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HAZWOPER COURSE > Toxicology > Flashcards

Toxicology Flashcards

1
Q

What is toxicology

A

This is the danger of workers being exposed to dangerous chemicals. “OSHA - chemical exposure in the workplace. Poisinous toxins and target organs and how to identify if the issue is toxicology. PELs permissible exposure limits - informs employees and employers as to the safety limits when working around and with hazardous toxic chemicals.

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2
Q

What is toxicology

A

This is the study of chemical toxicity. Toxicity is the degree to which a chemical has a harmful effect on us or other living things.

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3
Q

The two sources of information where we gather information on toxicity are

A
  1. Epidimiological Studies - compare affected people in one group to affected people in another group. Sometimes the information comes from actual exposure to a chemical in a workplace.
  2. Animal studies - provide most of what we know about the dangerous effects of toxic substances. Humans may react differently than animals when exposed to toxic substances.
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4
Q

HAZCOM

A

Thanks to hazardous chemical communication programs (HAZCOM or Right-to-Know), chemical toxicity information can be found in a number of ways. Today all hazardous chemicals in the workplace must be labeled to identify and warn against toxicity. More detailed information can be obtained from the Safety Data Sheet (SDS).

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5
Q

Response to Chemical Exposure

A 
There are several factors that affect the severity of exposure to a chemical.
these include:
- toxicity of substance
- Route of exposure
- Chemical dose
- Interaction with other chemicals
- human response
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6
Q

Factors Affecting Response to Chemical Exposure

A
  • Toxicity - some chemicals produce immediate and dramatic biological effects or no effects at all or they may be delayed.
  • Route of exposure - some are harmless such as Carbon monoxide on the skin, however Carbon Monoxide inhaled into the lungs causes much more serious effects.
  • Chemical Dose - this is the amount and length of thime that one is exposed to a chemical
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7
Q

Inhalation

A
  • Chemical vapors dust or gasses - can be inhaled if not wearing a resperator or the right equipment
  • Absorbtion - can be inhaled or into the body through the skin - wear gloves and proper clothing
  • Ingestion - ingesting small doses of chemicals daily and not know it. Chemicals can be absorbed by food, cigarettes or drinks. can remain on skin and transferred into food before eating.
  • always be sure to wash hands before eating and store food away from the work area.
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8
Q

Human response

A

Humans response - humans and animals vary in response to chemical exposure.
Some serious others mild or no symptoms at all.
A prior exposure to a chemical affects the way they response at a different times - variation between different individuals or a different response to the same chemical by the same individual at different times.
Interations of other chemicals - The study of the interaction of various chemicals is called chemistry - acids and basis -
Chemicals in combination can have different responses than the responses seen when the exposure is to one chemical alone.

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9
Q

Toxic Substance Forms

A

The physical forms encounted at a wast site play a large part in the routs of entry into the body. PPE

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10
Q

Solids

A

The principal hazard is from dust or fumes produced when solids change from.
For eg. polyurathane - when burned gives off cyanide gas routs of entry inhalation, ingestion, saliva and
skin absorbtion

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11
Q

Fumes

A

Tiny particles are produced from heating, votalizaition and condensation of metals ( zinc oxide fumes from burning galvanize metal )
routes of entry are inhalation, ingestion (saliva) and skin abosorbtion it is important to know that toxic fumes can result from the burning of non-toxic substances.

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12
Q

Liquids, Vapors and Mists

A

Egs - of
*liquids include acids, organic solvents and chlorinated organic solvesnts. (eg. benzine sulphuric acid one triholorchane)
routes of entry - inhalation and skin absorbtion
*vapors are gasses that result from the evaporation of liquids or the sublimination of solids. (egs are gasoline
phosgene and iodine)
routes of entry inhalation and skin absorbtion
*mists are liquid droplets suspended in the air ( egs.
acid mists from electroplating processes and
solvent mists from paint spraying)
routes of entry are inhalation and skin absorbtion

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13
Q

Health Hazards

A

Safety hazards related to the physical characteristics of a chemical can be objectively defined by testing requirements, health hazards are less precise and more subjective . health hazards may cause changes in the body like Decreased pulmory function - breathing. signs and symptoms would be Shortness of breath from exposed employees.

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14
Q

Health Hazards 2

A

Any chemical meeting any of the following definitions would be a health hazard. All methods should be evaluated. Some chemicals may fall into more than one category and this information can be found on the SDS.

