Lab 3 - Aquatic Ecology and the Water Quality Index

Nine Test Parameters for WQI

Temperature

pH

Dissolved Oxygen(DO)

Biochemical Oxygen Demand(BOD)

Total Solids

Turbidity

Nitrates

Fecal Coliform

Total Phosphate

WQI Excellent Range

90-100

WQI Good Range

70-90

WQI Medium Range

50-70

WQI Poor Range

25-50

WQI Very Poor Range

0-25

How many ranges are there for WQI, and what are they

5- Excellent, Good, Medium, Poor, Very Poor

Lotic Water System

flowing: rivers, streams, creeks, brooks

Point Source Pollution

any contaminant that enters the environment from an easy identified and confined placed

Point Source Pollution Example

factories

Nonpoint-Source Pollution

results from many general sources such as run off, precipitation, and atmospheric deposition

pH scale

lower, more acidic

higher, more basic

DO units

% saturation

DO importance

it reflects the ability of a body of water to support aquatic life

do we want high or low DO

High DO, better quality

what does BOD measure

the resulting decrease in dissolved oxygen

do we want high or low BOD

Low BOD, this means clean water with little organic waste

what does Total Solids measure

measure of all the suspended, colloidal, and dissolved solids in a sample of water

Contributing factors to total solids

soil erosion, agricultural runoff

do we want high or low total solids

Low

what does Turbidity measure

measure of a body of water’s lack of clarity

do we want high or low turbidity

low turbidity

Turbidity Units

NTU

Lentic Water System

standing water: lakes and ponds

BOD units

mg/L

Total Solids Unit

mg/L