Diffuse Water Pollution (nutrient & pesticides)

Question 1

Release of potential pollutants

Answer 1

range of activities, no individual effect to water

Question 2

Catchment scale

Answer 2

significant impact, water quality problems, wildlife

Question 3

Cancers

Answer 3

agriculture practice, fertilizers & pesticides, urban surface run-off

Question 4

Eutrophication (nutrient enrichment): Effects

Answer 4

issue with N and P, urban source, agricultural fertilizers

Question 5

health impacts

Answer 5

nitrate controls, methaemoglobinaemia (blue baby) - rare, nitrite - stomach cancer “nitrosamines”, NO3- -> NO2- -> NH2

Question 6

Natural succesion

Answer 6

water progress, oligotrophic -> eutrophic

Question 7

Geomorphological (land/water resulting from chemical/physical processes)

Answer 7

in-fill, terrestrial succesion

Question 8

Eutrophication discussion

Answer 8

cultural, accelerated, enhancement of process

Question 9

Symptoms: Nutrient enrichment

Answer 9

not precise

Question 10

Symptoms: Parameters

Answer 10

more subjective, less objective, weather, season, sample collection

Question 11

Limiting Nutrient Concept: Law of minimum

Answer 11

Photosynthethic growth continues until one necessary contributing parameter falls below minimum requirement

Question 12

CO2 + H2O -> CH2O + O2

Answer 12

needs light, trace metals Fe, Mn, Cu, others

Question 13

N or P limiting

Answer 13

add supply - photosynthetic growth occurs

Question 14

N or P addition

Answer 14

alter growth rate, certain plant/algae, balance affected

Question 15

Assessment : N or P limitation? 2 parameters

Answer 15

N - as nitrate, nitrite & ammonium N>20microg/l, P - SRP in H2O >5microg/l. Check during normal growth period

Question 16

N:P ratio measure

Answer 16

Red field ratio 16:1 (molar) or 7:1 (mass). If ratio >16, P limitation (excessive N)

Question 17

N transport to rivers

Answer 17

soluble, mobile, transport from catchment effective, leaching

Question 18

P transport to rivers

Answer 18

low mobility, high partition coefficient (Kd), adsorbed to particles (clay), bonded to Fe

Question 19

Kd = [Mp]/[Md] stick to particles

Answer 19

[Md] -> [Mp]

Question 20

Phosphorus Cycling: Large supply

Answer 20

particulate form, discharge/input in dissolved form (SRP)

Question 21

Phosphorus Cycling: Re-solubilisation

Answer 21

local microenvironment, very rapid re-utilisation

Question 22

Phosphorus Cycling: Redox <200 mV

Answer 22

Release Fe-bound P

Question 23

Phosphorus Cycling: Increase pH

Answer 23

P binding by Al, Fe pH decrease, P binding by Ca pH increases

Question 24

Phosphorus Cycling: Increase temperature

Answer 24

microbe activity increase temp, redox/pH reactions temp decreases

Question 25

Nitrogen Cycling

Answer 25

NO3- NO2- NH4+ goes to N2 (lost from H20 to atm) goes to org-N (denitrfication) goes back (nitrification

Question 26

N recycling

Answer 26

décaying matter 80%

Question 27

Nitrfication

Answer 27

nitrogen fixation, cyanobacteria

Question 28

Denitrification

Answer 28

anaerobic processes, even in small O2 amount due to O2 diffusion rate in sediment

Question 29

Pesticide

Answer 29

Any substance, preparation or organism prepared or used for destroying any pest. E.g. herbicide, fungicide, insecticide

Question 30

Agrochemicals

Answer 30

some inorganic (Cu, H2SO4), thousands of organic compounds

Question 31

Insecticides

Answer 31

organochlorines (OC's): persistent, DDT, dieldrin, lindane

Question 32

Organophosphates (OP's)

Answer 32

highly toxis to humans, parathion, carbomates

Question 33

Concerns

Answer 33

toxicity (specific), persistence, bioaccumulation

Question 34

Controls: Usage

Answer 34

quantity (episodes/products), practice (application rate/ timing), management (drainage control/ soil cultivation)

Question 35

Controls: New developments

Answer 35

High octanol-water partition coefficient Kow >10, low persistence <20 mg/l

Question 36

Controls: Formulation advances

Answer 36

Controlled release, container - sprayer connections

Question 37

Controls: Waste control

Answer 37

tank/container washings, low-drift nozzles, buffer strips

Question 38

Buffer Strips

Answer 38

1-2m wide, trap leached pollutants, bioreactor zones, efficiency?