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15
Q

Asphyxiants

A

Are chemicals that deprive the body of oxygen
interefere to use the oxygen carried by the bloodstream. Any gas heavieer than air can displace oxygen and cause asphyxiation. EGs.
Carbon monoxide
Hydrogen cynaide

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16
Q

Carcinogens

A

cause cancer in humans and laboratory animals. this is a chronic affect athere is a time period that happens before the symptoms tumor appear. egs. Benzene, benzoprene, asbestos fibers acrylonitrite and DBCP (dibromochloroprane)

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17
Q

Irritants

A

aggravate various tissues causes redness, rashes, swelling coughing and even hemorrhaging
chlorine and ammonia are two examples of irritants.

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18
Q

Sensitizers

A

are allergens. cause an allergic type of reaction due to sensitivity due to prior exposure. swelling of the breathing tubes which causes breating difficulty. they can cause chronic lung disease. breathing tubes. epoxies, aromatic amines, formaldehyde, nickel, metal and malefic anhydride.

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19
Q

Mutagens

A

Cause alterations in the genes of the person exposed. the result is a malfunction of a specific tissue or organ. depending on the type of cell affected.
Alteration in the tissue; Passed on to children if the mutation occured in the sperm or egg of the parents.benzene, hydrezene, ethelyne oxide.

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20
Q

Teratogens

A

damage or kill a developing fetus. does not affect the genetic code. Egs. thalidomide, dioxins, lead and cadmium

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21
Q

Target Organ Poisons

A
  • Many chemicals target a particular organ or tissue and cause disease or damaga at that particular location .
  • Other chemicals toxins target Body systems and cause a variety of reactions.
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22
Q

Lungs and Skin

A

Lungs - asbestos fibers and silica dust may cause fibrosis effect in the lungs. the lung becomes scared and inflexible making the lung unable to expand or contract.
skin - chloracne is a result of being exposed repeatedly to PCBs - polychlorinated biphenyls and other chlorinated hydrocarbons

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23
Q

Eyes

A

lachrymator - chemicals that can cause instant tearing at low concentrations - eg. teargas and mase. other chemicals can cause cataracts optic nerve damage and retinal damage by circulating through the bloodstream and reaching the eye.
eg. valium, napthalene, methanol and thallium

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24
Q

Central Nervous System

A

Neurotoxins are chemicals that affect the brain and spinal cord.
Neurotoxins affect neurons that carry electrical signals inhibiting their functions. that can affect behavior changes. emotional changes alterations in walking
loss of hand eye coordination. Annoxia can occur.
due to a lack of oxygen to the brain cells - lack of oxygen results in cell death.

Egs of chemicals - tetraethyl lead, chlorinated hydrocarbon pesticides (DDT), melathyon , lead and mercury

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25
Q

Liver

A

Hepatoxins are substances that can cause damage to the liver. the liver is the main processing organ for eliminating toxins. It can convert toxins into non toxic forms. The liver can generate a more toxic by product that can cause Cellular and tissue damage.

An example of a hepa toxin is tetrachloride, chloroform,
tannic acid, trichloroethylne.

Examples of chemicals that cause Ciroccis is a fibrotic disease that results in liver dysfunction and jaundice.
are carbon tetrachloride, alcohol and aflatoxin.

Other effects can range from tumors enlargement of the liver and fat accumulation.

26
Q

Kidneys

A

The main function of the kidneys is to filter the blood and eliminate waste. Nephratoxins. Because the waste gets concentrated in the process.
Toxins that damage this organ nephratoxins
Mercury arsenic and lithium
Tetrochloroethlyene
Other chemicals carbon disulphide, methonal and ethelene glycol

27
Q

Blood

A

Substances capable of causeing blood disorder are called hemotoxins. Can affect the bone marrow are.
arsenic, benzene, bromine and methyl chloride
platelets - there are cell fragments that help in the process of blood clotting are asprin, benezne and tetrachloroethane
white blood cells help the body defend against infection are naphthalene and tetrachloroethane
red blood cells carry oxygen to the body and the chemicals that affect them are warfarine naphthalene and arsine.
effects can include reduced red blood count, anemia, reduced white blood count leaves the victim susceptible to disease and reduced platelet count and hemmoraging

28
Q

Reproductive Organs

A

toxins can couse sterility infertility or spontaneous abortions. and affect an individuals homorne levels and activity.
Male - zylene mercury lead dioxin DDT PCBs benzene toluene and xylene
Female - DDT PCBs and parathion and diathalstilvestrol

29
Q

Routes of exposure

A

how chemicals get into your body. Enter the body in any one of 4 ways.

