Question 1

Groundwater pollution can be reduced by introduction of microorganisms that may break down some of the wastes.

Accepted Answer

Microorganisms can play a vital role in breaking down pollutants in groundwater, thereby reducing pollution. In a process known as bioremediation, microorganisms like bacteria, fungi, and algae are used to degrade toxic chemicals into non-toxic compounds. This can help reduce the burden on traditional remediation methods and prevent further contamination of groundwater. However, it is important to note that the effectiveness of bioremediation varies depending on the type and concentration of pollutants present, as well as the specific microorganisms involved.

Question 2

An oxygen sag curve describes how oxygen in a body of water is consumed by organisms,such as fish.

Accepted Answer

An oxygen sag curve describes the reduction in dissolved oxygen in a body of water primarily due to the decomposition of organic materials by microorganisms, not the consumption of oxygen by fish or other aquatic animals.

Question 3

Mercury is so toxic in all its forms that it is no longer used except as a poison,as in fungicides.

Accepted Answer

Mercury is still used in various applications beyond fungicides, including in dental amalgams for fillings, in certain types of batteries, and in fluorescent lighting, despite its toxicity.

Question 4

If ground water is contaminated with petroleum products,pumping from a level close to the water table may selectively extract much of the pollution.

Accepted Answer

Pumping from a level close to the water table may selectively extract much of the pollution because petroleum products are denser than water and tend to sink towards the bottom of the water table. Therefore, pumping from a level close to the water table can help remove the contaminated groundwater more effectively.

Question 5

Chemical decontamination is principally used for small toxic-waste spills in surface waters.

Accepted Answer

Chemical decontamination is a method used to treat small toxic-waste spills in surface waters by introducing chemicals that can react with and neutralize the toxic substances present in the water. This method is not typically used for large spills or for removing contamination from soil or other surfaces.

Question 6

Groundwater pollution is most often and most effectively treated in situ,which minimizes the risk of spreading the pollution.

Accepted Answer

The answer of Groundwater pollution is most often and most...

Question 7

After the dangers of DDT were recognized,use of toxic organic chemicals in agriculture was virtually eliminated in the United States.

Accepted Answer

While the dangers of DDT did lead to stricter regulations and bans on certain pesticides, the use of toxic organic chemicals in agriculture has not been eliminated in the United States. Many pesticides and herbicides that are still in use have been found to have harmful effects on human health and the environment.

Question 8

Pollution of surface water has nothing to do with pollution of groundwater.

Accepted Answer

Pollution of surface water can lead to contamination of groundwater through seepage or infiltration. Chemicals and pollutants can travel through the soil and affect the quality of the groundwater. Therefore, the pollution of surface water is closely related to the pollution of groundwater.

Question 9

Eutrophication caused by excess runoff of nitrate and phosphate fertilizer from farmland could be avoided by substitution of natural,organic fertilizers,like manures,for synthetic fertilizers.

Accepted Answer

Natural, organic fertilizers like manures also contain nitrates and phosphates, which can contribute to eutrophication if they run off into water bodies in excess, similar to synthetic fertilizers.

Question 10

Heavy metals accumulate in organisms,increasing in their amount up a food chain because they are concentrated in larger and larger organisms.

Accepted Answer

This is known as biomagnification, where the concentration of heavy metals (or other pollutants) increases as it moves up the food chain, resulting in higher levels of accumulation in larger organisms at the top of the chain.

Question 11

Use of settling ponds below farm fields reduces sediment pollution of surface runoff water.

Accepted Answer

Settling ponds are designed to allow sediment to settle out of water before it is discharged. By installing settling ponds below farm fields, the sediment in surface runoff water can be trapped and allowed to settle out, reducing the amount of sediment pollution that enters streams and rivers. This can help protect aquatic habitats and improve water quality.

Question 12

Eutrophication does not occur naturally; it is the result of human activities altering the nutrient balance in water.

Accepted Answer

Eutrophication can occur naturally over centuries as lakes age and are filled with sediments, but it is often accelerated by human activities that increase nutrient runoff into water bodies.

Question 13

Discharge of effluent from a water treatment plant into a stream increases the BOD of the water.

Accepted Answer

Effluent from a water treatment plant contains organic matter and other pollutants that increase the biochemical oxygen demand (BOD) of the receiving water body. This can lead to oxygen depletion and harm aquatic life. Therefore, it is important to properly treat and manage wastewater before discharging it into water bodies.

Question 14

Chemical surveys by aircraft can help identify sites of particularly high probability of toxic-element contamination,such as areas affected by acid mine drainage.

Accepted Answer

Chemical surveys by aircraft are an effective way to identify areas with high levels of toxic element contamination, especially in cases of acid mine drainage.

Quiz 17: Water Pollution