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Are streams and ground water being contaminated by nutrients and bacteria?
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- Nutrient concentrations in streams are higher in areas with greater agricultural land use or downstream from wastewater-treatment plants than in forested areas. These higher concentrations may result in increased algal growth in streams.
- Nutrient concentrations in ground water are higher in areas with greater agricultural
land use than in forested areas. These higher concentrations seldom exceed
drinking-water standards.
- Bacteria concentrations in streams are higher in basins with greater agricultural
land use (mostly pasture). Fecal coliform bacteria concentrations occasionally
exceed State water-quality standards for whole-body contact recreation.
- Nutrient and bacteria concentrations are affected by hydrologic and geologic factors. Stream discharge and the presence or absence of confining geologic
layers are two factors that are important in predicting concentrations.
Are pesticides and other organic compounds more prevalent in the water, bed sediment, and fish or clam tissue from some land-use settings than from other settings?
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- In streams and ground water, pesticides were more prevalent in agricultural areas than in forested areas. Concentrations generally were low and seldom exceeded U.S. Environmental Protection Agency drinking-water criteria or standards, or criteria for the protection of aquatic life.
- In bed sediment, the greatest numbers of pesticides and other organic compounds generally were detected at sites downstream from urban areas. No concentrations exceeded U.S. Environmental Protection Agency criteria for the protection of
aquatic life.
- In biological tissue, pesticides were detected at 5 of 26 stream sites. Chlordane
was detected downstream from Springfield, Mo. DDT, DDE, or dieldrin was
detected at four sites in agricultural basins.
Are historical or active mining sites affecting the quality of surface water?
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Concentrations of sulfate and some trace elements in water from streams in areas
of active or historical lead-zinc mining tend to be higher than in areas where mining has not occurred. These trace element concentrations decrease with
increasing distance downstream from the mining activity. Concentrations usually
did not exceed Federal standards or criteria for the protection of drinking water,
human health, or aquatic life.
- Concentrations of lead and zinc in bed sediment and fish or clam tissue are substantially
higher at sites with mining activities (historical or active) in the basin.
Concentrations are high enough to suggest potential adverse biological effects.
The State of Missouri has issued a fish consumption advisory for some streams.
Are naturally occurring radionuclides present in ground-water supplies?
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- Radium (a product formed by the radioactive decay of uranium) is present in the
confined part of the Ozark aquifer. However, the levels of radium seldom
exceeded the U.S. Environmental Protection Agency drinking-water
standard.
- Radon (a gas produced by the radioactive decay of radium) levels exceeded a
proposed (but withdrawn) U.S. Environmental Protection Agency drinkingwater
standard in nearly one-half of the samples. Radon can enter homes through
their water systems. Homes served by private domestic wells and small public
waterworks using ground water can be particularly vulnerable.
- Radon levels are greater in the Springfield Plateau aquifer and the unconfined
part of the Ozark aquifer than in the confined part of the Ozark aquifer.
What are some factors that affect aquatic (instream and riparian) habitats of Ozark streams?
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- Several factors can affect aquatic habitats, which then affect biological
communities. Many habitat characteristics appeared to be influenced more
by basin size than by land use.
- Small streams in agricultural areas generally have fewer trees and other woody
plants in the riparian zone than do small streams in forested areas. This results in
more sunlight reaching the streams in the agricultural areas. More sunlight and
the higher nutrient concentrations probably result in faster growing attached
algae in these streams.
- Some other habitat characteristics were different between the agricultural and
forested sites studied. Of these characteristics, some are not likely the result of
agricultural practices, while others (canopy angle, channel width, and sinuosity)
may, at least in part, result from agricultural practices. These characteristics can affect biological communities.
- Although the effects of instream gravel mining in the Ozarks were not studied by
the NAWQA Program, some studies suggest that gravel mining has detrimental
effects on instream habitat.
Are fish communities being affected by land-use activities?
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- Stonerollers make up a greater percentage of the fish at agricultural sites than at
forested sites. Stonerollers graze on algae attached to rocks and other surfaces. More algae probably grow on these surfaces because of the higher nutrient concentrations
and greater amounts of sunlight reaching these streams.
- Sunfish (including the black basses) and darters make up a smaller percentage of
fish at agricultural sites than at forested sites. Members of the sunfish family (particularly
smallmouth bass) are important game fish. Several species of darters that
live in the Ozarks exist nowhere else in the world.
- Fish community composition appears to be related to stream size, canopy angle,
substrate, and water chemistry. Some of these factors are affected by human
activities.
Are periphyton (attached algae) communities affected by land use activities?
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- Periphyton communities are affected by natural and land use factors including nutrients, alkalinity, canopy
shading, stream morphometry, and velocity.
- Total biovolume is not significantly different among
forest, agricultural, and mining sites.
- Blue-green algae biovolume is higher at agricultural
sites than at forest or mining sites.
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