  1. Breathing
  2. Eye or skin contact
  3. Swallowing or ingestion
  4. Injection
30
Q

Inhalation

A

Toxic dose of chemicals can be inhaled in many ways
Gas
Mist
Fumes
Dust
Vapor
chemical enters through the airways - mucus membranes of the nose or may rach the smallest cavity of the lungs. - absorbed and cause an adverse reaction. Immediate - hydrogen sulfide gas or delayed - asbestos fibres

31
Q

Skin and eye contact

A

skin and eye contact results in damage at the point of contact. Sulfuric acid. Through the skin and into the blood stream. Once in the blood stream - pesticides and herbicides. If sweat can come out of your skin chemicals can get into it.

32
Q

Skin absorbtion

A

Skin absorbtion - ACGIH publication threshhold limit values for chemical substances and OSHA 29 CFR 1910.1000 - judgemental values.

33
Q

Eye Irritation

A

Quantitative data on eye irritation is not readily available - evaluate the data to determine the level of protection needed for workers.

34
Q

Ingestion

A

Not a common way for transmission industry workers. Need to follow a hygene program. Properly washing hands before eating.

35
Q

Injection

A

Chemicals can enter through the skin at any wound or injury site. Once the chemical enters the bloodstream it has the potential to impact all organs and tissues.

36
Q

Absorbtion

A

Allot of chemicals are not removed from the body but stored in the adipose tissue or fat cells

37
Q

Chemical Exposure

A
  • Acute - Chronic - immediate responses -shortly after exposure. headaches dizziness nasuea eye skin and respiratory problems, unconsciousness or evern death
  • Chronic - delayed - occur a long time after exposure - liver kidney and lungs
38
Q

Chemical Dose

A

Toxicity - dosage is indicated. quantity of chemical and exposure. The higher the chemical dose the greater the toxic reaction.
Toxic dose or lethal dose - Lethal Dose - LD 50 or Lethal Concentration - LC 100
LC 50 of 25 mg per cu m - lethal to 50% of test group of animals.

39
Q

Toxic Concentration

A

See chart

40
Q

High Toxicity

A

Highly toxic - a chemical that is highly toxic has a LD 50 lethal dose 50 %/ 1 kg of body weight
LC 50 of 200 PPM - continuous inhalatiion for 1 hours or less /

41
Q

Toxic

A

a chemical that is toxic has a LD50 or more than 50 mg / kg but less than 500 mg/kg of chemical per 1 kg of body weight administered orally.
LC 50 of more than 200PPM or
more than 2

42
Q

chemical interaction

A

many chemicalss act together in different ways when combined or used on different biological systems

43
Q

Additive effect

A

Additive effect - Some toxic chemicals add their affects together producing a biological effect. being exposed to double the dose of one of the drugs alone.
Synergitic effect - synergism is the exposure to two different toxic chemicals that produce a more severe affect tham simply double the dose. The alcohol breaks down the chemicals that would usually
Isprophyl alcohol -

44
Q

Potentiation

A

In some cases a chemical without any known toxic affect can act together with a known toxic substance to make the toxic substance more toxic.

45
Q

Antagonism

A

Producing a reduced amount. (4+6 = 8) the interaction of 2 chemicals can produce less than the desired amount
For example: A prescription drug being taken by a worker may interact with a hazardous chemical encountered in the workplace. Therefore, a doctor needs to know that a worker can be exposed to specific chemicals on the job.

46
Q

Individual Response

A

LD50#’s represent the average response for a population becaue there is a great deal of variability based on genetics. Given the same dosage one worker’s response can be at an opposite extreme thatn anothe worker response.
To afford the greatest protection to the individual worker. Exposure limits have been developed. The exposure limits the airborne concentration of a material that allows an individual worker to be exposed to the chemical several times without adverse effects.

47
Q

Measurement

A

The 2 common units of measurement are used for setting exposure limits:

  1. parts per million (ppm) or parts per billion (ppb)
  2. milligrams per cubic meter of air (mg/m3) air

The formula for converting ppm to i(mg/m3) is:

Molecular weight X ppm / mg/m3

The formula for converting mg/m3 to ppm is :

mg/m3 X 24.45/molecular weight

Note: Ppm and ppb are volume to volume and mg/m3 is weight to volume.

48
Q

Examples of ppm

A

PPM example = ozof chocolate in a million gallons of milk or a drop of vermouth in a rail car full of water
PPB example = 1 grain of sugar in a 10 lb bag of sugar.

49
Q

Vapors and Gasses Measurement

A

Vapors and gasses the constant rate of 24.45 litres of vapor per mole of containment @ 25 Degrees Celcius an d one atmosphere (760 mm Hg) of pressure is important. Some common examples of this are:

Chloroine 1 ppm = 2.95 mg/m3
Toluene 1 ppm = 3.83 mg/m3
Trichloroethylene 1 ppm = 5.46 mg/m3

Ppm and ppb are volume to volume and mg/m3 is weight to volume.

