AgdaPkt 2016-02-22 Closed and Interview and Joint SA PFA

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City of Redwood City, Public Works Division Initial Study & Mitigated Negative Declaration Document Date: October 15, 2015 Revision Date: January 25, 2016 Page 30 Blankinship & Associates, Inc. interspecies differences in copper toxicity (Grosell et al., 2007). Thus, similarity in size between the test organism and longfin smelt was an important consideration in the selection of an endpoint for TRV derivation. Additionally, test conditions, such as salinity and duration of exposure, were also considered in the selection process. After a substantial literature review, the 96-hour acute LC50 of 86.5 mg/L was selected from the following study as the endpoint used for TRV Derivation: Mohapatra and Rengarajan 1997 The acute toxicity of copper to wild-caught Liza parsia was evaluated. Liza parsia weighing between 15.0 to 30.0 grams (g) and measuring between 75.0 to 105.0 mm (approximately 3 to 4 inches) total length were collected from the brackish water canals of Puduvypeen area in Cochin. The fish were acclimatized to laboratory conditions for about one week at an approximate salinity of 9.8 parts per thousand (ppt), temperature of 28 °C, and total hardness of 2,956 ppm. Fish were exposed to copper sulfate pentahydrate in 5 separate aquarium bioassays to estimate the 12, 24, 48, 72, and 96 hour toxicity of copper. The metallic copper LC50 estimated for the 12, 24, 48, 72, and 96 hour bioassays were 35.9, 34.9, 28.0, 22.0, and 21.8 mg/L, respectively. We selected the 96 hour LC50 of 21.8 mg/L, consistent with acute endpoint selection recommendations (USEPA 2004). To derive a TRV from the 96 hour LC50, a safety factor of 20 was applied. The resultant derived TRV for the longfin smelt is estimated at 1.09 mg/L (i.e. 21.8 / 20 = 1.09) . It was estimated that applications of copper at the maximum label rate of 1.0 mg/L metallic copper will not lead to aquatic exposure greater than or equal to the derived aquatic TRV of 1.09 mg/L because the calculated risk value is 0.917 (unitless). The copper-containing algaecides and/or aquatic herbicides applied to the Lagoon are not anticipated to pose unacceptable risk to longfin smelt. To educate City or contractor staff working in the Lagoon of the potential presence of longfin smelt, a qualified biologist shall conduct a worker’s environmental awareness program (WEAP). The WEAP training will be completed prior to application of aquatic herbicides containing copper to control vegetation in the Lagoon. The WEAP will include, at a minimum, species identification, a description of suitable habitat for the species, and measures to implement in the event that this species is found during application. This training shall instruct personnel to recognize longfin smelt their habitats and life history. As described above, no unacceptable acute risk to the longfin smelt is anticipated due to applications of copper-containing algaecides and/or aquatic herbicides. A qualified biologist will conduct a WEAP training session prior to the application of copper-containing algaecides or aquatic herbicides to the lagoon after the City’s SIP Exception is granted. Item b): No Impact. The Project will take place in the Lagoon, therefore, will not impact any riparian habitat or other sensitive natural community identified in local or regional plans, policies, or regulations, or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service. Item c): No Impact. The Project will take place in the Lagoon and, therefore, will not impact any upland habitat or wetlands. However, the assessment of risk for species that live in these areas was considered. Specifically, the risk to longfin smelt was assessed and it was concluded that the use of aquatic herbicides containing copper does not pose an unacceptable risk to the species. 6.3.A. - Page 38