QUESTION 1

The effect of a hazardous substance depends on the concentration of the substance that is present in the body's systems. The concentration depends on the stages of toxicokinetics.

(a) What are the four main stages of toxicokinetics?

(b) What are the main objectives of xenobiotic metabolism?

(c) Discuss in details the principles of biotransformation differentiating clearly the phases involved. Illustrate your answer with relevant examples

(d) Briefly discuss the four routes of excretion of hazardous substances from the body?

(e) Why is the concept of ‘half-life' of a substance important?

QUESTION 2

(a) It is common that people are exposed to more than one hazardous substance at a time. The different substances may interact such that one substance may alter the toxicity of one or more of the chemicals present. Discuss the possible interactions that may occur supporting your answer with relevant example

(b) What are the main types of asphyxiants? How do they affect the body?

(c) What do you understand by the term ‘carcinogen'? What are the two mechanisms by which cancer may be caused?

QUESTION 3

(a) There is a range of different techniques that may be used to process and fabricate metal products. This includes grinding, machining and welding (or flame cutting) of metals and metal alloys. Discuss the main hazardous substances encountered during these process operations and their associated health effects

(b) What are the main hazardous substances encountered during painting operations?

QUESTION 4

(a) What is the Globally Harmonised System of Classification and Labelling of Chemicals?

(b) Briefly discuss 3 main types of sources of information about health effects of hazardous substances?

(c) What is the Strategic Approach to International Chemicals Management, SAICM?