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88 Cards in this Set
- Front
- Back
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How are pesticides introduced into the aquatic systems? |
-Incidentally in the course of their manufacturing -Through discharge consequent of their usage -Surface runoff from agricultural land -As a side effect of aerial spraying -Accidental or negligent discharge |
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How long have pesticides been around? How long have arsenic pesticides been around? |
Pesticides - more than 2,000 years Arsenic pesticides - 1,000 years |
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Are harmful pesticides taken off the market? |
Often pesticides that are forbidden are not taken from the market in developing poor countries. |
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How many pounds of pesticides are used year in the US? |
1.1 billion and about 20,000 different types. Equals to about 3.5lbs per person person year. |
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Define pesticide |
Any material that is used to kill a pest. |
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Define pest |
Any organism that competes with humans for food, fiber or living space or that detrimentally affects the way of life. |
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What are first generation pesticides? |
They consist of minerals and other substances containing mercury, lead and arsenic. |
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What are second generation pesticides? |
They are modern synthetic types and include: chlorinated compounds, organophosphorous pesticides and carbamates. |
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What are third generation pesticides? |
They are new chemical approaches that use greater knowledge of pests and controls and the potential impact on the environment. They are more specific in their target and have a narrower spectrum of toxicity to other species. |
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What is biomagnification in pesticides? |
The chemical nature of most synthetic pesticides results in their accumulation and retention in nature. Their lack of biodegradability results in long biological and chemical life. Many organisms do not have the mechanisms to break these compounds down. They end up in body fat and body organs like the kidney and liver. |
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What is persistence as it relates to pesticides? |
It is the length of time that a pesticide remains in the environment without being changed or broken down into different substances. |
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What is photolysis? |
The breakdown of a molecular structure by long-wave radiation. |
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What is volatilization? |
When the chemical evaporates, it can occur after biotransformation of the chemical. |
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What is sorption? |
Adsorption and/or absorption onto organic or inorganic molecules. |
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What is biodegradation? |
The first generation pesticides were very persistent and had a broad spectrum. |
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What is DDT? |
One of the insecticides more widely used in the past. It's a persistent chemical that bioaccumulates and is very toxic. It evaporates from water and has low solubility. After it volatilizes with the atomosphere it will degrade to DDE and DDD. DDE is less toxic and aerobically, DDD is more toxic and stable and anaerobically. |
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What is one of the worst problems with pesticide applications? |
Many farmers do not use adequate equipment to protect themselves from the pesticides. |
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What does DDT do? |
It inhibits the enzyme that controls calcium metabolism. This led to thin egg shells that would be crushed during incubation. Ospreys, bald eagles, falcons and pelicans suffered greatly because of this. |
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What is DDT and why was it created? |
It was created during WWII to kill mosquitoes carrying malaria and typhus. It's creator Paul Hermann Muller won the Nobel Prize for it. |
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How does DDE damage the body? |
-Reproduction: because of the calcium metabolism the egg shells get thinner and birds can not reproduce. -It affects the immune system -It affects the nervous system by dissolving the myelin layer that covers the nervous cells -It produces death |
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What does resistance mean? |
Because of genetic diversity, about 5% of any insect or pest population will be resistant to a pesticide at normal application rates. These survivors will then reproduce and pass the genes for the next generations. |
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What is the most pronounced effect of pesticides? |
The central nervous system sees the most impact. Organochlorine pesticides dissolve the fatty tissue membrane surrounding the nerve fiber which effects the transmission. It may also result in hormone reduction or imbalance in reproduction. |
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What is the more important herbicide? |
Herbicides account for 50% of pesticides in the US. One is Agent Orange formed by half and half of dichlorophenoxy and trichlorophenoxy acetic acids. When it is produced is creates a byproduct called dioxins (TCDD) which are highly toxic and carcinogenic. |
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What is atrazine? |
A herbicide proved to produce feminized effects in frogs and other animals. |
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What is nature and composition of oil? |
Compositions and types of hydrocarbons, from aromatic (ring structures) to aliphatic hydrocarbons (chain structures). Oil is of low and high molecular weight hydrocarbons that can be straight or branched chains. |
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How was petroleum originated? |
Deposition of marine phytoplankton into sediments; burial, temperature and pressure produced the chemical reactions to transform it over time. Each oil has it's own chemical fingerprint and it's possible to determine where the spill came from. |
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How is coal formed? |
From the plant material of swamp forest close to the ocean. Plants die, go to the bottom of the sediments and are buried by new sediments and subjected to high pressures and temperatures. The organic matter matures and forms coal. |
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Oil boiling point? |
The boiling point increases with the molecular weight of hydrocarbons. Lighter hydrocarbons like methane are distilled first. |
