Environmental Health and Toxicology

Question 1

Basophilic stippling of erythrocytes and increased urine aminolevulinic acid would be indicative of what toxicity?

a. Nitrate.
b. Mercury.
c. Arsenic.
d. Lead.
e. Thallium.

Answer 1

D

Question 2

Which one of the following elements, used as a fungicide, may be toxic to swine and to humans eating pork from swine that have ingested the element?

a. Mercury.
b. Iron.
c. Copper.
d. Molybdenum.
e. Cobalt.

Answer 2

A

Question 3

Legionnaire’s Disease is caused by a:

a. Virus.
b. Rickettsia.
c. Bacteria.
d. Fungus.
e. Preformed toxin.

Answer 3

C

Question 4

Soil types and underlying geological structure recommended by EPA for feedlots are:

a. highly permeable loose soils.
b. shallow soils over fractured bedrock.
c. soils with shallow water tables.
d. heavy soils with low infiltration or seepage rates.
e. sandy loam.

Answer 4

D

Question 5

Contamination of ground water from feedlots is hazardous because of the threat of:

a. nitrate poisoning.
b. algae poisoning.
c. enterotoxemia.
d. spreading tetanus.
e. mercurial poisoning.

Answer 5

A

Question 6

Which of the following has proven to be most effective in the screwworm eradication program in the United States?

a. Treatment of all wounds.
b. Use of sterile female screwworm flies.
c. Spraying all available livestock.
d. Releasing sterile male screwworm flies.
e. Spraying all swamp lands with insecticides.

Answer 6

D

Question 7

When potable water is discharged into any reservoir, air gaps are essential to:

a. provide additional oxygen.
b. prevent backsiphonage.
c. keep an open flow of water.
d. aid in collecting condensates.
e. maintain pressure.

Answer 7

B

Question 8

The primary vector for transmitting St. Louis Encephalitis is:

a. Cochliomyia macellaria.
b. Culicoides vaviipennis.
c. Culex tarsalis.
d. Aedes solicitans.
e. Cochliomyia americana.

Answer 8

C

Question 9

The most frequent carcinogenic effect of high levels of total body irradiation is:

a. thyroid carcinoma.
b. leukemia.
c. bone sarcoma.
d. skin carcinoma.
e. gum carcinoma.

Answer 9

B

Question 10

Idiopathic methemoglobinemia may be caused from water containing high amounts of:

a. mercury.
b. arsenic.
c. lead.
d. nitrate-nitrite.
e. phosphates.

Answer 10

D

Question 11

Triatoma vectors transmit Chagas’ disease by:

a. contaminating food supplies.
b. bite.
c. contamination of eye tissues.
d. fecal contamination of bite.
e. invasion through skin.

Answer 11

D

Question 12

In a mosquito program, fogging will control:

a. adults and larvae.
b. only larvae.
c. eggs and adults and larvae.
d. adults only.
e. eggs only.

Answer 12

D

Question 13

The Michigan problem associated with PBB in cattle, hogs, sheep, and poultry has been attributed to:

a. an infectious agent.
b. contaminated feed.
c. aerosol pollutants.
d. impurities in drinking water.
e. improper waste disposal.

Answer 13

B

Question 14

Seed oats treated with mercurial compounds on a farm:

a. may be mixed with 50% untreated grain and fed.
b. should be destroyed.
c. may be mixed with supplement and fed to hogs.
d. should be colored pink and sold as grain.
e. may be detoxified through the use of approved chemicals.

Answer 14

B

Question 15

The most common antibiotic causing public health problems is:

a. streptomycin.
b. penicillin.
c. virginiamycin.
d. erythromycin.
e. bacitracin.

Answer 15

B

Question 16

In lead poisoning in cattle, the highest concentrations of lead are most likely to be in the:

a. blood.
b. liver.
c. kidney.
d. brain.
e. gingivae.

Answer 16

C

Question 17

In the design and operation of a plant utilizing radiation for the preservation of food, concern must be given to the protection of operators because the:

a. alpha radiation used represents a potential source of skin cancer.
b. intensity of the radiation source used is extremely high.
c. preserving agent, a radioactive powder, must be dusted on the food AND thus constitutes a potential internal hazard.
d. neutron source used makes shielding difficult.
e. food after irradiation is itself radioactive for awhile and must be handled carefully.

