Refined Tunable Methodology for Characterization of Contaminant–Particle Relationships in Surface Water
- Christopher H. Marvin *a,
- Gary G. Leppardab,
- M. Marcia Westbc,
- Gary A. Sternd,
- Adrienne R. Bodene and
- Brian E. McCarryf
- a National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6
b Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1
c Electron Microscopy Facility, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada L8N 3Z5
d Freshwater Institute, Department of Fisheries and Oceans, 501 University Crescent, Winnipeg, MB, Canada R3T 2N6
e Ontario Ministry of the Environment, 125 Resources Road, Toronto, ON, Canada M9P 3V6
f Department of Chemistry, McMaster University, Hamilton, ON, Canada L8S 3Z5
To understand contaminant transport in aquatic systems, it is essential to define the physical characteristics of the primary particulate carriers. The distribution of organic pollutants with particle-size class and particle morphology in a freshwater embayment (Hamilton Harbor, western Lake Ontario) was studied using a sequence of novel sample preparation and characterization techniques. Water samples (24 L) were fractionated according to particle-size distribution using differential cascade sedimentation and centrifugation methods. These size fractions were subsequently subjected to a physicochemical characterization using scanning transmission electron microscopy and energy-dispersive spectroscopy to identify flocs and individual colloidal particles in the size range of 1 nm to 1 mm in diameter. Analytical chemical analyses were performed to identify organic contaminants in extracts prepared from particle-size classes, including polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). The contaminant distribution trends were very similar for all compound classes studied; contaminants were primarily associated with fractions containing particles less than 2 μm in diameter. Morphological characterization of these fractions showed the majority of the particulates to be humic fractals. The results of this study show that contaminants in aquatic systems can be preferentially associated with specific types of particle carriers, the characteristics of which can be clearly defined in terms of size and morphology.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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