Name: Andy
Status: Student
Grade: 9-12
Location: OK
Country: United States
Date: May 2006
Question:
In a wetland, what would a high level of chloride
mean in a pond?
In earth science class we did a lab and I tested
for chloride. The level was the highest on the card, and I was just
wondering if it could be hazardous or if it helped to cleanse the
water.
Replies:
It is difficult to generalize what impact elevated levels of chloride
would have on a wetland or pond. Some species of plants and animals tolerate
high levels of chloride quite well. Others do not. Some ponds and wetlands
are "naturally" salty because they are near an ocean. It also depends upon
what the cation associated with the chloride is. Sodium would have a
different impact than calcium, for example.
The way to determine the effect of high chloride levels would be to
conduct an inventory of the plants and aquatic animals in the test pond and
compare that distribution of plant and animal population from a similar pond
that has a low level of chloride. Such studies aren't easy because effects
may be delayed and the chloride level may vary. For example, if the source
of the chloride was runoff from salting a nearby highway. The elevated
chloride may only last a matter of days and its effects might be minimal. On
the other hand, if the source of chloride is constant, one could see very
different effects.
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