Answer 17

B

Question 18

The color of blood observed in nitrate poisoning is:

a. bright red.
b. cherry red.
c. slight brown.
d. chocolate brown.
e. dark-unoxygenated.

Answer 18

D

Question 19

Raw garbage should be boiled for minutes before being fed to swine.

a. 5
b. 10
c. 20
d. 25
e. 30

Answer 19

E

Question 20

The most common source of arsenic toxicity for cattle is:

a. water contamination.
b. herbicides.
c. feed.
d. aerosol.
e. over medication.

Answer 20

B

Question 21

Bracken fern poisoning in the horse is characterized by:

a. motor irritability and severe icterus due to an unknown hepatoxic substance in the plant.
b. photosensitization resulting in the loss of hair and a sun-burned appearance of all unpigmented areas of the body.
c. incoordination due to a thiamine deficiency which is precipitated by an enzyme in the plant.
d. a highly fatal hemorrhagic syndrome with large subcutaneous hematomas, bleeding from the body orifices, and an elevated temperature.
e. a chronic syndrome with severe lameness and loss of the long hair of the mane and tail.

Answer 21

C

Question 22

The successful use of urea in cattle feed requires the consideration of several factors:

a. quality of urea used, amount of carbohydrates present in the supplement, amount of natural protein present in the ration.
b. amount of cobalt and sulfur present in the ration, rate of consumption, quality of the urea used.
c. percentage of urea contained in the total dry ration, percentage contained in the mixed protein supplement.
d. fertility of the soil where the roughage was produced, concentration of other sources of nonprotein nitrogen in the ration, rate of supplementing the feed with urea.
e. quality of the roughage, energy content of the ration, amount of natural protein present, rate of consumption, addition of urea following a preparatory period.

Answer 22

E

Question 23

PCB found in milk samples in dairy herds indicates:

a. a normal milk residue.
b. a need to embargo the milk.
c. a need to slaughter all animals.
d. a need to embargo the milk, determine the source of PCB, and test milk samples for compliance and tolerance levels.
e. Spring when cows go to pasture.

Answer 23

D

Question 24

A public drinking water supply is disinfected effectively if:

a. B.O.D. is absent.
b. coliform organisms have been destroyed.
c. the pH of the water is between 6.8 and 7.4
d. a chlorine demand test is negative.
e. the water is free from color and taste.

Answer 24

B

Question 25

The bacterial action in septic tanks has the effect of:

a. increasing the amount of solids to be handled.
b. improving the appearance of the effluent.
c. disposing of the sewage in a shorter period of time.
d. counteracting anaerobic bacterial action.
e. liquefying and gasifying some of the organic matter.

Answer 25

E

Question 26

The purpose of a trap in the home plumbing is to:

a. ventilate the house drainage system.
b. prevent sewer gas from entering premises.
c. prevent the entry of rodents through the system.
d. eliminate backflow from the lines.
e. trap or hold solids that are too large to enter the system.

Answer 26

B

Question 27

The major reason why a plan for discharging sewage into streams, rivers, lakes or other bodies of natural surface water should NOT be adopted is to:

a. prevent formation of sludge banks.
b. prevent increase of BOD.
c. eliminate offensive odors or gases.
d. prevent the pollution of drinking water supplies.
e. prevent the breeding of mosquitoes and insects.

Answer 27

D

Question 28

The ‘effective half-life’ of a radionuclide in the body is the time required for:

a. the amount of the nuclide to be reduced to half its original value as a result of radioactive decay and natural elimination.
b. 75% of the total of the lifetime absorbed dose from the radionuclide to be yielded to the tissue.
c. the body to eliminate half of the amount of the nuclide originally taken up.
d. the body to eliminate 25% of the amount of the nuclide originally taken up.
e. the radiation from the nuclide to reduce the life span of the person by one-half.

Answer 28

A

Question 29

The reason Strontium-90 is of health concern is that it concentrates in the:

a. reproductive system and produces damage to future generations.
b. bone and has a physical half life of about 30 years.
c. bone marrow and is a high-energy gamma emitter.
d. gastro-intestinal system and has a physical half-life of 27.7 years.
e. muscles and has a physical half-life of about 30 years.

