Due: 20 August
1. As an occupational safety and health consultant, you are asked to provide toxicological advice on the potential health hazards associated with the following two situations:
a) Workers’ exposure to cadmium fumes in an electroplating workshop.
b) A hairdressing salon has had several customers concerned about the use of paraphenylenediamine (p-phenylenediamine) in hair colourants.
For the above two substances undertake a toxicological assessment of each, and provide a short report, summarising:
• the physical properties and description of the substance
• uptake of the substance, physiological action and metabolism of the substance
• health hazard information and effects on the body
• recommendations and precautions for the use of the substance.
[Your reports should not exceed two pages for each substance. You should summarise and explain the key information clearly and simply. Reference your sources but do not attach this
material.] [40 marks]
2. A large manufacturing company has concerns about the risks posed by some of the chemicals workers are exposed to at the workplace. Preliminary monitoring of workers’ exposure has taken place to assess compliance with the Workplace Exposure Standards before undertaking a more detailed investigation. Your job is to evaluate the following exposures.
Comment on the exposures and whether they are excessive, using the information given to determine the appropriate methods and standards to evaluate against. Give reasons for your answers and note any relevant factors to be taken into account when assessing the risk for each substance.
a) Three 10 minute exposures to 30ppm trichloroethylene over the course of the day.
b) An average exposure concentration of 40ppm isobutyl alcohol over an 8-hour working shift.
c) Workers doing overtime had an average exposure over the 12 hours of 120ppm of methyl alcohol vapour.
d) A peak single exposure of 8ppm hydrogen chloride.
e) An average 8-hour exposure concentration of 10ppm ethylenediamine.
f) A 15-minute exposure to 120ppm toluene.
g) Workers in one area had differing exposures to one substance, methyl acetate, depending on the task, over the 8 hour day. Exposures were as follows: 4 hours at 120ppm, 3½ hours at 180ppm, 15 minutes at 280ppm and 15 minutes at 80ppm.
h) Air in a workroom contained a mixture of solvents: tetrachloroethylene at 40ppm and ethyl acetate at 120ppm. [30 marks]
3. Why are the hazard classifications of a hazardous substance important for managing the risks associated with their use in the workplace? [10 marks]
4. Describe and discuss the roles of the EPA and Worksafe NZ in managing hazardous substances in New Zealand workplaces. [15 marks]
5. A large open plan office has 6 air inlet grills in the ceiling. The average inlet air velocity for each grill is: 1.2 m/s, 1.4 m/s, 1.3 m/s, 0.5 m/s, 0.6 m/s, 1.6 m/s.
The dimensions of each grill are the same: 0.6 x 0.6 m.
The dimensions of the room are: 25m x 15m x 3.8m high.
Determine the number of air changes per hour for the room.
Q1 x t
n = [5 marks]
Total = 100 marks