Part V. Applied Toxicology: Public, Environmental, and Occupational Health Flashcards
(82 cards)
1
Q
Why are alcohol-containing beverages considered Group 1 carcinogens by the International Agency for Research on Cancer (IARC)?
A. There is clear evidence that ethanol is mutagenic .
B. It causes forestomach tumors in mice.
C. Epidemiologic studies associate the alcoholic beverage consumption to an increased incidence of several tumor types in humans.
D. There is clear evidence that ethanol is carcinogenic in laboratory animals
A
Answer: C
Explanation and Reference:
The IARC rating is based on the occurrence of a variety of tumors in humans that have been causally related to ingestion of alcohol. Hayes 6th, p. 701; C&D 8th, pp. 1069-72
2
Q
- What is the primary health effect in humans associated with agricultural use of elemental sulfur as a pesticide?
A. alopecia
B. dermatitis
C. neurotoxicity
D. male reproductive effect
A
Answer: B
Explanation and Reference:
Dermatitis is the primary health effect observed. C&D 8th, p. 970
3
Q
- What hydrolysis product is primarily responsible for the soil fumigant toxic action of metam sodium toward nematodes, fungi and weed seeds?
A. methamidophos
B. methyl parathion
C. methyl isothiocyanate
D. alpha-methyl cyanuric acid
A
Answer: C
Explanation and Reference:
Methylisothiocyanate is the active toxic hydrolysis product. C&D 8th, p. 970
4
Q
- What is the largest single outdoor source of the air pollutant, carbon monoxide?
A. refuse disposal plants
B. power and heating plants
C. petroleum refining
D. vehicle emissions
A
Answer: D
Explanation and Reference:
Motor vehicles account for two thirds of urban carbon monoxide. C&D 8th, p. 1265-1266
5
Q
- What agent, when inhaled, is associated with onset of Silo-Filler’s Disease?
A. hydrogen sulfide
B. carbon dioxide
C. phosgene
D. nitrogen dioxide
A
Answer: D
Explanation and Reference:
Nitrogen dioxide can be liberated from fermenting fresh silage and displace oxygen from the base of a silo; this is a real-world problem for farmers. C&D 8th, p. 1262-1263
6
Q
- What rare type of respiratory cancer is causally linked to exposure to some forms of asbestos?
A. mesothelioma
B. endothelial cell carcinoma
C. small cell carcinoma
D. pulmonary adenoma
A
Answer: A
Explanation and Reference:
Mesothelioma is a rare tumor associated with asbestos exposure. https://www.epa.gov/asbestos/learn-about-asbestos#effects (accessed 4 October 2020); C&D 8th, p. 720
7
Q
- What group of spiders are associated with the most serious spider envenomations in North America?
A. funnel-web spiders
B. black widow spiders
C. banana spiders
D. grass spiders
A
Answer: B
Explanation and Reference:
These spiders are found in all climates and are very common. C&D 8th, p. 1148-49
8
Q
- What group of toxic responses are most prominently linked to consumption of oleander, foxglove, lily- of-the-valley, and/or mistletoe?
A. dermal sensitization reactions
B. seizures, disorientation, and/or coma
C. irregular heart rates, arrhythmias and/or cardiovascular collapse
D. hepatotoxicity with elevation of ALT and AST serum enzymes
A
Answer: C
Explanation and Reference:
This group of plants are all identified as being toxic to the cardiovascular system. C&D 8th, p. 1137- 1138, Table 26-6
9
Q
- In most parts of the world, what is recognized as by far the greatest food-borne risk facing consumers?
A. microbial contamination
B. food allergy
C. Aflatoxin B1
D. pesticide residues
A
Answer: A
Explanation and Reference:
Microbial contamination is the greatest food-borne risk for most of the world’s consumers. C&D 8th, p. 1342-1343/
10
Q
- What glycol ether is both a male and female reproductive toxicant and a teratogen?
A. propylene glycol methyl ether acetate
B. ethylene glycol monobutyl ether
C. ethylene glycol monomethyl ether
D. propylene glycol monomethyl ether
A
Answer: C
Explanation and Reference:
EGME is metabolized to methoxyacetic acid which can affect both the testes and ovary as well as the developing fetus. C&D 8th, p. 878-880, 1078-1079
11
Q
- What is the most commonly used antidote in the treatment of anticholinesterase poisoning?
A. desferrioxamine
B. atropine
C. N-acetylcysteine
D. dithiocarbamate
A
Answer: B
Explanation and Reference:
Atropine is the cornerstone of treatment for OP poisoning. C&D 8th, p. 941
12
Q
- The WHO-recommended classification of pesticides by hazard is based, in part, on what model of toxicity?
A. inhalation LC50 in rats
B. carcinogenicity studies in rats and mice
C. oral LD50 in rats
D. dermal LD10 in rats
A
Answer: C
Explanation and Reference:
Oral acute lethality in rats is used by WHO to classify pesticides by hazard. C&D 8th, p. 937, Table 22-6
13
Q
- What substance produced by a mold found on spoiled sweet clover has been associated with a hemorrhagic disorder in cattle?
