Case Studies Flashcards
PFAS
per- or polyfluoroalkyl substances
“Forever chemicals”
long life spans and stability = difficult to break down in the environment
PFAS structure
Contain carbon and fluorine bonds = very difficult to break down
- oxidation by ozone, H2O2, and persulfate
- DBPs made, PFAS can break down into other PFAS chemicals and even reform into more dangerous ones
2 main ways to make PFAS
electrochemical fluorination and fluoro telomerization
Sources of PFAS in water and soil
Discharge from industrial facilities
Landfill runoff/leachate
PFAS effects on human health
Hormone disrupting
- immune system problems, cancers
- developmental delays, lower birth weights, learning/behaviour problems in children
Relation of PFAS to the PBs
Novel entities
Aragonite
crystalline form of calcium carbonate
- used by marine organisms to create their shells & and by corals to form their skeletons
- buffering agent
Climate change and Ocean acidification
Ocean = carbon sink (25% of all atmospheric CO2 emissions absorbed)
Radiative forcing decreases ocean’s ability to act as a CO2 sink (Henry’s Law)
“Carbon sequestration”
Conventional Agriculture
Farming methods taht rely on high inputs of machinery, fossil fuels, and synthetic chemicals (fertilizers and pesticides) & use of monocrops
Regenerative Agriculture
Farming approach that uses soil conservation to enhance the environmental, social and economic dimensions of sustainable food production
Cash crops
Crops intended to be sold to generate income (canola, spring wheat and barley)
Pulse crop
plants from the legume family (peas, beans, lentils)
Silage
crops that are generally used as animal feed and cut while green (alfalfa, corn, clover, barley)
Principles of Regenerative Agriculture
- produce highly nutritous food at high yields
- increase soil productivity and health
- protect/increase biodiversity
- carbon capture is important
Microbes role in regenerative agriculture
- matter breakdown and nutrient cycling (nitrogen, phosphorus, potassium, sulfur)
- 80-90% total soil metabolism
- 5% SOC but contribute 50% total SOC
Higher SOC/SOM levels _________ water retention in soil
increase
Regenerative Agriculture techniques
No/Zero-till
Cover crops
Crop rotation
Stubble retention
Chemical application reduction
Multi-species crops
Wastewater
water from homes, businesses, industries, and institutions that drain into sewers
- may be combined with stormwater from rain or melting snow
Major components of wastewater
human and other organic waste, nutrients, pathogens, microorganisms, suspended solids, household and industrial chemicals
Chlorination takes place in what step of wastewater treatment?
Tertiary treatment
What major materials react together to form DBPs?
A disinfectant (Cl) with organic and/or inorganic matter
2 common DBPs in chlorine treated water
THMs and HAAs
(trihalomethanes and haloacetic acids)
THMs are formed when chlorine reacts with ________ groups
alkyl
- ie. chloroform
HAAs form when chlorine reacts with __________ containing organic compounds
carboxylic acid
Clay Illuviation
translocation of clay particles in water from upper soil layers to lower ones
- important for soil formation (Bt-Horizon), development, and quality
Bt Horizon
made of luvisols (layer of dense clay)
- important for agriculture fertility and forms a water basin for plant roots
- site of ion exchange (Ca2+, Mg2+ and K+)
Floods/Droughts impact on soils
Floods = wash away clay particles and nutrients
Droughts = long-term increase in erosion (dry soil), limit clay illuviation and Bt horizon formation, water-holding capacity is reduced, more nutrient runoff
Eutrophication due to Climate Change
increased need for fertilizers due to polarizing weather patterns = increased runoff into water bodies
- N and P lead to algal blooms = suffocate plants and organisms below, decreased DOC
