TOXICANTS AND HAZARDOUS WASTES---CH 43---WEEK 14--Q = 10 Flashcards
CHAPTER 43
Quantitative toxicity
The median lethal DOSE (LD50):
= The smallest DOSE of a given chemical that will kill 50% of a test group of animals
–All chemicals except the ________
inhaled
CHAPTER 43
Quantitative toxicity
The median lethal CONCENTRATION (LC50):
= The smallest CONCENTRATION of a given chemical that will kill 50% of a test group of animals
—applicable to chemicals that are _______
—- The LC50 is expressed relative to the ________ of exposure
inhaled
duration
CHAPTER 43
Quantitative toxicity
The threshold limit value (TLV):
= The ________ amount of a chemical that is considered safe.
—Industrial and governmental hygienists provide an official listing of the TLV levels of airborne poisons to which workers may safely be exposed for an 8- hour period.
maximal
CHAPTER 43—EXAMPLES OF SPECIFIC POISONS
I. Gaseous poisons
- Simple asphyxiants: usually inert industrial gases
Examples: 1-Nitrogen (N2) 2--Carbon dioxide (C02) .3--Methane (CH4) -------DECREASE the \_\_\_\_\_\_\_ available to the lungs and cause \_\_\_\_\_\_\_
oxygen
hypoxia
CHAPTER 43——EXAMPLES OF SPECIFIC POISONS
- Irritants
Affecting the respiratory tract can cause asphyxia.
A. Water-SOLUBLE irritants
- –affect the _____ and upper respiratory tract
- – affect the ______ and can be corrosive
Examples :
- Hydrochloric acid (HCL)
- Hydrofluoric acid (HF)
- Sulfur dioxide (S02)
- Ammonia (NH3)
B. Water-INsoluble irritants
—Trapped in ____________ secretions and can descend into the alveoli, causing pneumonitis and ________ __________
Examples :
- chlorine gas
- ozone
eyes
lungs
nasopharyngeal
pulmonary edema
CHAPTER 43——EXAMPLES OF SPECIFIC POISONS
- SYSTEMIC toxicants
- -The gas is absorbed by inhalation or percutaneously
a. CYANIDE (hydrocyanic acid, HCN)
—One of the most rapidly acting poisons
– Form complexes with ferric ions of the _______ ________ System
–Interfering with electron transfer in the _________
— Blockage In oxygen transfer to tissues
–Cytotoxic hypoxia
– Patient’s breath (characteristic odor of oil of bitter
almond)
Treatment of cyanide poisoning:
= ______________ = Antidote
—- By inhalation, + intravenous
— Hemoglobin to methemoglobin, (greater affinity for
cyanide ion)
—- If the cyanide has been ingested, (gastric lavage)
cytochrome oxidase
cytochrome
Amylnitrite
CHAPTER 43——EXAMPLES OF SPECIFIC POISONS
- SYSTEMIC toxicants
- -The gas is absorbed by inhalation or percutaneously
b. CARBON MONOXIDE
- ——-Odorless, colorless, and tasteless gas
- —- The affinity of HB CO ____ times greater than its affinity for O2
- — Absorbed and excreted by the ________
- — Ambient concentrations of carbon monoxide can result in rapid DEATH with NO premonitory signs.
- —Running automobile engine
- —– patient’s “______ ________” cyanosis
Treatment
- – The patient should be removed from the air containing carbon monoxide.
- – One hundred percent oxygen should be administered.