A. coumarol
B. dicoumarol
C. chlorophacinone
D. brodifacoum
A
Answer: B
Explanation and Reference:
Dicoumarol is the toxic agent in Sweet Clover Disease of cattle. Research into the cause of this disease lead to the development of anticoagulant rodenticides. C&D 8th, p. 968
14
Q
- What widely used industrial chemical is classified by IARC as a probable human carcinogen because high doses cause nasopharyngeal carcinoma in rats?
A. silica
B. formaldehyde
C. sulfur dioxide
D. nitrogen dioxide
A
Answer: B
Explanation and Reference:
Nasal carcinomas were induced in rats in a two-year bioassay. C&D 8th, p. 1264-1265
15
Q
- What product of dinoflagellates causes paralytic shellfish poisoning often observed during times of algal bloom?
A. saxitoxin
B. ciguatoxin
C. tetrodotoxin
D. domoic acid
A
Answer: A
Explanation and Reference:
The etiological agent in dinoflagellate poisoning is saxitoxin or related compounds. C&D, 8th, p. 1341
16
Q
- What is the primary mechanism of action of ricin, a component of castor beans?
A. conversion in the liver of monocrotaline into an active pyrrolic metabolite and the resultant production of cardiopulmonary toxicity
B. competitive antagonism of sphingosine in associated blocking of enzyme activity related to sphingolipid biosynthesis
C. inactivation of the 60s ribosomal subunit leading to inhibition of protein synthesis
D. combination of the cyclic heptapeptide with actin in muscle cells to and resultant interference with muscle function
A
Answer: C
Explanation and Reference:
This is the specific mechanism of action of the ricin amino acid lectin chain. C&D 8th, p. 1136
17
Q
- What substance has been linked to the oral toxicity of bitter almonds and peach kernels?
A. linamarin
B. carboxatractyloside
C. ptaquiloside
D. amygdalin
A
Answer: D
Explanation and Reference:
Amygdalin is a cyanogen present in bitter almond and peach kernels. C&D 8th, p. 1140
18
Q
- What creature’s venomous bite can cause large lesions characterized by severe, invading, muscular necrosis?
A. fire ant
B. black widow spider
C. brown recluse spider
D. Gila monster
A
Answer: C
Explanation and Reference:
This is characteristic of severe bites by the brown recluse spider. C&D 8th, 1149-1150
19
Q
- A patient comes to the emergency room with blurred vision, vomiting, abdominal cramps, salivation, sweating, and muscle weakness, without significant CNS effects. Atropine and charcoal are administered, and the patient improves in 2 hours without use of p
A. paraquat
B. aldicarb
C. diethyl parathion
D. aluminum phosphide
A
Answer: B
Explanation and Reference:
Inhibition of AChE by carbamates, such as aldicarb, is transient and use of 2-PAM is not recommended. C&D 8th, p. 947
20
Q
- What is the primary source of reducing-type air pollution?
A. CO
B. oxides of nitrogen
C. ozone
D. SO2
A
Answer: D
Explanation and Reference:
SO2 is the classic reducing-type air pollutant which causes an acidic atmosphere with reductive chemistry. C&D 8th, p. 1250-1253
21
Q
- What is radon’s primary respiratory effect in humans associated with its decay to the solid phase daughter product Polonium-218?
A. mesothelioma
B. nasal tumors
C. chronic bronchitis
D. lung cancer
A
Answer: D
Explanation and Reference:
Numerous epidemiology studies have linked radon to lung cancer. C&D 8th, p. 394 (Table 8-1), 434 (Table 8-32), 741
22
Q
- What is the currently accepted mechanism for the toxic action of ricin?
A. selective antagonism of spinal inhibitory neurons
B. interference with the sodium/potassium-ATPase
C. blockage of mitotic spindle formation
D. reduced protein synthesis due to inactivation of 60s ribosomal subunits
A
Answer: D
Explanation and Reference:
The A-chain of the ricin molecule binds to the 60s robosomal subunit and directly inhibits protein synthesis. C&D 8th, p. 1136
23
Q
- Hypericin causes photosensitization in livestock following consumption of Hypericum perforatum. What is the common name for this plant?
A. nettles
B. castor bean
C. mugwort
D. St. John’s wort
A
Answer: D
Explanation and Reference:
St. John’s wort is the common name for H. perforatum. C&D 8th, p. 1134
24
Q
- What is the principal toxic effect of the mycotoxin citrinin from Penicillium citrinum?
