| OCEANOGRAPHY 320 FINAL EXAMINATION May 16, 2002
2 Why are sugar yields from Hawaiian sugar cane fields irrigated with mill wastewater somewhat less than from fields irrigated with groundwater? 3 Recycling and modification of the production process are two methods that have been used by industries to reduce discharges of pollutants to the environment. Cite one example each of (a) the use of recycling and (b) modification of the production process by the Hawaiian sugar cane industry to reduce the discharge of pollutants to the ocean. 4 In 1967 Dr. G. M. Woodwell and co-workers published a paper in Science magazine in which they reported that the concentrations of DDT residues in the soil of an extensive salt marsh on the south shore of Long Island averaged more than 13 pounds per acre. At the 1972 DDT hearings in Washington, D.C., an effort was made to strike the article as misleading. What was the logic behind the criticism of the Woodwell et al. article? 5 During the second year of a two-year trial, mallard ducks given feed containing DDT actually produced more offspring than control ducks. This fact has been cited by DDT advocates as evidence that "DDT probably causes wild birds . . . to be healthier if they are exposed to moderate doses of it." Even if true, why is this fact irrelevant to the question of whether use of DDT has adversely impacted the reproduction of birds? 6 How were screwworm flies eradicated from the United States? 7 The principal reason that Sri Lanka switched from DDT to malathion in its effort to combat malaria was a) Publication of Rachel Carson's Silent Spring 8 In the United States pesticides are used primarily to control which one of the following types of pests? a) Weeds 9 Why are most of the conventional electric power plants in the United States ill suited for use in district heating/cooling networks? 10 The Davis-Besse, Bay Shore, and Acme power plants are all located in the same general area on the southern shore of Lake Erie. Although Davis-Besse generates more power than the other two plants combined and although there are more organisms in the vicinity of Davis-Besse than either of the other plants, the adverse effects of internal plant kills are much greater at Bay Shore and Acme than at Davis-Besse? How would you account for this fact? 11 A power plant with a once-through cooling system has been having a serious problem with inner plant kills (i.e., organisms being killed as they are drawn through the plant's heat exchangers) and has hired a consultant to recommend modifications to the plant's cooling system to mitigate the problem. The consultant recommends the installation of bubble curtains and a velocity cap on the intake structure. Why is this recommendation unlikely to help the inner kill problem? What would be a more effective way to reduce inner plant kills? 12 For several years the discharges of thermal effluent from the Hawaiian Electric power plant's once-through cooling system at Kahe Point killed shallow water corals in the vicinity of the plant. What corrective action did Hawaiian Electric take to overcome this problem? 13 Assume that you are hired as a consultant to review a study of the impact of a landfill suspected of being a source of toxic metals in an adjacent stream. The study concludes that the landfill is having little or no impact on the stream based on the fact that the concentrations of metals dissolved in the stream water are no different upstream and downstream of the landfill. What flaw is there in this reasoning? What sort of follow-up studies would you suggest to more intelligently address the issue of metal contamination? 14 The State of Hawaii Department of Health recently conducted an exhaustive study of heavy metal concentrations in fish from the Ala Wai Canal, which receives runoff from a large are of Honolulu. Of all the metals tested, only lead was found to be present in fish at concentrations above background levels. The average lead concentration was 3 ppm in whole fish and 0.5 ppm in fish fillets. How would you account for the fact that the lead concentration was so much higher in whole fish than in fish fillets? In the following questions, indicate which metal or metals is (are) described by the statement. More than one answer may be correct. 15 One of the two major uses of this metal in the United States is the production of batteries. a) Mercury 16 Recycling accounts for more than 50% of the use of this metal in the United States. a) Mercury 17 The best-documented effect of pollution by this metal on aquatic organisms has been associated with its consumption by waterfowl. a) Mercury 18 One of the most serious health effects associated with consumption of this metal is softening of the bones. a) Mercury 19 World production of this metal has declined by about 70% in the last 30 years. a) Mercury 20 The residence time of this metal in the human body is 16-33 years. a) Mercury 21 The single most important source of exposure to this metal in the United States was phased out during the 1970s as a result of concerns related to smog. a) Mercury 22 The Mad Hatter in Alice's Adventures in Wonderland suffered from exposure to this metal. a) Mercury 23 Suppose that you are a waiter/waitress in a local seafood restaurant. A pregnant woman and her husband come into the restaurant and are trying to decide what to order. The woman has narrowed her choices to the following: a) tuna Which one of the above would you recommend that she order and why? 24 Two oil supertankers run headfirst into each other in the middle of the Atlantic Ocean because their crews are below deck playing cards and are intoxicated. Several cargo compartments rupture. Large numbers of aquatic birds are in the area. Sea conditions are very rough for two weeks after the spill. If you were in charge of trying to minimize environmental damage during the first two weeks after the spill, which one of the following steps would take? a) Offload the remaining oil from the tanker