Answer 29

B

Question 30

The clinical syndrome that is most commonly associated with lead poisoning in cattle, especially in calves is:

a. a severe affection of the nervous system.
b. prolonged intestinal colic with blood-flecked stools.
c. prolonged respiratory distress with epistaxis.
d. lachrymation and nasal discharge.
e. hyperkeratosis and dermatitis with extreme emaciation.

Answer 30

A

Question 31

In ruminants, in the therapy of hydrocyanic acid poisoning when speed, method of administration, and potentiation of effects are considered, the choice of antidotes is:

a. methylene blue and sodium tetrathionate.
b. potassium permanganate and sodium nitrite.
c. sodium nitrite and sodium tetrathionate.
d. sodium nitrite and sodium thiosulfate.
e. amyl nitrate and sodium thiosulfate.

Answer 31

D

Question 32

An air pollution control department in a city with a great many electrochemical plants receives numerous complaints from residents concerning the emission of a gas. This gas has a yellow-green color with an irritating and suffocating odor, causes damage to trees and grass in the vicinity of residences, and corrodes brass and aluminum materials on homes. This gas is most likely:

a. hydrogen sulfide.
b. chlorine.
c. ammonia.
d. sulfur dioxide.
e. methane.

Answer 32

B

Question 33

The most harmful air pollutant produced from the complete combustion of oil or coal is:

a. carbon monoxide.
b. sulfur dioxide.
c. carbon dioxide.
d. nitrogen.
e. water.

Answer 33

C

Question 34

If the coliform mpn is 0-50, the water needs:

a. conventional treatment.
b. disinfection only.
c. extensive treatment.
d. no treatment.
e. filtration only.

Answer 34

E

Question 35

From a public health point of view, the greatest danger of defective plumbing is that it is associated with:

a. entrance of insects and rats from the drainage system.
b. the escape of sewer gas and air.
c. sewage leaks.
d. terminal ends.
e. cross connections.

Answer 35

E

Question 36

The main reason that the blood from a slaughter house should NOT be discharged directly into a stream of water is that it:

a. favors the breeding of houseflies.
b. renders the water nonpotable.
c. increases the biochemical oxygen demand (bod).
d. serves as a source if infectious disease agents.
e. makes the water unsafe for irrigation of crops.

Answer 36

C

Question 37

Salt poisoning or water deprivation has a mechanism of action which is NOT well understood; the etiology is well defined, however. Which of the following ions is the etiologic agent?

a. Nitrate.
b. Chloride.
c. Potassium.
d. Sulfate.
e. Sodium.

Answer 37

E

Question 38

The best means available for odor detection is:

a. the infrared odor detection and analysis system.
b. the photoelectric odor intensity measuring machine.
c. an instrument which compares the strength of an odor with that of pure air.
d. the instrument which electrically precipitates the odoriferous material.
e. the human olfactory system.

Answer 38

E

Question 39

When a ship with cargo arrives at port, and an inspection shows it is rat-infested, the best procedure is to:

a. unload the cargo and fumigate the ship.
b. fumigate the ship and cargo at once.
c. fumigate only that part of the cargo polluted by the rats.
d. destroy the cargo and fumigate the ship.
e. eliminate rats by trapping.

Answer 39

B

Question 40

During a period in which the rat population in a plague-affected area is decreased as a result of disease, the immediate danger of the spread of this disease to man is:

a. increased because the infected fleas are dispersed.
b. increased because the rats are the carriers of the bacteria.
c. increased because with decreased rats, there are more virulent organisms.
d. increased because there are more fleas per rat.
e. decreased because the fleas lose their natural animal host.

Answer 40

A

Question 41

Fluorescein dye is used by the sanitarian for the purpose of:

a. control of odors arising from industrial waste.
b. rating of water softness.
c. determination of hydrogen ion concentration in a sample of water.
d. determination of the source of pollution of a water supply.
e. tracing of food contamination.

Answer 41

D

Question 42

The origin of the agent in the transmission of Typhoid Fever is:

a. generally pools of stagnant water.
b. frequently spoiled oysters.
c. usually traced to the use of insanitary privies.
d. always human associated.
e. usually from an infected cow.

