MA6 Environmental Chemistry and Toxicology of Chiral Pollutants
202 Oregon Ballroom
8:00 AM - 12:00 PM, Monday
() Opportunistic Analytes: What Are Chiral Pollutants Trying to Tell Us About POPs Movement in the Soil-Plant System? Part B.
Mattina, MJ1, Eitzer, B1, Iannucci-Berger, W1, Isleyen, M1, White, J2, 1 CT Agricultural Experiment Station, Department of Analytical Chemistry, New Haven, CT, USA2 CT Agricultural Experiment Station, Department of Soil&Water, New Haven, CT, USA
ABSTRACT- Technical chlordane was introduced as an agrochemical in the late 1940s. Although the commercial formulation contained more than 140 compounds, approximately 30% by weight consisted of three active ingredients: chiral trans-chlordane, chiral cis-chlordane, and achiral trans-nonachlor. Over time these highly hydrophobic insecticides became sequestered within the soil matrix. Terrestrial plants, grown in soils contaminated with chlordane or other persistent organic pollutants (POPs), for example DDE, dioxins, furans, and polyaromatic hydrocarbons (PAHs) have not evolved mechanisms for the uptake and transport of the contaminants. If such contaminants are found in planta, it is reasonable to assume that the analytes are opportunistically crossing the root membrane, probably on the ′coattails′ of mechanisms evolved for acquisition of materials essential to the plant′s physiology. Rhizotron trials were established in which plants from the Cucurbitaceae family were grown in a well-characterized, contaminated soil. Bulk soil and the whole plant tissue compartments of root and aerial tissue were collected. Methods were developed for in situ collection of rhizosphere soil, soil pore water, and xylem sap. Each compartment was analyzed for all or some of the following analytes: elements (e.g., iron, cadmium, phosphorus), organic pollutants (e.g., chlordane components, DDE, PAHs). In addition, low molecular weight organic acids in the root exudates were determined via two approaches. The patterns of the enantiomeric fractions and the component fractions of the chlordane residues as the pollutant moves from the bulk soil, to the soil pore water, to the xylem sap are consistent and unique for a given plant. The data will be interpreted in terms of potential mechanisms of contaminant transport both ex and in planta.
Key words: POPs, rhizosphere, Cucurbitaceae