You may know that this is one of the highest concentrations of arsenic on the island and maybe the State. It was the result of a seed dipping facility...part of the Hakalau Plantation Infrastructure. (video segment from 30:43-31:06)
Four removal action alternatives (plus the No Action alternative) were evaluated in term of effectiveness, implementability, and cost. Alternative 5, Consolidation and Capping of Arsenic Category C and D Soils at Source Area ("Capping in Place"), was determined to be the optimal remedy. All other alternatives (2, 3 and 4) included significant excavation of arsenic-impacted soils from within the 40-ft shoreline setback adjacent to the cliff face, and were determined to be technically infeasible due to slope stability concerns. Upon approval of the recommended removal action alternative by HDOH, a removal action work plan will be prepared to provide design specifications and guidance in implementing the proposed remedy. (p. 8-1)