A. neurotoxicity
B. cardiotoxicity
C. nephrotoxicity
D. hepatotoxicity
A
Answer: C
Explanation and Reference:
The kidney is the target for citrinin. C&D 8th, p. 1338, Table 31-26
25
25. Cardiomyopathy has been observed in humans deficient in which essential metal?
A. selenium
B. magnesium
C. manganese
D. molybdenum
Answer: A
Explanation and Reference:
Endemic cardiomyopathy has been observed in humans with document selenium deficiency (Keshan disease) C&D 8th p. 1007
26
26. What ocular condition has been associated with accidental exposure to naphthalene?
A. cataracts
B. glaucoma
C. conjunctival melanoma
D. exophthalmos
Answer: A
Explanation and Reference:
The lens is subject to cataract formation from exposure to naphthalene. C&D 8th, p. 780
27
27. Why are the sprouts and young leaves of pokeweed (Phytolacca Americana) safer to eat than mature leaves?
A. Mature parts of the plant produce belladonna alkaloids.
B. Young leaves contain only the A-chain of a ribosomal inhibiting protein.
C. Mature leaves contain increased concentrations of a saponin, which can cause severe gastritis.
D. Mature leaves contain increased concentration of anemonin, which has marked irritant properties.
Answer: B
Explanation and Reference:
Pokeweed (Phytolacca americana) is one of several important plants in the Euphorbia family, which include the Ricinus and Abrus genera, that produce ribosomal inhibitory proteins. The A-chain cleaves purine bases from ribosomes but it is the B-chain tha
28
28. Under what conditions is a substance considered to be GRAS (generally recognized as safe)?
A. thoroughly tested according to all regulatory guidelines established by the US Food and Drug Administration
B. used at less than 1% of the diet for the average adult male
C. recognized as safe by experts based on currently available information published in the scientific literature
D. used as a food in a foreign country for at least five years
Answer: C
Explanation and Reference:
GRAS designation is based on the opinion of scientific experts through experiments or experience prior to 1958. FDA may make this designation but is not required to. Any food additive not designated as GRAS becomes a regulated additive under the Food, D
29
29. What organ system is most susceptible to lead poisoning in children?
A. hematopoietic system
B. nervous system
C. immune system
D. endocrine system
Answer: B
Explanation and Reference:
The brain and neurological system of children continues to develop for several years after birth. CD 8th p. 994
30
30. Pesticides often have adverse health effects for non-target species including humans. From a global perspective, what is the major health and safety issue problem in humans?
A. endocrine disruption
B. low-level, chronic exposure through contaminated food
C. increased incidence of cancer
D. acute poisoning
Answer: D
Explanation and Reference:
Acute poisoning remains largest concern world-wide, especially in developing countries. Most hospital admissions are related to intentional (suicidal) ingestion of these compounds. C&D 8th, pp. 936-37
31
31. What pulmonary effect is most likely to result from SO2 gas exposure?
A. decreased mucociliary clearance
B. bronchoconstriction via Type I hypersensitivity
C. local and centrally mediated bronchoconstriction via formation of sulfite
D. induction of pulmonary fibrosis following damage to epithelial cells
Answer: C
Explanation and Reference:
SO2 is a water soluble sensory irritant gas predominantly absorbed in the upper airways. C&D 8th p. 1250
32
32. What is the mode of action of the chemical warfare agent phosgene?
A. irritant induced Clara cell proliferation
B. autoimmune mediated tissue destruction
C. overt lipid peroxidation leading to lung toxicity and pulmonary edema
D. spindle poison-like suppression of immediate early gene activation
Answer: C
Explanation and Reference:
Phosgene can produce immediate alveolar damage leading to rapid death at high concentrations. At lower levels, phosgene compromises alveolar barrier function that leads to pulmonary edema which often can be fatal. C&D 8th, pg 712
33
33. What are the most common types of DNA damage caused by ultraviolet (UV) radiation?
A. intercalation and adducts
B. single and double-strand breaks
C. DNA protein cross-links abd 1,2-photo-radicals
D. cyclobutane pyrimidine dimers and 6,4-photoproducts
Answer: D
Explanation and Reference:
UV radiation causes cyclobutane-pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4PPs). Single and double-strand breaks are associated with ionizing radiation (x-rays); and altered DNA bases are most commonly associated with endogenous agents. DNA-prot
34
34. What is the toxin that makes castor beans poisonous?
A. ricin
B. cardiac glycosides
C. pyrrolizidine alkaloids
D. colchicine
Answer: A
Explanation and Reference:
The toxic agents of castor beans are two lectins: ricin I and ricin II of which ricin II is more toxic. C&D 8th, p 1136.
35
35. What is the source of a form of poisoning that causes soft tissue calcification in cattle?
A. eating feed supplemented with high levels of calcium
B. eating plants containing Vitamin D-like glycosides
C. eating plants contaminated by polychlorobiphenyls
D. eating feed contaminated by aflatoxin
Answer: B
Explanation and Reference:
Consumption of Cestrum spp, which include day-blooming jasmine, causes hypercalcemia and soft tissue calcification in grazing cattle and chickens. Aflatoxins mostly affect the liver; polychlorinated hydrocarbons are general toxins and probable carcinogens
36
36. The synthetic pyrethroids are a major class of insecticides modeled after a group of natural insecticides extracted from what flowers?
