[Music]
Beautiful landscapes, the urban forest.
The scenes are bucolic, but the
pesticides many people use to keep their
gardens and landscapes free of pests can
cause problems in the environment, even
when applied with care. Home and garden
pesticides don't always stay put.
Scientists have regularly found many of
these chemicals in nearby streams and
rivers at levels that may be harmful to
fish and toxic to the tiny creatures
small fish rely on for food. Most of the
pesticide applied to a plant is absorbed
by the plant's surface, absorbed onto soil
particles, leached into deeper soil
layers, or broken down by chemical
reactions, microbial activity, or sunlight,
reducing the chance or risk that they
will end up in surface waters. So how do
these chemicals get in our waterways?
Pesticides are often washed off the
property by lawn sprinklers or rain.
Additionally, droplets of spray material
may be moved off-site by air movement.
This is called drift. Another way
pesticides get into our waterways is by
pouring them down the drain. From here
the pesticide-contaminated water can
reach nearby streams, lakes, rivers, bays,
and eventually the ocean. Is it possible
that the small amount of pesticide that
rinses off a yard can cause problems
downstream? Multiply that one yard by the
number of other yards receiving similar
treatment in all the neighborhoods whose
storm drains feed into the same waterway,
and you can see the potential problem.
Isn't the small amount of pesticide from
my lawn going to be diluted by all that
water in the rivers and streams to the
point where it's harmless?
Just how much pesticide does it take to
make a fish sick anyway? The
organophosphate insecticide chlorpyrifos
is toxic to fish at concentrations of
about 10 to 50 parts per billion. 10
parts per billion? That's equivalent to
10 aspirin tablets dissolved in an
Olympic-sized swimming pool. Bifenthrin, a
pyrethroid insecticide
commonly used in landscapes is
toxic to fish at concentrations about
100 times lower.
