Often have direct physiological effects.Often have direct physiological effects. Stored and incorporated in living tissueStored and incorporated in living tissue

Fatty body tissueFatty body tissue Content in our bodies referred to as Content in our bodies referred to as body body

burdenburden..

Toxic Heavy MetalsToxic Heavy Metals

Chemical elements can become concentratedChemical elements can become concentrated Biomagnification- Biomagnification-

- the increased concentration of a toxic - the increased concentration of a toxic chemical the higher an animal is on the food chemical the higher an animal is on the food chain. chain.

Bioaccumulation-Bioaccumulation- the accumulation or increase in concentration of the accumulation or increase in concentration of

a substance in living tissue of a particular a substance in living tissue of a particular organism.organism.

E.g. Cadmium, mercuryE.g. Cadmium, mercury

Toxic PathwaysToxic Pathways

The Town of MinamataThe Town of Minamata Located on the coast Located on the coast

of the Yatsushiro Sea of the Yatsushiro Sea in southwestern in southwestern Japan.Japan.

The village was very The village was very poor. poor. Mostly fishermen and Mostly fishermen and

farmers.farmers. Villagers welcome Villagers welcome

Chisso Corporation in Chisso Corporation in 19071907 http://www.jnto.go.jp/tourism/img/map/86.gif

Chisso CorporationChisso Corporation Chisso = nitrogenChisso = nitrogen

Produced fertilizerProduced fertilizer 1907: Chisso Corp. 1907: Chisso Corp.

builds a fertilizer plant builds a fertilizer plant in the Minamata.in the Minamata.• Job openingsJob openings

1925: plant begins 1925: plant begins dumping untreated dumping untreated wastewater into wastewater into Minamata BayMinamata Bay Kills fishKills fish Fisherman PayoffsFisherman Payoffs

http://www.japanfocus.org/images/592-3.jpg

Chisso CorporationChisso Corporation 1932: Chisso plant begins to 1932: Chisso plant begins to

produce acetaldehyde to be produce acetaldehyde to be used in the production of used in the production of plastic, perfume and drugs.plastic, perfume and drugs.

• Acetaldehyde is made from Acetaldehyde is made from acetylene and water with a acetylene and water with a mercury catalyst.mercury catalyst.

After WWII plastic production After WWII plastic production boomed and Chisso Corp. boomed and Chisso Corp. grew. grew.

By 1970: Chisso brought Japan By 1970: Chisso brought Japan 60% of its income and owned 60% of its income and owned nearly 70% of the land in nearly 70% of the land in Minamata.Minamata.

http://www-personal.umich.edu/~tobin/Smith2.jpg

Bizarre Behavior in Bizarre Behavior in AnimalsAnimals

Early 1950’s:Early 1950’s: Dead fish wash ashoreDead fish wash ashore Crows fall out of skyCrows fall out of sky Suicidal dancing catsSuicidal dancing cats

Mercury moves up Mercury moves up the food chain. the food chain.

http://flickr.com/photos/tropicalrips/127535537/

Mid 1950’s: Behavior Mid 1950’s: Behavior Seen in HumansSeen in Humans Behaviors witnessed:Behaviors witnessed:

Loss of motor control in Loss of motor control in handshands

Violent tremorsViolent tremors Swaggered walkSwaggered walk InsanityInsanity

They called it the “Cat-They called it the “Cat-dancing” diseasedancing” disease

Nobody knew the cause Nobody knew the cause of the epidemic.of the epidemic. Many hid for fear of Many hid for fear of

ridiculeridicule

http://www.hamline.edu/personal/amurphy01/es110/eswebsite/ProjectsSpring03/ebarker/Minamata%20Web%20Page.htm

Putting the Pieces Putting the Pieces TogetherTogether

1956: Epidemiological and medical researchers at Chisso 1956: Epidemiological and medical researchers at Chisso Corp. Hospital begin researching the cause of the epidemicCorp. Hospital begin researching the cause of the epidemic

• They determine that the disease is from mercury poisoning by They determine that the disease is from mercury poisoning by consuming the contaminated fish and shellfish of Minamata consuming the contaminated fish and shellfish of Minamata Bay.Bay.

• In 1959 Dr. Hosokawa performs tests on cats at the hospital In 1959 Dr. Hosokawa performs tests on cats at the hospital and has direct evidence that the acetaldehyde waste water is and has direct evidence that the acetaldehyde waste water is to blame for the diseaseto blame for the disease

Chisso corp. forbids Dr. Hosokawa from conducting any Chisso corp. forbids Dr. Hosokawa from conducting any further experiments and redirects the flow of wastewater further experiments and redirects the flow of wastewater from the bay to the river to avoid being caught.from the bay to the river to avoid being caught. A larger geographical area contaminated. A larger geographical area contaminated. Children born with horrifying deformities.Children born with horrifying deformities.

Putting the Pieces Putting the Pieces TogetherTogether

http://www.nimd.go.jp/archives/english/tenji/a_corner/image/hasseimap.gif

1968: Government ran Public Health service traces the 1968: Government ran Public Health service traces the contamination to the Minamata Chisso plant. contamination to the Minamata Chisso plant.

