Evaluation of Contaminated Suspended Sediment in the Exposure Pathway

Abstract

The pollution of surface water in the United States is a significant environmental concern. Pollution from regulated or non-regulated physical, chemical, or microbial contaminants from a wide variety of origins, naturally occurring or manufactured, can significantly impair the quality of surface water. Water quality investigations have historically focused on dissolved-phase concentrations of contaminants alone, though there has been an increasing amount of work done to sample and analyze settled (bed) sediments in recent years. Although some work on examining the release of dissolved contaminants during resuspension has been done, direct investigation of suspended sediment (SS), however, has not been very well incorporated into water quality investigations. The sampling and analysis of SS as a potential exposure source may have increasing importance with regards to the investigation and monitoring of ubiquitous, low-concentration contaminants (metals) or contaminants of emerging concern, such as pesticides, pharmaceutical and personal care products (PPCPs), nanoparticles (engineered or other), and their respective chemical breakdown products. Of even more recent concern is the possibility that nanoparticles (NPs), particles have a size less than 0.1 micron, could be new contaminants of concern. This study is a qualitative evaluation of whether SS sampling and analysis should be included in the performance of environmental investigations. Specifically, this study will consider the metals copper (Cu), iron (Fe), lead (Pb), titanium (Ti), and zinc (Zn). The use of an emerging analytical technique for sub-micron particulates in water, single particle Inductively Coupled Plasma Mass Spectrometry (spICP-MS) will also be examined for its relevance in environmental investigations.