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| Titel |
Reconstruction of the pollution history of Mumbai mudflat sediments using magnetic, chemical, and 210Pb dating methods |
| VerfasserIn |
Ulrich Blaha, Basavaiah Nathani, Deenadayalan Kannan, Dnyandev Vaman Borole, Ramesh Dadu Mohite |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048887
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| Zusammenfassung |
| The onset and rise of urban and industrial pollution in Mumbai was reconstructed from an
anthropogenically contaminated mudflat sediment profile situated at Thane Creek estuary
using magnetic parameters, polycyclic aromatic hydrocarbon (PAH) data, metal contents and
the 210Pb dating technique. The 1.8 m vertical section at Airoli, which is located in the
north-eastern part of Thane Creek in the Navi Mumbai area reveals an increase of magnetic
susceptibility (Ï) from background values of (20-50) to (75-100) Ã 10Ë-8 [mË3 kgË-1] in the
anthropogenically affected zone above ~93 cm. A sharp rise of Ï from (75-100) to (130-215)
à 10Ë-8 [mË3 kgË-1] subdivides the anthropogenically affected zone at a depth of
~63 cm. Characterization with rock magnetic parameters (SIRM, Soft IRM and
S-ratio) reveals a significant contribution of ferri(o)magnetic phases in the upper zone.
Based on the magnetic classification, sampling intervals for cost-intensive PAH and
metal analyses were determined. Steadily increasing contents of PAH and metals
of anthropogenic origin are observed above the boundary depth at ~93 cm. For
example, Pb, Zn and Cu as well as their pollution load indices (PLIS) increase
continuously towards the top of the profile. A sediment accumulation rate of 1.2±0.3
cm/yr provided by 210Pb dating dates the ~63 cm boundary to 1951. Increasing
industrial activity, including the establishment of a coal-fired power plant in 1956, and
refineries between 1955 and 1960, correlates well with the substantial increase of Ï,
PAH and metal contents. Scanning electron microscopy (SEM) investigation on
magnetic extracts from the contaminated zone reveals the presence of magnetic
spherules derived from industrial high-temperature processes. These spherules and other
anthropogenic particles which are embedded in the upper part of the sediment section are
responsible for the magnetic changes along the profile. The visual observation of a
significant amount of anthropogenic particles in the younger sediment part supports the
information provided by magnetic data as well as the enhancement of anthropogenic
pollutants with respect to an increasing environmental stress in the Mumbai region. |
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