Assessment of Drinking Water of Al-Abbasia River using Water Quality Index
Authors: AL-Janabi Wisam Sabah , Berktay Ali 
Published: May 2022

Water Quality Index (WQI) is one of the most effective indicators assessing the water quality of the surface water. The
Water Quality Index was used to determine the quality of raw water used for drinking purposes at the AL-Abbasia
River. The water samples were taken from six stations along AL-Abbasia River for during a twenty - month period
started from January to October in (2019) to (2020). fifteen parameters of water quality were evaluated including
Temperature (C°), Hydrogen power (pH), Total Hardness (T.H), Turbidity (Turb.), Total Dissolved Solid (T.D.S),
Chloride (Cl-), Calcium (Ca+2), Electrical Conductivity (E.C.), Magnesium (Mg+2), Sodium (Na+), Potassium (K+), Sulfate
(SO4
-2), Total Suspended Solids (T.S.S), Aluminum (Al). Data analysis revealed that some of these parameters exceeded
the World Health Organization (WHO) standards such as Total Hardness (T.H), Total Dissolved Solid (T.D.S),
Magnesium (Mg+2) and Sulfate (SO4
-2). Other parameters were within the WHO standards. In this thesis three different
methods were used to calculate WQI, the WAWQI, CWQI, and Nemerow’s Pollution Index. For WAWQI, the computed
overall WQI value of all samples and stations along AL-Abbasia River was (64.5) which implies that the water was
generally "poor". The computed monthly overall WQI along AL-Abbasia River for all samples and stations was (64.114).
The monthly WQI variation ranged to a higher value of (78.42) in February 2019, due to high pollutants and heavy
rainfall in this month and a lower value of (53.92) in July 2019 along AL-Abbasia River, and classified as (very poor) in
terms of drinking water quality. The annual river water quality index variation along AL-Abbasia River ranged between
(64.31) " Poor quality" at the upstream near station (A1) and (64.1) "poor" at the downstream near station (A6) which
indicates that the ratio is very close between the river upstream and downstream. The water quality assessment was
recorded as “poor” because of the high values of Total Hardness (T.H), sulfate and Total Dissolved Solid (T.D.S) where
it exceeded the limits. If we excluded (T.H, sulfate and T.D.S) values from water assessment, the result will be changed
from (64.5) to (48.86) and the quality of water will be changed from “Poor” to “Good”. According to CWQI, the result
calculated by Canadian Water Quality Index method showed that the water quality was fair along the main stream of
AL-Abbasia River. The annual average water quality index recorded during the two years was fair in the upstream at
station A1 with a value of 74.57 and downstream at station A6 with a value of 61.6. The water quality index during
2019 ranged between fair at A1, A2, and A6 stations and good at A3, A4, and A5 stations with a value ranged between
61.04 at A2 and 82.83 at A3. The water quality index during 2020 year ranged between fair at A1, A2, A3, A4, and A6
stations and marginal at station A5 with values between 77.63 at station A1 and 58.23 at station A5. The Nemerow’s
Pollution Index is another method used to calculate WQI. This method gives a statistical analysis to show the state of
the river water quality for each parameter and each station along the river. When the value of NPI is greater than 1,
then this means that there is a high concentration of this parameter, thus increasing the water pollution. The results
obtained from this method indicate that high sulfate, T.H, and turbidity concentrations had a significant impact on
water quality during the study period. In 2019, The high NPI was recorded for SO4 and T.H for all stations during the
study period, while in 2020, the highest NPI was recorded for T.S.S, SO4, T.H, T.D.S, Mg, and turbidity.