A. chrysanthemum (Chrysanthemum spp.)
B. oleander (Nerium spp.)
C. milkweed (Asclepias spp.)
D. lily of the valley (Convallaria majalis)
Answer: A
Explanation and Reference:
Pyrethroids are insecticides developed from compounds found in chrysanthemums. C&D 8th p. 947.
37
37. Snake venoms are complex mixtures, however, their poisonous effects are most commonly due to what substances?
A. enzymes and polypeptides
B. formic acids
C. toxic alkaloids
D. vasoactive amines
Answer: A
Explanation and Reference:
Proteins and peptides, enzymatic and non-enzymatic, make up over 90% of the dry weight of snake venoms. C&D 8th p. 1155
38
38. Ergot alkaloids from a fungal parasite (Claviceps purpurea) on grains of rye can cause blackening of limbs ("St. Anthony's fire") and, in pregnant women, abortion. These effects are due to what biological activity of the alkaloids?
A. peripheral neurotoxicity
B. disruption of mitochondrial respiration
C. peripheral vasoconstriction
D. peripheral vasodilation
Answer: C
Explanation and Reference:
Ingestion of the fungus Claviceps purpurea (ergot), which grows on grains that are used for food, causes vaoconstriction. C&D 8th, p. 1138.
39
39. Bisphenol A is a chemical of concern for what reason?
A. extensive use in plastic manufacturing and possible thyroid hormone disruption
B. bioaccumulation in the environment and potential as a chemical carcinogen
C. surfactant properties and potential for endocrine disruption
D. use in plastics and strong binding to the aryl hydrocarbon receptor
Answer: A
Explanation and Reference:
Possible leaching from polycarbonate-containing plastics makes this chemical a particular concern for childhood exposure. C&D 8th p. 922
40
40. Which aflatoxin is the most toxicologically potent and commonly occurs in produce?
A. Aflatoxin G1
B. Aflatoxin B1
C. Aflatoxin B2
D. Aflatoxin G2
Answer: B
Explanation and Reference:
Occurs in corn, peanuts and a variety of grains and is acutely toxic in all species, inducing a variety of types of hepatotoxicity. C&D 8th pp. 1338-39
41
41. What is an important class of chemicals that are formed during grilling or broiling of meat and is associated with cancer in humans?
A. aliphatic amines
B. hydrazines
C. heterocyclic amines
D. ethyleneimines
Answer: C
Explanation and Reference:
They are formed as a result of high temperature cooking of proteins, especially those containing high levels of creatinine and carbohydrates. C&D 9th p 1350-1351
42
42. For what therapeutic agent is the neurotoxicity associated with its use mediated by a disruption of microtubule dissociation into tubulin subunits?
A. atropine
B. d-tubocurarine
C. procainamide
D. paclitaxel
Answer: D
Explanation and Reference:
Paclitaxel is the correct answer. It is a chemotherapeutic used to treat a variety of neoplasms. Taxol's mechanism of action involves interference with the normal breakdown of microtubules during cell division. C&D 9th p. 854, Table 16-3
43
43. Furanocoumarins in grapefruit juice can increase the systemic exposure to certain orally administered drugs such as simvastatin (HMG-coA reductase inhibitor) and felodipine (calcium channel blocker) through what mechanism?
A. inhibition of hepatic CYP3A4
B. inhibition of intestinal CYP3A4
C. inhibition of hepatic CYP1A1
D. induction of UDP-glucuronosyltransferase
Answer: B
Explanation and Reference:
Furanocoumarin derivatives initially inhibit intestinal enzyme cytochrome P450 isoform CYP3A4 and are believed to be primarily responsible for the effects of grapefruit on the enzyme. Inhibition of hepatic CYP3A4 occurs later. C&D 9th p 308
44
44. The shape of the dose-response curve has many important implications in toxicity assessment. For example, essential nutrients can be potentially toxic at high doses. What phrase best describes the shape of the dose-response curve for essential nutrients?
