Chapter 5 - Toxicology Flashcards
Toxicology
study of the adverse effects of chemicals on living organisms
toxicity
degree to which a substance can harm an exposed organism
hazard
the potential for a substance to cause harm (toxicity plus exposure)
risk
quantitative measurement or estimate of a hazard
poisen
substance that is harmful to an organism
xenobiotic
substance found in an organism but which is not normally produced or expected to be present in it
dose response theory
increasing dose, increasing response
tolerance
increased ability to withstand exposure
chronic exposure
long term exposure
acute exposure
short term - minutes, hours, days
NOEL
no observed effect level
NOAEL
no observed adverse effect leel
LOEL
lowest observed effect level
LOAEL
lowest observed adverse effect level
latency period
period of time between exposure and onset of symptoms
LD50
lethal dose, amount of material (normally liquids or solid) that kills 50% of laboratory animals
LC50
lethal concentration . amount of material (normally air-borne concentrations) that kill 50% of laboratory animals
IDLH
immediately dangerous to life and health
Routes of entry
Inhalation, Ingestion, Absorption, Percutaneous and Intravenous Injections
Chemical combinations - additive
combined effect of chemicals equal to sum of each chemical acting independently
Chemical combinations - antagonistic
when combined the two chemical interfere with each other
Chemical combinations - synergistic
combined effect of two chemicals is much greater than the sum of the effect of each agent acting independently
chemical combinations- potentiating
one substance does not have a toxic effect on a certain organ system, however, when combined with another chemical, the combination can have a toxic effect
carcinogen
substance or agent known to cause cancer, carcinogens to do not adhere to dose response curve
caocarcinogen
these agents, when applied immediately before or with a genotoxic carcinogen, enhance the oncogenic (cancerous) effect of the agent
epigenetic
changes in phenotype or gene expression caused by mechanisms other than changes in the underlying DNA sequence
genotoxic
materials known to be potentially mutagenic and carcinogenic in nature. They act by directly altering the DNA
mutagen
physical or chemical agent that changes the genetic material (usually DNA) of an organism and thus increases the frequency of mutagens above the natural background level
teratogens
an agent that can disturb the development of an embryo or fetus
Four stages of cancer
initiation, latency period, promotion, progression
Cancer initiators
Can be reactive with DNA
Can require drug metabolizing enzymes in the body which make them available to cause changes in DNA
often specific to particular tissue , types or species
effects are irreversible
Cancer promotion
When mutation occurs as result of initiator, promoter compounds promote the proliferation of the cell, giving rise to a large number of daughter cells containing mutation
progression
transformation of a benign tumor to a neoplasma and to malignancy
Types of poisens
hepatoxin (liver or blood), nephrotoxin (kidneys), neurotoxin (nervous system)
Ames Test
procedure to determine whether a chemical is a mutagen
Uses Salmonella typhimurium
Cohort Study
Subjects with a certain condition and/or receive a particular treatment are followed over time and compared with another group unaffected by condition
Advantages- does not require strict random assignment of subjects, which is in many cases unethical or improbable
Disadvantages - causality difficult to prove due to influence of other factors, these studies more open to threats of validity
cohort
any group of individuals who are linked in some way or who have experienced the same significant life event within a given period
Case control study
compares two groups of people, those with the disease/condition and a very similar group of people without disease/condition
Cross sectional study
observation of a subset of a population all at the same time, in which groups can be compared with respect of independant variables
Asbestosis
Respiratory disease caused by inhalation of asbestos fibers and subsequent scarring of lung tissue
Strong correlation between asbestos exposure and smoking to the development of lung cancer
Latency period for asbestosis -10-20 years
Latency period for asbestos-related cancer is 20-30 years
Can cause asbestosis, lung cancer, and mesothelioma
Mesothelioma
rare form of asbestos related cancer in the lining of the lung or the lining of the abdominal cavity
PEL for asbestos
0.1 fibers/cubic centimeter
Sampled with a 0.8 micron mixed cellulose ester filter
Brucellosis
Bang’s disease, Gibraltar fever, Malta fever, etc…
