Question 4 of 7: Biological Hazards

Question 4: Biological Hazards (20 marks: 7/7/6)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

(i) Agents and Sources

• Agents: bacteria, viruses, fungi, parasites and their toxins; blood/bodily fluids.
• Sources: infected people/animals; contaminated water, air, food, surfaces; sewage/waste; laboratory cultures; agricultural/organic dusts; healthcare (needles, specimens); HVAC (mould, legionella).

(ii) Broad Examples

• Bloodborne pathogens (hepatitis B/C, HIV); airborne infections (TB, influenza, legionella); zoonoses (rabies, anthrax); moulds/organic dusts (asthma, "farmer's lung"); sewage-related infections; pathogenic lab cultures.

(iii) Classification (Risk / Biosafety Levels)

• Group 1 — unlikely to cause disease (minimal risk).
• Group 2 — can cause disease; treatment/prevention available, limited spread (moderate risk).
• Group 3 — serious disease, may spread; treatment usually available (high individual, limited community risk).
• Group 4 — serious, readily transmitted, no reliable treatment (high individual and community risk).
• In Canada these are the Risk Groups 1–4 of the Public Health Agency of Canada (Human Pathogens and Toxins Act and the Canadian Biosafety Standard); each dictates progressively stricter physical and operational containment, Containment Level CL1 to CL4 (equivalent to BSL-1 to BSL-4 elsewhere).