A Benthic Macroinvertebrate Analysis of Water Quality both Upstream and Downstream of a Local
Steel Manufacturing Facility
Introduction
Stream-bottom macroinvertebrates are a link in the aquatic food chain. In most streams, the energy
stored by plants is available to animal life either in the form of leaves that fall in the water or in the form
of algae that grows on the stream bottom. The algae and leaves are eaten by macroinvertebrates. The
macroinvertebrates are a source of energy for larger animals such as fish, which in turn, are a source of
energy for birds, raccoons, watersnakes, and even fishermen.
Some stream-bottom macroinvertebrates cannot survive in polluted water. Others can survive or even
thrive in polluted water. In a healthy stream, the stream-bottom community will include a variety of
pollution-sensitive macroinvertebrates. In an unhealthy stream, there may be only a few types of
nonsensitve macroinvertebrates present.
It may be difficult to identify stream pollution with water analysis, which can only provide information
for the time of sampling. Even the presence of fish may not provide information about a pollution
problem because fish can move away to avoid polluted water and then return when conditions improve.
However, most stream-bottom macroinvertebrates cannot move to avoid pollution. A
macroinvertebrate sample may thus provide information about pollution that is not present at the time
of sample collection.
Useful stream-bottom macroinvertebrate data are easy to collect without expensive equipment. The
data obtained by macroinvertebrate sampling can serve to indicate the need for additional data
collection, possibly including water analysis and fish sampling.
In 2002, it was reported that the South Branch of the Raritan River in Long Valley, New Jersey, USA was
being polluted by various industries in the area. The largest identified contributor to this pollution was
Frazier Industrial Corporation located at latitude 40.68589° and longitude 074.77962°. It was reported
that they released small amounts of hazardous chemicals into the surrounding air and water. If the
water pollution releases are significant, we would expect to see a decrease in benthic macroinvertebrate
diversity downstream of the manufacturing facility. (Harmon & Wiley, 2011)
Our class wanted to determine if Frazier Industrial Corporation was having adverse effects on the water
quality and ecological health of the Upper South Branch of the Raritan River.
Works Cited
Harmon, S. M., & Wiley, F. E. (2011). Effects of Pollution on Freshwater Organisms. Water Environment
Research, 1733-1788.
Research Question: How does the pollution from a local steel manufacturing facility affect the water
quality and ecological health of the Upper South Branch of the Raritan river?
Hypothesis: Based upon the work of Harmon and Wiley, it is predicted in this investigation that we will
observe a decline in benthic macroinvertebrate diversity downstream of the Frazier Industrial
Corporation manufacturing facility.
Variables:
Independent: Location of the testing site on the river
Dependent: Water quality as determined by the diversity of the benthic macroinvertebrate
population
Fixed: Water temperature, water pH, water flow, season
Materials
Waders
Kick seines
Small rocks
Tweezers
Observation containers
Benthic Macroinvertebrate Identification cards
Stream Guide to Freshwater Macroinvertebrates
GPS device
Procedure
1. Divide the class into groups of 2 students each.
2. Select two sites, one upstream of the local steel manufacturing facility (stream site A), and one
located downstream of the local steel manufacturing facility (stream site B).
3. Gather all materials and bring them to the first testing site located upstream of the local steel
manufacturing facility. Determine the latitude and longitude using the GPS.
4. Put on waders.
5. Place small rocks in the bottom of the kick seines.
6. Have one person hold the net upright facing the flow at the downstream edge of the sampling
area. The net should be stretched out to its full 3-foot width with the bottom edge lying firmly
against the stream bed. No water should wash under or over the net.
7. While one person holds the net, a second person first brushes all the cobbles in the sampling
area to dislodge the attached macroinvertebrates. As each cobble is brushed, it can be placed
outside the sampling area. When all the cobbles are brushed, stir up the entire sampling area
with hands and feet to dislodge any burrowing macroinvertebrates.
8. Lift the kick seine out of the water with a forward scooping motion. The object is to avoid losing
any macroinvertebrate specimens while the seine is lifted.
9. Carry the kick seine to the stream bank and spread it out flat. Carefully examine the net
and the collected debris for macroinvertebrates. Look carefully as many specimens will
be small and hard to see. Using tweezers or fingers, place all the specimens in clear
observation containers filled with stream water.
10. Repeat steps 6-9 four times for a total of five benthic macroinvertebrate collections.
11. Restore the stream bed to its natural state.
12. Transport the sample back to the classroom for observation.
13. Identify macroinvertebreates using the Benthic Macroinvertebrate Identification cards
and the Stream Guide to Freshwater Macroinvertebrates.
14. Return the benthic macroinvertebrates to the stream site from which they were captured.
15. Repeat steps 1-14 at stream site B.