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Hebron aquifer contamination with heavy metals

A total of 20 groundwater samples were gathered from Where Qi and Wi represent the sub-index and
20 different locations. Each sample was collected in unit weight of the i-th parameter, respectively; n
separate polypropylene bottles (Sigma, Germany) that denotes the number of parameters considered; Mi, Ii,
had been pre-conditioned and acid-washed. These and Si correspond to the monitored values, the ideal
samples were then filtered and treated with concentrated value, and the standard values of the i-th parameter,
nitric acid (Sigma, Germany) to lower the pH below respectively; − denotes the numerical difference
2.0, preventing precipitation and minimizing adsorption between values, without considering the algebraic sign.
onto the walls of the container. The metal quality index (MQI) serves as an early
Before filling, each bottle was thoroughly washed three warning threshold, where a value below one is the
to five times with groundwater from the sampling site to threshold of warning. MQI was calculated using
ensure integrity. An atomic absorption spectrophotometer Equation V.
(PerkinElemer, USA) was used to measure the
concentrations of heavy metals in the acidified filtrates. MQI n i1 Mi (V)
Si
2.3. HPI measurement Where n denotes the number of parameters considered;
The HPI is a quantitative tool used to assess the Mi and Si correspond to the monitored values, the
combined impact of individual heavy metals on the standard values of the i-th parameter, respectively.
overall quality of drinking water. Ranging from The HPI categorizes water quality into three levels:
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0 to 1, the HPI rating presents the relative significance low (HPI <100), threshold risk (HPI = 100), and high
of each quality parameter, and its deviation from the (HPI >100). When HPI exceeds 100, the water is
recommended standard (Si). 39-41 deemed unsuitable for drinking. The HPI values for the
The HPI was calculated following these steps: first, dry and wet seasons are presented in Tables 1 and 2. 42-44
the weight of each parameter (Wi) was calculated; In addition, the heavy metal evaluation index (HEI)
then the quality rating (Qi) for each heavy metal was was used to assess the quality of the water, specifically
determined; finally, the sub-indices were summed to targeting heavy metal contamination. The HEI was
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obtain the overall index. determined using Equation VI.
The Wi of each parameter (i) was determined using
Equation I. HEI n Hc (VI)
Wi = K/Si (I) i1 Hmac
Where Wi denotes the unit weight, Si is the Table 1. Water quality scale based on the heavy
recommended standard for the i-th parameter, and K is metal pollution index (HPI) 42
the proportionality constant. HPI (%) Water quality
The Qi for each metal was calculated using
Equation II. 0 – 24 Excellent
25 – 49 Good
Qi = 100 Vi/Si (II) 50 – 74 Poor

Where Qi represents the sub-index for the i-th 75 – 100 Very poor
parameter, Vi is the measured value of the i-th parameter >100 Unfit for drinking
(in µg/L), and Si is the standard or permissible limit for
the i-th parameter.
The HPI value, which indicates the overall quality Table 2. Water quality classification using metal
43,44
of the drinking water in relation to heavy metals, was index (MI)
calculated using Equation III and Equation IV. MI Characteristic Class
<0.3 Very pure I
n Wi Qi 0.3 – 1.0 Pure II
,
HPI i1 (III)
n Wi 1.0 – 2.0 Slightly affected III
i1
2.0 – 4.0 Moderately affected IV

Qi i Mi () Ii 100 (IV) 4.0 – 6.0 Strongly affected V
Seriously affected
>6.0
VI
Si Ii
Volume 22 Issue 2 (2025) 55 doi: 10.36922/AJWEP025040020