Project 1: Developing In Situ, Real-Time Sensors for Toxicants at Superfund Sites

Public health personnel and environmental engineers need timely and complete information to protect people from environmental toxicants and to design optimal remedies for contaminated sites. However, they face a near-universal problem: conventional field sampling, transport, and in-lab chemical analyses are slow, costly, and often unable to provide enough data on varying concentrations, patchy distributions, or inconsistent release rates of toxicants from contaminated sediments. Without adequate environmental data, biological research is severely hampered in contributing to public health protection. Project 1 aims to meet this problem with new concepts, methods and technologies intended to overcome the critical barrier to progress created by the shortcomings of slow and costly conventional analyses.

This project focuses on two important toxicants, N-nitrosodimethylamine (NDMA) and polycyclic aromatic hydrocarbons (PAHs), but also provides insights and methodologies relevant to the general problem of detection, mapping, and movement of harmful species. 

As part of this project, MIT SRP researchers develop and test in situ sensors to measure the concentrations of toxicants in water. The sensors are portable for use by field personnel, and can be moored at fixed locations long-term sentinels for toxicant mapping. Further reflecting the critical role of contaminated sediments, the research team is developing in situ technology to expeditiously determine location-specific rates at which sediment-borne toxicants are released to their surface waters (i.e., benthic fluxes). A benthic flux meter based on eddy correlation uses multiple high-speed sensors, including a fiber optic spectrofluorometer, to measure contaminant fluxes either directly or through tracer techniques. Technology has also been developed to measure the fluxes of bubbles, which were shown to transport particulate-associated contaminants, such as several toxic metals, from contaminated sediment to the water column. This information will help improve estimates of human exposure and optimize remediation strategies.

This project creates training opportunities for students to design and test novel sensors, deploy sensors in real-world settings and on novel platforms, and take part in community environmental affairs. Stay tuned for publications on exciting developments of colorimetric determination of NDMA in water samples. Paper-based indicators detect NDMA and we seek to create methods employing these methods and others that enable community members to test their water.