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| This is a stream around which rice fields extend. Phosphorus concentration tends to increase. Transparency is a bit low. |
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This is a straight stream located in an urbanized area. Phosphorus and nitrogen concentration are decreased. COD is a bit increasing. |
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| This is a stream at an exit of a community. Nitrogen and phosphorus concentrations have become greatly low. |
This is also a straight stream located in an urbanized area. COD is a bit increasing as well. |
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