Government halts the production of acetaldehydeGovernment halts the production of acetaldehyde 1972: Government publically announces Chisso Corp’s part in 1972: Government publically announces Chisso Corp’s part in

the Minamata epidemic and orders Chisso Corp to pay the Minamata epidemic and orders Chisso Corp to pay compensation to the families that were affected. compensation to the families that were affected.

http://www.icett.or.jp/lpca_jp.nsf/505b1fe895fd2a8c492567ca000d587d/e35dc782654b21d7492567ca000d8c50?OpenDocument

Centers for Disease Control and Prevention

The AftermathThe Aftermath

• 30-70 tons of methyl 30-70 tons of methyl mercury was dumped mercury was dumped into the Bayinto the Bay

• 10,000 people affected by 10,000 people affected by Minamata disease.Minamata disease.

– 3,000 died 3,000 died • Compensation has been Compensation has been

given to families as given to families as recently as 1990.recently as 1990.

– Highest compensation Highest compensation for the disaster was for the disaster was just under $3,000. just under $3,000.

http://www.physorg.com/news110359851.html

Methylmercury :Methylmercury :In the Body In the Body

Methylmercury exposure Methylmercury exposure in humans is from in humans is from consumption of fish, consumption of fish, marine mammals, and marine mammals, and crustaceanscrustaceans

95% of fish-derived 95% of fish-derived methylmercury is methylmercury is absorbed into the absorbed into the gastrointestinal tract and gastrointestinal tract and distributed throughout distributed throughout the body the body Highest in concentration in Highest in concentration in

hairhair

www.mercury.utah.gov/images/health_effects.jpg

Minamata Disease in the Nervous Minamata Disease in the Nervous System System Areas in red show areas typically Areas in red show areas typically

affected by the presence of affected by the presence of methylmercury in the system . The methylmercury in the system . The lesions show characteristic signs lesions show characteristic signs

and symptoms in Minamata and symptoms in Minamata disease.disease.

1. Gait disturbance, loss of balance 1. Gait disturbance, loss of balance (ataxia), speech disturbance (ataxia), speech disturbance (Dysarthria)(Dysarthria)

2. Sight disturbance of peripheral 2. Sight disturbance of peripheral areas in the visual fields areas in the visual fields (constriction of visual fields)(constriction of visual fields)

3. Stereo anesthesia (Disturbance of 3. Stereo anesthesia (Disturbance of sensation)sensation)

4. Muscle weakness, muscle cramp 4. Muscle weakness, muscle cramp (disturbance of movement)(disturbance of movement)

5. Hardness of hearing (hearing 5. Hardness of hearing (hearing disturbance)disturbance)

6. Disturbance of sense of pain, 6. Disturbance of sense of pain, touch or temperature (Disturbance touch or temperature (Disturbance of sensation)of sensation)

National institute of Minamata Disease Archives

Symptoms of the Disease Symptoms of the Disease Mild Mild

Ataxia Ataxia Muscle weaknessMuscle weakness Narrowed field of Narrowed field of

vision vision Hearing and speech Hearing and speech

damage damage Severe cases causeSevere cases cause

Insanity Insanity ParalysisParalysis Coma Coma Death Death

W. Eugene SmithTomoko Uemura in Her Bath

Minamata, 1972

More Symptoms More Symptoms A significant effect of A significant effect of

Minamata is the Minamata is the onset of symptoms onset of symptoms similar to those of similar to those of cerebral palsycerebral palsy

Fetal Minamata Fetal Minamata DiseaseDisease A pregnant mother A pregnant mother

ingests toxic fish and ingests toxic fish and the methylmercury the methylmercury concetrates inside the concetrates inside the placenta.placenta.

Harms the fetus while Harms the fetus while the mother is the mother is relatively unaffected relatively unaffected

http://picasaweb.google.com/jazzyv0504/SAKURA#5065603192708172658

These are all children with congenital (fetal) Minamata Disease due to These are all children with congenital (fetal) Minamata Disease due to intrauterine methyl mercury poisoning (Harda 1986).intrauterine methyl mercury poisoning (Harda 1986).

Mercury (Hg) is the only Mercury (Hg) is the only metal that is liquid at metal that is liquid at room temperature. It room temperature. It melts at -38.9melts at -38.9ooC and C and boils at 356.6boils at 356.6ooC.C.

Mercury conducts Mercury conducts electricity, expands electricity, expands uniformly with uniformly with temperature and easily temperature and easily forms alloys with other forms alloys with other metals (called metals (called amalgams).amalgams). For these reasons, it is For these reasons, it is

used in many products used in many products found in homes and found in homes and schools. schools.

Mercury: The BasicsMercury: The Basics

Mercury exists in three Mercury exists in three oxidation states:oxidation states: HgHg00 (elemental mercury). (elemental mercury). HgHg22

2+2+ (mercurous). (mercurous). HgHg2+2+ (mercuric). (mercuric).

Mercurous and mercuric Mercurous and mercuric form numerous inorganic form numerous inorganic and organic chemical and organic chemical compounds.compounds. Organic forms of mercury, Organic forms of mercury,

especially methyl mercury, especially methyl mercury, CHCH33Hg(II)X, where Hg(II)X, where ““XX”” is a is a ligand (typically Clligand (typically Cl-- or OH or OH--) ) are the most toxic forms.are the most toxic forms.

