ENVIRONMENTAL
GEOLOGY - GEOL 406/506 1. Abiotic: not living.
2. Absorption: the penetration of atoms, ions, or molecules into the bulk mass of substrate.
3. Acclimation: time elapsed before onset of detectable biodegradation of a contaminant.
4. Acid: compound with tendency to donate protons (hydrogen ions, H+).
5. Acidic: high concentration (activity) of free protons.
6. Activity: effective concentration. Normally effective concentration is lower than actual concentration due to dynamic interactions occurring in the environment.
7. Adsorption: the retention of atoms, ions, or molecules on the surface of another substance.
8. Advection: the process of transfer of fluids through a geologic formation in response to a pressure gradient.
9. Aeration: the process of bringing air into contact with a liquid.
10. Aerobic: with oxygen.
11. Aliphatic: of or pertaining to a broad category of carbon compounds distinguished by a straight, or branched, open chain arrangement of the constituent carbon atoms. The carbon-carbon bonds may be either saturated (all available sites are involved in bonds) or unsaturated. Alkanes, alkenes, and alkynes are aliphatic hydrocarbons.
12. Anaerobic: without oxygen.
13. Anisotropic: the condition in which hydraulic properties of the subsurface are unequal when measured in all directions.
14. Aquifer: a geologic formation capable of transmitting significant quantities of groundwater under normal hydraulic gradients.
15. Aquitard: a geologic formation that may contain groundwater but cannot transmit it at any significant rate. Aquitards frequently act as confining formations.
16. Aromatic: of or relating to cyclic organic compounds.
17. Attenuation (natural attenuation): the reduction or lessening in amount of a contaminant (usually used to refer to natural processes).
18. Autotrophic: "self-feeding". Refers to organisms that are able to make their own biological molecules form inorganic chemicals and an energy source.
19. Background concentration: naturally occurring concentrations of compounds of concern.
20. Base: compound with tendency to donate free hydroxide ions (OH~).
21. Basic: a high concentration (activity) of hydroxide ions.
22. Bioassay: method for determining compound toxicity.
23. Bioaugmentation (inoculation): addition of acclimated, non-native microbial species to a site.
24. Bioavailability: availability of a compound to degrading species.
25. Biodegradability: the relative ease with which chemical species will degrade will degrade as a result of biological metabolism.
26. Biodegradation: the biologically catalyzed, enzymatic destruction of a compound through reduction in complexity of the molecule. The ideal goal is to completely mineralize the contaminants.
27. Biomass: the amount of living matter in a given area or volume.
28. Bioremediation: using biological degradation to treat waste sites.
29. Biotic: living.
30. Borehole: hole drilled into the subsurface for soil sampling or placement of a well.
31. BTEX: Benzene, Toluene, Ethyl benzene and Xylenes.
32. Bulk density: the ratio of unit mass to unit volume of soil.
33. Capillary fringe: upper level of the water table, which is of variable height.
34. Condensate: the liquid that separates from a vapor during condensation.
35. Cone of depression: area around a pumping well where the water table has been artificially lowered.
36. Confining layer: a geologic formation characterized by low permeability that inhibits the flow of water.
37. Diffusion: the passive movement of a species from an area of higher concentration to one of lower concentration.
38. Dispersion: movement of a substance away from its source.
39. Down gradient: in the direction of decreasing head.
40. Drawdown: lowering the water table via pumping of groundwater.
41. Effluent: out-going (leaving the source).
42. Entrained: particles or vapor transported along with flowing liquid or gas.
43. Equipotential: areas of equal hydraulic head.
44. Equipotential lines: imaginary lines (water table contours) connecting areas of equal hydraulic head. Together they create a potentiometric surface (a map of the subsurface water table).
45. Evaporation: the process whereby liquid enters the gas phase.
46. Ex-situ: environmental medium in a different place than its original location.
47. Extraction well: a well used to remove substances from the subsurface.
48. Field capacity (water holding capacity): the maximum amount of water a soil can retain against gravity. This is the same as plant available water.
49. Flow net: a set of equipotential lines that indicates the direction of groundwater flow.
50. Free product: petroleum or petroleum products in excess of 0.01 ft in thickness floating on surface water or groundwater.
51 Gasoline analytical group: aviation gasoline, gasohol, and motor gasoline or equivalent petroleum products.
52. Gradient: the rate of change in value of a physical or chemical parameter per unit change in position.
53. Groundwater: water in the subsurface within the zone of saturation (or phreatic zone).
54. Grout seal: A mixture of clay and/or cement in water poured between borehole and well casing. Forms a protective seal.
55. Henry's law constant: the ratio of the concentration of a compound in vapor to the concentration in liquid at a given temperature and pressure.
