Environmental chapter 5
Describe how pollution from agriculture enters aquatic ecosystems.
72% of water pollution in rivers is attributed to agriculture. Fertilizer runoff causes enrichment because animal and plant residues produce high BODs, high suspended solids, as well as enrichment. Pesticides are widespread in U.S. rivers, streams, and ground water.
What is the main water pollution issue in developing countries?
A lack of disease-free drinking water
Oil Pollution Act (1990)
ALL oil tankers entering U.S. waters MUST be double hulled by 2015
Explain the water pollution issues in other countries.
According to the World Health Organization (WHO) ~1.4 billion people lack access to save drinking water and ~2.9 billion people do not have access to adequate sanitation systems. MOST in rural areas in developing nations. At least 250 million cases of water related illnesses each year with 5 million or more resulting in death (1.8 million from diarrheal illnesses alone). Municipal water pollution is a greater problem in developing countries because they lack water treatment facilities. Sewage is dumped directly into rivers or coastal harbors.
What is biological oxygen demand?
Biological oxygen demand is the amount of oxygen microorganisms need to decompose biological wastes into carbon dioxide, water, and minerals. It is expressed as mg of O2/L of water for a number of days at a given temperature. A large amount of sewage means a high B.O.D. which leads to a decrease in dissolved oxygen which allows anaerobic microorganisms producing compounds that decreases water quality.
.Describe the effects of sediment pollution on the environment.
Clay, silt, sand, and gravel, can be suspended and carried in water. Sediments settle out as a river flows into a lake or ocean and over time new land can form. Sediments aren't always pollutants, they can be important in regenerating soils to agricultural areas and providing nutrients to wetlands. Sediment pollution occurs when an excessive amount of soil particles eventually settle out and accumulate on the bottom of the body of water. This comes from erosion. It decrease light penetration, covers aquatic organisms, brings insoluble toxic pollutants into waterways. Sediment particles suspended in the water causes the water to become turbid (cloudy). This turbidity causes a decrease in light penetration which decreases photosynthesis, which decreases the organisms feeding on the primary producers. Sediments can form layer over coral reefs or shell fish or can clog the fills and feeding structures of aquatic organisms. The sediment can transport toxins and disease causing organisms.
Describe the formation of the Dead Zone in the Gulf of Mexico. Define dead zone.
Dead zone-a section of ocean or sea in which the oxygen has been depleted to the point that most animals and bacteria cannot survive; often caused by runoff of chemical fertilizers or plant and animal wastes. The dead zone in the Gulf of Mexico is a result of fertilizer runoff from the Midwest entering the Mississippi River and eventually entering the Gulf. This causes a dead zone to form from the sea floor through the water column to within a few meters of the surface. Floods, droughts, and temperature changes affect the size and shape. It occurs between March and April and lasting through September, with the worst months being June through August. The dead zone is getting larger and cannot support life larger than bacteria due to the low oxygen (hypoxia). In 2001 the EPA called for a reduction of nitrogen entering the Mississippi by 30% by 2015 and added phosphorous in 2004.
What are the issues with plastic pollution
Do not breakdown easily. Floating plastics aren't the most serious though animals can eat or get trapped in them. Raw plastic resins are the most dangerous. The pellets are 0.1-0.5 cm and are found on most beaches. They act like sponges-absorbing other pollutants that are highly toxic like PCBs or DDT.
Marine Protection, Research, and Sanctuaries Act
EPA could control intentional dumping of materials into the ocean and authorize any related research.
Define and describe eutrophication.
Eutrophication is an enrichment problem. Lakes, streams, and estuaries with minimal nutrient loads are called oligotrophic. These lakes have clear water and support small populations of aquatic organisms. Eutrophication is the enrichment of a lake, estuary, or slow-flowing stream by inorganic plant and algal nutrients like phosphorous. Bodies of water that are enriched are called eutrophic. This leads to an increase in photosynthetic productivity. The water is cloudy due to the high amount of algae and cyanobacteria.
Describe the sources of industrial pollution in aquatic ecosystems.
Food-processing industries: produce organic wastes that are quickly decomposed and produce a high BOD. Pulp and paper mills: high BOD and toxic compounds and sludge; now using less chlorine and other toxins. Many industries treat their wastewater before releasing it.
Define and describe disease causing organisms.
Infectious organisms that cause disease that come from the wastes of infected individuals. Wastewater usually contains bacteria, viruses, protozoa, parasitic worms, or other infectious agents that cause human or animal diseases. Ex: Cryptosporidium outbreak in Milwaukee area in 1993 lead to 370,000 people developing diarrhea and a small number of people with weakened immune systems died.
List and describe the inorganic water pollutants. Explain the effects of each
Inorganic compounds contain elements other than carbon. These compounds remain in a body of water for a long period of time. They come from industry, mines, irrigation runoff, oil drilling, urban runoff from storm sewers.
What are the sources of ground water pollutants?
Municipal sanitary landfills, underground storage tanks, backyards, golf courses, and intensively cultivated agricultural lands. Petroleum storage tanks at gas stations (expensive to clean up)
What are the concerns regarding ground water pollution
Nitrates contaminating shallow groundwater is a concern in rural areas. When it gets into the body, it is converted to nitrates which decreases the body's ability to transport oxygen. Recent concern as it was once thought that the soil and rock water seeped through removed the pollutants. The extent to natural pollution removal varies by area. Most ground water in the U.S. are of good quality and do not violate standards. Clean up is expensive and can take years, if at all possible.
Describe the differences between organisms found in eutrophic and oligotrophic lakes. Describe the process by which oligotrophic lakes become eutrophic.
