Sampling device optimization for organochlorine pesticides

Abstract

In this study, miniature sampling devices consisting of a polymeric bag filled with organic solvent were exposed to an aqueous solution containing organochlorine pesticides in environmental relevant concentration. The relative amount of contaminant accumulated from the water column was compared with respect to the following chemical and physical properties of the contaminant: the relative molecular length, the degree of chlorination, and the Henry’s law constant. The solvent/membrane systems accumulated contaminants to high levels and readily approached equilibrium fast. The polypropylene system was more universal in contaminant uptake. The membrane concentration factors (MCFs) calculated ranged from null to 1446 and were less than the biological concentration factors (BCFs) reported in literature due to the complex nature of biological systems. Dieldrin, the only oxygenated compound in the study did not follow a linear regression when the log MCF was plotted against the physical properties of the contaminant. The study showed a linear relationship of at least 4 orders of magnitude between the concentration of the contaminants accumulated by the devices and the original concentrations in the aqueous phase. The number of chlorine atoms, the molecules’ relative molecular length, and Henry’s law constant affect the equilibrium concentrations of the contaminant in the sampling device.
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Keywords: Sampling, membrane, polymeric, uptake, contaminants, equilibrium