highly contagious zoonosis caused by ingestion of unsterilized milk or meat from infected animals or close contact with their secretions
latency period is 3-60 days
Benzene- Related Illnesses
aromatic hydrocarbon produced by the burning of natural products
Used in manufacture of plastics, detergents, pesticides and other chemicals
Carcinogen - 5-30 year latency for leukemia
Can cause granulocytic leukemia or myelogenous leukemia
PEL for benzene
10ppm with a ceiling limit of 25 ppm for a 10 minute period
Maximum peak concentration for an 8h shift is 50 ppm
Byssinosis
Disease of the lungs as a result of breathing in cotton dust or dusts from other vegetable fibers such as flax, help or sisal
Textile industry
Being exposed many times can lead to chronic lung disease
PEL for cotton dust exposure
1.0 mg/m3
Arsenic Related Illness
Patchy hyperpigmentation, anemia, leukopenia, thrombocytopenia, eosinophilia, and liver injury
Can cause lung cancer or hemoglobinuria
High risk arsenic exposure/ occupations
applying arsenic preservatives to wood pesticide manufacturing sawing or sanding arsenic treated wood smelting or casting lead smelting or refining zinc or copper
PEL for arsenic
10um /m3 (8hr time weighted average)
2mg/m3 NIOSH 15 minute limit for airborne arsenic concentration
Berylliosis and Beryllium-related illness
Berylliosis lung disease from inhalation of beryllium- used in lightweight metals, especially in valves in aeronautical and space industries
chronic beryllium disease- slow onset- caused by exposure to dust of rumes from beryllium metal oxides, alloys, ceramics or salts
acute beryllium disease- quick onset symptoms resemble pneumonia or bronchitis
PEL beryllium
2.0 um/m3 (8h-twa)
ceiling limit of 5ug/m3 not to be exceeded for more than 30 min and never to exceed limit of 25 mg/m3
exposures to beryllium even at levels below PEL may cause CGD so proper respirators are advised
Can cause CBD or beryliosis
Copper related illnesses
Primary route of entry through inhalation or absorption through the eyes or skin
Short term may cause metal fume fever
Long term exposure may cause hair or skin to change color- chronic respiratory disease or Wilson’s disease (hepatolenticular degeneration)
PEL for copper
0.1 mg/m3 (8hr-twa)
Cadmium-Related illness
Acute exposure can result in delayed pulmonary edema and acute renal failure
Chronic exposure to cadmium dust and fume toxic to kidneys and bones - renal damage
Biological monitoring mandated by OSHA
Latency period = 10 years
Exposure from solder, machining or welding cadmium alloyed or plated steel, making/removing cadmium coated products, plating metal with cadmium, reclamation, smelting or casting lead, zinc, or copper
PEL for cadmium
5mg/m3 (8 hour shift)
Action level established by OSHA is 2.5 ug/m3
Chromium - related illness
Chronic exposure - contact dermatitis and ulcerations of skin and nasal mucosa
Inhalation of chromium dust/fumes, or mist - acute bronchoconstriction
Hexavalent chromium is the bad one- found as pigments in dyes, paints, inks, etc… also used as anticorrosive agent to paints, primers, surface coating
Exposures through welding stainless steel, heating chromium alloys, mining, plating metal with chromium, making, removing or sanding paints/ pigments, printing, tanning
PEL for chromium (hexavalent)
5ug/m3 (8hr-TWA)
Coal dust
Pneumoconiosis (black lung disease)
Early stages simple pneumoconiosis- progresses to progressive massive fibrosis
Creosote col tar from wood preservatives causes lung cancer
PEL for coal dust
2.4 mg/m3
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Acute Cobalt related illnesses
acute exposure- irritation of eyes, skin- can cause asthma-like attack with wheezing, bronchospasm and dyspnea- ingestion may cause nausea, vomiting, diarrhea, and a sensation of hotness
Chronic cobalt related illnesses
respiratory and dermatological
obstructive lung disease
Hard metal disease or lung cancer
increased fibrotic changed and shortness of breath
polycythemia, hyperplasia of bone marrow and thyroid gland pericardial effusion and pancreatic damage
high risk exposure for cobalt
machining cobalt alloys
manufacturing or using cemented carbide materials or tools
PEL for cobalt metal, dust, and fume
0.1 mg/m3 (8-h TWA concentration)
Formaldehyde-related ilnesses
Potential human carcinogen, preservative in labs, fungicide, germicide, and disinfectant
Inhalation of gas or absorption through skin
High risk- health care professionals, medical lab technicians, mortuary employees, teacher/students of biology
PEL for formaldehyde
0.75 ppm (8-h TWA)
2ppm short-term exposure limit
action level is 0.5 ppm over 8 h
Lead - Related Illness
Exposure through inhalation of lead dust or fumes. Lead particles may be ingested.
