SBIR-STTR Award

Mercury is a hazardous pollutant that threatens human and ecosystem health, and exists in many contaminated subsurface environments. Monitoring mercury contamination in groundwater is challenging due to the considerable effort and expense involved in collecting samples, maintaining sample integrity during transport and storage, and subsequent laboratory analysis. These constraints often make high frequency sampling unfeasible and limit opportunities for long-term monitoring. Yet mercury export from contaminated subsurface systems and input to surface waters is often episodic, with the majority of the load coming during storm events. At present, it is virtually impossible to characterize the mercury dynamics of such systems. In order to decrease the effort and expense associated with field sampling and subsequent laboratory analysis for mercury determination, we propose an automated, field-deployable mercury monitoring system for groundwater and surface water. This system will run unattended, and will be capable of storing data or transmitting it to a remote location. In order to have sufficient sensitivity to measure mercury concentrations in uncontaminated waters, as well as the dynamic range required to measure contaminated sites, the system will incorporate an atomic fluorescence detector. To avoid the use of reagents, the system will be based on thermal decomposition of the sample and catalytic oxidation of combustion products. The proposed system will use a sample injection loop system to introduce a sample into a combustion chamber. The sample will be evaporated and later combusted in the chamber, before being swept downstream, through a catalytic oxidation chamber, under purified air flow, to a gold amalgamation trap. The sample will be thermally desorbed from the gold amalgamation trap under ultra-pure argon flow, and will be quantified by a highly sensitive atomic fluorescence detector. The proposed system will be useful to the managers of sites contaminated with mercury in the subsurface and surface water, including the U.S. Department of Energy, because it will reduce the cost of monitoring and increase the amount of data available. It will be useful to researchers involved in long-term monitoring projects, studying remote sites, or interested in increasing the efficiency of field sampling campaigns. It will also be useful to the operators of large environmental monitoring networks, such as the Mercury Deposition Network or the U.S. Geological Survey stream gauge network, because it will allow for data collection at greater frequency than is currently available.

Monitoring mercury contamination in groundwater, surface water, and other natural environments is challenging and expensive, and because samples have to be collected in the field and analyzed in a laboratory, there is a long delay before results are available. The expense of monitoring limits the number of samples researchers collect, which can lead to inaccurate estimates of mercury contamination. The delay in the availability of results makes it difficult to remediate subsurface mercury contamination, because it can take months to accurately trace a contaminant plume to its source. The lack of mercury data leads to uninformed public health and environmental management decisions. To address these problems, we have developed a prototype instrument that collects water samples and analyzes them for total mercury in the field. It does not use any reagents, which makes it inexpensive to operate and allows it to run for periods of weeks to months without human intervention. It measures mercury with an atomic fluorescence detector, giving it sufficient sensitivity and range for both natural and contaminated systems. The instrument can be monitored and controlled and data can be accessed by Wi-Fi, cellular, or satellite data network from a web browser on a computer or smartphone. During Phase I of this project, we built a working prototype that quantitatively measures mercury but cannot run unattended for long periods of time. During Phase II, we will refine the design of the instrument and several components to improve its unattended runtime and prepare it for extended field testing. We will field test one instrument near our offices in Seattle, and will send four others to potential customers for beta testing at sites around the country. These beta testers represent a wide range of potential applications of the new instrument: from monitoring of natural surface water, to contaminated groundwater monitoring, to wastewater treatment plant optimization. Commercial Applications and Other

Benefits:
Once commercialized, the instrument will have numerous benefits for the mercury research and regulatory community and the public. It will greatly lower the cost of field sampling and analysis, which will enable much more mercury monitoring than is currently possible. It will make real-time data available both to researchers in the field and to the public via the internet. Enhanced mercury data availability will lead to better regulatory and environmental management decisions to protect public health, and will lead to a public better-informed about the water quality around them. We expect this project to generate 5.5 new permanent full time-equivalent jobs.