Mercury ChemistryMercury Chemistry

We use its unique properties We use its unique properties to conduct electricity, to conduct electricity, measure temperature and measure temperature and pressure, act as a biocide, pressure, act as a biocide, preservative and preservative and disinfectant and catalyze disinfectant and catalyze reactions.reactions. It is the use of mercury in It is the use of mercury in

catalysis that contributed to the catalysis that contributed to the events in Minamata.events in Minamata.

Other uses include batteries, Other uses include batteries, pesticides, fungicides, dyes pesticides, fungicides, dyes and pigments, and the and pigments, and the scientific apparati.scientific apparati.

Uses of MercuryUses of Mercury

Upwards of 70% of the mercury Upwards of 70% of the mercury in the environment comes from in the environment comes from anthropogenic sources, anthropogenic sources, including:including: Metal processing, waste Metal processing, waste

incineration, and coal-incineration, and coal-powered plants.powered plants.

Natural sources include Natural sources include volcanoes, natural mercury volcanoes, natural mercury deposits, and volatilization from deposits, and volatilization from the ocean. the ocean.

Estimates are that human Estimates are that human sources have nearly doubled or sources have nearly doubled or tripled the amount of mercury in tripled the amount of mercury in the atmosphere.the atmosphere.

Mercury in the Mercury in the EnvironmentEnvironment

The Aquatic Mercury The Aquatic Mercury CycleCycle

In soil, mercury is relatively harmless in its elemental, divalent In soil, mercury is relatively harmless in its elemental, divalent or particulate forms. It is only when Hg2+ is converted to or particulate forms. It is only when Hg2+ is converted to methylmercury (CH3Hg+) that it becomes a hazard.methylmercury (CH3Hg+) that it becomes a hazard.

Methylmercury is produced as a byproduct of the metabolic Methylmercury is produced as a byproduct of the metabolic processes of sulfate reducing bacteria in anaerobic processes of sulfate reducing bacteria in anaerobic environments.environments.

In the environment, sulfate-reducing bacteria take up mercury In the environment, sulfate-reducing bacteria take up mercury in its inorganic form and through metabolic processes convert in its inorganic form and through metabolic processes convert it to methylmercury. Sulfate-reducing bacteria are found in it to methylmercury. Sulfate-reducing bacteria are found in anaerobic conditions, typical of the well-buried muddy anaerobic conditions, typical of the well-buried muddy sediments of rivers, lakes, and oceans where methylmercury sediments of rivers, lakes, and oceans where methylmercury concentrations tend to be highest.concentrations tend to be highest.

Sulfate-reducing bacteria use sulfur rather than oxygen as their Sulfate-reducing bacteria use sulfur rather than oxygen as their cellular energy-driving system. One hypothesis is that the cellular energy-driving system. One hypothesis is that the uptake of inorganic mercury by sulfate-reducing bacteria uptake of inorganic mercury by sulfate-reducing bacteria occurs via passive diffusion of the dissolved complex HgS. Once occurs via passive diffusion of the dissolved complex HgS. Once the bacterium has taken up this complex, it utilizes the bacterium has taken up this complex, it utilizes detoxification enzymes to strip the sulfur group from the detoxification enzymes to strip the sulfur group from the complex and replaces it with a methyl group: HgS → complex and replaces it with a methyl group: HgS → CH3Hg(II)X + HCH3Hg(II)X + H

The Minamata SpillThe Minamata Spill Dredging Dredging

Other ways of cleaning mercury spillOther ways of cleaning mercury spillMercury-resistant bacteria, developed by researchers Mercury-resistant bacteria, developed by researchers from Inter American University of Puerto Rico, from Inter American University of Puerto Rico, Bayamon Campus, contained either the mouse gene Bayamon Campus, contained either the mouse gene for metallothionein or the bacterial gene for for metallothionein or the bacterial gene for polyphosphate kinase. Both strains of bacteria were polyphosphate kinase. Both strains of bacteria were able to grow in very high concentrations (120µM) of able to grow in very high concentrations (120µM) of mercury, and when the bacteria containing mercury, and when the bacteria containing metallothionein were grown in a solution containing metallothionein were grown in a solution containing 24 times the dose of mercury which would kill non-24 times the dose of mercury which would kill non-resistant bacteria, they were able to remove more resistant bacteria, they were able to remove more than 80% of it from the solution in five days.than 80% of it from the solution in five days.

Cleaning upCleaning up

What’s is Dredging?What’s is Dredging?

– – the process of removing sediment for the bottom the process of removing sediment for the bottom of bodies of water.of bodies of water. Underwater excavationUnderwater excavation

Minamata CleanupMinamata Cleanup

Minamata CleanupMinamata Cleanup

DredgingDredging TypesTypes

MechanicalMechanical - The process of - The process of removing sediment with a removing sediment with a scoop or bucket.scoop or bucket.

HydraulicHydraulic - The process of - The process of removing sediment by removing sediment by sucking a mixture of sediment sucking a mixture of sediment and water from the bottom of and water from the bottom of the body of the water.the body of the water.

AirliftAirlift - The process of - The process of removing sediment by air removing sediment by air pressure.pressure.

Mechanical

Hydraulic

Airlift

Minamata CleanupMinamata Cleanup Disposal of SedimentDisposal of Sediment

Landfills - Storage site for Landfills - Storage site for solid mercury.solid mercury.

