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Toxins
Toxins are chemicals that can cause human and wildlife health problems. They
include organic chemicals and metals, pesticides, herbicides, formaldehyde,
household chemicals, paint, paint cleaners, gasoline, motor oil, battery acid,
and roadway salt. Toxins accumulate in fish and shellfish either killing them or
making them more susceptible to disease. Infected fish and shellfish can have a
direct impact on humans in the food chain.
Pesticides—insecticides, herbicides, rodenticides, and fungicides—are
chemicals widely used by farmers, foresters, exterminators, and homeowners to
kill harmful insects and weeds, to increase crop and timber harvests, and to
prevent the spread of plant, animal, and human parasites and diseases.
When improperly applied, pesticides can pollute waters and poison fish,
plants, and animals living in and around water. Pesticides are considered NPS
pollutants because their source of origin is often difficult to locate. They can
migrate considerable distances via air or water and be released by rainfall,
complicating the process of pinpointing the source.
Although targeted at pests, certain pesticides inadvertently can harm
non-target organisms—stream insects, fish, wildlife, domestic animals, and
humans.
Alternatives to Toxic Pesticides
Use less toxic pest control products. When used according to label instructions,
insecticidal soap, BT (Bacillus Thuringiensis), milky spore, and dormant oil
sprays are less toxic to the environment than other commercial products.
Integrated Pest Management (IPM) emphasizes frequent monitoring to assess
pest population buildup and the evaluation of factors, including environmental
effects, prior to pesticide application.
IPM Tactics
- Use natural predators.
Introduce animals and insects that eat pests.
- Time plantings. Regulate
planting and harvesting to avoid times when insects are most abundant and
damaging.
- Do a little hand work. Remove
eggs, larvae, cocoons, and adults from plants by hand.
- Use resistant plants.
Cultivate plants that are relatively free of major pests and diseases.
- Know the appropriate growing
conditions. Make sure the amount of shade and sunlight, moisture, and pH
levels are appropriate for plants.
- Mix plant varieties. A mixed
stand of vegetation is less susceptible to insect damage than single species
crops.
- Introduce natural pathogens
and parasites. Use bacteria, viruses, and insect parasites to kill pests
without harming other non-pests.
- Control insect hormones.
Prevent an insect from growing into a sexually mature adult.
- Use chemicals only as needed.
Smaller amounts and careful application ensure a healthier environment and
better pest control.
- Mulch. Use where appropriate
to control weeds.
- Rotate plants/crops. Yearly
rotation of garden plants decreases the need for pesticides.
Minimize Pesticide Hazards
- Read and follow the label
carefully.
- Buy only the quantity needed.
- Wear any protective clothing
specified on the product label.
- Wash hands immediately after
application.
- Apply only the amount
specified on the product label and only on the plants and areas listed in the
instructions
- Make sure people and pets are
out of the area during application and until the spray has dried.
- Never apply near wells,
streams, ponds, or marshes unless the instructions specifically allow such
use.
- Never apply to bare soil.
- Don't apply if rain is
forecast, unless specified on the label (some pesticides do need to be watered
after application).
- Dispose of containers
according to label directions.
- Choose the least toxic
pesticide. Those with the signal word Caution on the label are considered the
least toxic, whereas the signal word Warning indicates moderate toxicity.
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