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What are the two types of water pollution from petroleum? |
-Natural: (15%) Seeps from the soil or sediment that are discharged directly or indirectly to the aquatic system -Anthropogenic (85%) Wastewater discharges, Tanker Operations, Tanker Accidents, Atmospheric fallout, Refinery wastewaters, Offshore oil production |
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Most significant discharge of oil and petroleum? |
On land - They are spilled, leaked, dumped on land. Leaking underground storage tanks account for 56% of the discharge to the aquatic system |
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What are the 8 processes that determine the fate of oil in water? |
Spreading, volatilization, dispersion, emulsification, photo-oxidation and decomposition |
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What is drift? |
The movement of the center of mass of the oil body. It's transported by the fluid movement. |
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What is volatilization mean? |
Certain fractions of oil spills will evaporation based on the volatility. -Degree of spreading (larger surface more evaporation) -Temp (high temps means higher evaporation) -Wind speed (higher speed means higher evaporation) -Sea conditions (more turbulent water means higher evaporation) |
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What is dispersion? |
When oil enters the water columns form small droplets due to the polar nature of water molecules and oil molecules. |
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What is emulsification? |
It's produced by the water in oil mixtures. Water droplets become surrounded and enclosed by a thick covering of oil. A thick, sticky floating mass (mousse) is formed. |
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What is photo-oxidation? |
The reaction of oil with light. The hydrocarbons are converted to alochols, esthers and other compounds that are more soluble in water. |
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What is the difference between dispersion and emulsification? |
Dispersion is oil in water. Emulsification is water in oil. |
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What does decomposition of oil mean? |
Several organisms can decompose biologically the oil to simpler compounds. |
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How much water is needed to break down 1 gallon of oil? |
320,000 gallons of water |
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What affects biological breakdown of oil? |
Temperature, composition of the hydrocarbon, surface to volume ratio, oxygen concentration, and nutrient availability. |
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What is deposition? |
Evaporation, dissolution and oxidation removes the lighter fraction from oil. With time the spilled oil becomes thicker, denser and more sticky and will sink to the bottom. |
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What are short term effects of spill? |
-Smothering of all life it touches -Acute toxicity of some petroleum compounds to organisms -Decrease in reaereation due to covering of the water surface -Reduction of dissolved oxygen due to decomposition reactions |
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What are the long term effects of spill? |
-Oil pollution decreases diversity of species -Destruction of benthic species because of contamination of sediments when it settles at the bottom, subsurface dwellers are asphyxiated -Destabilization of the land-water interface -Damage to human resources, commercial and sport fishing industries |
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What are the ways that water supplies can be contaminated? |
-Chemicals from industrial and agricultural water discharges -Pathogenic organisms of human origin -Excessive silt and other solids can make it unsightly and aesthetically unpleasant -Heavy metal pollution caused by corrosion of the pipes carrying the water |
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What are the types of water treatment? |
Coagulation and flocculation Settling Filtration Disinfection |
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What is coagulation and flocculation? |
Adding alum (aluminum sulfate) to water to cause the clay particles to stick together and sink to the bottom (called flocs). Alum can form aluminum oxides and hydroxides that aide in the process. |
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How are flocs removed from the water at the treatment plant? |
They sink to the bottom of settling tanks and the sludge exits through a mud valve at the bottom into a sewer or drying pond |
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Why are natural spring waters so clear? |
The water filters through soil particles, rock pores and unconsolidated sands. Engineers have applied this to water treatment and call it rapid sand filter |
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What is rapid filtration? |
After the water goes through a settling tank it goes through a filtration tank with gravel, anthracite and sand |
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What is slow sand filtration? |
Filter tank of sand, called slow because it takes longer to get through then rapid filtration. |
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What is filtration and backwashing? |
When water is processed through rapid filtration it gets stored in a clear well when the filtration tank becomes clogged and the flow is hydraulically inverted to forces the sand and gravel to to rub against each other to clean it |
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What is disinfection? |
After filtration, water is disinfected with chlorine to kill the remaining microorganisms in the water - the chlorine oxidizes the organic matter and reduces it to inactive chlorides |
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What is ozonation? |
Ozone is an oxygen molecule with 3 atoms and is formed by passing dry air through a system of high voltage electrodes. Advantage is shorter contact time, but it is unstable and must be produced onsite. |
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How is ultraviolet light used to treat water? |
It uses short wavelength light to kill organisms. Advantage is it requires short contact time and is effective and is easy to operation. Disadvantage is that it doesn't kill Giardia lamblia and cryptosporidium cysts. |
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How are domestic waste waters (sanitary wastes) transported? |
-Into storm sewers which carries both sanitary and stormwater in a combined sewer -Underground pipes to remove wastewater (sanitary sewers) in newer cities |
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What are the discharges into a sanitary sewage system? |
