Partitioning of polychlorinated dibenzo-p-dioxins and dibenzofurans between the atmosphere and corn

Journal Article · Sat Aug 15 04:00:00 EDT 1998 · Environmental Science and Technology

DOI:https://doi.org/10.1021/es9706920· OSTI ID:653156

Wagrowski, D M; Hites, R A ^[1]

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1. Indiana Univ., Bloomington, IN (United States)

Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) are lipophilic atmospheric contaminants that accumulate in vegetation, a process which may lead to the contamination of food. Thus, knowledge of PCDD/F accumulation in vegetation is crucial to evaluating human exposure. In an effort to determine this accumulation mechanism, the authors analyzed matched atmosphere, corn kernel, and corn leaf samples from a private farm in Felicity, OH. Corn is an important feed crop in the US; both corn kernels and corn leaves (silage) are widely used. PCDD/F concentrations were below the detection limits in the corn kernels. However, they found PCDD/F concentrations of 510 {+-} 75 fg/m{sup 3}, 1,300 {+-} 300 fg/m{sup 3}, and 4.2 {+-} 1.2 ng/g lipids in the atmospheric gas phase, atmospheric particle phase, and corn leaves, respectively. For each set of air and corn leaf samples, the authors calculated corn leaf-atmosphere partition coefficients for both the atmospheric gas and particle phases, K{sub v,g} and K{sub v,p}, respectively. On the basis of plots of the natural logarithm of these partition coefficients versus the reciprocal of the average, atmospheric temperature, they conclude that the partitioning of PCDD/F between the atmosphere and corn leaves is dependent on temperature. They calculated the enthalpies of phase change between the vegetation and air for all PCDD/F homologues; the values are comparable to literature values for polycyclic aromatic hydrocarbons and polychlorinated biphenyls. The ratio of K{sub v,p} to K{sub v,g} is a log-log function of the average vapor pressure for each PCDD/F homologue, indicating that vapor pressure plays an important role in the partitioning of both the gas and particle phases to corn leaves.

• OSTI ID: 653156
• Journal Information: Environmental Science and Technology, Journal Name: Environmental Science and Technology Journal Issue: 16 Vol. 32; ISSN ESTHAG; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
AIR POLLUTION
BENZOFURANS
BIOLOGICAL ACCUMULATION
BIOLOGICAL INDICATORS
DIOXIN
FOOD CHAINS
MAIZE