These increasingly destructive techniques, coupled with the San Francisco peninsula’s population exploding from roughly 1,000 people in 1848 to over 36,000 in 1

These increasingly destructive techniques, coupled with the San Francisco peninsula’s population exploding from roughly 1,000 people in 1848 to over 36,000 in 1852, irrevocably changed the landscape of California, pulling up old growth forests, pushing aside rivers, and literally washing away into the Pacific Ocean some of the richest arable land on the North American continent. The Gold Rush turned huge swathes of California into “sacrifice zones” — geographic areas that have been permanently damaged or poisoned by industry. We're still dealing with the environmental impact from those days. Precisely the places one is likely to find gold, one is likely to find other heavy metals like mercury. Those places are also the part of California where SF gets its water from. Fortunately, metallic mercury is fairly nonreactive. Much of that washed-away soil is still making its way down into reservoirs. There are actually plans to safely mine that sediment for the mercury and gold.