Answer 42

D

Question 43

Gamma rays and X-rays, although exhibiting the same ionizing properties, differ in that:

a. gamma rays consist of electromagnetic waves and X-rays consist of blood-type radiation.
b. gamma rays originate within the nucleus of the atom and X-rays originate in the electron shell of the atom.
c. gamma rays are associated only with fissionable materials and X-rays are associated with man-made isotopes.
d. gamma rays are ejected from naturally occurring radionuclides and X-rays are ejected from artificially produced radionuclides.
e. gamma rays are produced by beta radiation and X-rays are produced by protons.

Answer 43

B

Question 44

An example of a viral infection transmitted by an arthropod vector is:

a. Brucellosis.
b. Louping-ill.
c. Foot and Mouth Disease.
d. Shigellosis.
e. Anaplosmis.

Answer 44

B

Question 45

The ionizing radiation used to preserve foods is:

a. cosmic rays.
b. Alpha rays.
c. X-rays.
d. Gamma rays.
e. Beta rays.

Answer 45

D

Question 46

The primary target organ for aflatoxin is the:

a. lung.
b. stomach.
c. liver.
d. spleen.
e. kidney.

Answer 46

C

Question 47

Which one of the following statements regarding nitrate-nitrite toxicity is most accurate?

a. Toxicity is less likely when animals are on a marginal plane of nutrition.
b. Nitrate oxidizes the iron of hemoglobin to the ferric form.
c. Nitrate toxicity is in reality an ammonia intoxication.
d. Nitrate can accumulate in certain plants in amounts toxic to animals.
e. Toxicity is less likely when plants have been shaded than when exposed to sunlight

Answer 47

D

Question 48

In December 1972, the United States Food and Drug Administration issued a regulation prohibiting, with certain restrictions, the importation of live turtles or turtle eggs. The purpose of this regulation was to prevent the spread of:

a. Arizona and E. coli.
b. Salmonella and Arizona.
c. Shigella and Arizona.
d. Hepatitis.
e. Pasteurella and Corynebacterium.

Answer 48

B

Question 49

Silo fillers disease is associated with toxic levels of:

a. NH.
b. CO.
c. H2.
d. CH.
e. NO2.

Answer 49

E

Question 50

Farmers Lung Disease is a result of exposure to dust containing:

a. virus.
b. rickettsia.
c. bacteria.
d. fungi.
e. particulate matter.

Answer 50

D

Question 51

Which of the following gases that may occur in livestock confinement is lighter than air?

a. NH3.
b. CO2.
c. H2S.
d. SO2.
e. NO2.

Answer 51

A

Question 52

Which one of the following statements concerning aflatoxins is NOT correct?

a. Aflatoxins are potent carcinogens and liver toxins and constitute a potential threat to human as well as animal health.
b. Aflatoxin B1 and B2 are converted to M1 and M2 toxins in milk.
c. There is a direct correlation between aflatoxins levels in feed and the resulting aflatoxin levels in milk.
d. Aflatoxins will be found in milk for several weeks after the toxin is eliminated from the diet.
e. Removing cracked kernels, “fines”, weed seeds, storage below 14% moisture, and regular aeration significantly lower or prevent aflatoxin buildup in stored grain.

Answer 52

D

Question 53

Which of the following plants causes rapid death in livestock due to a cardiac depressant alkaloid?

a. Taxus spp (Yew).
b. Brassica napus (Rape).
c. Melilotus spp (sweet clover).
d. Solanum spp (Nightshades).
e. Xanthium spp (cocklebur).

Answer 53

A

Question 54

One of the following terms best describes the disease state which results from exposure to a poison or toxicant?

a. Toxicology.
b. Toxicity.
c. Toxicosis.
d. LD50.
e. Minimum toxic dose.

Answer 54

C

Question 55

The amount of a toxin which can be ingested without deaths, illness, or physiopathologic alterations occurring in any of the animals fed the toxicant for a stated period of time is referred to as:

a. toxicity.
b. no-effect level.
c. toxic high dose.
d. toxic low dose.
e. lethal dose.