a) Apply fertilizer 26 If ingested, which one of the following types of hydrocarbons is considered
to be the most toxic? 27 What is meant by the acronymns SBT and CBT and how have they been used to reduce oil pollution of the ocean? 28 The Exxon Valdez oil spill is generally considered to have had little impact on benthic organisms. How would you account for this fact? 29 How would you account for the fact that sea otters suffered almost twice as much mortality after the Exxon Valdez oil spill than did harbor seals? 30 The Buzzards Bay oil spill near Cape Cod is generally agreed to have killed more marine organisms than the Ixtoc I oil well blowout in the Gulf of Mexico, even though the latter released about 840 times as much oil. How would you account for the greater impact of the Buzzards Bay spill? 31 Water is considered to be neutral if the pH is 7.0, but acid rain is often defined as rainwater with a pH less than 5.6. Why? 32 Why are high-elevation lakes generally more susceptible to acidification than low-elevation lakes? 33 Why is wet stack gas scrubbing much more effective in removing SOx than NOx from stack gases? 34 Why is pretreatment and conversion of coal to a gas or liquid not a practical way to reduce emissions of NOx from electric power plants? 35 The mortality of fish in high-elevation Adirondack lakes has been
attributed to mobilization of which one of the following toxic metals
by acid rain. 36 The freshwater aquifer beneath the island of Oahu could become unfit
for drinking purposes if rates of groundwater withdrawal exceed recharge
rates. Evidence that this was happening would be which one of the following: 37 A person who owns a vacant lot is allowing people to dispose of items
such as old refrigerators, broken-down cars, discarded batteries, etc.,
in his lot. The person has no license to operate a solid-waste disposal
facility. He could be prosecuted under which one of the following pieces
of federal legislation? 38 The Tóxica Basura Company operates a landfill for several decades and then goes bankrupt. Subsequently the aquifer under the landfill is found to be contaminated. Which one of the following pieces of federal legislation could be used to appropriate funds to clean up the contaminated aquifer? a) RCRA 39 Why has the EPA's policy of "pump and treat" been characterized as a waste of taxpayers' money by critics of the agency's approach to restoring contaminated aquifers? 40 What is the most likely explanation for the fact that sea turtles swallow plastic bags? 41 What is the meaning of the term "ghost fishing"? 42 Seasonal anoxia was a serious problem in the central basin of Lake Erie for many years. How would you account for the fact that seasonal anoxia was never a problem in Lake Washington, although phosphorus concentrations in Lake Washington just prior to diversion of sewage discharges from the lake in the 1960s were about four times higher than the phosphorus concentrations in Lake Erie at the peak of eutrophication? 43 The two most serious water quality problems associated with land runoff are a) heavy metals and BOD 44 Why would construction of a sedimentation basin on the Manoa-Palolo drainage canal reduce the overall costs of removing sediment from the Ala Wai Canal, i.e., why not just remove the sediment after it gets into the Ala Wai Canal? 45 The principal mechanisms used to remove nitrogen from wastewater are ammonia stripping and denitrification. Which one of these two methods is more likely to lead to eutrophication problems caused by high concentrations of inorganic nitrogen in rainwater? Explain your reasoning. 46 How would you account for the fact that only about 2% of the wastewater produced in the United States is recycled for irrigation purposes, but 36% of municipal sewage sludge is applied to the land as a soil conditioner? 47 The State of Hawaii Department of Health (DOH) monitors recreational waters to ensure that they are safe for water contact. The principal concern from a public health standpoint is the presence of pathogens derived from human excrement. Why is it that the DOH does not directly determine whether such pathogens are present or absent, but instead monitors for the presence of so-called indicator organisms, which are not themselves pathogens? 48 In country Hambriento Para el Pez, people eat an average of 100 grams of fish and shellfish per day. Water quality criteria in that country specify that for surface waters used as sources of drinking water, the maximum permissible concentration C of a noncarcinogenic toxic substance should be calculated from the expression. C = ADI/(2 + 0.100R) where ADI is the acceptable daily intake of the substance and R is the average biological concentration factor for fish/shellfish taken from the given surface water. The calculation assumes that people drink 2 liters (2 kilograms) of the water and eat 0.100 kilograms (100 grams) of fish and shellfish daily from the same body of water. If the biological concentration factor for toxic substance X is 980 and the ADI is 40 micrograms per day, what is the maximum allowable concentration of X in the water? 49 Correct the grammar and/or spelling in the following sentences: a) What is going on up stream? 50 Correct the grammar and/or spelling in the following sentences: a) People can change old water taps, which does not close tightly |