50
Q

Exposure Limits

A

Published exposure level standeds have been determined in the workplace. exposure limits
are expressed as permissible exposure Limits PELs - are enforcable standards. propagated by OSHA - they are derived from threshold limit values TLVs published in 1968 - PEL is an average exposure 8 hour work day TWA time weighted average or a ceiling concentration C above which workers cannot be exposed - PPE may not be required for exposures below the PEL it is advisable to use in a PEL it is advised as there is a potential of overexposure

51
Q

Threshhold Limit Value TLVs

A

TLV the american conference of governmental industrial hygenists the ACGIH publishes annually.

TLVS are developed as guidelines to assist in the control for health hazards - appropriate level of employee protection . TLVs intended for use in the practice of industrial hygiene not legal standards. rather OSHA s PELs are enforceable standards.
TLVs best practices for employers and are sometimes more restrictive than PELS
3 categories
1. TWA - Time-weighted average
2. STEL - short term exposure limit
3. C - ceiling
They can be useful in selecting levels of protection at a hazardous waste site.
Refer to the TLVs for chemical substances and physical agents publication for additional details

52
Q

Time Weighted Average TWA

A

is a dose measurement that is more chronic in nature. It is a time weighted for a normal 8 hour day and 40 hour week where employees can have repeatedly exposure without adverse effects.

53
Q

Short Term Exposure Limit STEL

A

STEL- ACGIH defines this as a 15 min TWA exposure that should not be exceeded without the needs proper protective measures should not be more than 15 min and not more than 4 times a day with at least 60 min between exposures -This is not a separate independent exposure limit it supplements the TWA limit where there are recognized acute effects from that substance that normally has chronic effects.

54
Q

Ceiling - C

A

This is the level that can never be exceeded during any part of the working exposure without protective actions.
It is not an average unless it cannot be measured any other way, then it can only be measured within a 15 min time period

55
Q

REL - Recommended Exposure Limit

A

REL - a niosh exposure limit or is the workplace exposure concentration recommended by niosh for promolgulation by OSHA as a PEL
In some cases niosh has time weighted in terms of 10 hr rather than 8 hours exposures.averages.
exposures measured over any lenghth of time can be compared to an 8 hour TWA calculated with a mathematical formula

56
Q

IDLH - Immediately Dangerous to Life and Health

A

IDLH - exposure concentrations have been establishesd by the Niosh OSHA standards completion program SCP as a guideline to respirators for some chemicals.

IDLH varies depending on the source.

Eg. : The Mine Safety and Health Administration Standard defines IDLH conditions as those that pose an immediate threat to life or health or that pose an immediate threat of severe exposure to contaminants such as radioactive materials that are likely to have adverse cumulative or delayed effects on health.

57
Q

CDC - NIOSH Guide

A

IDLH concentration the maximum level from which one can escape within 30 min without escape-imparing symptoms or any irreversible health effects.
American National Standards Institute ANSI - any atmosphere that poses a threat to life or produces immeidate irreversible debilitating effects on health.”
Regardless of their exact definition all idlh values indicate those concentrations of toxic substances from which escape is possible without irreversible harm should the worker’s protective equipment fail.

58
Q

IDLH Concentrations

A

assumed to represent concentrations above which only workers wearing respirators that provide the maximum protection (i.e a positive pressure full face piece, supplied air respirator with positive pressure SCBA) are permitted. specific IDLH values for many substances are to be found in the NIOSH pocket guide to chemical hazards.

59
Q

Protection from Toxins

A

The human body can break down and detoxify or eliminate if the dose is not too great. exposure to toxins puts stress on the body.

60
Q

Protect yourself

A

the potential for toxicity of the materials that you work with to adequately protect yourself from exposte. Once establlished, The associated hazards should be determined. Information on the chemical physical and toxicological chemical should The properties and Should be recorded on a hazardous chemicals logs. health and safety personnel should record in one place inform all staff and new personnel should be briefed.

61
Q

Completing Documentation

A

Many Reference sources should be used to complete the sheets because information may vary from one source to another. as data is gathered a worst case scenario is to bedeveloped so all necessary precautions can be added. Use SDS sheets as they are a source for this information.

62
Q

Protection against hazards

A

one can protect against the known hazard by doing the following

  1. use ventilation systems - engineering controls provided
  2. Administrative Controls
  3. Common sense - never rely solely on it
  4. select and use ppe
  5. wash exposed areas thoroughly before eating drinking and or smoking

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