Glosari
| Parameter | Unit | Class I | Class II | Class III | Class IV | Class V |
| Ammoniacal Nitrogen | mg/l | < 0.1 | 0.1 - 0.3 | 0.3 - 0.9 | 0.9 - 2.7 | > 2.7 |
| Biochemical Oxygen Demand | mg/l | < 1 | 1 - 3 | 3 - 6 | 6 - 12 | > 12 |
| Chemical Oxygen Demand | mg/l | < 10 | 10 - 25 | 25 - 50 | 50 - 100 | > 100 |
| Dissolved Oxygen | mg/l | > 7 | 5 - 7 | 3 - 5 | 1 - 3 | < 1 |
| PH | mg/l | > 7.0 | 6.0 - 7.0 | 5.0 - 6.0 | < 5.0 | > 5.0 |
| Total Suspended Solids | mg/l | < 25 | 25 - 50 | 50 - 150 | 150 - 300 | > 300 |
| Water Quality Index | > 92.7 | 76.5 - 92.7 | 51.9 - 76.5 | 31.0 - 51.9 | < 31.0 |
Ammonia ( NH3 )
A colorless gaseous alkaline compound which is soluble in water. It has a characteristic pungent odor, and is used as a fertilizer. In water and soil, ammonia is present primarily as NH4+ ions and is and is ready assimilated by plants during nutrition.
Ammonium ( NH4+ )
Ammonium is a form of ammonia by the addition of a hydrogen ion (H+) to an ammonia molecule (NH3). Ammonia is converted to ammonium as the pH of a solution drops. Ammonium is less harmful to aquatic life than. Below a pH of 7.3, more than 99% of the total ammonia is present as ammonium.
Chloride (CI-)
A common anion, present in both fresh and sea water. It is essentially non–toxic, and is present in all living cells.
Conductivity
Conductivity is inversely related to the resistance of a solution. Conductivity is the ratio of the electric current density to the electric field in a material, also known as electrical conductivity. In limnology, conductivity is a measure of the ability of water to pass an electrical current. Compensation of this measurement to 25 °C constitutes specific conductance. This parameter indicates the amount of dissolved substances (salts). Salts and their concentration dictate osmoregulatory (salt –balancing) functions in plants and animals. The ionic strength of water also regulates the toxicity of many substances.( See: Specific conductance )
Depth
The vertical distance between the water surface and another level.
Dissolved oxygen (or D.O)
A measure of the amount of oxygen present in the water and available for respiration. The concentration of D.O. is controlled by many factors including consumption by aerobic (requiring D.O) organisms (bacteria, fish, amphibians, and invertebrates); consumption by plants (algae, vascular plants, particularly during dark hours); and water temperature, water flow, and depth
MilliSiemens (mS)
millimo (m) – Units of electrical conductance.
Millimho (m)
(See : MilliSiemens)
Nitrate (N03)
Nitrate is the most oxidized form of nitrogen, and is the primary form of biologically available nitrogen present in aerobic environments. Nitrate is a less toxic form of nitrogen than ammonia, and is readily assimilated by plants and bacteria.
Oxidation reduction potential (or ORP) –
(See: Redox potential )
pH
Describes the hydrogen–ion activity of a system: pH 0-7: acid solution, pH7: neutral, pH 7-14: alkaline (or basic) solution. The “p” in pH stands for power (puissance) of the hydrogen ion (H+) activity. pH is a major factor affecting the availability of nutrients to plants and animals. It control in part the concentration of many biochemically active substances dissolved in water, and it affects the efficiency of hemoglobin in the blood of vertebrates (e.g. fish) and invertebrates (e.g. shrimp), as well as the toxicity of pollutants.
Redox potential
Oxidation-reduction potential (or ORP) = Eh –Voltage measured at an inert electrode immersed in a reversible oxidation-reduction system; measurement of the state of oxidation of the system. The redox potential measures the tendency of electrons to “flow” either toward or away from a noble metal electrode. A substance gains electrons in a reduction reaction and loses electrons in an oxidation reaction. ORP varies from substance, and oxidation-reduction reactions occur simultaneously, hence the determination of the “potential” rather than of a discrete or qualitative value. Oxidation and reduction are in a constant state of flux, continuously seeking equilibrium. Application for ORP measurement include, but are not limited to, the following : monitoring oxidation of cyanide and chromate wastes (e.g. metal plating), bleaching pulp (e.g. paper manufacturing), manufacture of bleach (e.g. monitoring chlorination), water pollution (e.g. acid mine drainage) and monitoring ozone treatment (e.g. water disinfection). ORP data has been used to understand more about how substances in sediments affect the water quality at the bottom of lakes, reservoirs, and ponds.
Reduction
A reaction that increases the electron content of a substances.
Salinity
Salinity is the measure of the total quantity of dissolved salts in water. Salinity refers to the ionic strength of natural waters. Salinity and salt concentration are the only terms that can be used when referring to the relative concentration of certain salts in bays estuaries, and oceans.
Specific conductance
conductivity at 25 °C – The ratio of the electric current density to the electric field in a material. The ability of a fluid to conduct electricity. Specific conductance is the inverse of electrical resistivity, corrected at 25 °C, since fluids conduct more at higher temperatures.
Temperature
A measure of heat present in water. Aside from dissolved oxygen, temperature is considered the single most important parameter. Knowledge of water temperature is essential to the measurement of dissolved oxygen, conductivity (salinity), pH, alkalinity, biological/biochemical oxygen (needed to meet the metabolic needs of aerobic - requiring D.O – organisms) and virtually every other water quality parameter. Temperature controls metabolism (utilization of inorganic and organic matter for life processes) of aquatic animals and plants. Temperature is largely responsible for biochemical reactions and is one of the most important cues for beginning and ending of spawning , migration, and many other phenomena.
Total dissolved solids (TDS)
The amount of materials in a body of water that are dissolved or too small to be filtered. These solids include ions which are important to the internal water balance in aquatic organisms. The amount of substances (calculated in Kg/l) dissolved in one liter of water. A measure primarily of alkaline earth metals and their salts dissolved or in very fine suspension. It provides information regarding the potential buffering capacity of water, water hardness, and the potential lethality of toxins. The concentration of dissolved solids affects osmoregulation (salt balancing) of fish eggs and other organisms.
Turbidity
The measure of the clarity of a liquid by using colorimetric scales. It is also the expression of the optical property that causes a light to be scattered and absorbed rather than transmitted in straight lines through a sample. Turbidity is the opposite of clarity (ITM). A measure of the opacity or translucence of water. The main objective is to determine the scattering of light by particles of a body of water and report that scattering in some unit of measurement, usually nephelometric turbidity units (or NTU) based on a primary turbidity standard called formazin. Turbidity is caused by plankton (both animal and plant), clay, suspended clay, slit etc. Although these substances impart color, color resulting from turbidity is referred to as “apparent color” and should not be confused with true color (resulting from dissolved substances). Apparent color can also result from overshading by vegetation or substrate (bottom material) color.