Answer 55

B

Question 56

One hundred grams per ton of a drug equals how many parts per million (ppm)?

a. 1.10
b. 11.0
c. 110.0
d. 1100
e. 11000

Answer 56

C

Question 57

Clinical signs of organophosphorus and carbamate poisoning are those of:

a. blockage of impulses at the neuromuscular junction.
b. blockage of the sympathetic nervous system.
c. blockage of the parasympathetic nervous system.
d. over stimulation of the sympathetic nervous system.
e. over stimulation of the parasympathetic nervous system.

Answer 57

E

Question 58

Which one of the following is NOT usually associated with chronic fluorosis in livestock?

a. Intermittent lameness.
b. Dry and roughened hair coat.
c. Mottled teeth.
d. Intermittent diarrhea.
e. Exostosis and other bone deformities.

Answer 58

D

Question 59

Which of the following statements is most correct concerning the epidemiology of animal toxicoses?

a. In recent years, the low level contamination of meat, milk, and egg producing animals has become more important for the toxicologist and epidemiologist.
b. Housing and management of livestock and poultry in large confinement units has reduced the problems with environmental toxicants and residues.
c. Toxicosis, deaths, and overt illness due to toxicity are usually more difficult to diagnosis than the cause of insidious production losses.
d. Proper housing, nutrition and management do not greatly affect susceptibility of livestock to the effect of chronic or insidious toxins.
e. Most livestock production problems can be solved by proper usage of drugs, chemicals, and vaccines.

Answer 59

A

Question 60

The major goal of a veterinarian in dairy herds with a severe coliform mastitis problem should be.

a. identify pathogenic organisms and do antibiotic sensitivity testing.
b. identify and cull infected cows.
c. treat entire herd with antibiotic infusions in the udder.
d. vaccinate the entire herd with an autogenous bacterin.
e. initiate health management procedures to prevent new infections.

Answer 60

E

Question 61

Which one of the following statements is most correct regarding Brucellosis?

a. Calves born to infected cows are usually infected and will develop a titer by two months of age.
b. Brucellosis is a true zoonosis and control in man is directly related to the prevalence in animals.
c. Artificial insemination helps control Brucellosis spread in a herd since the herd bull plays a major role in the spread of Brucellosis.
d. Eradication of the disease in an infected herd is best accomplished by vaccination with strain 19 Brucella abortus vaccine.
e. The infected cow sheds the brucella organism in large numbers throughout her lifetime.

Answer 61

B

Question 62

Polioencephalomalazia of cattle, sheep, and goats is associated with which one of the following?

a. Lead poisoning.
b. Salt poisoning or water deprivation.
c. Thiamine deficiency or destruction.
d. Haemophilus somnus infection.
e. Viral infection.

Answer 62

C

Question 63

Which of the following would you expect to be highest in calcium on a dry matter basis?

a. Corn grain.
b. Alfalfa hay.
c. Fescue hay.
d. Corn silage.
e. Soybean meal.

Answer 63

B

Question 64

Which one of the following has the greatest energy density on a dry matter basis?

a. Corn grain.
b. Alfalfa hay.
c. Corn silage.
d. Cottonseed hulls.
e. Wheat straw.

Answer 64

A

Question 65

Which one of the following would you recommend to raise the calcium level of a ration without changing the phosphorus level?

a. Dicalcium phosphate.
b. Steamed bone meal.
c. Sodium acid phosphate.
d. Ground limestone.
e. Dried casein.

Answer 65

D

Question 66

Which one of the following should NOT be recommended as pasture for brood mares?

a. Kentucky bluegrass.
b. Tall fescue.
c. Orchard grass.
d. Bromegrass.
e. Timothy.

Answer 66

B

Question 67

Which of the following is least likely to be an important water contaminant for animals?

a. Cyanide.
b. Nitrate.
c. Chlorinated hydrocarbon pesticides.
d. NaCl.
e. Salmonella spp.

Answer 67

A

Question 68

Generally, use of organophosphate insecticide are preferred over chlorinated hydrocarbons, if efficacy is equal, because:

a. chlorinated hydrocarbons are more likely to cause acute toxicity in man and animals.
b. chlorinated hydrocarbons are generally degraded more rapidly in the environment.
c. organophosphates are degraded more rapidly in the environment and less likely to persist in the food chain.
d. Chlorinated hydrocarbons are not as effective against most insect pests.
e. Antidotes against organophosphates are much more effective.

Answer 68

C