Risk assessment and ecotoxicology: limitations and recommendations for ocean disposal of mine waste in the Coral Triangle

Mining is an important contribution to the economy of many developing tropical regions. Many sites of mining interest in the tropics have island geographies and potentially limited land area. While the limited land area may drive consideration of tailings disposal to the ocean, it is important to recognize that local communities depend on the ocean as a major supplier of dietary protein. Impact assessment of tailings disposal to the ocean is usually limited by budgets and time frames that result in a limited capacity to understand longer-term risks to food chains and marine ecosystems, including the interactions between deeper- and shallower-water ecosystems. This article reviews three factors—tailing characterization, ecotoxicology, and bioaccumulation/biomagnification—in relation to the current application of these methods to risk assessment of submarine tailings disposal (STD), and it identifies ways to improve current practices. A decision-tree approach has been developed specific to STD risk assessment for implementation at the pre-proposal stage of a project. This decision tree highlights the urgent need for development and application of suitable and relevant risk assessment tools for tropical marine environments and identifies opportunities for intergovernmental standards for risk assessment of marine disposal of mine tailings within the framework of the Coral Triangle Initiative