A. R step function (threshold dose response)
B. S shaped sigmoid curve
C. U shaped parabolic curve
D. / straight line (linear dose-response)
Answer: C
Explanation and Reference:
The U-shape of the dose-response curve (i.e., hormesis) is the result of physiological homeostatic control. C&D 9th p 37-38
45
45. What factor most commonly accounts for the differential effects observed with isoniazid in some people?
A. inhibition of the CYP3A isoform of cytochrome P450
B. genetic polymorphism of an N-acetyltransferase enzyme
C. competition for Phase I metabolism by phenytoin or phenobarbital
D. polymorphism of the CYP2D6 isoform of cytochrome P450
Answer: B
Explanation and Reference:
Isoniazid is metabolozed by hepatic acrylamine N-acetyltransferase type 2 (gene, NAT2). Isoniazid clearance in patients has been traditionally classified as one of two phenotypic grous (slow and fast) but recently an intermediate group has also been ident
46
46. Gallium compounds, such as gallium arsenide and gallium nitrate, are used in electronics manufacturing and medicine, both diagnostically and therapeutically. In humans, these compounds can decrease DNA synthesis by initial binding to what plasma transport
A. metallothionein
B. transferrin
C. hemoglobin
D. albumin
Answer: B
Explanation and Reference:
The primary valence state of gallium is +3, resembling the ferric state of iron. Because of this, gallium binds to transferrin and interacts with the iron -dependent ribonucleotide reductase resulting in a decrease in DNA synthesis. C&D 9th p 1142
47
47. What is the International Conference on Harmonization of Technical Requirements for the Registration of Pharmaceuticals for Human Use (ICH)?
A. ICH is a joint effort of the Food and Drug Administration (FDA), the Environmental Protection Agency (EPA), and the Occupational Safety and Health Act (OSHA) to develop a common approach to the safety assessment of chemicals.
B. ICH is a joint regulatory/industry project to improve, through harmonization, the efficiency of the process for developing and registering new medicinal products in Europe, Japan, and the United States, in order to make these products available to patient
C. The ICH process was completed in 1997 and the international standards for safety and efficacy of pharmaceuticals recommended by the ICH have been adopted by Europe, Japan, and the United States.
D. ICH is an Agency of the United Nations Food and Agricultural Organization that is intended to establish international equivalents to the safety and efficacy standards of the US FDA and the European Agency for the Evaluation of Medicinal Products (EMEA).
Answer: B
Explanation and Reference:
These are definitions (glossary) that an entry-level toxicologist should know. C&D 9th, p. 1583; Hayes 6th, p. 2091
48
48. What is the purpose of the US Food and Drug Administration's (FDA) Good Laboratory Practices (GLP) regulation?
A. assure the quality and integrity of safety data file for products regulated by FDA
B. assure appropriate interpretation of product safety data submitted to FDA
C. assure the validation of all data submitted to the FDA in support of product registration
D. provide testing guidelines for nonclinical safety testing
Answer: A
Explanation and Reference:
The good laboratory practice (GLP) standards created by the Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) primarily establish requirements for the planning, conduct, and reporting of research results used
49
49. According to Good Laboratory Practices (21 CFR 58) reagents must be labeled with what basic information?
A. identity, titer or concentration, storage requirements, date opened and expiration date
B. identity, titer or concentration, date opened and expiration date
C. identity, titer or concentration, identity of person opening the bottle, and expiration date
D. identity, titer or concentration, storage requirements and expiration date
Answer: D
Explanation and Reference:
All reagents and solutions in the laboratory areas shall be labeled to indicate identity, titer or concentration, storage requirements, and expiration date. Deteriorated or outdated reagents and solutions shall not be used. This is from 21 CFR 58.105 su
50
50. What type of toxicology study is no longer required prior to filing an Investigational New Drug (IND) application for a Phase I clinical trial in healthy volunteers?
A. single-dose toxicity studies by oral and/or intravenous routes in two rodent species
B. repeat-dose toxicity study in two species (one rodent and one nonrodent)
C. cardiovascular safety pharmacology
D. mutagenicity and genotoxicity
Answer: A
Explanation and Reference:
Acute toxicity is no longer required. The information can be obtained from appropriately conducted dose-escalation studies or short-duration dose-ranging studies that define an MTD (Maximum Tolerated Dose) in the general toxicity test species. Repeated-d
51
51. The United States Animal Welfare Act and Animal Welfare Regulations (Code of Federal Regulations, Title 9, Chapter 1, Subchapter A) lists what membership requirement for the Institutional Animal Care and Use Committee (IACUC)?
A. .IACUC members must serve at least three years of appointment
B. The IACUC must be comprised of a Chairman and at least three additional members.
C. At least one member of the IACUC must not be affiliated with the facility.
D. The Chairman of the IACUC appoints IACUC members.
Answer: C
Explanation and Reference:
IACUC committee has to have at least a chairman and two other members, one member must be a veterinarian and one member must not be affiliated with the facility. Code of Federal Regulations, Title 9, Chapter 1, Subchapter A, paragraph 2.31 section 3 item
52
52. According to the ICH Guidelines, a carcinogenicity study of a pharmaceutical compound is required when the expected continuous clinical usage is expected for what period?
A. testing depends on the type of drug only and not the duration of usage
B. daily regardless of the expected duration of clinical usage
C. daily use of a period of at least 6 months
D. daily for a period of up to one month
Answer: C
Explanation and Reference:
Carcinogenicity studies should be performed for any pharmaceutical whose expected clinical use is continuous for at least 6 months. ICH Guidelines - Safety: S1A The need for long-term rodent carcinogenicity studies of pharmaceuticals, Issue Date 11/1995,
53
53. The use of dental amalgam fillings is an occupational health concern because it may expose workers to what element at a level greater than recommended standards?
