Threats To The FW Envs

Question 1

Pollution

Answer 1

Man made addition to the envs of substances or energy liable to cause a health hazard, harm living systems, damage structure of amenity or interfere with legitimate uses of the envs (hold gate 1979)

Question 2

Organic pollution

Answer 2

Organically enriched effluents
E.g.
Domestic (mainly faecal)
Industrial (brewing or abattoirs)
Rainwater drainage (rubbish dump runoff)
Organic material from farm land (fertiliser)

Question 3

Biological oxygen demand

Answer 3

The amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down the organic material present

(High BOD=low O2 saturation)

Question 4

Dissolved oxygen deficit

Answer 4

Describes the difference between the amount of O2 that should be dissolved in the water vs. the actual amount found

Question 5

Fluvial

Answer 5

Of or found in a river

Question 6

Heavy metals

Answer 6

Any metal that has potential to cause damage at relatively low concentrations to living organisms

Not necessarily a heavy molecular weight

Question 7

Common heavy metals

Answer 7

Hg Mercury
Cd cadmium
As arsenic 
Cr chromium
Tl thallium
Pb lead

Question 8

LC 50

Answer 8

Lethal concentration (over a specific time period)

Question 9

LT 50

Answer 9

Lethal time (at a specific concentration)

Question 10

EC 50

Answer 10

Concentration where a specific sub-lethal ‘effect’ is seen

Question 11

HC 50

Answer 11

Hazardous concentration, the concentration at which the chemical is likely to impact in any way or at any point in the life cycle