AP Environmental Science Unit 8 Practice Test: Aquatic & Terrestrial Pollution

The correct answer is (D). Consumption of perchlorates is known to affect the thyroid gland by inhibiting the absorption of iodide and reducing thyroid hormone production. This lack of hormone inhibits the optimal function of the human body. The other hazardous materials mentioned here are deleterious to the human body, but are not known to specifically impede the function of the thyroid gland.

The correct answer is (B). The Safe Drinking Water Act sets the national standards for safe drinking water. The Clean Water Act is legislation that supports the “protection and propagation of fish, shellfish, and wildlife and recreation in and on the water” by maintaining and when necessary, restoring the chemical, physical, and biological properties of surface waters. The Resource Conservation and Recovery Act (RCRA) is the principal federal law in the United States governing the disposal of solid waste and hazardous waste. The Federal Water Pollution Control Act was the first major piece of legislation affecting water quality. The Water Quality Act protects and ensures the quality of surface and ground waters.

The correct answer is (C). Recall that a leachate is a liquid that absorbs and carries particles of a material through which it passes. In a modern sanitary landfill, the leachate collection system’s function is to remove water and contaminants and transport them to a wastewater treatment plant.

The correct answer is (B). Dispersants act by reducing the surface tension that stops oil and water from mixing. Smaller droplets of oil are then formed, which helps promote rapid dilution of the oil by water movements. In theory, this allows the oil to be more rapidly degraded by bacteria (bioremediation) and prevents it from accumulating on beaches and in marshes. However, studies have indicated that chemical dispersants are toxic to marine life. A dispersant called Corexit was used in unprecedented quantities during the 2010 Deepwater Horizon oil spill in the Gulf of Mexico. This was highly controversial and the long-term environmental effects of this are still being examined.

The correct answer is (C). Passed in 1980, Superfund was designed to clean up sites that were contaminated with hazardous waste. It is also known as CERCLA.

The correct answer is (A). Cathode ray tube (CRT) televisions and computer monitors may contain toxic metals such as lead, mercury, and cadmium.

The correct answer is (A). Enacted in 1976, the RCRA set federal standards for the treatment, storage and disposal of hazardous waste in the United States.

The correct answer is (A). Biomagnification occurs across food chain levels when a producer or primary consumer ingests a toxic substance and is in turn consumed by a predator. At each level of the food chain, the concentration of the toxic substance increases. Bioaccumulation and Bioconcentration occur within an organism. Biodilution is the opposite of biomagnification.

The correct answer is (C). Polychlorinated biphenyls, or PCBs, are a group of industrial compounds that have caused many environmental problems. Until 1979 they were manufactured in plastics and insulating electrical transformers. Even though they are no longer manufactured, they are still present in the environment because of their long-term persistence.

Dichlorodiphenyltrichloroethane, or DDT, is an insecticide designed to target nerve transmissions in pests. It was found that DDT moved up the aquatic food chain up to eagles, causing eagles to produce thin shells that broke before the embryo developed.

Perchlorates are used for rocket fuel and are easily leached from contaminated soil into the groundwater where they can persist for many years. Perchlorates can affect the thyroid gland and reduce important hormone production.

Polybrominated diphenyl (PBDEs) ethers are flame retardants added to a variety of items including construction materials, furniture, and clothing. Since the 1990s, scientists have been detecting them in fish, aquatic birds, and human breast milk. Exposure to some types of PBDEs can lead to brain damage. Several states, including Washington and California, have banned the manufacture of several types of PBDEs. Pharmaceuticals are not components of plastics and insulating electrical transformers.

The correct answer is (D). Electric power plants use water for cooling to cool the steam converted from water back to water again. This is done by bringing in cold water from river, lakes or oceans to cool the steam. The water is then returned back to nature at a significantly warmer temperature. Hydroelectric energy production does not create thermal pollution. Geothermal energy production uses the energy from the earth to heat homes. Cultural eutrophication is the process of nutrients polluting surface water and the cascade of events that follow. Heat islands are urban areas that are up to 10°F warmer that surrounding areas.

The correct answer is (A). The pretreatment stage removes large debris as well as grit. This is followed by primary treatment, which uses settlement tanks to separate organic solid matter. Secondary treatment then removes dissolved and suspended biological matter with the help of water-borne microorganisms. Tertiary treatment is the final treatment and typically includes a disinfection process. Autolysis is not a stage of sewage treatment.

The correct answer is (C). Endocrine disruptors are chemicals that interfere with the normal functioning of hormones in an animal’s body. Neurotoxins are chemicals that disrupt the nervous systems of animals. Carcinogens are chemicals that cause cancer. Teratogens are chemicals that interfere with the normal development of embryos or fetuses. Allergens are chemicals that cause allergic reactions.

The correct answer is (D). Solid waste includes materials discarded from homes and industries that do not pose a toxic hazard to organisms.

The correct answer is (A). Adding nitrates would accelerate the process of eutrophication. Dredging the lake removes built-up waste that causes eutrophication. Insects that consume nuisance algae allow sunlight to reach deeper into the lake. Pumping oxygen into the deeper layers of the lake reverses the impact of eutrophication.

The correct answer is (D). Agricultural runoff gathers from all regional agricultural fields and builds up in local waterways. The other examples are all easily identifiable sources you can “point” to.

The correct answer is (B). The US imports crops from many other countries that still use DDT as a pesticide. DDT is not water-soluble, is not naturally occurring, and is not the result of newer pesticides breaking down.

The correct answer is (A). Fat-soluble substances tend to gradually build up in a bodies fat reserves. Because they are not water-soluble, these substances are not typically removed by the kidneys or the liver.

The correct answer is (C). LD50 stands for Lethal Dose 50%. LD50 and ED50 (effective dose 50%) are used to predict safe concentrations for humans. Typically the LD50 is divided by 1000 to get the value that may be safe for human exposure.