Anatomy of a decision II: Potential effects of changes to Tier I chemical approaches in Canadian Disposal at Sea program sediment assessment protocols.

The effects of possible changes to the Canadian 2-tiered assessment framework for dredged material based on outcomes of the 2006 Contaminated Dredged Material Management Decisions Workshop (CDMMD) are evaluated. Expanding on the "data mining" approach described in a previous paper, which focused solely on chemical lines of evidence, the efficacy of Tier 1 approaches (increases to the number of chemical analytes, use of mean hazard quotients, and the use of a screening bioassay) in predicting toxicity are evaluated. Results suggest value in additional work to evaluate the following areas: 1) further expanding minimum chemical requirements, 2) using more advanced approaches for chemical interpretation, and 3) using a screening-level bioassay (e.g., Canadian solid-phase photoluminescent bacteria test) to determine whether it would complement Tier 1 chemistry as well as or better than the solvent-based Microtox™ test method evaluated in the present study. Integr Environ Assess Manag 2017;13:1072-1085. © 2017 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).