Effectiveness of Water Quality Index for Monitoring Malaysian River Water Quality

Abstract

The Skudai River has experienced a general decline in water quality over the last several years due to agricultural practices, economic development, and other human activities in the river catchment. The spatial trend of water quality index (WQI) and its sub-indexes are important for determining the locations of major pollutant sources that contribute to water quality depletion in the Skudai and its tributaries. In this study, we have developed WQI for eight sections of the Skudai watershed. Ammonia-nitrogen (NH 3 -N) was identified as a major pollutant downstream from the Skudai, with the lowest WQI index (i.e. 38). WQI for the Skudai (natural) was 94, i.e., Class I (very clean) category of river water quality. The Senai River has WQI value of 85 and Class II category (slightly polluted). However, the Kempas River, which was in suburban parts of the Skudai watershed, had WQI of 53 (Class III, polluted). The Melana and Danga rivers were also polluted rivers with WQI of 69 and 57, respectively, in Class III (polluted). Overall water quality in the Skudai and its tributaries was downstream of the river. The study also assessed water quality of the Skudai and its tributaries from other water quality parameters such as conductivity, turbidity, temperature, total dissolved solids, total phosphorous, and nitrogen, which were not part of the WQI formula developed by the Department of the Environment (DOE), Malaysia. The study found that Department of Education (DOE) formula for WQI was not effective in water quality assessment as many important parameters such as nutrients, heavy metals, and fecal coliform (or E. Coli) were missing in the WQI formula.

Water quality evaluation of Al-Gharraf river by two water quality indices

“…The pH in this study ranged 7-7.9, within the Iraqi standard, and each station has almost the same pH. River water tends to be alkaline, because the natural existence of the carbonates and bicarbonates, and that is typical for Iraqi rivers (Naubi et al 2016).…”

“…T in°C, pH in pH unit, FC in CFU/100 ml, Tur. in NTU, and the rest in mg/l BOD is the quantity of oxygen used by bacteria and fungi to break down water organic compounds during 5 days (Naubi et al 2016). In Al-Gharraf River, it ranged from 0.8 to 10.1 mg/l and it was relatively low.…”

“…There are some parameters reaching out of the Iraqi standard for drinking water [World Health Organization (WHO) 2011], WHO for drinking water (Naubi et al 2016), and Iraqi standard for rivers maintaining (IQS 2009); those parameters were temperature (in summer and early autumn), turbidity, total phosphate, BOD, and FC, Table 4. The NSF-WQI values ranged 61-70 demonstrated that the exercises of the general population had no huge negative impact on the water quality particularly on the upper part of the waterway and the nature of the water at each station was verging on same.…”

Study of Water Quality at West Sunter Reservoir, North Jakarta Based on Physical and Chemical Parameters

“…The relative value of DO for water quality standards is 5 mg/L (Alobaidy, 2010). While the value of COD for good water quality of 26 mg/L (Naubi, 2016).…”

Estimate Groundwater Suitability for Drinking Purposes by using WQI Technique in Al-Teeb area- Maysan Governorate - South Iraq

“…The benefit of WQI value includes the skill to represent measurements of a selection variable in a single number, and the capacity to combine various measurements in a single metric value, in addition to the facilitation of communication the results [8]. (WQI) is used to relate a group of parameters to a common scale and combining them into a single number [9]. It is one of the most effective tools to provide reaction on the quality of water to the plan makers and environmentalists.…”