WATER QUALITY
Feb 23, 2016
WATER QUALITY
WATER QUALITYWater quality is a term used to describe the chemical, physical, and biological characteristics of water.
Factors that affect water quality are broken down into two categories: biotic and abiotic.
WATER QUALITYBiotic Factors: Living factors affecting water quality
Abiotic Factors: Non-living factors affecting water quality
WATER QUALITYWater quality is also described in
terms of the water’s intended use.Water that is drinkable is called
potable.Water than can be used for
swimming or bathing is referred to as safe.
WATER QUALITYWater quality standards outline
the water pollution control program that is mandated by local, state and federal government agencies.Primary among these is the
Environmental Protection Agency (EPA)
WATER QUALITYEnvironmental Protection Agency
(EPA)Acts as a Steward of the
environmentSets maximum levels for the 90
most common water contaminants
WATER QUALITY Water quality standards are based on the
following questions: What is the intended use of the body of water? How can we protect that use? What long term dangers might the body of water
face?
ABIOTIC FACTORS Temperature – the temperature of water in
rivers and lakes determine the kinds of organisms that can survive there. Certain species have preferred water
temperature ranges. The temperature of water affects what solids and
gasses are dissolved within it. Warm Water = Less Oxygen Colder Water = More Oxygen
ABIOTIC FACTORS Dissolved Oxygen – (DO) Oxygen that is
dissolved in water. DO is a measure of the amount of oxygen in
water that is available for chemical reactions and for use by aquatic organisms.
DO is vital for the survival of micro-organisms, and higher organisms such as zooplankton and fish.
Dissolved Oxygen gets into the water through diffusion with the air (the higher concentration of oxygen in the air causes oxygen to move from the air to the water) and as a by-product of photosynthesis by water plants.
High DO levels in potable water make it taste better
MAJOR AFFECTS THAT ADJUST DO Water temperature increases and DO goes
down. Increased eutrophication.
Eutrophication: Decreased amount of DO in a body of water due to increased algae and plant growth.
ABIOTIC FACTORS pH
A measure of how acidic or basic the water is On a scale of 0 to 14 – 7 is neutral, below 7 is
acidic, above 7 is basic The pH of pure water is 7 Water that is too acidic may cause other
elements that are always present to become toxic to organisms living there
ABIOTIC FACTORS Turbidity – A measure of how clear water is
Higher turbidity in potable can mean pathogens are present
Higher turbidity in lakes and rivers can lead to increased temperatures, lower DO, and bad conditions for aquatic organisms
ABIOTIC FACTORS Phosphates and Nitrates
If these levels are too high they pose a risk to humans in potable water.
The major sources of phosphates are: humans and animal waste, detergents, cleaning and industrial waste.
The major sources of nitrates: runoff contaminated with fertilizers, animals waste and septic waste.
BIOTIC FACTORS Bioindicators – living things whose presence,
condition, and numbers are indicators of the health of a body of water
THINKING QUESTION On the left hand side of your notes: What are
some connections between water quality factors?
Right hand side: Look back in your notes and try to find as many connects between the abiotic factors just discussed.