lect 18 part 1

Question 1

what is the outline?

Answer 1

chapter 7: water pollution
-the following information will be left as a reading assignment
-this information will be drawn upon in the follow-up chapter on water treatment in chapter 8 in next lecture

Question 2

what is the markers and biomarkers of water pollutants?

Answer 2

markers of water pollution that show presence of pollution sources
-herbicides indicate agricultural runoff
-fecal coliform bacteria indicate sewage sources
-pharmaceutical metabolites in domestic wastewater

biomarkers of water pollution are organisms that indicate pollution
-may accumulate pollutants that appear in analysis
-may show effects from pollutant exposure
-fish lipid tissue accumulates persistent organic pollutants
-osprey at top of aquatic food web is a good biomarker

Question 3

what are elemental pollutants?

Answer 3

trace elements (harmful at a few parts per million or less) (in table 7.2)
-heavy metals are among the most harmful: cadmium, mercury, lead (most are sulfur seekers)
-metalloid may be significant water pollutants: most important is arsenic but selenium and antimony can also be harmful

Question 4

what is table 7.2 of trace elements in natural waters?

Answer 4

Question 5

what are heavy metals?

Answer 5

cadmium
-highly toxic
-chemically very similar to zinc
-from mining and industrial wastes (especially metal plating)

lead
-widely used and distributed in the past
-plumbing (lead pipe, solder) used to be a major source
-uses (such as in gasoline) have been greatly curtailed

mercury
-highly toxic
-minimata bay incident
-mobilized by bacterial methylation- HgCH3+, Hg(CH3)2

Question 6

what are important metalloids?

Answer 6

arsenic is the most significant
-from coal combustion
-occurs with phosphate minerals
-byproduct of copper, gold, lead refining
-natural occurrence in some groundwaters
-formerly in pesticides: Pb3(AsO4)2, Na3AsO3, Cu3(AsO3)2
-Bangladesh tube well poisonings may have affected millions

Question 7

what happened in the tube wells in bangladesh?

Answer 7

Question 8

what are organically bound metals and metalloids?

Answer 8

have metal (metalloid) bonded to carbon
-alkyl groups such as ethyl in Pb(C2H5)4
-pi electron donors such as ethylene, C2H4
-carbonyls with bound CO

-tetraethyllead, C2H4, in gasoline introduced large quantities of lead into the environment until it was banned
-methylation of mercury by anoxic bacteria mobilized otherwise insoluble inorganic mercury

organotin compounds were widely used as marine biocides in ship and boat paints
-tributyltin chloride commonly used industrial biocide
-endocrine disruption in shellfish and oysters
-uses now being phased out

Question 9

what are some inorganic species?

Answer 9

-cyanide
-ammonia
-free carbon dioxide
-hydrogen sulfide
-nitrite ion
-sulfite ion
-perchlorate ion
-asbestos

Question 10

what is cyanide?

Answer 10

HCN, CN-
-extremely toxic
-industrial uses including metal cleaning, electroplating
-produces by coke ovens
-water pollution and fish kills from mineral processing
-concern for terrorist attacks on water supplies

Question 11

what is ammonia?

Answer 11

generally as NH4+, NH3 at high pH
-added to drinking water for residual disinfection from chlorination

Question 12

what is free carbon dioxide, CO2?

Answer 12

-in water from decay of organic matter and geochemical sources
-makes water corrosive, harmful to aquatic life (due to pH)

Question 13

what is hydrogen sulfide?

Answer 13

H2S
-from industrial sources, decay of organosulfur compounds, geochemical sources
-foul odor, very detrimental to water quality, very toxic
-precipitates heavy metals

Question 14

what is nitrite, sulfite, perchlorate ion?

Answer 14

nitrite ion: NO2, intermediate in reduction of NO3-
very toxic but rare water pollutant

sulfite ion: SO32-
-added to water as O2 scavenger

perchlorate ion: ClO4-
-industrial pollutant in some cases
-recognized as pollutant fairly recently

Question 15

what is asbestos?