A. mercury
B. silver
C. gold
D. cadmium
Answer: A
Explanation and Reference:
Dental amalgam contains elemental mercury that can be released at levels high enough to cause concern for dental workers. There is no scientific consensus regarding the adverse health effects of this exposure. Hayes 6th, p.852.
54
54. Experimental fish screening assays for endocrine active substances are most likely to utilize what specific indicator to demonstrate exogenous estrogen simulation effects?
A. induction of mixed function oxygenases
B. delta-aminolevulinic acid dehydratase inhibition
C. synthesis of vitellogenin (VTG)
D. induction of metallothionein
Answer: C
Explanation and Reference:
VTG is a good example of such a biomarker in that it provides an insight to the mode of action (estrogenicity) that is vital to fish reproductive health. C&D 8th, p. 1279 & 1294
55
55. Sulfur dioxide is considered a component of outdoor ambient air pollution. How are the toxicological properties of SO2 best characterized at environmentally-relevant concentrations?
A. Sulfur dioxide is an insoluble particulate absorbed predominantly in the upper airways and can stimulate bronchoconstriction.
B. Sulfur dioxide is an insoluble particulate absorbed predominantly by swallowing particles trapped in the respiratory mucous of the upper airways and typically causes erosion of the gastric mucosa.
C. Sulfur dioxide is a water-soluble irritant gas absorbed predominantly in the upper airways and can stimulate bronchoconstriction.
D. Sulfur dioxide is a non-irritating water-soluble gas that is not absorbed in the airways or dermally to any significant extent and stimulates bronchoconstriction only in individuals with existing asthmatic or emphysematous conditions.
Answer: C
Explanation and Reference:
Sulfur dioxide is highly soluble in water and, therefore, is efficiently absorbed in the upper respiratory tract as sulfurous acid. Greater than 90 percent of inhaled sulfur dioxide is absorbed in the nasopharynx. However, mouth breathing (voluntary hyper
56
56. In the US, what is a legally enforceable standard related specifically to occupational exposure?
A. Biological Exposure Index
B. Threshold Limit Value
C. Time-Weighted-Average Exposure Limit
D. Permissible Exposure Limit
Answer: D
Explanation and Reference:
The permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States for exposure of an employee to a chemical substance or physical agent. C&D 9th p 1554
57
57. What substance is recognized as an antidote for ethylene glycol poisoning by a mechanism involving inhibition of alcohol dehydrogenase?
A. N-acetylcysteine
B. methanol
C. disulfiram
D. 4-methylpyrazole
Answer: D
Explanation and Reference:
A potent inhibitor of alcohol dehydrogenase, fomepizole (4-methylpyrazole) blocks the metabolic bioactivation of ethylene glycol, thus minimizing the formation of toxic metabolites and allowing ethylene glycol to be eliminated unchanged by the kidneys. C&
58
58. The American Conference of Governmental Industrial Hygienists (ACGIH) lists a ceiling limit (TLV-C) of 1 ppm for ethylene chlorohydrin. What does this mean?
A. A worker can be safely exposed to this material at concentrations up to 1 ppm for 8 hours per day, five days per week.
B. The general population can be safely exposed to 1 ppm for 30 minutes per day.
C. The 1 ppm concentration should never be exceeded in the work place.
D. Workers can be exposed to 1 ppm of this material for 15 minutes as long as there is 60 minutes between exposures.
Answer: C
Explanation and Reference:
A Threshold Limit Value (Concentration) means the absolute exposure limit that should not be exceeded for any time, in this case 1 ppm ethylene chloride. C&D 8th, p 1394
59
59. Prior to conducting a research study in the United States to assess the effects of an industrial chemical's effect on reproductive function in laboratory animals, a university investigator will have to get his study protocol approved by what entity?
A. ICCVAM
B. US EPA
C. IACUC
D. APHIS
Answer: C
Explanation and Reference:
No approval from the Regulatory Agencies are required before performing this study, however IACUC approval is required before any animal study. Before animals can be used, the proposed animal use must be reviewed and approved by an Institutional Animal
60
60. Measurement of abnormally high levels of vitellogenin in the blood of fish is an indication of exposure to what class of compounds?
