Y@W Presenters

Yale School of Forestry
B.S., Yale UniversityM.S., Ph.D., Massachusetts Institute of Technology-Woods Hole Oceanographic InstitutionCV - Download
Email: gaboury.benoit@yale.edu

Gaboury Benoit

Grinstein Class of 1954 Professor of Environmental Chemistry, Co-Director of the Hixon Center for Urban Ecology

As a teacher I believe strongly in fostering students’ curiosity and facilitating their own natural inclination for learning. I also favor a participatory approach to the teaching of science, so that students learn by direct involvement in research from the earliest possible opportunity. I strive to serve as a role model, revealing my passion for science in order to excite the students’ own enthusiasm.

Professor Benoit’s research and teaching focus on the behavior, transport, and fate of chemicals in natural waters, soils, sediments, and biota. Two special areas of interest are nonpoint source pollutants and biogeochemistry of trace metals and radionuclides. Most of his research involves state-of-the-art analytical methods and carefully designed field sampling programs, with results verified by laboratory simulations or simple mathematical models. His research is conducted in a watershed context, and study sites include freshwater and terrestrial systems, as well as estuarine and coastal environments. Four current research emphases are the use of modern clean techniques to investigate trace metals; micronutrient limitation by Cu and Fe; spatial and temporal variability of nonpoint source pollution; and human-environment interactions in urban areas.

My work in this area will be summarized in a book Land and Natural Development (LAND) Code

Watershed-based water quality studies have immediate applicability, and indeed, their goal often is to actually clean up streams. Contaminants of special concern include excess nutrients, eroded sediment, bacteria, and toxic metals, such as mercury. The challenge, increasingly, is to identify and reduce impacts from nonpoint sources, pollution caused by how we use land. Research in my group tackles this problem on three fronts. First, we conduct surveys of water quality with high resolution in space (location on a stream and its tributaries) and time (variations with season, time of day, and during storms). From this information we pinpoint critical events and pollution hotspots and design management strategies to control them. Second, we seek novel tracers to help identify sources of pollution. For example, we currently are investigating caffeine as a tracer of sewage contamination. Once perfected, this tool could be used to identify defective septic systems, leaking sewer lines, or illegal discharges. Finally, we work to design recommendations for developing land in a way that will cause the least environmental harm.

Land and Natural Development (LAND) Code (2007)

Land and Natural Development (LAND) Code offers a pioneering method to develop sites in harmony with natural processes. While the LAND Code can be readily used in conjunction with LEED, EPA, and other guidelines, it features several unique characteristics, including recommendations based on peer-reviewed scientific research, a system that is accessible to non-experts, and extensive use of photographs and diagrams to illustrate practices and procedures.

Purchase on Amazon Land and Natural Development (LAND) Code

Mass balance of heavy metal in New Haven Harbor, Connecticut: The predominance of nonpoint sources.

ROZAN T.F. and G. BENOIT (2001)


A mass balance was constructed quantifying all known sources and sinks for the metals Ag, Cd, Cu, and Pb in New Haven Harbor, Connecticut, USA. Sources included direct atmospheric deposition, rivers, treated sewage effluent, combined sewer overflows, and permitted industrial discharge. Sinks were burial in sediments, tidal exchange with Long Island Sound, removal in salt marshes, and dredging. All of these fluxes were measured directly, rather than estimated, and uncertainties were quantified. The mass balance closed successfully within the uncertainty of the measurements. Riverine inputs account for most of the total yearly metal flux. Metal concentrations in the river can be approximated as a simple linear function of discharge. Salt marshes remove an amount of metal equivalent to 20%–30% of the flux from the river before it reaches the harbor. Burial in sediments is the major sink for all metals examined, but dredging acts as a substantial short‐circuit of this sink. Tidal exchange appears to be a relatively small term; however, it is also the least well quantified. Sewage treatment plant (STP) effluent and combined sewer overflow discharge are minor contributors to the overall metal balance, except in the case of Ag. Metal concentrations in STP effluent are a linear function of discharge. Atmospheric deposition is of minor importance but is comparable to sewage effluent. Lakes can be used as natural collectors and indicators of atmospherically deposited metals.