Sources, Vertical Fluxes and Accumulation of Petroleum Hydrocarbons in Sediments from the Mandovi Estuary, west Coast of India

Document Type: Original Research Paper

Authors

CSIR – National Institute of Oceanography, Dona Paula, Goa - 403 004, India

Abstract

The Mandovi estuary is highly influenced by mining and tourism related activities in the central
west coast of India. Vertical fluxes and accumulation of petroleum hydrocarbons (PHCs) in three sediment
cores (D1, C1 and OG) from the Mandovi estuary were assessed using Ultra-Violet Fluorescence (UVF)
spectroscopy. The range of PHCs values in estuarine sediments varied from 5.4 to 12.34 μg/g Enrichment of
PHCs values in the upper parts of three sediment cores were mostly derived from terrestrial and marine
related sources including petrogenic (discharge of land based effluents and petroleum products), pyrogenic
(emission of fly ash from industries and vehicles and combustion of petrol from ore-filled barges, boats and
ships) and biogenic (mangrove vegetation along the banks of the estuary) sources. The significant positive
relationship between mud (silt + clay) and PHCs unveiled that high specific surface of area of mud content
raise the level of petroleum hydrocarbons. Cluster analysis was used to discriminate the sediment samples
based on their degree of contamination. Values of PHCs in the upper part of sediment cores were distinctly
higher than the background but were lower than those found in the Thane creek, west coast India (7.6–42.8
μg/g) and off Chennai, east coast of India (1.8 – 39.72 μg/g). This baseline PHCs data can be used for regular
ecological monitoring and effective management for the mining and tourism related activities in the Mandovi
estuary.

Keywords