LEAD ISOTOPES AND HEAVY METAL CONCENTRATIONS IN GALVESTON BAY, TEXAS SEDIMENTS

Galveston Bay, Texas, is an anthropogenic estuary where industrial runoff, wastewater, and vessel oil enter the bay with freshwaters. These freshwaters can contain heavy metals, either dissolved in the waters or sorbed onto inflowing sediments, that can be toxic for marine organisms [1]. Galveston Bay surface sediments were analysed for heavy metal concentrations and Pb isotopes to identify heavy metal pollution hotspots, understand pollutant mobility, and constrain pollutant sources [2]. During sediment analysis all samples underwent a leaching procedure to distinguish leachable pollutant Pb from residual non-pollutant Pb [3]. Preliminary leachate Pb isotope data form a nearly linear array in isotope-isotope ratio space indicating the mixing of two or three dominant Pb inputs to the area. Comparison of the leachate isotopes with literature data suggests that pollutant Pb from U.S. and Central American aerosols and old U.S. Pb smelters/refineries may be influencing the bay. These pollutant sources might be expected from Houston area industries [4, 5]. Analysis of heavy metal concentration data (Pb, Cr, Ni, Cd, Zn, Sb, As, Hg) from June 2017-June 2019 will also be used to assess the spatiotemporal variability of pollutant fluxes to Galveston Bay, especially in the context of enrichments over lithogenic loadings, effectively shedding light on local estuarine pollutant cycling and potential toxicity to benthic ecosystems.

[1] Tchounwou et al. (2012) Mol. Clinl. & Env. Toxicol. 101, 133-164. [2] Komarek et al. (2008) Env. Intl. 34, 562-577. [3] Berger et al. (2002) Jour. Geophy. Res. 113, 1-16. [4] Rabinowitz (2005) Sci. of the Tot. Env. 346, 138-148. [5]