DO, BOD, and Water Quality

Dissolved oxygen

It is the amount of oxygen dissolved into a water source (Units of measure: mg/L or ppm)

Impact of DO on aquatic systems

Aquatic organisms require specific amounts of dissolved oxygen to survive, Depending on the amount of DO different aquatic organisms will be present

Biological Oxygen Demand

The amount of DO that is consumed by aquatic organisms through cellular respiration

Sources that increase BOD

sources of nutrient pollution (fertilizers, animal feedlots/waste, wastewater treatment plants,etc.), decaying vegetation (deforestation)

DO and BOD.

There is an inverse relationship between

cellular respiration

oxygen is needed for

burning that food

cell obtains energy from a food source is by

Indicator species

Species whose presence or absence reflect the overall health of the ecosystem

Good health

Salmon, frogs, lichens

Poor health

catfish, presence of almost only bacteria or invertebrates

Toxic chemicals

pesticides, petroleum products, synthetic chemicals, toxic metals As, Pb, Hg, acids from rain and mining salts

Pathogens and waterborne diseases

viruses, protists, bacteria entering drinking water through contamination of human waste or animal waste/feedlots.

Nutrient Pollution

when excess nitrogen and/or phosphorus enters a body of water, it fertilizes algae and aquatic plants, boosting their growth (creates dead zones)

Dead zone

area of very low dissolved oxygen levels

Reduce nutrient pollution

treating wastewater, reducing fertilizer application, using phosphate-free detergents, and planting vegetation for nutrient uptake

Wastewater

water affected by human activities. toilets, sinks, showers, dishwashers, washing machines, water used in manufacturing or industrial use, stormwater runoff.

Sediment

eroded soils carried by rivers, changes aquatic habitat can kill fish adapted to clean water, etc

Thermal pollution

increase in temperature of water reduces the amount of dissolved oxygen that can be present. Occurs from industrial use, removal of shady vegetation over water surface.