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WHAT
IS IT?
Total suspended solids
(T.S.S.) are particles of sand, dirt, soil, silt, plant debris,
microscopic organisms, and other solids floating in the water.
One of a river's natural functions is to carry T.S.S. from natural
erosion to the oceans. The Mississippi River is naturally high
in solids, and in Louisiana, T.S.S. approaches 300mg/L.
Faster
flowing water transports more solids. Coarse material settles
out first, followed by finer and finer material. Some fine solids
always remain suspended in the water.
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WHY
IS IT IMPORTANT?
1. Suspended
material can clog or damage fish and insect gills.
2. Suspended material can cover spawning beds, inhibiting
reproduction of fish and other organisms. Sand, dirt and other
solids settle on eggs, suffocating them by preventing oxygen
from getting to them. Sedimentation can also clog up spaces between
rocks in the streambed. These spaces for used by aquatic organisms,
and therefore, sedimentation can reduce available habitat.
3. Total suspended solids can cary toxins with them as they move downstream.
They can then be released downstream. Therefore, if T.S.S. is
high, toxins have more opportunities to find sites on which to
transport themselves.
4. Solids can affect the productivity of aquatic ecosystems:
Water quality criteria for suspended solids
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Less than 25 mg/L T.S.S. |
No harmful effect on fisheries |
|
25-80 mg/L T.S.S. |
May reduce fish production |
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80-400 mg/L T.S.S. |
Unlikely to support good fisheries |
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Greater than 400 mg/L T.S.S. |
Poor fisheries likely |
Source: Alabaster and Lloyd (1980)
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WHAT
INFLUENCES IT?
1. Non-point
Source Pollution: Non-point source pollution can come from logging,
agriculture, ranching, construction, developmnent, pavement,
dirt roads, construction of culverts (or failing culverts), channelization,
etc.
2. Point Source
Pollution: Point source pollution can come from industry, waste
water treatment plants, aqua culture industry, etc.
3. Geology and Soil: As a river flows over land, the
amount of suspended solids in the water accumulates depending
on the geology, soils, and geography of the surrounding area.
4. Climate and Precipitation.
5. Stream Velocity: Faster flowing water transports
more solids. When the water slows or ceases to flow, the suspended
matter is deposited on the bottom of the lakes or stream. Coarse
material settles out first, followed by finer and finer material
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