Disposal facility– Disposal Disposal facility– Disposal site for sedimentsite for sediment

Ocean placementOcean placement Confined Disposal Confined Disposal

Facilities (CDFs) – Disposal Facilities (CDFs) – Disposal site for sedimentsite for sediment

Recycling

Separation

Precipitation/ Co precipitation - Most common process Precipitation/ Co precipitation - Most common process used to treat mercury-contaminated water. Uses chemical used to treat mercury-contaminated water. Uses chemical additives to transform dissolved contaminants in the additives to transform dissolved contaminants in the insoluble solids that are then removed by filtration or insoluble solids that are then removed by filtration or clarification.clarification.

Absorption treatment - Contaminated water is passed Absorption treatment - Contaminated water is passed through a column where contaminates are removed from through a column where contaminates are removed from the water.the water.

Membrane Filtration - Separates mercury from water by Membrane Filtration - Separates mercury from water by passing the water through a semi-permeable membrane.passing the water through a semi-permeable membrane.

Biological treatment - Uses microorganism that act Biological treatment - Uses microorganism that act directly on other organism that are contaminant or directly on other organism that are contaminant or creates a ambient condition that causes the mercury to creates a ambient condition that causes the mercury to leach from the soil or precipitate/coprecipate from water.leach from the soil or precipitate/coprecipate from water.

U.S. Mercury Cleanups U.S. Mercury Cleanups

CappingCapping of Mercury – of Mercury – contaminated Sediments w/ contaminated Sediments w/ sandsand

Inhibition of Mercury Inhibition of Mercury Methylation by Iron SulfidesMethylation by Iron Sulfides

Immobilization of Aqueous Hg Immobilization of Aqueous Hg (II) by Iron Sulfides(II) by Iron Sulfides

Other ways of Clean UpOther ways of Clean Up

Nanotechnology- This research is an absorbent that developed by Nanotechnology- This research is an absorbent that developed by Thiol Self-Assembled Monolayers on Mesoporous Silica (Thiol-Thiol Self-Assembled Monolayers on Mesoporous Silica (Thiol-SAMMS). The absorbent is made of a nanoporous ceramic substrate SAMMS). The absorbent is made of a nanoporous ceramic substrate with a high surface are made functional by monlayer of thiol groups.with a high surface are made functional by monlayer of thiol groups.

Phytoremediation - Uses plants to remove, transfer, stabilize or Phytoremediation - Uses plants to remove, transfer, stabilize or destroy mercury in the sediments, and groundwater. Plants can be destroy mercury in the sediments, and groundwater. Plants can be genetically engineered to remove mercury (Detoxify). First test was genetically engineered to remove mercury (Detoxify). First test was done with transgenic rice.done with transgenic rice.

Air Stripping - The process adds stannous chloride to reduce HgAir Stripping - The process adds stannous chloride to reduce Hg+2+2 to Hgto Hg00. The mercury goes to a gas form which is removed from the . The mercury goes to a gas form which is removed from the water as gases bubbles. The process has a more than 90% removal water as gases bubbles. The process has a more than 90% removal of mercury from water.of mercury from water.

In SituIn Situ Thermal Desorption (ISTD) - This a soil remediation process Thermal Desorption (ISTD) - This a soil remediation process that uses heat and a vacuum to remove mercury from sediment. In that uses heat and a vacuum to remove mercury from sediment. In one experiment this was performed at 244one experiment this was performed at 244C and an airflow rate of C and an airflow rate of 76mL/min. This process removed 99.9% of mercury.76mL/min. This process removed 99.9% of mercury.

Experimental Experimental ResearchResearch

Minamata Bay TodayMinamata Bay Today

Eco Park of Minamata Bay has 2 purposesEco Park of Minamata Bay has 2 purposes A stone memorialA stone memorial Landfill for Mercury Landfill for Mercury

Questions???Questions???

Organic compoundsOrganic compounds compounds of carbon produced compounds of carbon produced

naturally by living organisms or naturally by living organisms or synthetically by human industrial synthetically by human industrial practices.practices.

Synthetic organic compoundsSynthetic organic compounds Used in industrial processes, pest Used in industrial processes, pest

control, pharmaceuticals, and food control, pharmaceuticals, and food additives.additives.

Over 20 millionOver 20 million

Organic CompoundsOrganic Compounds

POPs may produce a hazard for POPs may produce a hazard for decades or hundreds of years.decades or hundreds of years. First produced when their harm was not First produced when their harm was not

knownknown Now banned or restrictedNow banned or restricted

Persistent Organic Persistent Organic PollutantsPollutants

POPs have several properties that POPs have several properties that define them:define them: They have a carbon-based molecular They have a carbon-based molecular

structure, often containing highly reactive structure, often containing highly reactive chlorine.chlorine.

Most are synthetic chemicals.Most are synthetic chemicals. They do not easily break down in the They do not easily break down in the

environment.environment.


They are polluting and toxic.They are polluting and toxic. They are soluble in fat and likely to They are soluble in fat and likely to

accumulate in living tissue.accumulate in living tissue. They occur in forms that allow them to be They occur in forms that allow them to be

transported by wind, water, and sediments transported by wind, water, and sediments for long distances.for long distances.


