Ecology

Question 1

Define bioaccumulation

Answer 1

Increase in concentration of a toxic chemical in tissues of an organism over time, from contaminated air, water, or food

Question 2

Define biomagnification

Answer 2

Increase in concentration of a toxic chemical in organisms up the trophic levels in the food chain.

Question 3

Describe sewage treatment

Answer 3

Step 1: Preliminary treatment.
Wastewater passed through bar screens to remove large coarse materials
Step 2: Primary treatment:
Water flows through large tanks called primary clarifiiers. Solid suspensions settle to bottom, sludge, light materials flow to top.
Step 3a: Secondary treatment:
Water enters aeration tank, mixed with aerobic bacteria (activated sludge)
Bacteria absorbs and breaks down organig pollutants
Step 3b: Water with bacteria enters final clarifier. Bacteria settles to the bottom. Clear water at the top discharged as final effluen.