IB Environmental Systems & Societies
AP Environmental Science
Lab #2
2011-2012
Research question: Does the Passaic River adjacent to the Mendham High School campus
show signs of eutrophication?
IB Topics:
2.2
2.3
2.7
5.2
5.4
Measuring abiotic components of the ecosystem
Measuring biotic components of the ecosystem
Measuring changes in the system
Detection and monitoring of pollution
Eutrophication
AP Topics:
I.C. Global Water Resources
& Use
VI.A.3. Water Pollution
Internal assessment rubric criteria to be graded:
 Planning
 Data Collection & Processing
 Discussion, Evaluation and Conclusion
 Personal Skills
Procedure: Use chemical testing and observation of biotic conditions to determine whether the
Passaic River adjacent to MHS shows signs of eutrophication
Available water quality tests:
1. Biological Indicators of Water Quality
Observe and record any features of the sample location that may provide information on water
quality. (For example, is there an odor? Is the water murky? What type of plant and animal life
is present or absent?)
2. Nitrate:
Nitrogen compounds are essential for healthy plant growth. Therefore, nitrogen is a major
constituent of commercial fertilizers. Unfortunately, nitrogen and nitrates enter groundwater and
surface water from fertilizer runoff, sewer and sewage-treatment discharges, and industrial
processes. Nitrogen is also discharged to the atmosphere from the combustion of fossil fuel.
Excess nitrogen in the aquatic ecosystem can stimulate plant growth and cause eutrophication
and algal blooms, or "red tides."
Less than 1 ppm N-NO3
Less than 10 ppm N-NO3
ideal conditions for organisms in aquatic ecosystems
NJ drinking water standard
Note: 1 part per million ("ppm") = 1 milligram/liter ("mg/l")
3. Phosphate:
Like nitrogen, phosphate is essential for healthy plant growth and is a major constituent of
commercial fertilizers. Also like nitrogen, phophates enter groundwater and surface water from
fertilizer runoff, sewer and sewage-treatment discharges. Excess phosphate in the aquatic
ecosystem, especially when combined with nitrogen, can stimulate plant growth and cause
eutrophication and algal blooms, or "red tides."
less than 0.05 ppm
less than 0.1 ppm
natural level in aquatic ecosystems
algal blooms rare
4. Dissolved Oxygen
Dissolved oxygen analysis measures the amount of gaseous oxygen (O2) dissolved in an aqueous
solution. Oxygen gets into water by diffusion from the surrounding air, by aeration (rapid
movement), and as a waste product of photosynthesis. Adequate dissolved oxygen is necessary
for good water quality. Natural stream purification processes provide adequate oxygen levels for
a healthy and balanced aquatic ecosystem. Some aquatic species are more sensitive to DO levels
than others.
less than 5.0 ppm
6 - 15 ppm
oxygen deficit; aquatic life stressed
suitable for aquatic life
 carp can survive at DO levels as low as 1 ppm
 bass require DO levels ~ 5 ppm or above
 brown trout require DO levels ~ 11 ppm
5. Turbidity
Turbidity is caused by suspended particles in water. It is not specific to the type of particle in the
water and the particles can be suspended or colloidal matter, as well as inorganic, organic or
biological. At high concentrations, turbidity is perceived as cloudiness or haze.
Turbidity analysis is an optical measurement of scattered light. When light is passed through a
water sample, particles change the direction of the light, scattering it. If the turbidity is low,
most of the light will continue in the original direction. Light scattered by the particles allows the
particles to be detected in the water, just as sunlight can illuminate dust particles in the air.
The units of measurement for turbidity are nephelometric turbidity units (NTU). The United
States Environmental Protection Agency has adopted a standard of less than or equal to 0.3 NTU
to achieve maximum removal of dangerous pathogens from water supplies.
N