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Professor Emeritus
Earth and Environmental Sciences
Special Research Scientist
Lamont-Doherty Earth Observatory
61 Route 9W - PO Box 1000
(845) 365-8155


Fields of interest: 
Geochemistry of natural waters and implications for mitigation strategies.

Understanding the geochemistry of natural waters lies at the heart of designing effective environmental policies on many issues. For a number of years, I have worked on the Hudson River, where large influxes of nutrients, toxic chemicals and anthropogenic radionuclides can be considered as inadvertant tracer "experiments" that permit critical riverine/estuarine processes to be unraveled, and thus provide guidance to mitigation strategies. Examples include the influence of waste-water treatment discharges in the New York City area, as well as residual polychlorinated biphenyls (PCBs) and toxic metals in Hudson sediments, on future water quality of the system.

Some of my research on natural waters in addition to the Hudson include: impacts of human activities on rivers in Australia and Egypt, forecasting of river discharge probabilities in relation to the El NiƱo/Southern Oscillation for Australia and other regions, chemistry of precipitation in urban industrial regions, which may stimulate additional growth of regional forests, and mobilization of arsenic in groundwaters near contaminated sites in the NE USA, and in groundwaters of Bangladesh.

List of degrees from highest to lowest:
Bachelor of Science
California Institute of Technology

Referenced in the Following News Items:

Selected Publications:

Twentieth century atmospheric metal fluxes into Central Park Lake, New York City Chillrud, S. N.; Bopp, R. F.; Simpson, H. J.; Ross, J. M.; Shuster, E. L.; Chaky, D. A.; Walsh, D. C.; Choy, C. C.; Tolley, L. R.; Yarme, A. Environmental Science & Technology Mar 1 Volume: 33 Issue: 5 p.: 657-662 (1999)
Trends in chlorinated hydrocarbon levels in Hudson River basin sediments Bopp, R. F.; Chillrud, S. N.; Shuster, E. L.; Simpson, H. J.; Estabrooks, F. D. Environmental Health Perspectives Aug Volume: 106 p.: 1075-1081 (1998)
Annual River Discharge in Southeastern Australia Related to El-Nino Southern Oscillation Forecasts of Sea-Surface Temperatures Simpson, H. J.; Cane, M. A.; Herczeg, A. L.; Zebiak, S. E.; Simpson, J. H. Water Resources Research Nov Volume: 29 Issue: 11 p.: 3671-3680 (1993)