A. neurobehavioral compounds
B. alkylating agents
C. endocrine disruptors
D. sensitizers
Answer: C
Explanation and Reference:
Primary biomarker of effect in Fish EDSP assays. C&D 9th p 1438
61
61. Naloxone is an antidote for what type of poisoning?
A. opiates
B. ethylene glycol
C. digoxin
D. cyanide
Answer: A
Explanation and Reference:
Naloxone marketed under the trade name Narcan among others, is an opioid antagonist. Naloxone is a medication used to counter the effects of opioids especially in overdose. C&D 8th, p.615
62
62. For what air pollutants were the U.S. National (Primary) Ambient Air Quality Standards established?
A. all priority toxic air contaminants
B. ozone, sulfur dioxide, carbon monoxide, and inhalable particulates (PM10)
C. benzene and gasoline
D. ammonia, diesel fuel, and polychlorinated biphenyls
Answer: B
Explanation and Reference:
EPA has set National Ambient Air Quality Standards for six principal pollutants, which are called "criteria" pollutants. They are Carbon Monoxide; Lead; Nitrogen Dioxide; Ozone; Particle Pollution; and Sulfur Dioxide. C&D 8th, p. 1234, Table 29-1
63
63. What product category falls under the regulatory authority of the U.S. Food and Drug Administration, but does NOT require premarket approval?
A. veterinary drugs
B. medical devices
C. human drugs
D. cosmetics
Answer: D
Explanation and Reference:
With the exception of color additives, cosmetics are exempted from premarket approval under the law. C&D 8th, p. 1416-1417.
64
64. What is the primary source of lead exposure for adults in the general population?
A. outdoor lead dust
B. lead-based paint
C. industrial emissions
D. food and water
Answer: D
Explanation and Reference:
While lead-based paint and contaminated dust are primary sources for children, food and water represent primary sources for adults. C&D 8th, p. 993-994.
65
65. An arc welder works in a small enclosed area welding galvanized metal all day. She goes home at 5:00 PM feeling fine but at bedtime starts to experience breathing difficulty. Upon examination in the emergency ward the attending physician diagnoses pulmon
A. chlorine
B. hydrogen sulfide
C. zinc oxide
D. nitrogen dioxide
Answer: C
Explanation and Reference:
Zinc fume fever or metal fume fever is particularly common among welders who work with galvanized steel. C&D 8th, p. 1008-1009
66
66. Although a person registers a blood alcohol level of 0.3 percent, he/she can walk a straight line and talk coherently. This is an example of what phenomenon?
A. cross-dependence
B. dispositional tolerance
C. abstinence syndrome
D. tissue tolerance
Answer: D
Explanation and Reference:
Upregulation of metabolic enzymes by frequent use of alcohol can affect the symptoms of exposure to alcohol. C&D 8th, p. 1069-1072
67
67. The nuclear power station accident in Chernobyl in 1986 resulted in increased thyroid cancer in exposed children. What agent is stockpiled for quick distribution in the event of a similar accident elsewhere?
A. TSH
B. potassium iodide
C. iodine-131
D. EDTA
Answer: B
Explanation and Reference:
Potassium iodide blocks the thyroid from absorbing radioactive iodine. C&D 8th, p. 1125
68
68. How would you characterize a "class 2A" human carcinogen as defined by the International Agency for Research on Cancer?
A. having limited human, but sufficient animal, evidence that it causes cancer
B. having limited human evidence or inadequate human, but sufficient animal, evidence that it causes cancer
C. having sufficient human evidence that it causes cancer
D. demonstrating inadequate or absent human and animal evidence that it causes cancer
Answer: A
Explanation and Reference:
IARC has listed approximately 70 compounds in category 2A. Hayes 6th, pp. 56-57 Table 2.6.
69
69. Analgesics such as ibuprofen, aspirin, and cyclooxygenase-2 inhibitors exhibit both acute and chronic renal toxicity. Analgesic nephropathy is often irreversible and is best characterized by necrotic lesions where?
A. the distal tubule
B. the renal papilla
C. the proximal tubule
D. the glomerulus
Answer: B
Explanation and Reference:
Nephrotic injury from many analgesics occur in the renal papilla, initially occurring in the medullary interstitial cells, followed by degeneration of cells in the medullary capillaries, loops of Henle, and collecting ducts. C&D 8th, p. 683
70
70. A farmer came into the emergency department complaining of stomach pains, tingling in his extremities and hair loss. He indicated that he had been using a chemical found in his barn to kill rats. Exposure to what rodenticide is the likely cause of these
A. fluoroacetic acid
B. thallium
C. Coumadin©
D. nicotine
Answer: B
Explanation and Reference:
Exposure to Coumadin would be associated with hemorrhage. The main targets for fluoroacetic acid (Compound 1080) are the CNS and the heart. Nicotine primarily acts on the CNS, and depending on dose, can be either a stimulant or a depressant. Thallium als
71
71. What pathological changes characterize chronic exposure to cadmium?
A. renal tubular dysfunction resulting in proteinuria
B. accumulation of cadmium-metallothionein complexes in liver mitochondria
C. hypotension secondary to calcium channel blockade
D. renal carcinoma originating in the glomeruli
Answer: A
Explanation and Reference:
Cadmium accumulation in the renal cortex causes tubular dysfunction resulting in proteinuria. C&D 8th, p. 991
72
72. Why does beryllium, a metal used in ceramic plants, the nuclear industry, and space vehicles, cause a severe adverse reaction in some people?
