Water quality Flashcards
water quality definition
basic chemical & physical characteristics of water that determines its suitability for life or human uses
3 water quality parameters
biological
chemical
physical
list all physical water quality parameters
-water temperature
-electrical conductivity
-salinity
-alkalinity
-pH
-dissolved oxygen
-turbidity (Total Suspended Solids)
-total dissolved solids
water temperature use and trends with development of watershed
-use: determines suitability for various forms of aquatic life, generally follows mean daily air temperature without as much diurnal differences
-development of watershed:
-pavement heated by sun warms water flowing on it -> increased lake surface inflow temperature
-riparian vegetation removal increases temperature as the sun heats water surfaces directly
electrical conductivity definition
measures ability of water to conduct an electrical current, which is proportional to the number of ions in water
EC of different water types & impact of development
freshwater: low conductivity given in microSiemens per cm (uS/cm)
marine: very high conductivity given in milliSiemens (ms)
GW: higher conductivity than surface water
development of watershed: increase conductivity with increase in chemical washing into waterbodies
Total dissolved solids definition
total amount of dissolved substance in water -> measure of dissolved matter remaining behind after water evaporates
-1 TDS is 0.66 x EC
salinity and how it is reported
it is the amount of salts dissolved in water
-reported as ratio of EC to a standard :
-old : Copenhagen seawater
-now: KCI standard
using TDS to classify water
-freshwater: potable, generally <1000mg/L TDS
-brackish: non-potable, less saline than seawater
-seawater
how to assess water chemistry analysis
- commonly expressed as mass in liter of solution (mg/L, ng/L, etc.)
-closely related to parts per million or mg/kg (mass of solute in mass of solution)
-because density of natural water is near 1kg/L -> mg/L = ppm
Dissolved oxygen (DO) use and impact
oxygen is required for most living thing and scarcer in water because dissolved. Solubility depends on temperature and pressure -> 10 ppm at temp of 20 degrees C AND most aquatic organisms need >5mg/L
-decrease in DO = excess respiration because decomposition of OM inputs
-most natural stream close to saturation -> water discharge/velocity helps deliver O2-rich water
pH use and optimal range
measure of acidic or basic characteristics of water using -log[H+]
-organism prefer pH 5 to 9
alkalinity use, cause, potential and development impact
-use: ability of water body to resist acidification
-cause: amount of carbonate & bicarbonate ions in water because of rock & soils, salts, plant activities and industrial wastewaters
-potential: moderate-high alkalinity water is not subject to acidification (can buffer acid rain)
-development impact: increase alkalinity from mobilization & washing of carbonates & bicarbonates
turbidity definition, problems when high and cause
-definition: how clear the water is, relating to the amount of total suspended solids in water (TSS)
-problems of high turbidity: limit light penetration (less photosynthesis), covers aquatic plants & animals (affect biodiversity), brings insoluble toxins into waterways and threat to human infrastructure (hydroelectric turbines)
-cause: erosion of agri land, overgrazed grassland, strip mines, etc.
Biological factors list:
BOD
disease-causing agents
Biological factors list:
BOD
disease-causing agents
disease causing agents definition and examples
-definition: infectious organisms causing disease originating from waste of infected individuals
-examples: typhoid, cholera, polio
Biological Oxygen Demand (BOD) definition and factors influencing it
-definition: amount of DO consumed by aquatic organisms while degrading OM -> higher BOD = higher chance of depleting DO
-factors influencing OM degradation: temperature, flow and volume
oxygen sag definition
region where oxygen level sharply decline downstream of pollution sources as decomposers metabolize waste materials
-after oxygen sag = recovery zone -> clean zone
chemical factors list:
heavy metals
nutrients
nutrients: 2 main ones and sources
-nutrients are usually limited in aquatic envr (excess is detrimental)
-P and N are very important because building blocks of biological molecules and stimulate growth of plants and algea
-sources: human & animal waste, plant residues, atmosphere deposition, fertilizer runoff
pollution definition
presence of a substance in the environment that, because of its chemical composition or quantity, prevents the functioning of natural processes AND produces undesirable environmental and health effects
environmental consequences of water pollution
-health hazards
-loss of biodiversity
-loss of aesthetic
-impact and leisure & sporting activities
point source pollution definition and examples
-water pollution that can be traced to a specific origin (single point of entry) and is easy to regulate and monitor
-examples: landfills, drainpipes, factories
non-point source definition and examples
-pollutants entering the water body over large area as scattered or diffuse but having a large cumulative effect. Difficult to trace & regulate
-examples: runoff from agricultural fields, urban runoff, golf course
atmospheric deposition definition
contaminant carried by air current and precipitated into watershed or directly onto surface water as rain, snow or dry particles.
-non-point source pollutant
sewage treatment steps and actions
-primary treatment: physical separation of large solids from waste stream
-secondary treatment: biological degradation of dissolved organic compound in trickling bed or aeration -> usually disinfected before release into waterway
-tertiary treatment: removal of plant nutrients using chemical which bind OR natural wetlands
sewage treatment issue
sanitary sewers connect to storm sewers -> heavy storm can overload the system and cause raw sewage to runoff directly into waterways.
polluted agricultural runoff: products, causes and effects
-products: nutrients, sediments, pathogens
-causes: agricultural activities like grazing, plowing, fertilizing, planting and Animal Feeding Operation (farms with high concentration of livestock generating lots of waste)
-effects: leading source of water quality problems in lakes & rivers
polluted urban runoff: products, causes and effects
-products: sediment, oil & greases, heavy metals, debris, road salts, fertilizers, pesticides & herbicides
-cause: impervious surfaces causing water to accumulate and runoff in large amount while carrying large amount of waste from urban envr
-effect: large source of water quality impairments to river
eutrophication process and consequences
-process: increasing biological productivity of algea in water body via the addition of nutrients by runoff -> leading to algal bloom and depletion of oxygen as they decompose
-consequences: depletion of DO, significant changes in ecological dynamics, human health consequences
Oligotrophic VS eutrophic and cultural eutrophication
oligotrophic: waterbodies with clear water & low productivity
eutrophic: waterbodies rich in organisms and OM
cultural eutrophication: increase in bio prod & ecosystem succession caused by human activities
watershed export definition, units and calculation
def: amount of a substance exported from a watershed
unit: kg/ha/yr
calculation: (flow x pollutant concentration) / watershed area
watershed load def and units
def: amount of a substance delivered to a waterbody
unit: mg/m2/yr OR kg/m2/yr
3 basics pollution management strategies
-reduce/remove pollutant
-treat/purify tainted water
-monitor downstream waterbodies
water quality classification
good: sufficient to meet all designated uses
impaired: insufficient to meet AT LEAST ONE designated water use
How to regulate water quality and types of water uses
different jurisdictions designating different water uses:
-food supply
-water supply
-recreation
-ecosystem health
heavy metals problem and source
problem: highly toxic and persistence metals that can bioaccumulate in the food chain
source: mine drainage and leaching
