Heavy metals (Bergfelt)--toxic gases Flashcards
What are possible sources of ammonia toxicity?
- Decomposing manure in confined animal houses
- Burning nylon/plastics
- Anhydrous ammonia used in agricultural fertilizer
- Transported, applied under high pressure
- Broken hoses/valves
- Formation of a vapor cloud
T/F: Ammonia has a characteristic sharp odor and is heavier than air
TRUE
Anhydrous gas is lighter than air but in the presence of moisture forms vapors that are heavier
Is ammonia soluble in water?
Yes
What does ammonia react with in mucous membranes?
Readily reacts with hydroxyl ions in moist mm to form ammonium hydroxide, which is irritant and caustic
Where are high concentrations of ammonia most frequently found?
Animal houses–may reach 50ppm during normal operations
Which animals are more susceptible to ammonia toxicity?
Livestock (swine, poultry)
What level of ammonia can cause acute death?
Exposure to 5000ppm
What is ammonia converted to on mucous membranes?
A strong irritant (ammonium hydroxide)
How is ammonia absorbed/distributed?
By inhalation and is distributed to tissue cells
Ammonia toxicity increases susceptibility to what?
Respiratory infections due to continuous irritation
At what level will ammonia decrease an animal’s ability to clear bacteria from the lungs?
50-75ppm
At what level will ammonia decrease growth in young animals?
100ppm: decreased growth rate by 32% in swine and additive w/ other causes (ascarid infection)
What does inhalation of large ammonia concentrations cause?
Pulmonary edema and lung congestion due to increased permeability of lung capillaries
T/F: Ammonia toxicosis causes acidosis and compensatory alkalosis
FALSE–it causes alkalosis and compensatory acidosis
T/F: Ammonia toxicosis may inhibit the TCA cycle
TRUE
What might death of ammonia toxicosis be due to?
May be partly due to asphyxia and partly due to electrolyte and cellular metabolic effects
What are the clinical signs associated w/ ammonia toxicosis?
- Red mucous membranes, lacrimation, coughing, sneezing, nasal discharge (serous and mucous), keeping eyes shut
- Decreased growth rate and dec. egg production in birds
- Dyspnea, poss. fluid in lungs due to pulmonary edema
What terminal signs are assoc. w/ ammonia toxicosis?
Cyanosis, CNS stimulation, and clonic convulsions
T/F: Chemical analyses are not routinely made with toxic gases
TRUE
DDx for ammonia toxicosis?
- Diseases that cause respiratory insufficiency
- Inhaled irritants (hydrogen sulfide, nitrogen oxides, sulfur oxides, fumes, dusts, vapors)
- Organophosphates
- Polychlorinated biphenyls
- Cardiac glycosides
Treatment for ammonia toxicosis?
- Removal of the source and animal
- Premises must be kept clean and well-ventilated
- Fresh air is a good treatment for dyspnea
- Soothing ointments applied to the eyes
- Antibiotics may prevent secondary infections
- Diuretics for pulmonary edema
- Treat any secondary infections (pneumonia)
What are some sources of hydrogen sulfide (H2S) toxicosis?
- H2S, NH3, CO2, and methane are liberated from decomposition of urine and feces in underfloor waste pits, deep litter, manure packs, sewage, and other organic matter containing sulfur
- By-product or waste from industrial industry
- May be liberated in coal pits, gas wells, or sulfur springs
- Liquid manure holding pits (swine)
- Also assoc. w/ natural gas and crude oil production, some coal-deposits, by-product of some industrial applications, and burning rubber
Why are liquid manure holding pits (swine) dangerous?
- H2S is retained in the liquid within the pit
- Released when liquid is agitated (to pump)
- Normal H2S levels ~10ppm
- When slurry is agitated may reach 1000ppm
T/F: H2S is the most dangerous sewage gas
TRUE