Toxicology

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Toxicology

• Prevalent Environmental Toxins

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PrevalentEnvironmental Toxins

• Polychlorinated Biphenyls
• PCBs

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Polychlorinated Biphenyls (PCBs)

• A chlorinated hydrocarbon produced by Monsanto
  since 1930
• Ranges from a waxy solid to an oily liquid
• Were considered a miracle product with amazing
  properties
• extremely stable
• Non-flammable
• Unsurpassed insulation properties
• Low electrical conduction

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PCB Uses

• Widespread uses
• Transformer coolant
• Lubricants
• Hydraulic fluids
• Cutting oils
• Waterproof coatings
• Liquid sealants

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PCB Prevalence

• Bioaccumulation
• In 1964, Dr. Soren Jensen, a Swedish chemist,
  trying to find DDT in human fat, made an alarming
  discovery instead of DDT, he found large
  amounts of PCBs.
• Subsequent studies substantiated his findings and
  also confirmed the presence of PCBs in nearly all
  living organisms
• PCBs have been confirmed in virtually all humans,
  breast milk ITS THE MOST WIDESPREAD CHEMICAL
  CONTAMINANT KNOWN

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PCB Environmental Issues

• PCB-laden waste
• Vaporization of PCBs from paints, landfills, or
  burning PCB-containing materials
• Leaks in PCB-containing equipment
• Accidental spills or illegal dumping.
• Although production ceased in 1977, over 1.4
  billion pounds were produced between 1929 and
  1977.

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PCBs Landmark Dumping

• In August 1978, 210 miles of North Carolina
  roads, through 14 counties, were contaminated
  with PCBs.
• Over 31,000 gallons of PCB-contaminated waste oil
  were deliberately leaked from the tap of a tanker
  truck owned by Ward Transformer
• Led to the coined phrase Midnight Dumping

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Warren County, NC

• The 1978 midnight dumping incident led to a
  controversy over how the state chose to clean-up
  and dispose of the waste the final disposal
  site chosen was Warren Co.
• Warren Co. was a predominantly poor, African
  American county which lacked the environmental
  qualities for containing the wastes.

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PCBs and Human Health

• In animal studies have shown PCBs, in very small
  amounts cause liver disorders, miscarriages, low
  birth weight, abnormal multiplication of cells,
  and liver cancer.
• We presume that these effects are also likely
  to occur in humans as well
• The most common effects that are evident
• Chloracne a severe dermatitis from direct
  contact with PCBs

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Chloracne From PCBs
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PCB Effects crossbill
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PrevalentEnvironmental Toxins

• Dioxin or TCDD

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Dioxin

• Chemically, very similar to PCBs (a chlorinated
  hydrocarbon)
• Also highly persistent in nature
• Highly toxic, however, unlike PCBs, no major
  human insults are recorded.
• Not intentionally manufactured it has no
  industrial usefulness it is formed as an
  unwanted by-product during the production of
  herbicides and hexachorophene

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Environmental Issues

• May be carried long distances as air pollutant
• If exposed to light, will break down relatively
  quickly
• If only slightly below the soil surface, may
  remain for 10 years or more without appreciable
  breakdown.

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Dioxin Health Issues

• Most humans have dioxin contamination in lipid
  tissue
• Often called the most toxic of all synthetic
  chemicals
• This is often disputed the statement was based
  upon the toxicity to guinea pigs however, the
  toxicity to hamsters is 1900 X less than guinea
  pigs
• Rabbits, monkeys and mice appear to be better
  models of human toxicity

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Dioxin Health Issues

• Like PCBs causes Chloracne
• Muscle aches and pains
• Nervous system disorders
• Psychiatric effects
• Undoubtedly cause reproductive effects.
• Likely to be a carcinogen
• Soft tissue sarcoma
• Respiratory cancer

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Dioxin (TCDD)

• In the Spring of 1983, the EPA announced that the
  inhabitants of Times Beach, MO needed to relocate
  to preserve their health.
• The towns dirt roads and nearby horse track had
  been oiled (to reduce dust) with TCDD
  contaminated waste oils.
• Today, you will not see Times Beach on any map.

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Workers Cleaning up what used to be Times Beach
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Dioxin Events

• Serveso, Italy the 1976 explosion of a chemical
  plant exposed 37, 000 residents to considerable
  amounts of dioxin.
• Agent Orange Vietnam, U.S. Soldiers
• 1949 Monsanto spill in Nitro, WV
• Viktor Yushchenko, 2004 ??

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Chloracne from TCDD
Serveso, Italy
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Dioxin and Chloracne
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PCBs vs TCDD

• Both cause Chloracne
• TCDD were never intentionally manufactured
• PCBs are (probably) more widespread
• TCDD is the most toxic anthropogenic substance

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Examples of Toxic Substances

• Asbestos

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Asbestos

• Group of 6 fibrous silicate minerals 3 of which
  are of sufficient abundance and toxicity to
  warrant our study
• Amosite
• Chrysotile
• Crocidolite
• Thought to be responsible for more deaths than
  any other single hazardous substance

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Asbestos Types

• Chysotile most common, least toxic, a.k.a.
  white asbestos
• Amosite 2nd most common, name comes from
  Asbestos Mines of South Africa, a.k.a. brown
  asbestos
• Crocidolite least common, most toxic, a.k.a.
  blue asbestos

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Asbestos Properties

• Like PCBs, asbestos was considered a miracle
  product. Its properties are unmatched
• Inflammable
• Great insulator
• High tensile strength
• Has been used by humans since the Stone Age.