Oligotrophic: pike, sturgeon, and white fish in cold, deep water where there is more oxygen Eutrophic: cold, deep water has less dissolved oxygen because the decaying algae settle there so the fishes are replaced by catfish and carp. Oligotrophic lakes become eutrophic over long periods of time. Bodies of water are enriched slowly and become shallower because of the large number dead organisms that settle in the sediments over long periods of time. Plants like water lilies and cattails take root in the sediment and form a marsh.
Describe the effects of organic compounds on aquatic ecosystems
Organic compounds are compounds that contain carbon. Human produced chemicals like pharmaceuticals, pesticides, solvents, industrial chemicals, and plastics come from landfills, runoff, or direct dumping into waterways. Volatile organic compounds (VOCs) have been found in domestic wells.
Define artificial eutrophication
Over nourishment of an aquatic ecosystem by nutrients such as nitrates and phosphates, due to human activities such as agricultural discharge from sewage treatment plants
What are the most common pollutants affecting ground water
Pesticides, fertilizers, and organic compounds
Differentiate between point-source and nonpoint source pollution. Provide examples of each
Point-source pollution: water pollution that can be traced to a specific region. This is easy to control through legislation. Examples include: sewer pipes from factories or sewage treatment facilities. Nonpoint source pollution: pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry. This is polluted runoff. It is difficult to regulate through legislation. Examples include agricultural runoff, mining wastes, and construction sediments.
Describe the sources of municipal water pollution
Sewage and runoff from storm sewers. Urban runoff is more polluted than sewage because it contains salt from roadways, untreated garbage, animal wastes, construction sediment, and traffic emissions. It can also contain asbestos, chlorides, copper, lead, motor oil, and organic wastes. Combined sewer systems: human and industrial wastes are mixed with urban runoff from storm sewers before flowing into the sewage treatment plant. This leads to combined sewer overflow when it rains too much. Separate sewer systems: one sewer for human and industrial waste and one for urban runoff. This is expensive and requires streets to be dug up.
Explain the Gulf Oil Spill (Deepwater Horizon).
The spill occurred between April 20 and July 15, 2010. The Deepwater Horizon caught fire and exploded due to a methane gas build up. It leaked ~4.9 million barrels of oil (largest in U.S. history), this is equivalent to ~210,000 gallons/day. The spill threatened the Chandeleur Islands, shrimp, and tourist industry. The clean-up involved: capping the well, using chemical dispersants, using booms to contain the oil, burning it off the water, mechanically removing it from beaches, and cleaning animals that were affected by the spill and housing them until they were healthy. As of January 2011 tar balls were still being found on beaches.
Explain the Exxon Valdez Oil Spill.
The spill occurred in 1989 in Prince William Sound Alaska Spilling 37,000 tons of oil. The ship hit Bligh Reef. The clean-up involved using chemicals as well as mechanical methods. The spill killed 400,000 sea birds, 1,000 of 5,000 sea otters, and 200 of 3,000 harbor seals.
Describe the effects of nitrogen and phosphorous on aquatic ecosystems.
They simulate the growth of plants. These nutrients are essential in low concentrations, but are harmful in high concentrations. Nitrate and phosphates come from human and animal wastes, plant residues, atmospheric deposition, and fertilizer runoff. Nutrients lead to an increase in the algae and plants causing a disruption between producers and consumers. This can lead to enrichment and bad odors. High BOD occurs when excessive amounts of algae die and decompose.
How are diseases monitored for? Describe the safe levels for fecal coliform for drinking water, swimming water, and general recreation.
Typically E. coli is analyzed because it isn't found in the environment unless it is contaminated. Fecal coliform test-a water quality test for the presence of fecal coliform bacteria, which indicates a chance that pathogenic organisms may be present as well. Safe drinking: no more than 1 coliform bacterium/100 mL of water Safe swimming: no more than 200 coliform bacterium/100 mL of water Safe general recreation: no more than 2,000 coliform bacterium/100 mL
Clean Water Act (CWA)
affects the quality of rivers, lakes. Aquifers, estuaries, and coastal waters in the U.S. There are two goals: eliminate discharge of pollutants into U.S. waterways and to attain water quality levels that make those waterways safe for fishing and swimming
Define water pollution
any physical or chemical change in water that adversely affects the health of organisms
MARPOL 73/78:
main international convention covering pollution by ships.
Describe the issues it causes with oxygen demand.
microorganisms decompose sewage and other organic molecules into carbon dioxide, water, and other organic compounds through cellular respiration. This requires the presence of oxygen but water can only hold a limited amount of dissolved oxygen so the more sewage pollution, the more organisms decomposing it, the less oxygen available to other organisms.
Marine Mammal Protection Act
prohibits any actions that could harm endangered marine mammals
Describe radioactive and thermal pollution
radioactive substances: contain atoms that emit radiation. They get into water from mining and processing of radioactive minerals. Thermal pollution: occurs when heated water produced during industrial processes enters the waterways. -Effects: Chemical: decomposition of wastes and other reactions occur faster, lowering the oxygen Warm water doesn't dissolve oxygen as well as cool water which affects aquatic life Can change behaviors, reproductive cycles, digestion rates, respiration rates, fish need to eat more food to maintain weight have shorter life spans, and smaller populations.
Safe Drinking Water Act:
set uniform federal standards for drinking water to guarantee public water supplies throughout the U.S.
What is sewage?
wastewater from drains or sewers (from toilets, washing machines, and showers); includes human wastes, soaps, and detergents
