Characterisation of Temperate Urban Lacustrine Surface-Sediments for Minerals and Metals in Comparison with Geochemical Indices and Sediment Quality Criteria ()
ABSTRACT
The present surface sediment assessment in two
temperate lacustrine ecosystems in the region of anthro-urban intensification
in less than a century of progressive human history identifies ecosystem
responses through space-time monitoring of variable spectrum and their
gradients. Sediments have almost no outliers in box-plots across the select
sites that suggest their tranquil nature. But temporal fluctuations in pH,
bicarbonates, conductivity, OC, OM, TN and C/N can be visualised during Ca-Si
dominance. The estimated percentage elemental composition of surface sediments
on dry weight basis revealed the order Si > Ca > Mg > K > Na > P > S > Cl. Besides, the micro and trace
element quantification represent the descending series of Fe > Al > Zn
> Mn > Cu > Cr > Ni > Co > As > Sn > Pb > Cd while
Hg and Se remained below detection level (BDL). Sediment pH remained on the
basic side but slight acidic nature is noticed during late summer. Significant
correlation occurs for conductivity with organic C and organic matter (p <
0.01) as the latter serves an established source for nutrient ions. Similar is
the case with sediment organic C, organic matter and total N as being
complementary to one another. A general slight gradual decline in nutrient
concentration till culmination of active macrophytic growth phase can be
associated with active/passive bioaccumulation or anoxic release from
sediments. The Enrichment Factor classifies each trace element into “No
Enrichment” class to “Very High Enrichment” category. The Geochemical Index (Igeo)
scale labels “Unpolluted” to “Highly Polluted” element groups in sediments. The
construal of Contamination Factor differentiates between “Contaminated” and
“Uncontaminated” score of elements. Integrated Pollution Index (IPI) and
Pollution Load Index (PLI) also categorize the sites and lakes. Sediment
Quality Guidelines (SQG’s) when compared to observed mean values for various
elements point to pollution status and associated ecological risks involved.
Share and Cite:
Nazir, U. and Khan, A. (2018) Characterisation of Temperate Urban Lacustrine Surface-Sediments for Minerals and Metals in Comparison with Geochemical Indices and Sediment Quality Criteria.
Journal of Environmental Protection,
9, 1092-1112. doi:
10.4236/jep.2018.910068.
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