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9 <br /> <br />3.0 POTENTIAL ADVERSE PROJECT IMPACTS <br /> <br />Potential short-term adverse impacts to the lagoon's beneficial uses from the application of <br />Reward are restricted to: 1) reducing the natural feed for waterfowl with the removal of <br />widgeon grass; 2) human skin irritation upon contact with treated waters; and 3) direct and/or <br />indirect negative impacts on non-target aquatic biota. However, because only isolated <br />shoreline sections are chemically treated on an intermittent basis and are relatively small <br />as compared to the lagoon as a whole, the risk of adverse impacts are considered small. <br /> <br />An assessment of the potential for long-term adverse impacts from the application of Earth <br />Tee focuses on the accumulation of copper in the sediments. Each use of copper- based <br />pesticides make an incremental addition to the accumulation of copper in the sediments and <br />biota of the waters where applied, and potentially the bay waters into which the treated <br />lagoon ultimately drains. Deposit-feeding clams and other benthic invertebrates bio- <br />accumulate copper and pass it upward into the food web. Elevated levels of copper are <br />particularly toxic to plankton and larval fish and invertebrate. The application of copper-based <br />algaecides to Redwood Shores Lagoon may contribute incrementally to this long-term <br />accumulation of copper in the lagoon and nearby estuary. Mitigation of this copper contribution <br />to the long-term accumulation consists of applying the minimum algaecide concentration <br />needed to be effective, and to use copper-based pesticides in a judicious and prudent manner. <br />The use of Earth Tee instead of less expensive copper-based algaecides is a mitigation <br />measure. Because the Earth Tee tends to stay in suspension in the water column, the copper is <br />biologically available for uptake by algae for a longer time period and less copper is needed for <br />an effective dose. <br /> <br /> <br /> <br /> <br />6.3.A. - Page 174