TITLE:
The Distribution and Accretion of Some Heavy Metals in Makkah Wells
AUTHORS:
Nezar H. M. Khdary, Ahmed E. H. Gassim
KEYWORDS:
Makkah Wells, Water Contamination, Heavy Metals, Rural and Urban Areas, ICP/MS
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.6 No.11,
August
20,
2014
ABSTRACT: The aim
of this study is to determine the types of heavy metals frequently present in
Makkah wells and the possible environmental causes of their distribution and
accumulation. Makkah lies in a mountain range dominated by different types of
rocks from the Precambrian and Lower Paleozoic eras, as well as subordinate
sedimentary rocks and basaltic lava flow from the Tertiary and Quaternary
periods. Natural contaminants in Makkah wells water can be attributed to the
unique location. Many epidemiological studies have identified associations
between the ingestion of wells water contaminated with heavy metals and
increased risk of some illnesses. This study presents exclusive information on
the levels and distribution of 9 heavy metals—arsenic, barium, cadmium,
chromium, cobalt, copper, lead, mercury, and selenium—in the wells water in
various rural and urban areas of Makkah city. These naturally occurring
elements are considered significant markers of water purity. More than 160
wells were involved in this three-year investigation. Water samples were
collected during different seasons in order to assess any changes in the
distribution and concentration of these heavy metals throughout the year. The
collected water samples were filtered and digested before analysis using
inductively coupled plasma mass spectrometry (ICP/MS). We found the following
sequence of concentrations of heavy metals in the studied wells: Ba > Se
>Cr > As > Co > Cu> Hg > Pb > Cd. Arsenic, barium,
chromium, and selenium were the most abundant contaminants in the wells
studied. The concentrations of the other heavy metals ranged from non-detectable
to 3 μg/L. Although low, these values are also reported in comparisons with the
local and international strict values and standards which govern the maximum
contaminant levels permitted for long-term daily consumption.