Abstract:
Metals in the untreated combined wastewater pose a serious threat to the soil
and water environment in general and to human health in particular. Samples from
Paharang Drain, Faisalabad, one of the major carriers of combined industrial,
predominantly textile, and municipal effluents, were collected from six different
locations between July 2008 and December 2008. The objective was to examine the
state of metallic pollution and its variation with time and space. Metal concentrations
in separate industrial and municipal streams falling into the Paharang Drain, were also
studied independently for the baseline development. Metals selected for scrutiny were
Cr, Ni, Cd, Mn, Zn, Cu, Fe, Pb, As and Hg. Standard Methods were adopted for
sample collection, preservation and analysis. Benthic zone soil samples were also
analyzed for the same metals by using the Flame Atomic Absorption Spectrometer
(FAAS) and X-ray Fluorescence technique. Concentrations of most of the metals were
found below Pakistan National Environmental Quality Standards (NEQS) in the
Paharang Drain wastewater. Effects of seasonal variations on metal concentration in
the drain water have also been elucidated. In addition, correlation between metals
concentration and other physicochemical parameters such as pH, total suspended
solids and total organic carbon etc. were examined. Good exponential correlation was
found between metal concentrations and total suspended solids (TSS). Metal
concentrations were found to be more sensitive to temporal variations than spatial
ones. The pollution load indices, bioaccumulation factors, enrichment factors and
geoaccumulation indices of selected metals were also assessed for benthic soil of the
drain.
