Download USING DNA TO TRACE WATER FLOW PATHS IN THE

USING DNA TO TRACE WATER FLOW PATHS IN THE ENVIRONMENT
Why?
One of the most significant risks to water
quality is “nonpoint” source pollution.
This type of pollution is caused by
pollutants flowing into stream and lakes
with storm runoff or groundwater. It is
challenging to determine the source of the
pollutants. DNA-based tracers provide a
tool for determining which potential
pollutant sources are likely contributors to
a particular water body.
Photo Credit: Finger Lakes Daily News . com
Microscope images of the tracers. The DNA is wrapped-up in
tiny plastic-like balls to protect it from the environment. The
colors here represent different tracers.
Why?
Because of DNA’s unique composition, we
How can fabricate millions of unique DNA
strands that are distinguishable from one
does another. This means we can introduce
it work? tracers to multiple potential pollutant
sources at the same time. Each batch of
DNA tracers has its own unique sequence
of several hundred chemical bases, often
identified by the letters A, T, C, and G.
Algal blooms like this one in Seneca Lake
are often the result of excessive
phosphorus contamination. Potential
sources include fertilizers, animal
manure, and septic systems.
Then we regularly sample the stream or
lake where there is a pollutant problem.
The samples are taken back to the Cornell
Soil and Water Lab and analyzed for the
different tracers.
blogs.cornell.edu
Mentalfloss.com
Collecting a water sample
from Fall Cr.
An analysis called qPCR allows us to count how
many of each kind of tracer is in our sample
There is a curious fear of DNA. Every time we toss an
apple core into the weeds or spit or brush dandruff flakes
Is it safe? off our head we are putting DNA into the environment. In
the case of our tracers, we are using synthetic DNA,
which has no biological code embedded in it, so it is safer
than the DNA in your spit. By contrast, recombinant DNA
is biologically available … that is what was used in Jurassic
Park, but not here.
Also, the protective
coating is made out of
the same material as
biodegradable cups.
For more information contact Todd Walter, Dept. of Biological and Environmental Engineering, Cornell University ([email protected])