一些水质指标的英文注释

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1.Turbidity (浊度)
: C" w5 ?& @5 tTurbidity provides a measure of the clarity of the water. As water becomes more murky, turbidity increases. Turbidity is caused by inputs of suspended and dissolved solids in the water which decreases the amount of light penetration. Sources contributing to turbidity include: soil erosion; runoff from urban and agricultural areas; wastewater and stormwater inputs; algae and plant materials; and bottom feeders stirring up sediment. Materials causing turbidity may also be responsible for clogging fish gills, reducing available habitat, interfering with egg and larvae development, smothering fish eggs and aquatic insects larvae, and suffocating newly-hatched insect larvae.

2.Total Phosphorus (总磷)
  [7 M5 b; |- M+ ~[size=+2]Phosphorus is an essential element and is needed for growth and other metabolic processes. In freshwater lakes, phosphorus is often found to be the growth limiting nutrient because it occurs in the least amount relative to the needs of plants. Phosphorus can occur in many forms, but it is inorganic phosphate (PO4) that readily is utilized and taken up by plants for growth. Phosphorus does not readily dissolve in water and can form insoluble forms with iron, calcium, and aluminum and precipitate to the bottom of lakes. Under anaerobic conditions, phosphorus can be released back into the water column. Sources of phosphorus may include: human, animal, and industrial waste; storm water; soil erosion; and excessive use of fertilizers for crops, lawns, and home gardens.
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3.Total Alkalinity (总碱度)
[size=+2]Alkalinity refers to the amount and types of chemical compounds that can shift the pH toward the higher side of neutrality. Alkalinity is usually measured by the presence of bicarbonate (HCO3-) and carbonates (CO3=) and acts to buffer lakes from acidic inputs, thus is a measure of the buffering capacity of a lake.
' j9 q& z/ @" ]. b2 SLakes with high alkalinity have high pH values while lakes with low alkalinity have low pH values


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[size=+2]Dissolved Oxygen (DO) is necessary for the maintenance of a healthy aquatic ecosystem. Aquatic organisms differ in the amount of oxygen they require for survival. For example, fish such as trout and pike require higher concentrations of DO for survival, while carp and catfish are able to survive at much lower concentrations (less than 5 mg/L).
- o# ?* d+ P6 G0 J/ P2 H4 g% hDissolved oxygen is supplied to a water body through the atmosphere where oxygen mixes with water through wind and wave action, and through photosynthesis by algae and other aquatic. Oxygen is more easily dissolved in cold water than in warm water; therefore, the amount of oxygen that water will hold increases as the temperature decreases.
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5.Biochemical Oxygen Demand (生化需氧量)
[size=+2]The amount of oxygen used by microorganisms in the aerobic oxidation of organic matter is a measure of the Biochemical Oxygen Demand (BOD).
Nutrients contribute to high BOD in water systems by stimulating plant growth. When the plants die, aerobic bacteria utilize oxygen in breaking down the decaying organic matter which leads to an increase in BOD.
A five day incubation period of the water sample is often used to determine the BOD.

6.Total Solids (总固体)
4 }1 B& Q4 B6 J1 y[size=+2]Total solids include dissolved solids (portion of solid matter found in water that passes through a filter) and suspended solids (portion of solid matter trapped by a filter). Dissolved solids may consist of calcuim, bicarbonate, nitrogen, phosphorus, iron, sulfer, and other ions found in a water body. Suspended solids may include particles from plankton, soils, and various wastes. Both dissolved and suspended solids may enter water systems through runoff from urban, industrial, or agricultural areas or from wastewater treatment plants.
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7.Water Temperature (水温)
[size=+2]Water temperature is directly related to water quality. Temperature affects the physical, biological, and chemical characteristics of a water system. Gases are more easily dissolved in cold water than in warm water, therefore, cold water holds more oxygen than does warm water. Factors influenced by temperature include the amount of oxygen that can be dissolved in water; photosynthetic rate of algae and other aquatic plants; and the metabolic rates of aquatic organisms. Water is heaviest at 4oC, and is lighter at temperatures both above and below.
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8.Hardness (硬度)
Hardness is measure of polyvalent cations (ions with a charge greater than +1) in water. Hardness generally represents the concentration of calcium (Ca2+) and magnesium (Mg2+) ions, because these are the most common polyvalent cations. Other ions, such as iron (Fe2+) and manganese (Mn2+), may also contribute to the hardness of water, but are generally present in much lower concentrations. Waters with high hardness values are referred to as "hard," while those with low hardness values are "soft".
1 ?4 r( M4 d, P5 h. g7 k  ^- OHardness affects the amount of soap that is needed to produce foam or lather. Hard water requires more soap, because the calcium and magnesium ions form complexes with soap, preventing the soap from sudsing. Hard water can also leave a film on hair, fabrics, and glassware. Hardness of the water is very important in industrial uses, because it forms scale in heat exchange equipment, boilers, and pipe lines. Some hardness is needed in plumbing systems to prevent corrosion of pipes
Hardness mitigates metals toxicity, because Ca2+ and Mg2+ help keep fish from absorbing metals such as lead, arsenic, and cadmium into their bloodstream through their gills. The greater the hardness, the harder it is for toxic metals to be absorbed through the gills.

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