Hydrogeology Lecture 2- Groundwater chemistry

Question 1

Eutrophication

Answer 1

Arises when groundwater sources are not managed properly

Question 2

Fresh water

Answer 2

<1000 ppm TDS

Question 3

TDS

Answer 3

Total dissolved solids

Question 4

Amount of salt that can dissolve in water (the dead sea0

Answer 4

342g/kg

Question 5

Sea water salt/kg

Answer 5

~35g/kg

Question 6

Brackish water- 0.5-30ppt

Answer 6

Estuaries, coastal swamps etc.

Question 7

Climate change

Answer 7

changes water levels and water table

Question 8

Capillary Pump

Answer 8

Capillary pumping is a passive liquid actuation method, but its flow rate depends on viscosity and surface energy, making it unreliable when these properties vary.

Question 9

8 major species

Answer 9

Sodium, Potassium, Calcium, Chlorine, Sulphate, Nitrate and Bicarbonate

Question 10

Measurables (other than chemical amounts)

Answer 10

Temperature, pH, Eh (reduction potential), Electrical conductivity

Question 11

Units of electrical conductivity

Answer 11

S/m

Question 12

Hydrochemical provinces

Answer 12

can influence properties of water

Question 13

Piper diagram

Answer 13

Graphical representation of the chemistry of a water sample or samples, based on the electroneutrality of dissolved salts

Question 14

Meq/L

Answer 14

Milliequivalent/L of water

Question 15

Different Stiff diagrams in an area

Answer 15

Indicate water has flowed through different geological medias

Question 16

Sampling rules:

Answer 16

• Bottle rinsed twice with sample water
• Taken upstream just below surface
• No air left in the bottle
• Acidified (keep cations in solution
• Cooled

Question 17

To measure main species

Answer 17

Must acidify sample to <ph2

Question 18

Causes for inaccuracy

Answer 18

• High organic contents leading to extra negative sites for cation attraction
• Large cation concentrations due to mining influences

Question 19

Fractionation

Answer 19

Despite having the same chemical properties there is a difference in uptake between heavier and lighter isotopes, examples include evaporation or different processes of mineral interaction.

Question 20

What impacts the isotropic nature of water

Answer 20

Pressure and temperature