-Domestic wastewater -Industrial discharge -Infiltration |
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What is the composition of domestic sewage? |
Feces, urine and water from sinks, bathtubs and sprinklers |
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What variables are used to assess the amount of organic matter in the sewage? |
-Total organic carbon (TOC) -Biochemical oxygen demand (BOD) -Chemical oxygen demand (COD) |
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What is the most common onsite sewage disposal method? |
Septic tank with a tile drain field |
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What is a septic tank? |
Consists of a concrete box that removes the solids and promotes partial decomposition. The solids eventually fill the tank and the water overflows into a tile drain that promotes seepage of water discharge. |
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How does a conventional on-site septic system work? |
Effluent leaves home through a pipe, enters a septic tank, and travels through a distribution box to a trench absorption system composted of perforated pipe. |
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What does pretreatment mean? |
Screening and removing large objects |
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What is primary treatment? |
Removal of nonhomogenizable solids of the waterwater. Physical rather than biological or chemical processes. |
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What is secondary treatment? |
Removes the demand of oxygen using biological processes |
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What is tertiary treatment? |
Any clean up process with the purpose of removing nutrients like phosphorous and other chemicals including heavy metals. Process includes physical filters, biological ponds or chemical precipitation. |
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What is a comminutor? |
A circular grinder designed to grind the solids coming through the screens to pieces less than 0.3cm |
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What is the most common chemicals used to remove phosphate? |
Lime Ca(OH)2 and alum Al2(SO4)3 |
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How is hazardous waste defined? |
By the degree of ignitability, corrosivity, reactivity and toxicity. |
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Where is more than 80% of hazardous waste? |
Inadequately designed and operated pits, ponds, landfills and incinerators |
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What is chemical stabilization/fixation for hazardous waste? |
Chemicals are mixed with waste sludges, the mixture is pumped onto land and then solidification occurs in days or weeks |
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What is volume reduction for hazardous waste? |
The incineration process |
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What is waste segregation for hazardous waste? |
Wastes are separated by type and chemical characteristics to prevent reactions at disposal sites |
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What is detoxification for hazardous waste? |
Thermal, chemical and biological processes are used to detoxify chemical waste including neutralization, ion exchange, incineration, aerated lagoons and stabilization ponds |
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What is degradation for hazardous waste? |
Chemically degrading the waste to render them safer |
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What is encapsulation for hazardous waste? |
Encapsulate the waste with materials like concrete and asphalts |
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What aspects must be considered when selecting a site for hazardous waste disposal? |
-Hydrology (above ground water levels) -Climatology (outside paths of recurring severe storms) -Geology (located on stable geologic formations) -Ecology (ecological balance - low fauna and flora density) -Alternative land use (low land use) -Environmental health (away from wells) -Transportation (easily accessed) -Socioeconomic factors (citizen acceptance) |
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How are incinerators used in hazardous waste facilities? |
A controlled process that uses combustion to convert a waste to a less bulky, less toxic material. Products include carbon dioxide, water and ash. Advantage - Basic and understood and large expansive land is not required Disadvantage - Costly to operate, ash remains toxic, and fumes are toxic |
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What are the three types of radiation? |
Alpha radiation Beta radiation Gamma radiation |
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What is alpha decay? |
Nucleus has too many protons which cause excessive repulsion forces and in attempt to reduce it a helium nucleus is emitted |
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What is beta decay? |
A neutron is turned into a proton and an electron and the electron is emitted |
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What is gamma decay? |
The nucleus is at too high of energy and falls down to a lower energy level and emits a high energy photon or gamma particle |
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What are the types of radioactive wastes? |
High-level waste (HLW) Uranium mining and mill tailings Transuranic waste Byproduct material Low-level waste (LLW) |
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What is high-level waste? |
Spent nuclear fuel from nuclear reactors and solid/liquid waste from reprocessing spent fuel for defense purposes |
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What is uranium mining and mill tailing waste? |
Pulverized rock and leachate from uranium mining and mill operations |
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What is transuranic waste? |
Radioactive waste that is not HLW but contains more than 100 nancuries per gram - byproduct of defense processing |
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What is byproduct material? |
Any radioactive material, except fissle nuclides that is produced as waste during plutonium production or fabrication |
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What is low-level waste? |
Everything not otherwise classified: Class A - short-lived or extremely low concentration and can be disposed in landfills Class B - high radioactivity and must be stabilized before transporting or disposal Class C - waste that will not decay in 100 years and must be isolated from environment for 300 years or longer |
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What are the long-term disposal options? |
Land disposal, subsea bed disposal, disposal in polar ice sheets, disposal in space and transmutation into shorter-lived or stable waste |
