Influence of anoxic pore water dissolved organic matter on the fate and transport of hydrophobic organic pollutants
Pore water dissolved organic matter is an overlooked pool of organic matter important to the environmental fate of hydrophobic organic pollutants. The association of polychlorinated biphenyls, polyaromatic hydrocarbons and chlorinated pesticides with pore water dissolved organic matter influences their distribution and mobility within the bottom sediment environment. Steep physical, biological and chemical gradients at the sediment/water interface isolate the pore water and create unique conditions within the sediment. This study indicates that any disturbance of this environment will alter the distribution and mobility of organic pollutants by changing their association to the pore water dissolved organic matter. A small volume closed equilibration method was developed to measure the solubility enhancement of 2,2' 4,4'-tetrachlorobiphenyl (TeCB) by natural dissolved organic matter. Chemical coated micro-glass beads were equilibrated with anoxic and laboratory aerated (oxic) pore water samples in flame sealed ampules. The TeCB enhanced solubilities were used to determine the pore water dissolved organic matter partition coefficient, K[sub pwdom]. The measured TeCB solubility and K[sub pwdom] were much smaller for anoxic than oxic pore waters. The dissolved organic matter sorptive capacity for the TeCB increased as the water was aerated. This change is attributed to coagulative fractionation and structural changes of the pore water dissolved organic matter during aeration and was characterized by differences in the dissolved organic matter concentration, UV absorption at 254 nm, interfacial surface tension, and sorption capacity of molecular weight fractions of anoxic and oxic pore water dissolved organic matter. The increase in partitioning indicates that there will be an increase in the mobility of the TeCB as an anoxic bottom sediment environment is disturbed and aerated.
- Research Organization:
- Drexel Univ., Philadelphia, PA (United States)
- OSTI ID:
- 6086085
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540320* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
ANAEROBIC CONDITIONS
AROMATICS
CHLORINATED AROMATIC HYDROCARBONS
DISTRIBUTION
ENVIRONMENTAL TRANSPORT
HALOGENATED AROMATIC HYDROCARBONS
HYDROCARBONS
MASS TRANSFER
MATTER
MOBILITY
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC MATTER
PESTICIDES
POLLUTANTS
POLYCHLORINATED BIPHENYLS
SEDIMENTS
SOLUBILITY
SPATIAL DISTRIBUTION