Answer 15

-causes cancer when inhaled, but unknown effects in water
-asbestos-like fibers in lake superior, reserve mining

Question 16

what are algal nutrients and eutrophication?

Answer 16

eutrophication means “well nourished”

eutrophication in excess is detrimental causing heavy growth of biomass followed by decay
-consumes O2
-fills shallow water bodies

of numerous algal nutrients (table 7.3) phosphorus is generally limiting and is controlled to control eutrophication

Question 17

what s acidity, alkalinity, and salinity?

Answer 17

acid
-pollutant acids generally strong acids
-one of the most common is acid mine water (H2SO4)
-potential industrial sources of pollution

alkalinity
-generally due to NaHCO3
-from natural geological sources
-can be worsened by irrigation practices

salinity
-salts such as NaCl and Na2SO4
-increased in municipal water systems
-increased by irrigation
-major problem, especially in heavily irrigated areas

Question 18

what is oxygen, oxidants and reductants?

Answer 18

dissolved oxygen, DO, is important in water
-depleted by oxidation of NH4+, Fe2+, SO32- and especially biodegradation of biomass {CH2O}
{CH2O}+O2->CO2+H2O
-biochemical oxygen demand, BOD, refers to amount of oxygen consumed in a volume of water by the biodegradable organic matter in it
-total organic carbon, TOC, is often substituted for BOD

Question 19

what is the bioaccumulation of organic pollutants?

Answer 19

bioconcentration factor (BCF):
BCF=substance conc in organism/conc in water

bioaccumulation factor, BAF, considers a pollutant concentration in food as well as sewage
-contains many pollutant including pathogenic microorganisms, detergents, salts, solids (table 7.4)
-most significant pollutant in sewage is biodegradable organic material ({CH2O}) manifested as biochemical oxygen demand (BOD)
-main objective of wastewater treatment is elimination of BOD

Question 20

what is the graph of the settling of solids from an ocean-floor sewage discharge?

Answer 20

Question 21

what are soaps?

Answer 21

Question 22

what does alkyl polyethoxylate surfactants act as?

Answer 22

Question 23

what are naturally occurring chlorinated and brominated compounds?

Answer 23

produced mostly by marine organisms
-chemical defense agents

detected in arctic samples
-air, fish, seabird eggs, marine mammals, human milk

Question 23

what are microbial toxins in water? (toxins from aquatic bacteria and protozoa)

Answer 23

many such as cylindrospermopsin from cyanobacteria

protozoal dinoflagellata toxins cause many maladies
-gastrointestinal, respiratory, skin disorders in humans
-mass kills of marine mammals
-sometimes fatal paralytic conditions from eating infested shellfish

red tides from explosive growth of dinoflagellates
-turn water red, yellow, olive-green
-kill marine organisms
-make sea spray very irritating to humans

Question 24

what are pesticides in water?

Answer 24

numerous kinds of compounds added to soil and plants -insecticides, herbicides, molluscicides, fungicides, bactericides, slimicides, avicides (birds), piscicides (fish), plant growth regulators, plant defoliants, plant desiccants -insecticides and fungicides most important for human exposure because of application near harvest time -herbicides most important water pollutants because of widespread application directly onto soil

Question 25

what are main chemicals of concern for water pollution?

Answer 25

1. highly biodegradation resistant compounds 2. known or probable carcinogens 3. substances with adverse reproductive or developmental effect 4. neurotoxins including cholinesterase inhibitors 5. acutely toxic substances 6. known groundwater contaminants

Question 26

what are the natural product of insecticides?

Answer 26

-nicotine from tobacco -rotenone from some legume roots pyrethrins -products such as pyrethrum I from chrysanthemum varieties grown in Kenya -used in China 2000 years ago pyrethroids are synthetic analogs of pyrethrins -allethrin -fenvalerate -cypermethrin

Question 27

what is DDT and organochloride insecticides?

