Unit 8 practice questions

A sanitary landfill with a surface area of 6000m squared receives a yearly rainfall amount of 300 mm. About 20 percent of this precipitation is runoff and does not infiltrate the surface. A leachate collection system, which is installed underneath the landfill, is 90 percent effective collecting and treating any water that infiltrates the surface of the landfill. Assuming consistent yearly rainfall amounts, what is the volume of leachate, in m cubed, that the landfill will be able to treat per year?

1,296 m cubed

The LD50 for arsenic in humans is 13 mg/kg. Which of the following approaches should be used to calculate the number of grams of arsenic it would take to reach the LD50 in a 140-pound person?

140lb x 1kg/2.2lb x 13mg/1kg x 1g/1,000mg

Which of the following best describes the action of an endocrine disruptor

An endocrine disruptor blocks the receptor protein binding site of a hormone so that the cell cannot receive a signal

The risk that many career causing chemicals pose to humans can be estimated using laboratory tests on rats. A significant scientific limitation of such tests is that

Animal models may not reflect human responses

Based on the LD50 values, which of the following best describes the toxicity level of the household substances shown in the table

Antifreeze is more toxic than aspirin

The graph above shows the effect of sewage on biological oxygen demand and dissolved oxygen in a flowing stream. The smallest fish populations will most probably be found at a point

C

An individual is exposed to the water in the stream from which the sample show in the graph was taken. If the individual was exposed to the highest dose of the bacteria, which of the following bacteria would have the lowest probability of causing illness if ingested

C.jejuni

Which of the following is the most likely route for mercury to enter the food web.

Coal-burning emissions->deposition->ocean->plankton->fishes

Alligators in a Florida lake polluted by high levels of dioxins had low testosterone levels and failed to reproduce. scientists came to the conclusion that dioxins were acting as which of the following.

Endocrine disruptors

The dangers of disposing of toxic chemicals underground came to public attention in which of the following locations?

Love Canal, New York

significant increases in water temperate can drastically changed dissolved oxygen levels in a lake. Why does the combined effect of these two environmental changes result in algal blooms

Low dissolved oxygen leads to death for aerobic organisms, like fish, whose decomposition provides an overabundance of nutrients for the algae, resulting in the large blooms

chemical compound that can cause algal blooms and cultural eutrophication in streams

Nitrates

A massive bluegill fish was observed in a lake near a power plant during the winter months. It was determined that the plant was releasing large amounts of hot water into the lake. Which of the following explains what likely caused the death of so many bluegills in the lake?

The influx of warmer water caused an unexpected increase in the metabolic rate of the bluegills, which led to increased physiological stress from limited resource availability

Although the use of the use of DDT was banned in the united states in 1972, a test of the body tissue of an average United States resident today would most likely reveal the presence of DDT because

other countries that export produce to the United States still use DDT

which of the following is the best description of bioaccumulation

the absorption of a substance by an organism at a greater than the rate of elimination