Unit 3: Water Chemistry & Contaminants Exam Review

1. Unit 3: Water Chemistry & Contaminants Exam Review

3. Exam Review • Organic vs. Inorganic • Organic contains carbon • Percentage of Freshwater • 2.5% of the planet’s water is fresh water • Common elements in organic molecules • Carbon, hydrogen, and oxygen • Hydrophilic • “water loving” • A solute that will dissolve in water • Hydrophobic • “water fearing” • A solute that will not dissolve or mix in water

4. Exam Review • Alkalinity • The ability of a solution (body of water) to buffer against a change in pH, specifically an increase in acidity

5. Exam Review • Carbonate system Carbonic Acid Carbonate CO2(g) Bicarbonate CO2(aq) H2CO3 HCO3– CO32- H+ H+ H2O Ca2+ CaCO3(s)limestone 4 6 8 10 pH

6. Exam Review • Diatoms – • Most common brown algae • Euglena – • Has both animal & plant features, protist, prominent flagella • Paramecium – • Protist covered in cilia • Hydra – • Animal with a tremendous regenerative ability • Amoeba – • Protist that uses phagocytosis to consume other organisms

7. Exam Review • Microbes & biomass • Microbes account for ~ 50% of all biomass on Earth • They are ubiquitous on the surface and deep within the earth • Species richness • the total number (biodiversity) of different species present • Species abundance • the total number of individuals in a sample

8. Exam Review

9. Exam Review • Guilds • Metabolically related microbial populations • Microbial species richness and abundance is a function of the kinds and amounts of nutrients available in a given habitat • Niche • Job/role an organism plays within its environment • Prime Niche • For each organism there exists at least one niche in which that organism is most successful (thrive)

10. Exam Review • Biofilms • Assemblages of bacterial cells adhered to a surface and enclosed in an adhesive matrix excreted by the cells • The matrix is typically a mixture of polysaccharides • Formation & purpose of biofilms • Self-defense • Biofilms resist physical forces that sweep away unattached cells, phagocytosis by immune system cells, and penetration of toxins (e.g., antibiotics) • Allows cells to remain in a favorable niche • Allows bacterial cells to live in close association with one another

11. Exam Review

12. Exam Review • Biochemical Oxygen Demand (BOD) • The microbial oxygen-consuming capacity of a body of water • Prochlorococcus • > 40% of the biomass of marine phototrophs • ~50% of the net primary production • Most of the primary productivity in the open oceans

13. Exam Review • Psychrophilic/tolerant • cold-loving • Can survive the cold, but does not thrive • Barophilic/tolerant • pressure-loving • Can survive the pressure, but does not thrive

14. Exam Review • Change in ratios of archaea/bacteria through aquatic life zones

15. Exam Review • Hydrothermal vent microbes • Chemolithotrophic prokaryotes that utilize reduced inorganic materials emitting from the vents form endosymbiotic relationships with vent invertebrates such as vent tube worms • Chemolithotrophic • Organisms that use inorganic matter (chemicals) to create their own food (chemo-auto-trophs)

16. Nitrogen Cycle

17. Exam Review Simplified Nitrogen Cycle Nitrogen Fixation Nitrosofying Bacteria Nitrifying Bacteria Denitrifying Bacteria NH4+ Ammonium NO2– Nitrite N2 Nitrogen NO3– Nitrate Nitrification Denitrification Aerobic Anaerobic

18. Exam Review • Bioremediation • Refers to the cleanup of oil, toxic chemicals, or other pollutants from the environment by microorganisms • Often a cost-effective and practical method for pollutant cleanup • Xenobiotics – • chemically synthesized compounds that have never occurred in nature (pesticides, herbicides, plastics). • Phytoremediation: • Degrading a pollutant using sunlight/UV light • Downsides: only the surface is effected, and its slow

19. Exam Review • Chemical Cocktails – • A mixture of chemicals that, when consumed independently cause no/little harm, but when put together can have damaging, and rarely studied effects.