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Asbestos Uses

• Building materials like floor tiles
• Brake/Clutch linings
• Textiles
• Thermal pipe insulation
• Acoustical surface coatings
• Additive for paints, adhesives, plaster
• Water pipes (transite)

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Asbestos Deposition

• As materials containing asbestos breakdown, the
  materials become Friable and asbestos fibers
  are released into the air.
• Fibers of asbestos may remain in the air for days
  or even weeks.
• Asbestos fibers may be inhaled where they lodge
  into the deepest part of the lungs the alveoli

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Asbestos Diseases

• Asbestosis a result of chronic (long term),
  high exposures to asbestos most likely
  chrysotile.
• Asbestosis is a scarring of the lung tissue.
• Lung function becomes irreversably impaired
• Takes 20-40 years of exposure
• In U.S., will not be a health issue of the future
  due to OSHA regulations

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Asbestos Diseases

• Lung Cancer 60x greater risk among smokers
• Mesothelioma A rare cancer of the pleural or
  peritoneal linings, highly fatal.
• GI Cancer cancer of the stomach, colon, rectum,
  and esophagus.

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PrevalentEnvironmental Toxins

• Lead

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Lead
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Lead

• Uses date back to 4,000 B.C. plumbing (from the
  Latin word Plumbum, where we get the chemical
  symbol Pb), paints, glazes, metal alloys,
  cosmetics, gas additives
• Today, is still used in batteries, ammunition,
  brass, cable insulation, glass TV tubes, solder,
  and pigments

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Lead

• Lead is found throughout the environment its
  one of the most prominent environmental
  pollutants
• World production is 3 million tons annually.
• Can be found in soil, water, air and food
• The phase-out of lead in gasoline (mid-1980s)
  lowered the environmental lead burden in the U.S.

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Lead Toxicity

• Lead is devastating to children and fetuses
  irreversible brain damage is almost guaranteed.
• Symptoms anemia, abdominal pain, weakness,
  seizures, CNS damage
• Continuum of toxicity any degree of exposure
  will lead to some degree of harm

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Lead Routes of Entry

• Pb gets into the body via
• Inhalation soldering, sanding, grinding,
  burning
• Ingestion plumbing, drinking water,
  contaminated food, leaded food containers
• Number 1 source is PAINT

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Lead Exposures

• Paint lead acetate comes to surface of paint
  house paint, bridges, water towers, other outside
  structures.
• Plasticizers mini blinds
• Solder drinking water
• Plumbing
• Toys
• Ceramics

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Lead Treatment

• Blood-Lead monitoring is conducted for children
  and lead industry workers
• Medical removal if necessary
• Chelation drug administered to a leaded
  individual which helps reduce the body burden of
  lead.
• A common chelating drug is EDTA -
  ethylenediamine tetra-acetic acid

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Map Legend Number of Housing Units with a High
Risk of Lead Hazards
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PrevalentEnvironmental Toxins

• Mercury

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Mercury

• One of the next big environmental toxins the
  asbestos of the 21st Century
• Pollutes the air, soil, food, and water
• Historically, one of the earliest known toxins
• Alchemists, slaves, miners, physicians, etc. were
  among the earliest to be intoxicated.
• Was once the primary treatment for diseases such
  as syphilis

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Mercury

• The only liquid metal a.k.a. quicksilver
• Is a valuable constituent of many industrial
  processes
• Is found in paints, pressure measuring devices,
  thermometers, electroplating, paper milling,
  chemical intermediates, textiles,
  pharmaceuticals, burning of fossil fuels

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Health Effects

• Attacks the liver and kidney, can be absorbed in
  alveolar region of lungs transported to brain
  and cross the blood-brain barrier.
• Causes what was once known as Mad Hatters
  Disease

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Health Effects of Mercury

• Organic Mercury Far more toxic than elemental
  Hg.
• Compounds such as methyl mercury (CH3Hg) destroys
  brain cells causing serious CNS problems
  slurred speech, difficulty walking (Chicken
  Walk), deafness, vision impairment, neurotic
  behavior, and death.

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Mercury Poisoning
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Mercury Poisoning

• Minamata Bay, Japan 1953-1961, individuals
  located adjacent to the bay who ate fish from it
  became severely intoxicated with methyl mercury.
  

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Minamata Bay - Biomethylation

• Mercury had been discharged into the bay by
  manufacturing
• The Hg became Bio-methylated by organisms in
  the water (such as plankton) and bioaccumulated
  in the food chain.
• 700 deaths and more than 9,000 severely
  injured/deformed
• Methylmercury readily passes through the placenta

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Minamata Bay, Japan
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Methylmercury Deformation from Minamata Bay Victim
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PrevalentEnvironmental Toxins

• Cadmium

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Cadmium

• Soft, silvery highly toxic metal
• No beneficial role in metabolism
• Uses
• Electroplating (yellow in color)
• Ni-Cad batteries
• Pigments (yellow)
• Highly polluting water, air, soil, food
• Like Mercury, Cd bioaccumulates

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Health Effects - Cadmium

• A Single Cigarette - 2 µg of Cd
• Absorption of Cd is nutrition dependant those
  w/Fe, Ca or protein deficiency are more
  vulnerable to Cd
• Itai-Itai (ouch, ouch) the disease name given to
  Cd poisoning in Japan after 1,000s became
  intoxicated the disease causes excruciating
  pain.
• Excess Cd causes kidney failure/death

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Itai-Itai

• Severe Pain
• Kidney Damage
• Excessive Osteoporosis to the point where
  merely the bodys weight will cause bone breakage

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Less Understood Toxic Exposures

• Sometimes, we just dont know what the
  consequences will be for certain toxic soup
  exposures
• It may be many years before we know the results
  to chronic toxins

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Child With Brittle Bone Disease
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Gulf War Birth Defects
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Toxic Exposure.. or Just Bad Choices?
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