Atrazine is one of the most widely used agricultural pesticides in the U.S.

Question 1

1. Atrazine is one of the most widely used agricultural pesticides in the U.S. that may be applied before and after planting to control broadleaf and grassy weeds. It is used primarily on corn, sorghum, sugarcane, Christmas trees, and other crops. If the oral LD₅₀ of Atrazine is 2,000 mg/kg, what is the oral lethal dose in ounces of this pesticide for a 190-lb pesticide applicator?

		12
		8
		6
		4

Question 2

1. Using a pulse CO-oximeter, a paramedic establishes that the blood of an on-duty fire fighter contains carboxyhemoglobin at a concentration of 55,000 ppm by volume. What would be the symptoms?

		No symptoms
		Fainting, increased respiration and pulse, coma with intermittent convulsions
		Possible death
		Respiratory failure and death

Question 3

1. Below is a list of chemicals with their oral LD50 in mg/kg (rats). Select the substance that is MOST toxic to rats.

		DDT, 87 mg/kg
		malathion, 885 mg/kg
		carbaryl (sevin), 307 mg/kg
		parathion, 3 mg/kg

Question 4

1. Which health effect is manifested when an injury or disease occurs only after an extensive period of time?

		acute
		chronic
		latent
		no effect

The OSHA regulation at 29 C.F.R. §1910.1000(d) requires employers to determine the cumulative exposure of workers to certain gases over an 8-hr work shift using the following formula:

E = C_aT_a + C_bT_b + …. + C_nT_n

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E is the equivalent exposure for the work shift,

C is the concentration during any period of time in which the concentration remains constant, and

T is the duration of time in hours of the exposure.

The regulation further stipulates that no employee can be further exposed to the gas when the value of E exceeds the 8-hr time-weighted average limit set for the given substance. If a worker is exposed to ammonia concentrations throughout the workday as follows, 125 ppm for 4 hr; 75 ppm for 2 hr; and 25 ppm for 2 hr, determine the equivalent exposure (E):

		28.
		75.
		88.
		90.