Local waters are now being tested for the toxic legacy of the area's Gold Rush history.Carrie Monohan and Rosemary Gregor hiked under a steady drizzle Wednesday near old mining sites on restricted Nevada City public land. The two researchers tramped through thorny bushes so they could get to the banks of Deer Creek and sample sediment flowing in the muddy water.The pair was working for Friends of Deer Creek. Their goals include garnering grants for any needed cleanup, such as removing highly contaminated sediment, so the land can be used for recreation. "Everybody's thinking about this now," Monohan said about …