Research Article
Assessment of a Physicochemical Indexing Method for Evaluation of Tropical River Water Quality
Table 3
The guidelines of water quality according to the National Water Quality Standards (NWQS) for Malaysia.
| | Parameters | Classes | | I | IIA | IIB | III | IV | V |
| | pH | 6.5–8.5 | 6–9 | 6–9 | 5–9 | 5–9 | - | | Conductivity (μS/cm) | 1000 | 1000 | - | - | 6000 | - | | TSS (mg/L) | 25 | 50 | 50 | 150 | 300 | 300 | | Turbidity (NTU) | 5 | 50 | 50 | - | - | - | | DO (mg/L) | 7 | 5–7 | 5–7 | 3–5 | <3 | <1 | | BOD (mg/L) | 1 | 3 | 3 | 6 | 12 | >12 | | COD (mg/L) | 10 | 25 | 25 | 50 | 100 | >100 | | NH3-N (mg/L) | 0.1 | 0.3 | 0.3 | 0.9 | 2.7 | >2.7 | | FCC (counts/100 mL) | 10 | 100 | 400 | 5000 (20,00) | 5000 (20,00) | - |
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Maximum not to be exceeded.
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