Could You Pass This Basic GMAT Reading Comprehension Practice Test?

1.

How did the study authors determine the toxicity of the sediment being tested?

A.

By identifying the substances in the sediment.
B.

By comparing the concentration of the contaminants in the sediment to known chemical benchmarks.
C.

By examining sediment-dwelling organisms.
D.

By testing fish, birds and animals in the area of the contamination.
E.

By analyzing the water in the river.

Correct Answer
B. By comparing the concentration of the contaminants in the sediment to known chemical benchmarks.

Explanation
The passage states: "Comparison of measured contaminants to the chemical benchmarks that were established in this report demonstrate that discharges of sewage sludge, municipal wastewaters, and other toxic or bioaccumulative substances have created conditions in the West Branch of the Grand Calumet River that are sufficient to cause or substantially contribute to sediment injury."

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2.

How did the authors conclude that the contamination in the WBGCR could injure humans?

A.

The toxicity of the sewer sludge pulled from the river exceeds safety benchmarks.
B.

Tests on birds living near the river revealed physical defects.
C.

Tests on fish caught in the river showed contamination.
D.

Reduced fish populations, degraded physical habitats, and alterations in the benthic vertebrate community are all evidence of contamination.
E.

Increased physical defects in fish, increased water staganation and increased populations of sediment dwelling organisms are all evidence of contamination.

Correct Answer
D. Reduced fish populations, degraded physical habitats, and alterations in the benthic vertebrate community are all evidence of contamination.

Explanation
According to the passage: "When taken together, these multiple separate lines of evidence provide a weight-of-evidence for concluding that the levels of chemical contaminants and other substances in WBGCR sediments are sufficient to severely injure sediments, sediment-dwelling organisms, wildlife or human health."

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3.

Why couldn't the study authors develop a list of priorities for cleanup in the WBGCR?

A.

They did not have a complete list of the contaminants.
B.

The contaminants combined to make several unknown substances.
C.

Chemical benchmarks were not available for several of the identified substances.
D.

Only a limited area of the WBGCR was contaminated.
E.

The study funding was too limited to permit exhaustive testing of the substance.

Correct Answer
C. Chemical benchmarks were not available for several of the identified substances.

Explanation
According to the passage: "Chemical benchmarks were not available for many other substances, which limited our ability to develop a complete list of priority substances in the WBGCR."

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4.

What does the location of the highest concentrations of contaminated sediment suggest?

A.

The injury to the sediment is greatest in these locations.
B.

The most highly contaminated sediment is close to the source of the contamination.
C.

The turbidity of the water causes contaminants to congregate in certain parts of the river.
D.

People should be warned about fishing in these parts of the river.
E.

The most precise results of the levels of contaminants can be found in these locations.

Correct Answer
B. The most highly contaminated sediment is close to the source of the contamination.

Explanation
Although the passage states that all sediment in the river is contaminated, the areas of State Line Avenue, Sohl Avenue and Molsberger Place are extremely contaminated. Since the authors choose to identify the contamination in the river by road names, it is likely that the source of the contamination can be found along these roads.

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5.

Based upon the list of contaminants, what process is likely to have been responsible for the contamination?

A.

Dumping from ships in the river.
B.

Rainwater runoff from the surface streets.
C.

Airborne pollution that settled in the river.
D.

The contamination occurred naturally.
E.

Untreated manufacturing waste directly dumped into the water.

Correct Answer
E. Untreated manufacturing waste directly dumped into the water.

Explanation
The contaminants are commonly used in manufacturing. The most likely source of contamination was direct dumping of manufacturing wastes from sites along State Line Avenue, Sohl Avenue and Molsberger Place.

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