of creeks, rivers, and oceans
California creeks, rivers, and oceans
are being contaminated with pesticides and other chemicals commonly
used around our homes and gardens. These garden
chemicals are not only
a threat to aquatic life, but they can also affect the quality
of our drinking water.
to living organisms
All pesticides are toxic at
some level, but each varies in their toxicity to humans and other
animals. Organophosphates, including diazinon and chlorpyrifos, are
insecticides that contain phosphorus; they are nerve poisons and
act by inhibiting important enzymes in the nervous system in animals.
Pyrethroids are another class of insecticides that are not as toxic
to humans and other mammals, but are quite toxic to fish and invertebrates. Both
the organophosphates and pyrethroids pose serious threats to aquatic
Known problem pesticides: pyrethroids and
common residential insecticides, found in products for ant control,
home lawn, garden and landscape care, as well as in structural pest
control products. Common pyrethroid
active ingredients in home use products include bifenthrin, cypermethrin,
permethrin, and cyfluthrin. Pyrethroids mimic the mode of action
of the plant-derived pesticide pyrethrin, but are much more toxic
and persistent in the environment. They attach to soil particles
and are washed into waterways on sediment.
Organophosphate pesticides containing
diazinon and chlorpyrifos were widely used in the 1990s but were
withdrawn from the market for home use in the early 2000s because
of risks to children. These
materials are highly soluble in water and have been found in California
creeks at levels toxic to aquatic invertebrates. The U.S.
EPA's Office of Pesticide Programs summary sheets explain why these
pesticides are no longer available to urban users.
Known problem pesticides (cont.)
You may still have products containing diazinon and chlorpyrifos
on a shelf in your garage. If you have these products, dispose of
them at your local Household Hazardous Waste site. Call 1-800-CLEANUP
(1-800-253-2687) to find a disposal site in your area.
organophosphate insecticides are still available for home use include
malathion, acephate and disulfoton. These products are also
water soluble, broadly toxic and pose risks for aquatic organisms.
Avoid their use where possible and keep them out of our waterways.
Select pesticides carefully before
you buy or apply
The first step in choosing a pesticides
is to accurately identify the pest. If a pesticide is needed, select
one that is effective against your pest and also poses the least
risks to human health and the environment. Refer to the home
and garden pests section of this website for environmentally
Pesticide labels provide information on the active (toxic) ingredients
contained in a product. Always read the label before applying a
All pesticides must be used with caution and should never be allowed
to go into stormwater, drains, or creeks. For some pesticides,
the full impact on the environment is not known.