Polychlorinated biphenyls are heavy

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Polychlorinated biphenyls are heavy

by patanjali.purpose » Tue Aug 02, 2011 10:50 pm
Polychlorinated biphenyls are heavy, syrupy hydrocarbons that were first synthesized in the 1880s. Because they conduct heat but not electricity and are water-insoluble, fire-resistant, and extremely stable (withstanding temperatures of up to 1600° F), they were found, in the 1930s, to be extremely useful as components in cooling systems and electrical equipment (transformers and capacitors). They were widely used for these purposes and also in the composition of sealants, rubber, paints, plastics, inks, and insecticides.

PCBs were banned in 1979, after researchers linked them to cancer and developmental problems in humans. However, PCBs persist in the environment for extremely long periods. Because of an affinity for fat, they have a marked tendency to accumulate in living organisms; increasing in concentration as they move up the food chain.

At sites where dumping of chemical wastes had occurred, such as warehouses, landfills, and even rivers, uncontrolled or abandoned hazardous wastes still remained. To locate, investigate, and clean up the worst of these sites nationwide, Congress in 1980 established the Superfund Program, administered by the Environmental Protection Agency (EPA). Due to dumping over a period of 35 years by two capacitor manufacturing plants located along the northern part of the Hudson River in New York State, EPA has estimated that 1.1 million pounds of PCBs have accumulated.

Field surveys of the river have found substantial contamination in 40 submerged sediment ?hot spots,5 exposed shoreline remnant deposits, dredge spoils on riverbanks, and estuary sediments. Today, because of PCB contamination, human consumption of fish caught in the most affected areas of the Hudson River is prohibited. But, while fish consumption remains the most potent route of PCB exposure, exposure can also occur through other routes. Eight municipalities currently draw drinking water from the Hudson and another, New York City, draws it during emergencies.

EPA's report recommending dredging indicates that, due to opposition of local residents, neither a landfill nor a thermal treatment facility (for high temperature incineration) can be locally-sighted and the PCBs should therefore be transported to a solid waste landfill outside of the area. The report does not, however, identify a specific location.

Furthermore, air along the river contains elevated concentrations of PCBs, and individuals living along the River show PCB residue in their bodies, paralleling the river's contamination. The EPA has recommended that PCBs be removed from the river bottom by dredging, thus reducing contamination and possibly eventually permitting revitalization of commercial fishing, which once generated $40 million income annually. However, the corporation blamed for the dumping argues that dredging may stir up the PCBs (which they describe as now lying undisturbed in the riverbed), causing the water, air, and riverbanks to become even more contaminated. Some area residents echo these concerns and also argue that dredging will subject them to years of unacceptable noise, disruption, and curtailed recreational activities

1. Based on information provided by the author of the passage, it can be inferred from the passage that PCBs are:
I. heavier than water.
II. toxic to fish.
III. readily biodegradable.
A. I only
B. I and II only
C. I and III only
D. II and III only
E. I, II and III


2. According to the passage, the EPA differs from local residents and the company responsible for PCB contamination in that it affirms that it bases its recommended action on benefit to:
A. commercial fishing interests.
B. residential interests.
C. the environment as a whole.
D. recreational activities.
E. the general American populace

Can we discuss the right answer? OA after some discussion pls

regards,
Patanjali
Source: — Reading Comprehension |

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by smackmartine » Tue Aug 02, 2011 11:08 pm
Time- 6:12
1. IMO A the corporation blamed for the dumping argues that dredging may stir up the PCBs (which they describe as now lying undisturbed in the riverbed).

Other two options are not true.
II - toxic to fish. (Talks about "Today, because of PCB contamination, human consumption of fish caught in the most affected areas of the Hudson River is prohibited. But, while fish consumption remains the most potent route of PCB exposure, exposure can also occur through other routes."---> doesn't say that PCBs are toxic to fish. )

III- biodegradable --> definitely not true because they still exit.

2. IMO A
"The EPA has recommended that PCBs be removed from the river bottom by dredging, thus reducing contamination and possibly eventually permitting revitalization of commercial fishing, which once generated $40 million income annually.
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by patanjali.purpose » Wed Aug 03, 2011 12:04 am
smackmartine wrote:Time- 6:12
1. IMO A the corporation blamed for the dumping argues that dredging may stir up the PCBs (which they describe as now lying undisturbed in the riverbed).

Other two options are not true.
II - toxic to fish. (Talks about "Today, because of PCB contamination, human consumption of fish caught in the most affected areas of the Hudson River is prohibited. But, while fish consumption remains the most potent route of PCB exposure, exposure can also occur through other routes."---> doesn't say that PCBs are toxic to fish. )

III- biodegradable --> definitely not true because they still exit.

2. IMO A
"The EPA has recommended that PCBs be removed from the river bottom by dredging, thus reducing contamination and possibly eventually permitting revitalization of commercial fishing, which once generated $40 million income annually.
Hi,

Thanks. your answers are correct.

Moreover, I amazed at the time you have taken to complete both questions.

I took ~10 mins to complete but both wrong.

Could you pls suggest how you attack RC. Just thinking if I can learn something from you.

regards,
Patanjali

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by smackmartine » Wed Aug 03, 2011 12:28 am
I would say more than the actual reading I have developed a "Love" for RCs now. I just think wao!! I am gonna learn something out of this passage(I slap myself in mind for lying to my self though ;)). Believe me or not all the passage are excerpts from some articles or newspapers and most of these passages are true. For example : This passage - I take fish oils as a dietary supplement for fatty acid that is good for brain functioning. In fact I started taking them 4 months ago.(GMAT is surely the reason :)). While researching about these fish oil pills, I came through the term PCBs which are found in marine fishes, but dint know much about PCBs until I read this passage.

The actual deal : Read for purpose. Details are fluffs.
I will highly recommend you to watch Ron's Manhattan Videos on RCs. Search on Google by "Thursday with Ron".I have learnt a lot from his videos and explanation. Read- Read -Read at least 1 hour daily. This keeps mind up & running. Aristotle RC 99 is also a good source because it gives you a flavor of all possible types of passage you will see on GMAT. In fact the passages are tougher than GMAT RCs, but after you have completed RC 99 you'll feel that actual deal is easier and you will easily cruise on.
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by patanjali.purpose » Wed Aug 03, 2011 2:14 pm
Thanks a lot Smack.

I will make an attempt.

regards,
Patanjali

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by smackmartine » Wed Aug 03, 2011 10:48 pm
I think you are already following RC 99 because today I saw the same passage. Its passage # 23 . Good luck!
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by tanviet » Thu Aug 11, 2011 6:39 am
descriptive passage. very easy to understand the passage but hard to answer the questions because the questions are designed to be hard to realize and take a lot of time to do.

Normally, gmat passage is not like this. passage is hard to understand but questions is easier. Because the purpose of gmat passages is to test comprehension not to test inference from a relevant lines on which the questions like these is based.
IMO A and C.