Water Pollution Practice

The use of which of the following to control agricultural insect pests is most likely to have a negative and persistent impact on a given ecosystem?

• Chlorinated hydrocarbon

• Soap

• Plant-derived toxin

• Parasitic wasp

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

• Biomagnification

• Bioaccumulation

• Biohazardous waste

• Biodegradable

Some toxic compounds are ingested and retained in the tissues. These pollutants pose special risks to humans and other organisms high on the food chain because of which process?

• Compound contamination

• Heredity

• Biomagnification

• Bioaccumulation

Which of the following components of a wastewater treatment plants designed to facilitate the decomposition of organic material by aerobic microorganisms?

• Bar screen

• Grit-settling tank

• Activated-sludge tank

• Chlorination tank

The presence of which of the following contaminants would be the strongest reason for judging municipal sewage sludge unfit for use as fertilizer?

• Human poopies

• Phosphates

• Nitrates

• Heavy metals

What is LD-50?

• The concentration of a material in air which, on the basis of laboratory tests, is expected to kill 50% of a group of test animals when administered as a single exposure (usually 1 or 4 hours)

• the least amount of drug that can produce death in a given animal species under controlled conditions

• the amount of an ingested substance that kills 50 percent of a test sample

• the dose that produces a quantal effect (all or nothing) in 50% of the population that takes it

Based on the LD-50 values, which of the following best describes the toxicity level of the household substances shown in the table?

• Table salt is the most dangerous substance.

• Antifreeze is less toxic than aspirin.

• Vinegar is less toxic than antifreeze.

• Table salt is more toxic than vinegar.

Which of the following human health issues is linked to exposure to pollutants released during the incineration of plastic waste?

• Dysentery

• Cancer

• Asthma

• Mesothelioma

Which of the following human health issues is linked to exposure to asbestos?

• Dysentery

• Cancer

• Asthma

• Mesothelioma