4%). The next test protocol applies the DaS LAL values for Cd, Hg, tPAH and tPCB, but considers a broader suite of metals by applying the CCME ISQG values, where available, as LALs for those metals. When a broader suite of metals is considered (Ag, Cd, Cr, Pb, Cu, Zn), outcomes change significantly – there is a 33.2% increase relative to the DaS list alone in the number of samples that would require further assessment. Individual contaminant failures for the additional metals are most common in Cu (47.2%), followed by Ag (45.3%), Cr (40.9%), Pb (30.5%) and Zn (26.5%). The addition of organic

constituents for which CCME ISQG values could be found for use as LALs also results in an increase in samples requiring

screening assay further assessment. However, most of the samples that failed for these parameters had already failed for one or more analytes, as 29.1%, 15.2% and 11.4% failures in tDDT, dieldrin and chlordane, respectively, result in only a 2.3% increase in overall sample failures. The next test protocol considers the same list of analytes, but, for consistency, applies CCME ISQG values for all contaminants. Although this is not currently part of the DaS approach, a decision to apply LALs from a consistent source is plausible. The ISQG LALs are somewhat less conservative for Cd, but are more conservative for Hg, tPAH and tPCB than are the DaS values. As a result, there is a small decrease in failure rates for Cd, but Natural Product Library chemical structure 4-Aminobutyrate aminotransferase slight increases in failure rate for tPCB and significant increases in failure rates for Hg and tPAH. The overall increase, however, in samples requiring further assessment is only 2.3%, due to the fact that samples that fail for one contaminant often fail for several. Many dredging programs consider Ni, but the CCME ISQG does not include a LAL for this metal. To evaluate potential effects for the inclusion of Ni in a decision framework,

TEL SQGs, which include all the contaminants in the CCME list as well as Ni, were applied to the dataset. It should be noted that, although many of the TEL values are the same as the ISQG values (primarily for metals), there are differences in the organic values; this also affects overall outcomes. 51% of samples in the database fail based upon the Ni TEL. This results in a slight increase (2.1%) in overall failure rates, in spite of a significant decrease in tPAH failures due to a less conservative tPAH LAL. To examine the potential effects of considering pesticides not currently examined in other dredging programs, there was a need to draw candidate LAL SQGs from other sources. As stated above, the Consensus L1 LALs are a compilation of values based either on a range of international dredging programs, or, when those are not available (tTBT, lindane, aldrin, HCB), from other marine sediment SQG sources.