Dioxins & incineration:Dioxins & incineration: A) historyA) history B) chemistryB) chemistry C) biologyC) biology D) health threatD) health threat

Dioxins Dioxins

AIR EMISSIONS

CO2 + H2O

ACID GASES:HCI, HF, SO2

NOx

TOXIC METALS:Pb, Cd, Hg, As, Cr etc

COMPOUNDSCOMPOUNDS::PCB’sPCB’sPCDDs (DIOXINS)PCDDs (DIOXINS)PCDFs (FURANS)PCDFs (FURANS)

NANONANOPARTICLESPARTICLES

1960s, 1970s Most people hear of dioxins in 1960s, 1970s Most people hear of dioxins in relation to use of Agent Orange in Vietnamrelation to use of Agent Orange in Vietnam

1949 - 1976 dioxins produced in industrial 1949 - 1976 dioxins produced in industrial accidents in plants making 2,4,5 Trichlorophenol. accidents in plants making 2,4,5 Trichlorophenol. Most famous Seveso, Italy in 1976.Most famous Seveso, Italy in 1976.

1977 dioxins found in trash incinerator emissions1977 dioxins found in trash incinerator emissions 1977 -’85 Engineers argue that dioxin problem 1977 -’85 Engineers argue that dioxin problem

solved by running incinerator furnaces at high solved by running incinerator furnaces at high temps. temps. They were wrongThey were wrong

1985 - find dioxins formed 1985 - find dioxins formed after after the furnace.the furnace.

HistoryHistory

Biggest source of dioxin is from food, Biggest source of dioxin is from food, particularly animal fat.particularly animal fat.

Biggest source of dioxin entering food Biggest source of dioxin entering food chains = combustion esp. of municipal chains = combustion esp. of municipal waste.waste.

Medical, municipal and hazardous waste Medical, municipal and hazardous waste incineration, backyard burning (PVC), incineration, backyard burning (PVC), Fires (PVC), copper recycling (PVC), Fires (PVC), copper recycling (PVC), metal smeltingmetal smelting

1990’s better dioxin control from 1990’s better dioxin control from incineration. Many plants retrofitted and incineration. Many plants retrofitted and older plants closed down.older plants closed down.

Dioxin 1980s - 1990sDioxin 1980s - 1990s

DIOXINSDIOXINSThe chemical structuresThe chemical structures

3 families3 families PCBsPCBs PCDFs (furans)PCDFs (furans) PCDDs (dioxins)PCDDs (dioxins)

Dioxin like compounds Dioxin like compounds (DLC)(DLC)

One of 209 PCBSOne of 209 PCBS

PCBs = a family of compounds in which chlorine atoms are substituted for hydrogen

at 1 to 10 positions of BIPHENYL .

Polychlorinated biphenyls

Furans (or PCDFs) have an oxygen atom forminga five membered ring (the furan) between the two benzenes of PCBs. There are 135 furans.

Furans (or PCDFs) have an oxygen atom forminga five membered ring (the furan) between the two benzenes of PCBs. There are 135 furans.

Furans (or PCDFs)

2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN

Dioxins (or PCDDs) have two oxygen atoms linking the two benzene rings, forming the

dioxin ring. There are 75 dioxins.

2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN

Dioxins (or PCDDs) have two oxygen atoms linking the two benzene rings, forming the

dioxin ring. There are 75 dioxins.

Dioxins (or PCDDs)

There are 17 extremely toxic dioxins and furans. They have chlorine at the 2,3,7 and 8 positions: 7 Dioxins and 10 Furans

Dioxins accumulate in animal fat. One literDioxins accumulate in animal fat. One liter of of cows’ milk gives the same dose of dioxin as cows’ milk gives the same dose of dioxin as breathing air next to the cows for breathing air next to the cows for EIGHT EIGHT MONTHSMONTHS . .

In In one dayone day a grazing cow puts as much dioxin a grazing cow puts as much dioxin into its body as a human being would get in into its body as a human being would get in 14 14 yearsyears of breathing! of breathing!

Dioxins steadily accumulate in human body fat.Dioxins steadily accumulate in human body fat. The man cannot get rid of them BUT A woman The man cannot get rid of them BUT A woman can…can…

……by having a baby!by having a baby! Thus the Thus the highest dosehighest dose of dioxin goes to the of dioxin goes to the fetus fetus

and then to the and then to the new born infant via new born infant via breastfeeding…breastfeeding…

Dioxins - major health Dioxins - major health concernsconcerns

Dioxins act like fat soluble Dioxins act like fat soluble hormoneshormones

Disrupt at least six different Disrupt at least six different hormonal systemshormonal systems..

Dioxins interfere with fetal and Dioxins interfere with fetal and infant devlopmentinfant devlopment

OUT OF OUR BABIES!OUT OF OUR BABIES!

WE WANT DIOXINWE WANT DIOXIN

Fetuses and breastfeeding infants may be Fetuses and breastfeeding infants may be at particular risk from exposure to dioxin at particular risk from exposure to dioxin like compounds (DLCs) due to their like compounds (DLCs) due to their potential to cause potential to cause adverse adverse neurodevelopmental, neurobehavioral, and neurodevelopmental, neurobehavioral, and immune system effectsimmune system effects in developing in developing systems…systems…

Institute of Medicine, Institute of Medicine, 20032003

……The committee recommends that the The committee recommends that the government place a government place a high public health high public health prioritypriority on reducing DLC intakes by girls on reducing DLC intakes by girls and young women and young women in the years well before in the years well before pregnancy is likely to occur.pregnancy is likely to occur.

