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Freshwater Pollution Science Project

Plants, humans and other animals all require freshwater to survive. Pollution -- such as chemicals and pesticides -- can enter rivers, lakes and streams in water that runs off roofs and paved surfaces. Some sources of pollution can be clearly identified, such as a spill from a factory. Nonpoint source pollution, however, does not have an easily identifiable source but still affects organisms that live in or use the freshwater.

Nonpoint Source Pollution
- Collect and document litter found at local ponds -- both manmade and natural. Look on the shore and in the shallow parts of the ponds. On a map, mark the locations of the litter and their possible sources -- such as nearby highways and restaurants. Categorize the data to categorize and present the results as bar and line graphs. Propose solutions for eliminating the litter, such as working with restaurants to improve trash receptacles.
Soil Filters
- Soil and plants filter many of the pollutants before water reaches rivers and lakes. To investigate this, line three funnels with a coffee filter. Then fill them with sand, potting soil or a mixture of the two. Place the funnels in three tall jars, pour water mixed with food coloring into the soil and observe the water that collects in the jars. Repeat this process with fresh soil and a mixture of vegetable oil and water.
Fertilizers and Algal Growth
- Two of the most common pollutants in freshwater are nitrogen and phosphorus from fertilizers. These can cause an overgrowth of algae and bacteria, which eventually die and deplete the oxygen in water. Animals that need to extract oxygen from water to survive, such as fish, will also be killed. Collect 2 liters of pond water that is clear of algae and sediment. Fill six foam cups with pond water and different amounts of fertilizer. For example, the first cup will have 1.5 milliliters of fertilizer, and the last will have 0.09 milliliters. Place the jars in a well-lit spot and observe the growth of algae, if any. Repeat the experiment two more times and combine the data.
Effect of Pollution on Plants
- In this project, use phosphorus-containing dishwater soap, chlorine bleach and ammonia to represent pollutants. Dilute 2 tablespoons of each with 1 cup of water. Plant eight lima beans in foam cups. Water the plants with plain water or one of the diluted pollutants, using two plants for each. Water the plants the same amount and at the same time. Monitor and record the growth, including height, leaf size and whether the plants did not survive.

Nature