1. Water Pollution
Close to home…

2. Types of Water Pollution
The contamination of bodies of water by pollutants either directly or indirectly
Types of water pollution
Can be anthropogenic or natural
Point source or non-point source
Organic or inorganic
Direct or indirect
Sources of freshwater pollution
Agricultural Run-off, sewage, industrial discharge, solid domestic waste
Sources of marine pollution
Rivers, Pipelines, the atmosphere, human activities at sea, discharges (both on purpose and on accident)

3. Types of Water Pollution
Types of aquatic pollution include…
Organic Material, inorganic plant nutrients, toxic metals, synthetic compounds, suspended solids, hot water, oil, radioactive material, pathogen, light, noise, biological (invasive species)
Lowers the waters ability to hold dissolved oxygen

4. Measuring Water Pollution
Biological Oxygen Demand (BOD)
Organic material can be “biodegraded” by aerobic microbes,
Therefore certain types of organic pollutants increase the “BOD.”
This can lead to anoxic conditions
Definition: A measure of the amount of dissolved oxygen required to breakdown the organic material in a given volume of water through aerobic biological activity by microorganisms.

5. Measuring Water Pollution
Biotic Indices
Indicator Species: Plants and animals that show something about the environment by their presence, absence, abundance, or scarcity.
Early warning signs that are sensitive to change
Ex: Canary in a coal mine, benthic macroinvertebrates,
Biotic Index: Indirectly measures pollution by assaying the impacts on species within the community according to their tolerance, diversity, and relative abundance
Doesn’t measure pollutants, just their effect on biodiversity
Biotic Indices are used in combination with other measures such as BOD

6. Eutrophication When excess nutrients are added to an aquatic ecosystem
Can be natural, but we will focus on cultural or anthropogenic eutrophication
The Process…
1. Fertilizer runs off into river or lake
2. High nutrient levels make algae grow faster (phosphate is often a limiting factor to growth)
3. Algal bloom forms blocking light to littoral/benthic plants which die
4. Big feeding party at surface
5. Eventually algae die too
6. Decomposed by aerobic bacteria
7. Not enough oxygen and everything dies!

7. Impacts of Eutrophication
Water ways affected by cultural eutrophication are usually covered by green scum and/or duckweed (lemna)
They also usually give off smelly gasses like hydrogen sulfide
Other impacts include…
Lack of oxygen
Loss of biodiversity
Increased turbidity of water
Where do these nutrients come from????
Detergents (major phosphate source)
Fertilizers (n, p, k)
Livestock runoff (nitrates)
Sewage
Increased erosion of topsoil

8. Eutrophication management Strategies
The Clean Water Act