UNIT 8 Aquatic and Terrestrial Pollution

point source

refers to a single, identifiable source of a pollutant, such as a smokestack or waste discharge pipe

nonpoint sources of pollution

these are diffused and can therefore be difficult to identify, such as pesticide spraying or urban runoff

impacts of pollutants on organisms

have a range of tolerance for various pollutants; have an optimum range for each factor where they can maintain homeostasis; outside of this range, they may experience physiological stress, limited growth, reduced reproduction, and in extreme cases, death

factors affecting coral reefs

include increasing ocean temperature, sediment runoff, and destructive fishing practices

oil spills in marine waters

cause organisms to die from the hydrocarbons

oil that floats on the surface of water

can coat the feathers of birds and fur of marine mammals

oil that sinks to the ocean floor

kills some bottom-dwelling organisms

oil that washes up on the beach

can have economic consequences on the fishing and tourism industries

oceanic dead zones

areas of low oxygen in the world's oceans caused by increased nutrient pollution

oxygen sag curve

a plot of dissolved oxygen levels versus the distance from a source of pollution, usually excess nutrients and biological refuse

heavy metals used for industry

generated by mining and burning of fossil fuels; can reach the groundwater, impacting the drinking water supply

litter

when it reaches aquatic ecosystems, besides being unsightly, it can create intestinal blockage and choking hazards for wildlife and introduce toxic substances to the food chain

increased sediment in waterways

can reduce light infiltration, which can affect primary producers and visual predators; it can also settle, disrupting habitats

mercury in aquatic environments

bacteria in the water convert it to highly toxic methylmercury

endocrine disruptors

chemicals that can interfere with the endocrine system of animals and can lead to birth defects, developmental disorders, and gender imbalances in fish and other species

wetlands

areas where water covers the soil, either part or all of the time

ecological services provided by wetlands

include water purification, flood protection, water filtration, and habitat

threats to wetlands and mangroves

include commercial development, dam construction, overfishing, and pollutants from agriculture and industrial waste

eutrophication

occurs when a body of water is enriched in nutrients

algal blooms

caused by an increase in nutrients in eutrophic aquatic environments

impact of algal blooms

when it dies, microbes digest the algae, along with the oxygen in the water, leading to a decrease in the dissolved oxygen levels in the water; the lack of dissolved oxygen can result in large die-offs of fish and other aquatic organisms

hypoxic waterways

those bodies of water that are low in dissolved oxygen

oligotrophic waterways

have very low amounts of nutrients, stable algae populations, and high dissolved oxygen

anthropogenic causes of eutrophication

include agricultural runoff and wastewater release

thermal pollution

occurs when heat released into the water produces negative effects to the organisms in that ecosystem

water temperature and dissolved oxygen

variations in temperature affect the concentration because warm water does not contain as much oxygen as cold water

persistent organic pollutants (POPs)

chemicals that do not easily break down in the environment because they are synthetic, carbon-based molecules (such as DDT and PCBs); can travel over long distances via wind and water before being redeposited

health impacts of persistent organic pollutants (POPs)

can be toxic to organisms because they are soluble in fat, which allows them to accumulate in organisms' fatty tissues

bioaccumulation

the selective absorption and concentration of elements or compounds by cells in a living organism, most commonly fat-soluble compounds; includes DDT, mercury, and PCBs

biomagnification

the increase in concentration of substances per unit of body tissue that occurs in successively higher trophic levels of a food chain or in a food web

effects of biomagnification in an ecosystem

include eggshell thinning and developmental deformities in top carnivores of the higher trophic levels

effects of biomagnification on humans

harmful effects include issues with the reproductive, nervous, and circulatory systems

solid waste

any discarded material that is not a liquid or gas; generated in domestic, industrial, business, and agricultural sectors

disposal of solid waste

often occurs in landfills; can contaminate groundwater and release harmful gases

electronic waste, or e-waste

composed of discarded electronic devices including televisions, cell phones, and computers

