Water Quality - Physical And Chemical Parameters

Question 1

How do suspended soils affect water? What are inert suspended soils and how do they affect water quality?

Answer 1

Total suspended soil and total dissolved soil both affect turbidity
Inert SS are chemically inactive
they kill by directly reducing growth rate or disease resistance
prevent successful development of eggs or larvae
modify natural movements or migrations
reduce abundance of food organisms
Absorb chemicals and form toxic sediments

Question 2

What effect do varying levels of Inert suspended soils have?

Answer 2

400mg/l = very poor

Question 3

What is turbidity and how does it affect aquatic life?

Answer 3

A measure of relative clarity of water - water becomes warmer as suspended particles absorb heat from sunlight causing oxygen levels to fall (warm water holds less O2 than cooler water). Photosynthesis also decreases due to the lack of light penetrating the water and reducing oxygen further

Question 4

What is water hardness?

Answer 4

Measure of dissolved mineral content of water
Minerals include - calcite, quartz, mica and clays
soft water has low mineral content
hard water has high levels of metal ions mainly Ca from limestone or chalk and Mg from dolomitic limestone

Question 5

What are the factors that contribute to a tolerance to high temperatures of water?

Answer 5

species
stage of development
acclimatisation temperature
dissolved O2
pollution
season

Question 6

What temperatures do salmonid fish live at?

Answer 6

20-21 degrees C maximum in summer

small increases of 5-6 degrees C in autumn/winter adversely affect salmon fry

Question 7

What are the main nutrients that affect water quality and in what levels are they considered high?

Answer 7

Nitrate - >30mg/l

Phosphate - >0.1mg/l

Question 8

How are Nitrates damaging to water quality? and what is the directive that limits the nitrate levels in drinking water?

Answer 8

Eutrophication
Blue baby syndrome
Carcinogens
98/83/EC limits it to 50mg/l

Question 9

How much percentage of scotland is considered NVZs?

Answer 9

14%

Question 10

What are the ranges in which dissolved oxygen affects salmon and trout?

Answer 10

Lethal - 0-4ppm
Stressed - 4-6ppm
Best - >6ppm

Question 11

Name 8 of the physical and chemical parameters that affect water quality

Answer 11

suspended soils
pH
Temperature
Nutrients (nitrates, ammonia, phosphates)
Dissolved O2, BOD
Chlorine
Heavy metals
Pesticides