9.4 Case Study 4. Hawaiian Homelands Development

Site Name: Hawaiian Homelands Development, Kapolei, Oahu, Hawaii

Contact Name: Roger Brewer, HDOH

Site Location: The East Kapolei Affordable Housing Project property is located in East Kapolei, Kapolei, Oahu, Hawaii.

Background: This case study summarizes the investigation of the 401-acre former sugarcane field and a ½-acre pesticide-mixing area located within the field which is being developed for residential and commercial use. The primary COCs were arsenic, pentachlorophenol (PCP), dioxins (associated with past use of PCP), and triazine herbicides, each used in the past for weed control. A detailed discussion of the sugarcane field investigation is provided in the report East Kapolei Affordable Housing Project Kapolei, Oahu, Hawaii, Final Site Assessment Report (TTEMI 2007). A summary of the pesticide mixing area investigation is provided in the report Site Investigation Report and Environmental Hazard Evaluation, East Kapolei II Pesticide Mixing and Loading Site (ESTC 2007, 2010).

Lessons Learned:

  • There are no elevated concentrations of COPCs in the soil that suggest conditions are not suitable for residential reuse or that any additional sampling or evaluation is necessary.
  • The investigations confirm that ISM samples, essentially very good composite samples with additional laboratory requirements, are better able to capture small hot spots and overall contaminant heterogeneity within a targeted area.