sanitary municipal landfill

consists of a bottom liner (plastic or clay), a storm water collection system, a leachate collection system, a cap, and a methane collection system

factors in landfill decomposition

include the composition of the trash and conditions needed for microbial decomposition of the waste

incineration

solid waste disposal method where waste is burned at high temperatures; this method significantly reduces the volume of material but releases air pollutants

items not accepted in sanitary landfills

may be disposed of illegally, leading to environmental problems

impact of used rubber tires

when left in piles, can become breeding grounds for mosquitoes that can spread disease

ocean dumping

a method used by some countries to dispose of their waste; along with other sources of plastic, this has led to large floating islands of trash in the oceans; wildlife can also become entangled in the waste, as well as ingest it

recycling

a process by which certain solid waste materials are processed and converted into new products; this is one way to reduce the current global demand on minerals, but it is energy-intensive and can be costly

composting

the process of organic matter such as food scraps, paper, and yard waste decomposing; the product of this decomposition can be used as fertilizer; drawbacks include odor and rodents

reducing e-waste

by recycling and reuse

impacts of e-wastes

may contain hazardous chemicals, including heavy metals such as lead and mercury, which can leach from landfills into groundwater if they are not disposed of properly

landfill mitigation strategies

range from burning waste for energy to restoring habitat on former landfills for use as parks

decomposition of organic material in landfills

combustion of gases produced by this process can be used to turn turbines and generate electricity; reduces landfill volume

primary treatment of sewage

the physical removal of large objects, often through the use of screens and grates, followed by the settling of solid waste in the bottom of a tank

secondary treatment of sewage

a biological process in which bacteria break down organic matter into carbon dioxide and inorganic sludge, which settles in the bottom of a tank; the tank is aerated to increase the rate at which the bacteria break down the organic matter

tertiary treatment of sewage

the use of ecological or chemical processes to remove any pollutants left in the water after primary and secondary treatment

method of treating sewage

prior to discharge, the treated water is exposed to one or more disinfectants (usually, chlorine, ozone, or UV light) to kill bacteria

lethal dose 50% (LD50)

the amount of a chemical that kills 50% of the population of a particular species

dose response curve

describes the effect on an organism or mortality rate in a population based on the dose of a particular toxin or drug

cause and effect between pollutants and human health issues

it can be difficult to establish this because humans experience exposure to a variety of chemicals and pollutants

dysentery

caused by untreated sewage in streams and rivers

mesothelioma

a type of cancer caused mainly by exposure to asbestos

impacts of tropospheric ozone

elevated levels can cause respiratory problems and overall lung function

pathogens

adapt to take advantage of new opportunities to infect and spread through human populations; specific ones can occur in many environments regardless of the appearance of sanitary conditions

spread of disease due to climate change

as equatorial-type climate zones spread north and south in to what are currently subtropical and temperate climate zones, pathogens, infectious diseases, and any associated vectors are spreading into these areas where the disease has not previously been known to occur

sanitary waste disposal

poverty-stricken, low-income areas often lack this and have contaminated drinking water supplies, leading to havens and opportunities for the spread of infectious diseases

plague

a disease carried by organisms infected with the plague bacteria; transferred to humans via the bite of an infected organism or through contact with contaminated fluids or tissues

tuberculosis

a bacterial infection that typically attacks the lungs; spread by breathing in the bacteria from the bodily fluids of an infected person

malaria

a parasitic disease caused by bites from infected mosquitoes; most often found in sub-Saharan Africa

West Nile virus

transmitted to humans via bites from infected mosquitoes

severe acute respiratory syndrome (SARS)

a form of pneumonia; transferred by inhaling or touching infected fluids

Middle East respiratory syndrome (MERS)

a viral respiratory illness that is transferred from animals to humans

Zika

a virus caused by bites from infected mosquitoes; can be transmitted through sexual contact

cholera

a bacterial disease that is contracted from infected water