Typical dissolved oxygen levels in river water are around _____________ ppm?
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Answer: A. 5
Explanation
Healthy natural river water typically contains dissolved oxygen around five parts per million. Aquatic ecosystems require adequate dissolved oxygen levels to sustain fish and macroinvertebrates. Oxygen dissolves into river water from atmospheric aeration and photosynthetic aquatic plant activity. Dissolved oxygen measures the amount of gaseous oxygen dissolved in aqueous aquatic systems. Water temperature heavily influences oxygen solubility, with colder water holding more gas. Biological oxygen demand from pollution can deplete natural river oxygen levels rapidly.
Environmental agencies monitor river water quality to protect native fish and aquatic wildlife. Wastewater treatment plants aerate effluent before discharge to prevent river oxygen depletion. Low dissolved oxygen concentrations serve as a primary indicator of organic water pollution. One hundred parts per million exceeds natural aquatic saturation limits for river water. Two hundred fifty parts per million is chemically impossible for normal ambient surface water. Five hundred parts per million is excessively high and found only in specialized oxygenated waters.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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