EXH1280051181

Comment #16 states that lead and zinc concentrations in cutthroat trout exceed their respective tissue screening concentrations (herein termed Shephard TSCs) derived by Shephard (1999). Before commenting on the applicability of these TSCs to cutthroat trout, it is important to emphasize that, as the name suggests, these are just screening concentrations. This is a particularly important consideration for mobile fish species (e.g., trout) that may be exposed to metals that are ubiquitous in urban environments. In these cases, it is not possible to unequivocally link the measured metal concentration to an individual source. The remainder of this response focuses on the applicability of the TSCs derived by Shcphard to trout and developmertts of alternative fish-specific TSCs that we believe are more applicable. Note that the TSC t_a'ninology is also used for these alternative values provided below to emphasize that any tissue-based toxicity value for fish should be consid_l a screening concentration and does not provide conclusive evidence of potential risk or link potential risk to an individual chemical source. The Shephard TSCs reported in comment #16 (as the basis of Dr. Strand's contention that lead and zinc are chemicals of concern) are 0.32 and 100 mg/kg dry weight (dw) for lead and zinc, respectively. While neither of these values appear in the citation in Dr. Strand's declaration (Sh_hard 1999), they do appear to be based on a wet weight to dry weight conversion (assuming aquatic organisms are 80 percent moisture) of the TSCs published in Dyer et al. (2000). While…

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Call to order – Roll Call – Quorum Established – Land Acknowledgement We would like to acknowledge that our Agency operates in four present-day counties, which are the traditional lands of the Coast Salish people, past and present. This acknowledgement does not take the place of authentic relationships with indigenous communities in our jurisdiction and [...]