The Transport and Fate of Pesticides in the Soils of Central Oahu

Dr. Ghasem Alavi
Post-Doctoral Fellow
Department of Civil & Environmental Engineering
University of Hawaii at Manoa

The demand for agricultural productivity has caused a dramatic increase in the use of synthetic organic pesticides. During recent decades, many concerns have been raised about their potential adverse effects on the environment and human health. The greatest potential for unintended adverse effects of pesticides is through the contamination of hydrologic systems, as water is one of the primary transport media for pesticides. Contamination of ground water by pesticides is a major national issue in many countries because of the common use of ground water for drinking purposes. Small tropical islands are particularly vulnerable to environmental damage because of small land area, higher population density, and limited resources available. Protection of ground water from contamination by pesticides, as well as other chemicals, is therefore of great importance. Ground water resources in Hawaii are invaluable. For the island of Oahu, where more than 75% of the state’s population resides, greater than 95% of all water for domestic and agricultural use comes from groundwater, and nearly all drinking water is obtained from ground water. Past agricultural practices have led to contamination of ground water with chemicals in Hawaii. The tropical soils of Hawaii exhibit structural heterogeneity in addition to macroporosity caused by cracks, flora, and fauna. This seminar will focus on movement of pesticides in the soils of central Oahu and present the results of a recently finished project on the transport and fate of water and bromacil in a pineapple filed in Oahu.