M8 PM Chiral Chemistry: Toxicology of Environmental Contaminants and Phase Transfer
Monday, 14 November 2005: 1:50 PM - 5:30 PM in 337-338

(MAT-1117-740527) Movement of Bioavailable Contaminants from ex planta to in planta Regions of the Soil/Plant System: Differences among Cucurbitaceae Cultivars.

Mattina, MJ¹, Eitzer, B¹, Iannucci-Berger, W¹, Isleyen, M¹, White, J², ¹ Department of Analytical Chemistry, CT Agricultural Experiment Station, New Haven, CT, USA² Department of Soil&Water, CT Agricultural Experiment Station, New Haven, CT, USA

ABSTRACT- Data from field and greenhouse studies conducted in the past have established the exceptional ability of plants of the Cucurbitaceae family to uptake soil-sequestered pollutants. In the present set of experiments three representative Cucurbitaceae, Cucurbita pepo spp. pepo (cv. ′Black Beauty′), Cucurbita pepo spp. ovifera (cv. ′Zephyr′), and Cucumis sativis (cv. ′Marketmore′) were grown in rhizotrons containing soil contaminated with highly weathered technical chlordane, dichloro–diphenyl–ethanes and –ethenes, and polyaromatic hydrocarbons. Movement of the contaminants through the soil/plant system was studied by comparing contaminant concentration in the bulk soil, soil pore water, whole root tissue, xylem sap, and whole aerial tissue. Techniques were developed for collecting rhizosphere soil pore water and analyzing it to determine concentrations of organic pollutants. This permitted calculation of bioconcentration factors (BCFs) based on concentration of the analyte of interest in the xylem sap versus that in the pore water. The bioconcentration factors so determined for the sum of five chlordane residues (two enantiomers of trans-chlordane, TC; two enantiomers of cis-chlordane, CC; and achiral trans-nonachlor, TN) were 36, 40, and 23 for ′Black Beauty′, ′Zephyr′, and ′Marketmore′ respectively. Furthermore, there was consistent enantioselectivity based on cultivar noted for some of the chiral chlordane components. For the sum of dichloro–diphenyl–ethanes and –ethenes the comparable BCF values were 19, 4, and 0.8. Fluxes in ng/hr/root mass for chiral and achiral contaminants also showed consistent differences among cultivars. Thus, passage from the ex planta to the in planta regions of the soil/plant system is dependent on both the organic pollutant and the cultivar. Empirical data from this set of rhizotron experiments provide insight into mechanisms of movement of highly hydrophobic organic contaminants from ex planta to in planta portions of the soil/plant system

Key words: hydrophobic contaminants, enantiomeric pollutants