Question

The accepted toxic dose of mercury is \(300 \mu \mathrm{g} /\) day. Dental offices sometimes contain as much as \(180 \mu \mathrm{g}\) of mercury per cubic meter of air. If a nurse working in the office ingests \(2 \times 10^{4} \mathrm{~L}\) of air per day, is he or she at risk for mercury poisoning?

Short answer

Yes, the nurse is at risk for mercury poisoning.

Step-by-step solution

- Identify Known Values

The toxic dose of mercury is given as \(300 \, \mu g/day\). The concentration of mercury in the air in the dental office is \(180 \, \mu g/m^3\). The volume of air the nurse ingests per day is \(2 \times 10^{4} \, L/day\).

- Convert Volume of Air to Cubic Meters

Convert the volume of air ingested from liters to cubic meters using the conversion factor \(1 \, m^3 = 1000 \, L\). This gives \(2 \times 10^4 \, L/day \div 1000 = 20 \, m^3/day\).

- Calculate Total Ingested Mercury Per Day

Multiply the volume of air ingested per day by the concentration of mercury to find the total mercury intake: \(20 \, m^3/day \, \times \, 180 \, \mu g/m^3 = 3600 \, \mu g/day\).

- Compare to Toxic Dose

Compare the calculated mercury intake to the toxic dose. The intake, \(3600 \, \mu g/day\), is significantly higher than the toxic dose of \(300 \, \mu g/day\).

Key concepts

toxic dose of mercury

Mercury is a heavy metal that can be very harmful to your health if ingested in large amounts. The toxic dose of mercury is the amount that, if exceeded, can cause poisoning. For this example, the toxic dose of mercury is given as 300 micrograms per day \(\mu g/day\). This means that if you ingest more than this amount daily, you could be at risk of mercury poisoning.
Important points to remember:

• Mercury poisoning can affect the nervous system, digestive system, and even the immune system.
• Symptoms of mercury poisoning can include muscle weakness, poor coordination, numbness, and several other health issues.
• Keeping mercury intake below the 300 \(\mu g/day\) threshold is crucial to avoid health risks.

Understanding the toxic dose helps us assess whether a certain situation, like working in a dental office with a lot of mercury vapor, is safe.

mercury concentration in air

Mercury concentration in the air refers to the amount of mercury particles present in a certain volume of air. In this problem, the air in a dental office can contain as much as 180 micrograms of mercury per cubic meter \(\mu g/m^3\). This is quite high, especially when compared to standard air quality guidelines for mercury.
Why is it important to know the concentration of mercury in air?

• The higher the concentration, the more mercury you can potentially ingest.
• For workers in environments with high mercury concentration, regular monitoring and safety measures are important.
• Understanding this concept helps us determine exposure levels and necessary precautions.

Knowing the mercury concentration ensures that workplaces are safe and within legal health limits.

air volume conversion

Converting air volume between units is a common practice in science to make calculations easier. In this exercise, we convert the volume of air a nurse ingests from liters to cubic meters.
Here's how to convert:

• Given: Volume of air ingested is 20,000 liters per day (\(2 \times 10^4 \text{ L/day}\)).
• Conversion factor: 1 cubic meter (\(1 \text{ m}^3\)) equals 1,000 liters.

To convert:
\[2 \times 10^4 \text{ L/day} \div 1000 = 20 \text{ m}^3/day\]
This conversion ensures we use consistent units for further calculations, such as finding the total mercury intake.

ingested mercury calculation

The final step is to calculate how much mercury the nurse ingests from breathing the contaminated air. This involves multiplying the volume of air ingested by the concentration of mercury in that air.
Given:

• The nurse ingests 20 cubic meters of air per day (\(20 \text{ m}^3/day\)).
• The mercury concentration is 180 micrograms per cubic meter (\(180 \mu g/m^3\)).

Calculate the total ingested mercury:
\[20 \text{ m}^3/day \times 180 \mu g/m^3 = 3600 \mu g/day\]
This result shows the nurse ingests 3600 micrograms of mercury daily, which is significantly higher than the toxic dose of 300 micrograms per day. This indicates a high risk of mercury poisoning.
Remember:

• This high level of mercury intake highlights the need for proper ventilation and protective measures in work environments with high mercury levels.