Environmental Geochemistry of Heavy Metals and Plagioclase Background Enrichment Factor in Coastal Sediments at Lumpue - Parepare, South Sulawesi, Indonesia

Abstract

Lumpue Beach is an urban area in Parepare Bay with a harbour, tourism, and a landfill site. The purpose of this research was to determine the provenance, level and distribution of heavy metals in coastal sediments. Surface sediment samples were analysed for grain size, mineragraphy, petrography and total heavy metal content (Cu, Zn, Pb, Co, Ni, Fe). The minimum-maximum background enrichment factor (EF) range was calculated from the plagioclase mineral content of trachyte porphyry and andesite. Weathering alteration was quite high in trachyte porphyry rocks; andesite mineragraphy produced predominantly sedimentary plagioclase (25-45%), hornblende (10-40%), and rock fragments (40-45%). The grab sampling method produced samples dominated by plagioclase (30-50%), hornblende (15-40%) and alkaline chemical conditions were important in Fe, Ni, Pb, Cd, Cr, and Cu enrichment. Enrichment of heavy metals was supported by the mesokurtic-very leptokurtic dynamic sorting characteristics of Lumpue beach, becoming very leptokurtic - platykurtic to the north (Parepare Bay). The enrichment factor (EF) of Pb > 1 was calculated from the concentration of various non-earth sources. The order of heavy metal concentration based on EF 0.5 ≤ EF ≤ 1.5 was Pb> Zn> Cr> Fe> Cu> Ni, with Cu ≤ 0.5, indicating heterogeneous heavy metal sources correlated with urban area, river and ultrabasic regional lithology, with Trachyte-andesite alteration, especially enrichment in heavy metals Ni, Cr, Cu. Index of geoaccumulation (Igeo) was in the ranges: uncontaminated to heavily contaminated for Fe; uncontaminated to moderately contaminated for Cu, Zn, Ni, Cr and Cd; and uncontaminated for Pb. The intensity of heavy metal contamination followed the direction of sedimentation from various sources. Euclidian Cluster distance showed heavy metal distribution patterns correlated with rivers passing through urban areas and with regional geological lithology.