- – Severe, oxygen at a pressure of 2 to 3 atm is recommended
200
lungs
cherry red
CHAPTER 43——EXAMPLES OF SPECIFIC POISONS
II. ORGANIC SOLVENTS
- industrial environment (page 530)
- Fat-soluble
- Absorbed through the skin
- Accumulating in FAT & nervous tissue
4 Classes of Toxic organic solvents:
- ________ hydrocarbon: pentane, hexane, heptane, and octane
- __________ hydrocarbons: kerosene
- _______ compounds: benzene and toluene
- _________ hydrocarbons: methylene dichloride,
dichloromethane, chloroform, and carbon tetrachlorid
*****Only therapy = (remove the individual from the exposure to the solvent)
Saturated
Unsaturated
Aromatic
Halogenated
CHAPTER 43——EXAMPLES OF SPECIFIC POISONS
III. HEAVY METAL INTOXICATION
- Arsenic
– Used in household plant-spray pesticides as lead arsenate
IF ACUTE poisoning:
- – ____________
- —Capillary transudation
- —Muscle spasms
- — Vertigo
- —-Delirium
- —-Interference with KIDNEY function
IF CHRONIC poisoning of arsenic:
- Persistent capillary dilation
- – Malaise
- -Fatigue
- –Encephalopathy
- –Peripheral neuritis and sensory loss.
- – Sulfhydryl-rich tissues (nails and hair) take up arsenic
- – ______ ______ appear in the finger & toenails (useful in diagnosis)
- – Antidote is _____________
Hypotension
pale bands
dimercaprol
CHAPTER 43——EXAMPLES OF SPECIFIC POISONS
III. HEAVY METAL INTOXICATION
X
CHAPTER 43——EXAMPLES OF SPECIFIC POISONS
III. HEAVY METAL INTOXICATION
X
CHAPTER 43——EXAMPLES OF SPECIFIC POISONS
III. HEAVY METAL INTOXICATION
- Lead
= The most common cause of heavy metal poisoning, especially in large urban areas
- Acute poisoning is rare
- – The most common routes of absorption of lead are the GIT, RS
Signs
1. WRIST drop and to a lesser extent FOOT drop occur as a result of degenerative changes In motor neurons
2. abdominal syndrome consisting of constipation, anorexia, and a persistent metallic taste
3. A BLACK “____ _________“can occur on the GUMS
4. microcytic hypochromic anemia
5. A characteristic basophilic stippling RBC
6. Serious manifestation is lead _____________
= Clumsiness, irritability, vertigo, and projectile vomiting
Treatment: by antidote: dimercaprol, EDTA (edetate), pencillamine.
lead line
encephalopathy
CHAPTER 43——EXAMPLES OF SPECIFIC POISONS
III. HEAVY METAL INTOXICATION
- Mercury
= by inhalation, skin penetration, or ingestion of substances containing mercury
1.) Mercurial fungicides are present in some ____ ______
2) Dermal application of methylmercury ______ can result in absorption through the skin
Signs of intoxication
- Acute intoxication can result in cardiovascular collapse and anuria
- Chronic intoxication due to inhalation or skin penetration can result in:
a. Neurologic manifestations including irritability, tremors, and psychosis
b. Mercuria lentis, a brown discoloration of the anterior portion of the optic lens
c. Gingivitis and stomatitis
d. Progressive ________ ________
latex paints
ointments
renal damage
CHAPTER 43——EXAMPLES OF SPECIFIC POISONS
III. HEAVY METAL INTOXICATION
4. OTHER METALS A---Antimony -- Effects similar to those of ARSENIC -- Chronic poisoning can result In myocardial damage B----Gold -- Effects similar to those of ARSENIC C---Nickel -- Sensitizing agent and causes a dermatitis known as "\_\_\_\_\_\_\_ \_\_\_\_\_\_\_.” D---Beryllium -- Chronic granulomatous condition E---Zinc (Inhalation of fresh fumes) --“\_\_\_\_\_\_ \_\_\_\_\_\_\_ fever. " Delayed chills with fever lasting up to \_\_\_\_ hours can occur
nickel itch
metal-fume
36
CHAPTER 43——EXAMPLES OF SPECIFIC POISONS
COMMONLY OCCURRING OVERDOSES X 3
- Ethanol
– Ethanol accounts for approximately __________ of all
drug poisonings each year
– The lethal blood level of ethanol is considered to be
0.5 g/dl
Treatment :
- Intensive supportive care
- -Preventing hypoglycemia and ketoacidosis
one-fourth
