Superfund Research Program
PAH Bioremediation and Monitoring in Biowalls
Project Leader: Paul L. Bishop
Grant Number: R01ES015446
Funding Period: 2006-2009
Polycyclic aromatic hydrocarbons (PAHs) are significant pollutants at Superfund sites. They are often toxic and may be carcinogenic. Consequently, research is needed on practical methods to remove the PAHs from contaminated groundwater. PAHs are usually accompanied at these sites by heavy metals such as arsenic and cadmium. Unfortunately, little is known about the interactions between PAHs and heavy metals and the effect the presence of these metals may have on PAH bioremediation. Complex mixtures of toxic organics and metals are difficult to study and have, therefore, been largely ignored.
The goal of this research was to develop an integrated, reusable, polymer lab-on-a-chip (LOC) sensor system for long-term, rapid, efficient, and cost-effective monitoring of trace heavy metals in not only groundwater, but also surface waters such as oceans, rivers, lakes, and reservoirs. The research team successfully developed a disposable polymer LOC using a planar bismuth (Bi) electrode for heavy metal measurement and has incorporated the LOC devices into an automatic analyzer to perform on-site heavy metal sampling and monitoring in groundwater at shallow depths. One of the drawbacks of use of ready-to-use bismuth electrodes along with an integrated Ag/AgCl reference electrode and a gold counter electrode has been that it is typically a single-use disposable device, which is not an environmentally friendly and cost-effective way to continuously monitoring trace heavy metals at sampling sites. However, by replacing the single-use disposable polymer LOC using deposited-metal electrodes with a novel reusable polymer LOC using a thick-wire electrode, a new reusable polymer LOC was developed that could provide improved long-term stability of the LOC sensor, reproducibility of analyses, and renewability of electrode surfaces, as well as the convenience of easy fabrication.
Accordingly, it can be readily adapted to various environmental applications, such as in soils, rivers and streams, even in remote locations that are hard to be reached. In this project, based on the findings from previous and on-going studies, research was undertaken to build an advanced reusable polymer LOC sensor system to achieve long-term and continuous sampling and monitoring of heavy metals.