(by) (by) Substituting low-fat or skim milk, for Substituting low-fat or skim milk, for whole milk, whole milk, (and)…(and)… foods lower in animal foods lower in animal fat…fat…

Institute of Medicine, Institute of Medicine, 20032003

WE WANT DIOXINWE WANT DIOXIN

OUT OF OUR FOOD!OUT OF OUR FOOD!

Do not build Do not build incinerators within 50 incinerators within 50 km of food production km of food production - particularly grazing - particularly grazing animalsanimals

Promoters say that Promoters say that modern incinerators modern incinerators have solved the dioxin have solved the dioxin problem, but have problem, but have they?they?

When PVC was fed into the high-When PVC was fed into the high-temperature melter, a significant quantity temperature melter, a significant quantity of PCDD/Fs, cadmium and lead was of PCDD/Fs, cadmium and lead was emitted.emitted.

Wet scrubbing with rapid quenching, as Wet scrubbing with rapid quenching, as well as a low temperature two-step fine well as a low temperature two-step fine filtration, or both of them together filtration, or both of them together cannot cannot effectively control the volatile metal species effectively control the volatile metal species and gas-phase PCDD/Fs.and gas-phase PCDD/Fs.

The removal of PVC from the feed waste The removal of PVC from the feed waste stream must also be effective to reduce the stream must also be effective to reduce the emissions of the PCDD/Fs, cadmium and emissions of the PCDD/Fs, cadmium and lead species.lead species.

While modern While modern incinerators have incinerators have reduced dioxin emissionsreduced dioxin emissionsthere is no real there is no real accountabilityaccountabilityin most countriesin most countries

YOU NEED THREE THINGS TO PROTECT THE PUBLIC FROM TOXIC EMISSIONS.


STRONG REGULATIONS


STRONG REGULATIONS

ADEQUATEMONITORING


STRONG REGULATIONS

ADEQUATEMONITORING

TOUGHENFORCEMENT


STRONG REGULATIONS

ADEQUATEMONITORING

TOUGHENFORCEMENT

IF ANY LINK IS WEAK THE PUBLIC IS NOT PROTECTED

HAA are also POPs.HAA are also POPs. Have potential to cause Have potential to cause

developmental and reproductive developmental and reproductive abnormalities in animals, including abnormalities in animals, including humans.humans. Include a wide variety of chemicals, Include a wide variety of chemicals,

herbicides, pesticides, phthalates, and herbicides, pesticides, phthalates, and PCBsPCBs

Hormonally Active Hormonally Active AgentsAgents

Evidence in support of hypothesisEvidence in support of hypothesis Alligator populations in Florida exposed to Alligator populations in Florida exposed to

DDT have genital abnormalities, low egg DDT have genital abnormalities, low egg production and reduced genitalia size.production and reduced genitalia size.

Major disorders studied in wildlife have Major disorders studied in wildlife have centered on abnormalities including centered on abnormalities including thinning of eggshells of birds, decline in thinning of eggshells of birds, decline in

populations of various animals and birds, populations of various animals and birds, reduced viability of offspring, and changes in reduced viability of offspring, and changes in sexual behavior.sexual behavior.


In humansIn humans HAAs may be linked to breast cancerHAAs may be linked to breast cancer PCBs and neurological behaviorPCBs and neurological behavior Phthalates Phthalates (used as plastic softeners and are responsible (used as plastic softeners and are responsible

for that for that new car smellnew car smell, which becomes especially , which becomes especially pungent after the car has been sitting in the sun for a pungent after the car has been sitting in the sun for a few hours, is partly the pungent odor of phthalates few hours, is partly the pungent odor of phthalates volatilizing from a hot plastic dashboard. In the volatilizing from a hot plastic dashboard. In the evening's cool they then condense out of the inside air evening's cool they then condense out of the inside air of the car to form an oily coating on the inside of the of the car to form an oily coating on the inside of the windshield.windshield.

Endocrine and hormone disruptionEndocrine and hormone disruption


One of two main systems that regulate One of two main systems that regulate and control growth , development and and control growth , development and reproduction.reproduction.

Composed of a group of hormone Composed of a group of hormone secreting glandssecreting glands Thyroid, pancreas, pituitary, ovaries and Thyroid, pancreas, pituitary, ovaries and

testes.testes. Hormones transported by blood stream, act Hormones transported by blood stream, act

as chemical messengers.as chemical messengers.

Endocrine SystemEndocrine System

The National Academy of SciencesThe National Academy of Sciences recommends that there should be recommends that there should be

continued monitoring of wildlife and continued monitoring of wildlife and human populations for abnormal human populations for abnormal development and reproduction.development and reproduction.


