HISTORY OF TRACE-METAL POLLUTION IN SABINE-NECHES ESTUARY, BEAUMONT, TEXAS

Sabine-Neches Estuary, near Beaumont, TX, receives wastewater effluent s from over 160 industrial and municipal treatment plants. The concent rations of trace metals (Go, Cr, Cu, Ni, Pb, and Zn), Al, Fe, Mn, and organic carbon were determined in four dated sediment cores. A reliabl e geochronology and reconstruction of the history of trace metal input s of these sediments was possible because the Pu-239,Pu-240 profiles c losely trace the bomb fallout history into the environment. Down-core variations of aluminum-normalized enrichment factors for these metals demonstrate that the sediments of this estuary have remained relativel y 'pristine' with respect to trace metal contamination since 1860. Whi le the concentrations of Pb and Zn at various depths in the sediment c olumn are slightly enriched, Co, Cr, Cu, and Ni are depleted. The sedi mentary and biogenic particles that are presently being deposited are also depleted in trace metals. Lack of strong enrichment for trace met als like Cu can be attributed to the short residence time of water, lo w salinity conditions, and possibly strong complexation of these metal s with organic matter.