8. Water quality Flashcards
Water quality (def)
Basic chemical and physical characteristics of water that determine its suitability for life or for human use
Water quality parameters (3)
- physical water quality parameters
- biological water quality parameters
- chemical water quality parameters
Physical water quality parameters (8)
- water temperature
- electrical conductivity (EC)
- total dissolved salts
- salinity
- dissolved oxygen
- pH
- alkalinity
- turbidity / total suspended solids
PHYSICAL WATER QUALITY PARAMETERS: temperature
temperature determines the suitability of water for various forms of aquatic life
PHYSICAL WATER QUALITY PARAMETERS: temperature, what is it dependent on (4)
- generally follows daily mean air temperature, but does not vary as much as air temperature
- moderated by ground water (cooler in summer, warmer in winter)
- increased by removal of riparian vegetation
- increased by lake surface inflows
PHYSICAL WATER QUALITY PARAMETERS: electrical conductivity (EC)
- electrical conductivity measures the ability of water to conduct an electrical current
- it is a good way to determine the ionic strength of water
PHYSICAL WATER QUALITY PARAMETERS: electrical conductivity (EC)
→ fresh water vs ground water vs surface water (high or low)
- freshwater generally has low conductivity
- groundwater typically has higher levels of conductivity than surface water
PHYSICAL WATER QUALITY PARAMETERS: total dissolved solids (TDS)
- TDS is the measure of the dissolved matter or residue that remains behind after water has evaporated
- it is related to EC
PHYSICAL WATER QUALITY PARAMETERS: Salinity
- Salinity is the amount of salts dissolved in water
- it is often reported as the ratio of electrical conductivity to a standard
PHYSICAL WATER QUALITY PARAMETERS: Salinity
→ what can it be used for
It can be used to classify waters as freshwater (potable), brackish (non-potable, but less saline than sea water), or as seawater
PHYSICAL WATER QUALITY PARAMETERS: Dissolved oxygen (DO)
→ what does it depend on
- DO is often a function of water temperature
→ as water temperature increases, DO decreases - DO is also due to excess respiration in he water`
PHYSICAL WATER QUALITY PARAMETERS: pH
pH is the measure of the acidic or basic characteristics of water
PHYSICAL WATER QUALITY PARAMETERS: pH
→ what is the suitable pH for life?
5 to 9
PHYSICAL WATER QUALITY PARAMETERS: Alkalinity
- Alkalinity is the ability of water to resist acidification
→ low alkalinity = vulnerable to acidification - It is generally attributable to the amount of carbonate (CO3-2) and bicarbonate (HCO3-) ions in the water
PHYSICAL WATER QUALITY PARAMETERS: Alkalinity
→ what can influence alkalinity (4)
- soils
- salts
- plant activities
- industrial waste water discharges
PHYSICAL WATER QUALITY PARAMETERS: Turbidity / Total suspended solids
- turbidity is a water quality parameter that refers to how clear that water is
- it is the amount of total suspended solids (TSS) in the water
PHYSICAL WATER QUALITY PARAMETERS: Turbidity / Total suspended solids
→ causes (6)
- erosion of agricultural lands
- forest soils exposed to logging
- degraded stream banks
- overgrazed rangeland
- strip mines
- construction
PHYSICAL WATER QUALITY PARAMETERS: Turbidity / Total suspended solids
→ problems with high turbidity (4)
- limits light penetration → less photosynthesis
- covers aquatic animals an plants → affects biodiversity
- brings insoluble toxins into waterways
- threat to human infrastructure