A. because it initiates a cell-mediated immune response
B. because it can displace calcium in the bones, making them brittle and easy to break
C. because it binds to metallothionein and accumulates in the kidney
D. because it reacts with sunlight to cause skin lesions
Answer: A
Explanation and Reference:
Beryllium exposure may cause a delayed-type hypersensitivity reaction in skin which is a cell- mediated immune response. Skin testing and the lymphocyte proliferation test have been used to identify berylium-sensitive individuals. C&D 8th, p. 989
73
73. What is the first line treatment of choice for organophosphate toxicity?
A. ethanol
B. vitamin K1
C. atropine
D. methylene blue
Answer: C
Explanation and Reference:
Atropine represents the cornerstone of the treatment for OP poisoning as it is a muscarinic receptor antagonist and prevents the action of accumulating acetylcholine on these receptors. C&D 8th, p. 942-943
74
74. Carbon monoxide toxicity has been attributed to a reversible interaction with which critical protein?
A. cytochrome P450
B. methemoglobin
C. transferrin
D. hemoglobin
Answer: D
Explanation and Reference:
The toxic effects of CO have been attributed to the formation of carboxyhemoglobin, which decreases the oxygen carrying capacity of the blood. C&D 8th, p. 832
75
75. Why is it difficult to predict the toxicity of engineered nanomaterials based on their chemical composition?
A. They are very unstable and their properties change drastically over short periods of time .
B. Handling them requires specific techniques beyond most testing laboratories capabilities.
C. They are inert substances in vitro and require specialized in vivo assays to assess.
D. They have different physical and chemical properties than micro-scale products of the same chemical composition.
Answer: D
Explanation and Reference:
Nanoparticles are known to react differently than larger particles of similar composition. C&D 8th, p. 1193-1197, Table 28-2
76
76. In the treatment of patients with cyanide poisoning, upon what critical step does the therapeutic efficacy of sodium nitrite depend?
A. an increase in oxidative phosphorylation
B. the formation of methemoglobin
C. an increase in coronary arterial blood flow
D. relaxation of the nonvascular smooth muscle
Answer: B
Explanation and Reference:
Cyanide has a greater affinity for heme moieties with Fe3+, thus cyanide will bind to methemoglobin more readily than hemoglobin. Consequently methemoglobin will compete with Cytochrome c oxidase for binding to cyanide. Hayes 6th, p. 22
77
77. Consuming the leaves of the purple foxglove plant would be expected to cause what pathological change(s)?
A. cardiac arrhythmias
B. renal toxicity
C. hepatic toxicity
D. CNS stimulation
Answer: A
Explanation and Reference:
The main toxin in foxglove, digitalis, is known as a cardiac glycoside, as it can cause cardiac arrhythmias. C&D 8th, p. 1137
78
78. What source of contamination poses the greatest food-borne risk world-wide?
A. food additives
B. mycotoxins and food-borne molds
C. chemical contaminants/adulterants
D. microbial contamination
Answer: D
Explanation and Reference:
Of all the sources of food contamination and adulteration, microbial contamination is by far the most prevalent cause of toxicological concern worldwide. C&D 8th, p. 1342.
79
79. What is the primary physiochemical property used in quantitative structure-activity relationship (QSAR) models to predict bioconcentration in fish?
A. molecular weight
B. log octanol/water partition coefficient
C. affinity to organic carbon (Koc)
D. water solubility
Answer: B
Explanation and Reference:
Log octanol/water partition coefficient measures affinity to lipds, which has been correlated to a reduction in metabolism and excretion and substances tend to be stored in lipid rich tissues. C&D 8th, p. 1277
80
80. Phthalates are often classified as endocrine disruptors or hormonally-active agents (HAAs). What is a potential sauce if high-level exposure to phthalates in children?
A. mouthing of plastic toys
B. consumption of fruits and vegetables treated with pesticides
C. exposure to air emissions from coal-fired power plants
D. incidental ingestion of urban soils while playing outdoors
Answer: A
Explanation and Reference:
Phthalates are a class of plasticizers and until recently were used in pacifiers and other plastics children have been exposed to. C&D 8th, p. 922
81
81. What specific information do biomarkers in ecotoxicology studies provide?
A. community structure and function
B. organismal exposure and effect
C. ecosystem stability and resilience
D. trophic relationships and energetics
Answer: B
Explanation and Reference:
Biomarker in ecotoxicity is largely relegated to understanding whether exposure has occured and if levels are sufficient to induce adverse effects in individuals.C&D 8th, p. 1293-1294
82
82. What route of exposure is the one of primary concern in the majority of work environments?
A. dermal
B. oral
C. ocular
D. respiratory
Answer: D
Explanation and Reference:
The respiratory system is most often the primary pathway of exposure to substances in occupational settings. C&D 8th p 1394
