Notes from the Lab


ENVIRONMENTAL JUSTICE

After years of research on the health-monitoring process at polluted communities such as Love Canal, Professor Nicholas Ashford of the School of Engineering plans to integrate his findings to prescribe a strategy for successful community involvement at contaminated sites and dangerous manufacturing facilities.

The work is part of the emerging field of environmental justice, which aims to ensure that no group of people should shoulder a disproportionate share of negative environmental impacts, and further, that communities have a major role in addressing these impacts. To that end Professor Ashford, director of the MIT Technology and Law Program, is focusing on communities of color and economically disadvantaged areas. He will contrast the problems and successful approaches in these communities with those in other communities, and will draft recommendations for interagency coordination and policy changes.

The three-year project is funded by the Agency for Toxic Substances and Disease Registry, the EPA and the DOE.

MODELING THE OCEAN WITH SUPERCOMPUTERS

The ocean plays a major role in weather and climate.

Modeling of the ocean, however, is a formidable challenge. It's a turbulent fluid with important elements interacting on scales ranging from global down to the order of a few meters.

Now MIT oceanographers and computer scientists led by Professors John Marshall of earth, atmospheric, and planetary sciences and Arvind of electrical engineering and computer science have designed a novel algorithm so that the computing power of massively parallel machines- some of which were designed and built at MIT-can be put to the task.

Based on the Navier Stokes equations on the sphere, the new ocean circulation model is a significant step toward the goal of the Center for Global Change Science to improve the accuracy of climate-change predictions.

Professor Marshall and his colleagues are using the model to better understand the ocean's thermohaline circulation, the process by which water (and thus carbon dioxide and heat) in some areas of the globe is transferred from the upper "mixed layer" of the ocean to the deep. Current analyses indicate that the ocean is the largest carbon sink in the climate system. But determination of its capacity for uptake (as atmospheric carbon dioxide concentrations continue to rise) depends on understanding the action of the currents that cause the sinking of surface water to depth. The work was funded by the TEPCO/MIT Joint Environmental Research Program, ARPA and ONR.

--Anne Slinn, Center for Global Change Science

MAKING WAVES ABOUT SEAWALLS

While many seaside property owners view seawalls as a great way to protect against erosion, state regulators maintain the piles of quarry rocks actually cause erosion.

Thus, says Professor Ole Madsen of MIT's Department of Civil and Environmental Engineering, "the question is, if I build a seawall and come back in 10 years, would the beach have lost more or less sand than if there had been no wall?"

Madsen built a miniature beach in which one section of a water-filled basin had a stone wall fronted with sand and the other had just a sandy dune. Using a programmable wave-maker to simulate natural waves and their seasonal variations, he simultaneously pelted the seawall and the dune with identical waves and then monitored the erosion. With regard to the beach system as a whole, results show virtually no difference in erosion and accretion for the protected and unprotected areas, except for a lack of erosion right behind the seawall.

This suggests that seawalls may not necessarily deserve their bad reputation, Madsen says. The project is funded by the MIT Sea Grant College Program.

--Andrea Cohen, MIT Sea Grant College Program

WATERSHED STUDIES PROBE CHEMICALS' PATHS

For more than a decade, MIT researchers in the Department of Civil and Environmental Engineering have been studying the tainted Aberjona watershed near Boston.

To determine how much risk is associated with chemicals in the environment, the researchers want to understand how the chemicals move around, and if and how they are transformed into something else with a new set of toxicity or safety problems. In one Aberjona study, Professor Dennis McLaughlin and colleagues are making computer models of how groundwater carries contaminants as it flows through different types of soils. More accurate models could help determine where a contaminated plume might be likely to travel.

In another study, a team led by Professor Harold Hemond is studying the fate and transport of arsenic as it continues to be released from the soil into the streams, rivers and lakes of the watershed. The work is supported by the National Institute of Environmental Health Sciences, the Superfund Program and the NSF.

--Debbie Levey, Department of Civil and Environmental Engineering

A version of this article appeared in MIT Tech Talk on November 8, 1995.


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