Nuclear radiation is linked to serious Nuclear radiation is linked to serious health problemshealth problems Including cancerIncluding cancer

RadiationRadiation

Occurs when heat released into water Occurs when heat released into water or air produces undesirable effects.or air produces undesirable effects. Also called heat pollutionAlso called heat pollution Sudden acute event or long term, chronic Sudden acute event or long term, chronic

releaserelease Heated water released into rivers changes Heated water released into rivers changes

temp and dissolved oxygen contenttemp and dissolved oxygen content Thereby changing river’s species compositionThereby changing river’s species composition

Thermal PollutionThermal Pollution

Heating river water changes natural Heating river water changes natural conditions and disturbs the ecosystemconditions and disturbs the ecosystem Fish spawning cycles may be disruptedFish spawning cycles may be disrupted Fish may have heightened susceptibility to Fish may have heightened susceptibility to

disease.disease. Physical stress on fishPhysical stress on fish Easier preyEasier prey Change in type and availability of foodChange in type and availability of food


Solutions to chronic thermal heatingSolutions to chronic thermal heating Release of heat into air in cooling towersRelease of heat into air in cooling towers Artificial lagoonsArtificial lagoons Used to heat buildingsUsed to heat buildings


Small particles of dust released into Small particles of dust released into the atmosphere by many natural the atmosphere by many natural processes and human activities.processes and human activities. Modern farmingModern farming Burning oil and coalBurning oil and coal Dust stormsDust storms Volcanic eruptionsVolcanic eruptions

ParticulatesParticulates

The 1997 Southeast Asian haze was caused mainly by slash and burn techniques adopted by farmers in Indonesia. Slash and burn has been extensively used for many years as the cheapest and easiest means to clear the lands for traditional agriculture.

A term for several minerals that take the A term for several minerals that take the form of small, elongated particle or fibers.form of small, elongated particle or fibers. Use contributed to fire preventionUse contributed to fire prevention Insulation Insulation

Inhalation leads to asbestosis and cancerInhalation leads to asbestosis and cancer 95% of asbestos now in use in US chrysolite 95% of asbestos now in use in US chrysolite

(white asbestos).(white asbestos). Not particularly harmfulNot particularly harmful

Another type crocidolite (blue asbestos)Another type crocidolite (blue asbestos) Exposure can be very hazardousExposure can be very hazardous

AsbestosAsbestos

EMFs part of everyday urban lifeEMFs part of everyday urban life electric motors, transmission lines and electric motors, transmission lines and

appliances – all produce electromagnetic appliances – all produce electromagnetic fieldsfields

Controversy as to whether they pose a Controversy as to whether they pose a health riskhealth risk

Children may be at greater riskChildren may be at greater risk Studies have shown that associations Studies have shown that associations

between cancer and exposure to EMFs is between cancer and exposure to EMFs is not strong and not statistically significant.not strong and not statistically significant.

Electromagnetic FieldsElectromagnetic Fields

Unwanted soundUnwanted sound Sound is a form of energy that Sound is a form of energy that

travels as wavestravels as waves We hear sounds when waves vibrate We hear sounds when waves vibrate

our eardrumour eardrum Loudness a measure of intensity of Loudness a measure of intensity of

energyenergy Measured in units of decibelsMeasured in units of decibels

Noise PollutionNoise Pollution

Environmental effects of noise depend Environmental effects of noise depend onon EnergyEnergy PitchPitch FrequencyFrequency Time pattern Time pattern Length of exposureLength of exposure

Very loud noise can cause painVery loud noise can cause pain Any sound above 80dB can cause Any sound above 80dB can cause

hearing losshearing loss Rock concert 110dBRock concert 110dB• Constant high noise causes stressConstant high noise causes stress

Noise PollutionNoise Pollution

Sometimes referred to as exposure Sometimes referred to as exposure to personal pollutants.to personal pollutants. Tobacco Tobacco

30% of cancers tied to smoking30% of cancers tied to smoking Alcohol and other drugsAlcohol and other drugs

½ of all deaths in automobiles accidents tied ½ of all deaths in automobiles accidents tied to alcohol use by driversto alcohol use by drivers

Violent crimes, overdoses, chronic alcoholismViolent crimes, overdoses, chronic alcoholism

Voluntary ExposureVoluntary Exposure

Almost every part of the Almost every part of the human body is affected by one human body is affected by one pollutant or another.pollutant or another.

General Effects of General Effects of PollutantsPollutants

Five centuries ago, the physician and Five centuries ago, the physician and alchemist Paracelsus wrote that alchemist Paracelsus wrote that “everything is poisonous, yet nothing is “everything is poisonous, yet nothing is poisonous.”poisonous.”

For ExampleFor Example Selenium required in small amounts by living Selenium required in small amounts by living

thingsthings May be toxic in high concentrationsMay be toxic in high concentrations

Concept of Dose and Concept of Dose and ResponseResponse

The effect of a chemical on an The effect of a chemical on an individual depends on the individual depends on the dose.dose. Dose responseDose response Dose dependency can be Dose dependency can be

represented by a generalized represented by a generalized dose response curve.dose response curve.


Doses that are beneficial, harmful, or lethal Doses that are beneficial, harmful, or lethal may differ widely for different organisms may differ widely for different organisms and are difficult to characterize.and are difficult to characterize.

E.g. fluoride and dental healthE.g. fluoride and dental health Fluorine forms fluoride compounds that prevent Fluorine forms fluoride compounds that prevent

tooth decay and promote healthy bone tooth decay and promote healthy bone structure.structure.

Toxic effects are noticed at concentrations of 6-7 Toxic effects are noticed at concentrations of 6-7 ppmppm


How individuals will response to a How individuals will response to a chemical not know.chemical not know.

Instead predictions made about how a Instead predictions made about how a percentage of the population will percentage of the population will respond to a specific dose.respond to a specific dose.