Answer 27

organochloride insecticides have been mostly phased out of use because of persistence, harm to birds -endosulfan one of the last to be eliminated

Question 28

what are organophosphate insecticides?

Answer 28

though biodegradable and not generally environmentally harmful, some very toxic effects (acetylcholinesterase inhibitors)

Question 29

what is malation?

Answer 29

malathion is a commonly used organophosphate because mammals can hydrolyze it to non-toxic products

Question 30

what are carbamates?

Answer 30

esters of carbamic acid -biodegradable -acetylcholinesterase inhibitors but not unduly toxic

Question 31

what are fungicides?

Answer 31

Question 32

what are herbicides?

Answer 32

herbicides applied to millions of acres of cropland worldwide to control weeds herbicides commonly occur in surface water and groundwater, especially in intensely cropped areas -especially common are atrazine simazine, and cyanazine used for weed control on corn and soybeans -although widely used to control weeds on crops genetically engineered to resist it, glyphosate has a very strong affinity for soil and rarely gets into water

Question 33

what are the two major bipyridilium herbicides?

Answer 33

Question 34

what is common in corn-growing areas?

Answer 34

triazine herbicides of which atrazine is especially common in water in corn-growing areas

Question 35

what is chlorophenoxy herbicides?

Answer 35

Question 36

what are some other miscellaneous herbicides?

Answer 36

Question 37

what are pollutants from pesticide manufacture?

Answer 37

Question 38

what are polychlorinated biphenyls (PCBs)?

Answer 38

-very high chemical, thermal and biological stability -had many uses, especially in electrical equipment -highly persistent and found in water, sediments, bird and fish tissues -contamination of hudson river sediments from electrical manufacture -now banned

Question 39

what are the emerging water pollutants, pharmaceuticals and household wastes?

Answer 39

emerging water pollutants are relatively new substance coming into use that may get into water and that may have undiscovered pollution effects -nanomaterials composed of very small particles with many developing uses including pharmaceuticals -siloxanes (silicones) used in cosmetic products, water-repellant windshield coatings, detergents -disinfection byproducts (trihalomethanes) -household wastes including surfactants, flame retardants, and plasticizers (bisphenol-A)

Question 40

what are pharmaceuticals and partial degradation products?

Answer 40

Question 41

what are bactericides in water?

Answer 41

used in soaps, shampoos, deodorants, lotions, other -triclosan and its methyl derivative found in swiss waters

Question 42

what are estrogenic substances in wastewater?

Answer 42

disrupt endocrine gland activities regulating metabolism and reproductive functions of organisms aquatic organisms (fish, frogs, alligators) exhibit: -reproductive dysfunction -altered sex characteristic -abnormal serum steroid levels substances include -oral contraceptives -hormonal treatments -cancer treatments nonionic surfactant polyethoxylates are estrogenic substances -much less potent than hormonal substances -but released in enormous quantities

Question 43

what are biorefractory organic pollutants?

Answer 43

-poorly biodegradable organics -also called persistent organic pollutants (POPs) -include prominently chlorinated hydrocarbons -examples are benzene, chloroform, tetrachloroethylene -biorefractory compounds are not well removed by biological treatment and may require physical means such as carbon adsorption

Question 44

what are some radionuclides in the aquatic environment?

Answer 44

Question 45

what are some radionuclides that may be in water?

Answer 45

carbon-14 from cosmic processes radium-226 from uranium -especially significant water pollutant in some areas fission products important in health -strontium-90 that substitutes for calcium in bone -iodine-131 that affects thyroid -cesium-137 that substitutes for sodium radionuclides are characterized by half-lives in which had of the radioisotopes decay radiation from radionuclides damages living organisms by breaking bonds in biological macromolecules -bone marrow may be damaged in acute cases -genetic effects (damage to DNA) is of particular concern