56. Heterogeneous: varying in structure or composition.
57. Heterotrophic: organisms that derive carbon and energy for growth and maintenance from the breakdown of organic matter.
58. Homogenous: uniform in composition or structure.
59. Hydraulic conductivity: a coefficient of proportionality describing the rate at which water can move through a permeable medium.
60. Hydraulic gradient: the change in potentiometric (peizometric) head between two points.
61. Hydraulic head: the potential for a fluid to flow (it is an energy potential and can be pictured as "elevation" of the water table).
62. Hydrocarbon: chemical species composed of carbon and hydrogen only.
63. Hydrophillic: tending to dissolve in water. Hydrophillic species will generally dissolve into the groundwater, and be transported with it in the same phase.
64. Hydrophobic: tending not to dissolve in water. Hydrophobic compounds generally form a separate, non-aqueous phase when put into contact with water. (picture a glass of oil and water).
65. In situ: environmental medium left in its original location.
66. Indigenous: naturally occurring.
67. Infiltration: movement of fluids from surface, through the unsaturated zone (or vadose zone) into an aquifer.
68. Influent: incoming.
69. Injection well: a well used to inject a pressurized fluid into the subsurface.
70. Inlet well: a well through which a fluid enters the subsurface under normal pressure.
71. Lipophilic: "fat-loving"/hydrophobic.
72. MCLs: Maximum Contaminant Levels.
73. Mineralization: complete conversion of organic matter to inorganic matter. Such as the breakdown of petroleum hydrocarbon molecules resulting in water and carbon dioxide end products only.
74. Moisture content: the amount of water lost from a soil with drying, and expressed as a unit ratio.
75. Monitoring well: a well used to detect the presence of free product or to collect samples.
76. Non-aqueous phase liquid (NAP L): contaminants that have very low solubility in water and tend to remain in a separate bulk phase in the subsurface.
77. Nutrients: elements and compounds that are necessary for growth of organisms.
78. 0ff-gas treatment system: unit operations used to treat waste gas streams.
79. Permeability: the amount of hydraulic conductivity resulting from pore space alone.
80. Phreatic zone: the saturated zone or water table.
81. pH: acidity (or bascicity) level.
82. Piezometer: a temporary well used to determine the direction of groundwater flow.
83. Plume: the portion of the subsurface that is contaminated extending away from the source of pollution.
84. Polyaromatic hydrocarbon: aromatic hydrocarbon with more than one fused benzene ring.
85. Pore volume (porosity): total volume of pore space in a given volume of soil.
86. Pressure gradient: a pressure differential in a given medium.
87. Radius of influence: the maximum distance away from an air injection or extraction source that is significantly effected by a change in pressure or flow rate of air.
88. Recalcitrance: resistance to degradation.
89. Recharge: the annual amount of moisture that is returned to an aquifer.
90. Redox: oxidation/reduction.
91. Residence time: the amount of time a compound remains in a particular environmental compartment.
92. Saturated zone: zone of saturated conditions in the subsurface (also known as the water table or phreatic zone).
93. Soil moisture: water retained in the pore spaces of the vadose zone.
94. Solubility: amount of a substance that can dissolve in a given medium.
95. Sorption: adsorption plus adsorption.
96. Sparge: injection of air below a water table to strip dissolved volatile organic compounds and/or oxygenate groundwater to stimulate microbial decomposition of contaminants.
97. Specific gravity: ratio of density of a substance to the density of water.
98. Specific retention: amount of moisture retained by soil after gravity drainage.
99. Specific yield: amount of moisture yielded by a soil under gravity drainage.
100.Surfactant: Surface Active Agent.
101.Total petroleum hydrocarbons: the concentration of all petroleum species in a given sample or environmental compartment.
102 Total volatile organic aromatics: the sum concentrations of BTEX.
103.Transmissivity: ability of a material to permit passage of a fluid through its interior.
104.Unsaturated zone: the portion of the subsurface above the water table (also known as the vadose zone).
105.Vadose zone: the unsaturated zone.
106.Vapor pressure: pressure exerted by a vapor against a medium (solid, liquid or other gas) with which it has attained equilibrium.
107.Volatile organic compounds (VOC): organic compounds with high volatility that will generally pass into the vapor phase at normal temperatures and pressures.
108.Water table: the saturated zone.
109.WeII: hole drilled into the subsurface to reach groundwater.
110.WelI casing: steel or PVC pipe (typically) inserted into a well to prevent borehole collapse.
111.Well pack: sand or gravel pack placed in a well screen that acts to prevent plugging of the screen.
112.WeIl screen: part of the well casing which is slotted in the zone of interest, and allows fluids to enter the well.