Dose at which 50% of the population Dose at which 50% of the population diesdies Lethal dose 50, LD-50Lethal dose 50, LD-50

Dose-Response CurveDose-Response Curve

The ED-50 (effective dose 50%) is The ED-50 (effective dose 50%) is the dose that causes an effect in the dose that causes an effect in 50% of the population of observed 50% of the population of observed subjects.subjects. E.g. ED-50 of aspirin would be the E.g. ED-50 of aspirin would be the

dose that relieves headaches in 50% dose that relieves headaches in 50% of the people.of the people.


The TD-50 (toxic dose 50%) is The TD-50 (toxic dose 50%) is defined as the dose that is toxic defined as the dose that is toxic to 50% of the population. to 50% of the population. Often used to indicate responses Often used to indicate responses

such as reduced enzyme activity, such as reduced enzyme activity, decreased reproductive success, or decreased reproductive success, or onset of specific symptoms.onset of specific symptoms.


For a particular chemical, there may be a For a particular chemical, there may be a whole family of dose–response curves.whole family of dose–response curves. Which dose is of interest depends on what is Which dose is of interest depends on what is

being evaluated.being evaluated. Killing insects vs. pesticide residueKilling insects vs. pesticide residue Overlap between the therapeutic dose (ED) Overlap between the therapeutic dose (ED)

and the toxic dose (TD)and the toxic dose (TD) Measure of the relative safety of a particular Measure of the relative safety of a particular

drug is the therapeutic indexdrug is the therapeutic index Defined as the ratio of the LD-50 to the ED-50. Defined as the ratio of the LD-50 to the ED-50. The greater the therapeutic index, the safer the The greater the therapeutic index, the safer the

drug.drug.


Threshold is a level below which no effect Threshold is a level below which no effect occurs and above which effects begin to occurs and above which effects begin to occur.occur. If a threshold exists, then a concentration below If a threshold exists, then a concentration below

the threshold is safe. the threshold is safe. If there is no threshold dose, then even the If there is no threshold dose, then even the

smallest amount has some negative toxic effect.smallest amount has some negative toxic effect. A problem in evaluating thresholds for toxic A problem in evaluating thresholds for toxic

pollutants is that it is difficult to account for pollutants is that it is difficult to account for synergistic effects.synergistic effects.

Threshold effectsThreshold effects

Changes in vegetation with distance Changes in vegetation with distance from a toxic source define the from a toxic source define the ecological gradient.ecological gradient. Weedy species adapted to harsh Weedy species adapted to harsh

conditions may be closerconditions may be closer Farther away trees and shrubsFarther away trees and shrubs

Ecological GradientsEcological Gradients

The ability to resist or withstand The ability to resist or withstand stress resulting from exposure to a stress resulting from exposure to a pollutant or harmful condition.pollutant or harmful condition. Result from behavioral, physiological, or Result from behavioral, physiological, or

genetic adaptation.genetic adaptation. Behavioral tolerance- change in Behavioral tolerance- change in

behaviorbehavior Learning to avoid trapsLearning to avoid traps

ToleranceTolerance

Physiological tolerance- Physiological tolerance- the body the body of an individual adjusts to tolerate a of an individual adjusts to tolerate a higher level of pollutant.higher level of pollutant. Many mechanisms including Many mechanisms including

detoxificationdetoxification the toxic chemical is converted to a nontoxic the toxic chemical is converted to a nontoxic

formform Internal transport of the toxin to a part Internal transport of the toxin to a part

of the body where it is not harmful, of the body where it is not harmful, such as fat cells.such as fat cells.

ToleranceTolerance

Genetic tolerance- (adaptation) Genetic tolerance- (adaptation) when some individuals in a when some individuals in a population are naturally more population are naturally more resistant to a toxin than others.resistant to a toxin than others. Strains of mosquitoes resistance to DDT Strains of mosquitoes resistance to DDT Antibiotic resistanceAntibiotic resistance

ToleranceTolerance

Acute effect Acute effect is one that occurs soon is one that occurs soon after exposure.after exposure. Usually to large amounts of a pollutantUsually to large amounts of a pollutant

Chronic effect Chronic effect takes place over a takes place over a long periodlong period Often as a result of exposure to low Often as a result of exposure to low

levels of pollutantlevels of pollutant

Acute and Chronic Acute and Chronic EffectsEffects

The process of determining The process of determining potential adverse potential adverse environmental health effects environmental health effects to people exposed to to people exposed to pollutants and potentially toxic pollutants and potentially toxic materials.materials.

Risk AssessmentRisk Assessment

Such an assessment generally includes Such an assessment generally includes four steps:four steps: Identification of the hazard.Identification of the hazard. Dose–response assessment.Dose–response assessment. Exposure assessment.Exposure assessment. Risk characterization.Risk characterization.

Risk assessment is difficult, costly, and Risk assessment is difficult, costly, and controversial.controversial.

Risk management integrates the Risk management integrates the assessment of risk with technical, legal, assessment of risk with technical, legal, political, social, and economic issues.political, social, and economic issues.

Risk AssessmentRisk Assessment

http://www.youtube.com/watch?v=9IJn4A68dq8&feature=relmfu

Keystone ProjectKeystone Project

http://www.youtube.com/watch?v=jGcJ64q9BaM&sns=em

Tar Sands OilTar Sands Oil

chapter 15: environmental health, pollution and toxicology

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individual substances

multiple substances

separate substances

lake nyos disasterare

polluted environment

onthe water

clean water act

biologic response