However, implicit in this discussion is the continuing discussion about whether the early tiers of a tiered assessment should be based only on chemistry or whether some bioassays should also be included in a first tier (Agius and Porebski, 2008, Apitz, 2010 and Apitz, 2011), as in Fig. 1. The argument for a bioassay is that,

since not all chemicals are measured, even in an expanded analytical list, a bioassay in the first tier might detect the toxic CHIR-99021 cost effects of contaminants not measured in the action list. However, the validity of this argument depends upon the contaminants in the sediment, their modes of toxicity, and the bioassays considered; Apitz, 2010 and Apitz, 2011 review these issues in light of

DM and other decision frameworks. Although this issue is outside the scope of this phase of the analysis, it is important to note that ultimately, the potential regulatory outcomes of a range of potential chemical PKC inhibitor assessment protocols in a DaS framework will also depend upon when and how bioassessment is applied in the tiered framework. The objectives of Canada’s Disposal at Sea Program and of related national and international legislation mirror the London Convention, and more specifically, the London Protocol objective “to protect and preserve the marine environment from all sources of pollution and take effective measures, according to their scientific, technical, and economic capabilities, to prevent, reduce, and where practicable eliminate pollution caused by dumping or incineration at sea of wastes or other matter.” CEPA Part 7, Division 2 defines marine pollution as “the introduction by humans, directly or indirectly, of substances or energy into the sea that results, or is likely to

result, in (a) hazards to human health; (b) harm to living resources or marine ecosystems; (c) damage to amenities; or (d) interference with other legitimate uses of the sea.” The 1996 Protocol to the London Convention, Article 1, paragraph 10 states that “… pollution Non-specific serine/threonine protein kinase means the introduction, directly or indirectly, by human activity, of wastes or other matter into the sea which results or is likely to result in such deleterious effects as harm to living resources and marine ecosystems, hazards to human health, hindrance to marine activities, including fishing and other legitimate uses of the sea, impairment of quality for use of seawater and reduction of amenities”. CEPA (1999) states that: “pollution prevention” means the use of processes, practices, materials, products, substances or energy that avoid or minimize the creation of pollutants and waste and reduce the overall risk to the environment or human health. A careful examination of the wording of the London Protocol reveals that the programmatic objectives focus upon the prevention or elimination of pollution per se, and not of its effects.