20. Exam Review • Oxygen depleting contaminants • organic carbon + O2 + bacteria → CO2 + H2O + more bacteria • if oxygen is depleted in natural water, most aquatic life will die (Ex. fish kills) • C:N:P molar ratio ideal for bacterial growth • 100:10:1 • Phosphorous is often the limiting factor in bacterial/algal growth

21. Exam Review • Cyanotoxins - • Produced by algal blooms (blue-green algae) that is toxic to humans and most animals. Under the right conditions, these blooms can reduce DO to the point that nearby organisms will asphyxiate. • Effects of Total Dissolved Salts • Measured as Total Dissolved Solids (TDS) • High salt concentration can damage crops, reduce soil’s permeability • In drinking water, recommended thatTDS < 500 mg/L

22. Exam Review • Thermal pollution • Primarily cooling water from power plants and other industries • ↑Temperature, ↓Dissolved oxygen • ↑Temperature, ↑bacterial growth, ↓DO

23. Exam Review • Sources of Nitrates in water • Septic systems (on-site waste water disposal systems) • Runoff and leaching from agricultural land, residential lawns and gardens (nitrogenous fertilizers) • Animal wastes (ranging from confined animal feeding operations to horses in the pasture) • Methemoglobinemia • In humans, nitrate (NO3-) is reduced to nitrite (NO2-) • Nitrite binds with hemoglobin to form methemoglobin, a substance that cannot bind and transport oxygen • Methemoglobinemia effects children & preganacies

24. Exam Review • Chlorine byproducts (DBPs) • Chlorine is a common disinfectant in drinking water • Excellent oxidizing disinfectant • Inactivates most bacteria, viruses and certain protozoa • Most DBPs are regulated based on their suspected human carcinogenicity (known carcinogenicity to laboratory animals) • Epidemiologic evidence that chlorine DBPs, primarily trihalomethanes, are related to adverse reproductive outcomes

25. Exam Review • Trihalomethanes– • The most common DBP, highly volatile • Viruses – • Smallest known microbial contaminant • Consist of a DNA/RNA filled capsid & enzymes • Bacteria – • Simple internal organization, simple life cycle, flagellated • Creates spores when stressed

26. Exam Review • Protozoa – • Complex, single-celled organisms • Complex life cycle • Forms cysts/oocysts when stressed • Helminths – • Parasitic worms ranging in size from microscopic to over one meter in length • Very complex life cycles • Eggs serve as the environmentally resistant form for helminths

27. Exam Review • E. coli – • bacteria • Small number of US outbreaks & low number of cases. 3 to 5% fatal • Fomite – • An inanimate object that houses pathogens • Salmonella – • Bacteria • 12 to 30% mortality, low # of outbreaks, slightly higher # of cases

28. Exam Review • Vibrio cholera – • Bacteria • Low rate of infection within the US, but responsible for a many-decade pandemic in Asia, Africa, and Latin America • Giardia – • Protist • Larger number of US outbreaks higher rate of infection than common infectious bacteria

29. Exam Review • Cryptosporidium– • Protist • Small number of US outbreaks yielding an extremely high rate of infection (421,473 cases) • 1-3% US, 5% Asia, 10% Africa infected at any given time • Toxoplasmosis – • Oocysts are extremely resistant to common disinfectants • Cats are the definitive host for Toxo • Close to 25% of US population is infected • Life threatening to immuno-compromised individuals • Congenital infected children

30. Exam Review • Platyhelminthes – • “flat” worms • Common examples: tape worms, flukes • Ashelminthes – • “round” worms • Hookworms, ascaris, trichinella, etc • Lung Fluke – • Hookworms – • Extensive lifecycle: burrowing into skin, travelling through blood, lungs, stomach, then small intestine • Shed 10,000 to 20,000 eggs per day • Can consume 0.2mL of blood per adult per day

31. Exam Review • Trichinella– • “Biblical worm” • Most commonly found in swine muscle tissue & our first example of nature/parasites/illnesses changing/shaping human culture • Causes painful & aching muscles in infected humans • Ascaris– • Large (25-45 cm) & most common infectious worm • Common where sanitation is poor & human feces is used as fertilizer