If an industry discharges 10,000 gallons a day with a copper concentration of 5 mg/L, what is the concentration in pounds per day?

If an industry discharges 10,000 gallons a day with a copper concentration of 5 mg/L, what is the concentration in pounds per day?

• A. 0.25 lb/day
• B. 0.42 lb/day
• C. 0.50 lb/day
• D. 0.75 lb/day

Answer: (B)

To determine the concentration in pounds per day, we start with the given values: a discharge of 10,000 gallons per day and a copper concentration of 5 mg/L. First, we need to convert the volume of water from gallons to liters because the concentration is given in mg/L. There are approximately 3.785 liters in a gallon, so: 10,000 gallons/day * 3.785 L/gallon = 37,850 L/day Next, we take the concentration of copper, which is 5 mg/L, and apply it to the total volume of water. This allows us to calculate the total mass of copper in milligrams: 5 mg/L * 37,850 L/day = 189,250 mg/day To convert milligrams to pounds, we use the conversion factor where 1 pound is equal to 453,592 milligrams: 189,250 mg/day ÷ 453,592 mg/lb = 0.4167 lb/day Rounding this to two decimal places yields approximately 0.42 lb/day. Therefore, the correct answer reflects the calculated mass of copper discharged per day in pounds, confirming that the concentration aligns with option B.

To determine the concentration in pounds per day, we start with the given values: a discharge of 10,000 gallons per day and a copper concentration of 5 mg/L.

First, we need to convert the volume of water from gallons to liters because the concentration is given in mg/L. There are approximately 3.785 liters in a gallon, so:

10,000 gallons/day * 3.785 L/gallon = 37,850 L/day

Next, we take the concentration of copper, which is 5 mg/L, and apply it to the total volume of water. This allows us to calculate the total mass of copper in milligrams:

5 mg/L * 37,850 L/day = 189,250 mg/day

To convert milligrams to pounds, we use the conversion factor where 1 pound is equal to 453,592 milligrams:

189,250 mg/day ÷ 453,592 mg/lb = 0.4167 lb/day

Rounding this to two decimal places yields approximately 0.42 lb/day. Therefore, the correct answer reflects the calculated mass of copper discharged per day in pounds, confirming that the concentration aligns with option B.