Distribution of polychlorinated dibenzo- p-dioxins and dibenzofurans in suspended sediments, dissolved phase and bottom sediment in the Houston Ship Channel

• Published in: Chemosphere (Oxford) 2006, Vol.62 (3), p.417-429
• Main Authors: Suarez, Monica P., Rifai, Hanadi S., Palachek, Randy, Dean, Kirk, Koenig, Larry
• Format: Article
• Language: English
• Subjects: Applied sciences; Benzofurans - analysis; Biological and physicochemical properties of pollutants. Interaction in the soil; Bottom sediment; Dibenzofurans, Polychlorinated; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Monitoring; Exact sciences and technology; Geologic Sediments - chemistry; Models, Chemical; Partitioning; PCDD/PCDFs; Pollution; Pollution, environment geology; Polychlorinated Dibenzodioxins - analogs & derivatives; Polychlorinated Dibenzodioxins - analysis; Soil and sediments pollution; Solubility; Spatial distribution; Texas; Water column; Water Pollutants, Chemical - analysis
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2005.04.088

Spatial distributions of polychlorinated dibenzo- p-dioxins (PCDDs) and dibenzofurans (PCDFs) in the water column and bottom sediments of the Houston Ship Channel in Texas were measured three times over a 1-year period. Total TEQ concentrations in water ranged from 0.01 to 0.25 pg/l for the dissolved phase and from 0.09 to 2.91 pg/l for the suspended phase, while TEQ concentrations in bottom sediments varied from 0.9 to 139.8 ng/kg dry wt. The dissolved concentrations were lower than their respective suspended concentrations, with average dissolved/suspended ratios between 0.11 and 0.59 for individual congeners. More than 89% of the total concentration of 2378-substituted PCDD/PCDFs was attributable to OCDD but 2378-TCDD was the major contributor to total TEQ for the three sampled media. Average logs of organic carbon-normalized suspended sediment–dissolved partitioning coefficients ( log K oc obs ) varied between 4.92 and 8.59 l/kg-oc; while in the bottom sediment–dissolved interface, log K oc obs values ranged from 5.48 to 8.48 l/kg-oc. Observed log K ocvalues varied within a factor of 0.64–1.26 from equilibrium log K oc values, suggesting fluxes of PCDD/PCDFs across the interfaces. It was found that in the HSC, on average, the tendency of a compound to move from the particulate phase to the dissolved phase decreases with increasing K ow.