What are we looking for? Toxins introduced into the environment vary with different land uses. A very brief list of examples includes pesticides from agriculture, heavy metals from urban utilities, and hydrocarbons like petroleum from military projects. In the absence of comprehensive pollutant monitoring programs, understanding how land use history affects current pollution risks can help inform management and restoration strategies.

How do we get that information? In this project, we integrated maps spanning 200 years (1825-2023) to trace land use changes in ​​Pu‘uloa on Oʻahu, Hawai‘i, to assist in developing contaminant risk profiles. We observed a marked increase in agricultural land use following the United States annexation of Hawaiʻi in the late 1890s, followed by a decrease before World War I due to military activities. Post-World War II, there was a resurgence in agriculture. In the late 1960s, urbanization began to replace agricultural land. We also created layers over these maps that visualized potential environmental- or disaster-related risks that could always occur (e.g. sea level rise, average temperature, flooding, tsunami risks, etc.).