Lead dust can be brought home on contaminated clothes, boots, skin, and hair
Stored in bones and tissues for a long time
Health effects include: brain disorders, anemia, brain and nerve disorders, high blood pressure, kidney disorders, reproductive disorders, decreased red blood cells, slowed reflexes
PEL for Lead
50ug/m3
Action level 30ug/m3- if greater than action level for 30 days of the year, periodic determination of blood lead levels
If workers one time blood level greater than 40ug/dl - worker must be notified in writing
If greater than 60 ug/dl, worker must be removed from exposure
Manganese Related Illness
After chronic exposure of several months- neuropsychological tests reveal cognitive disfuntion (prodomal, intermediate, and established (similar to Parkinsons)
High risk for exposure- machining Mn alloys, mining or crushing Mn ores, Using ferromanganese in alloy production, using Mn-containing welding rods
PEL for Mn dust
5 mg/m3 (8-hr TWA)
Mercury - related illness
Peripheral neuropathy and neuropsychiatric disorder from chronic exposure
Inhalation of mercury vapor common route of exposure
High risk occupational exposures - extracting mercury ore, fabricating or repairing devices with mercury, including fluorescent lights, temperature gauge, and dental amalgams, reclaiming scrap metal with lead, cadmium, beryllium or mercury, using mercury to extract gold, working in a mercury cell room in a chloralkali plant
PEL for mercury
0.01 mg/m3
Ceiling limit 0.04 mg/m3
Pneumoconiosis
interstitial lung diseases caused by inhalation of certain dusts and the lung tissue’s reaction to the dust
asbestos fibers, silica dust and coal dust
Silica related Illness - Silicosis
Simple, Complicated, and Accelerated
Latency 2-5 years for accelerated, greater than 10 for simple
Complicated - PMF - progressive massive fibrosis
High risk exposures- working/quarrying rock, concrete, or brick, using abrasives, sawing, grinding, etc
Zinc related illness
Short term illnes = metal fume fever
Long term effects unknown
Used in commercial industries and can be released into the environment during mining and smelting activities- can be found in soil, drinking water, air
PEL for Zinc
15 mg/m3 of air for total dust and 5 mg/m3 for repirable fraction as an 8-h TWA
Aluminum related illnesses
Aluminum dust inhaled as aerosols can cause pulmonary fibrosis
Aluminum used bauxite ore can cause lung cancer, emphysema, and pneumoconiosis
Alzheimer’s may be correlated
speech disorders, dementia, or convulsions
High risk exposures - processing, transportation of aluminum, melting soldering of electrical transmission lines, when used in construction, manufacturing, explosives, petrochemical, and paper industries, desalination, cryogenic tech, used in testing for gold, arsenic and mercury, sugar refinement, containers for fissionable reactor fuels
PEL for Aluminum
15 mg/ m3 of air for total dust and 5mg /m3 for respirable fraction as an 8-hr TWA concentration
Antimony - related Illnesses
Inhalation- eye and lung irritation, heart and lung problems
Ingestion - vomiting, long herm liver damage and blood changes
Exposure through soil at hazardous waste sites, or in paint, ceramics industries
PEL for Antimony
0.5 mg /m3 for 8hr work day 40 hour week
Dust Related Illness
Most common industries- mines, quarries (coal, flint and silica), construction (cement and asbestos), farming and agriculture (grain), carpentry (wood), bakeries and mills (flour), textiles (leather)
My cause pneumoconiosis- any condition affecting the lungs and causing scar tissue- may take several decades for disease to develop
PEL for particulates otherwise not regulated (PONR)
5 mg/m3 - respirable fraction
15 mg/m3 total particulates
Thallium related illness
Used in manufacturing of electronic devises, semiconductors, special glass and certain medical procedures
Skin hazard
PEL for thallium
0.1 mg/m3 for 8-hr TWA
Pesticide related illness
Primary route through skin
Acetylcholinesterase poisonings
Other health effects, diarrhea, urination, miosis, bradycardia, emesis, lacrimation, secretion, sweating
High risk for application of OPs in field
Nickel related illness
Lung cancer and nasopharynx cancer
