Guest Speaker: Mike Thornton

Mike Thornton's lecture on the toxic legacy of gold mining was very informative. It has left dangerous chemicals throughout the Sierra Nevada region that's presence is predominately unknown by the average citizen. It was amazing to me, the example of the elementary school in El Dorado Hills that had been built on mine tailings is exposing children to asbestos on a daily basis. When these chemicals are left in the rocks in which they naturally occur, there is no harm or danger to the environment; however, with mining, these rocks are ground into a flour-like substance to extract as much gold as possible--releasing these chemicals into the atmospher, leaching into the ground, and contaminating our waterways. There are other poisons that mining has left in abundance contaminating the environments of the Sierra region: mercury, arsenic, and lead are also dangerous chemicals leftover from mining and the Gold Rush.

These chemicals are extremely dangerous as they can cause birth defects, cancers, lung disease, skin conditions, and developmental disorders. It is amazing that the gold rush, having occured more than 150 years ago has left such a long lasting issue to the Sierra environment. The poison i find of particular danger and the hot topic for news stories within the last few years is mercury. Mercury is in our waterways at unhealthily high levels. It has prevented the native peoples of the land from performing ritualistic ceremonies with salmon, since they're too dangerous to eat, and the reeds they use for basket weaving are too dangerous to put into their mouth. Also, the dangers of mercury, particularly at the human level, are that mercury biomagnifies. As it goes through the food chain, all the way from the producer to the tertiary consumer (humans), there are increased levels of mercury contaminating the tissues of the organisms; therefore, becoming more and more dangerous for human consumption. Thornton said that 26 million pounds of mercury was brought to the Sierra for mining, and only 50% of it was re-used. That means...13 MILLION POUNDS IS STILL LEFT IN OUR ENVIRONMENT!!! This is a huge problem!

Thornton provided alot of interesting information about mining that i never knew before. Miners re-routed 5,000 miles of riverin the sierra to get rid of the waste, which flooded farmland and waterways all the way to San Francisco Bay. Thats a huge amount of river, which, in re-routing it, was probably more contaminated. Apparently this later became PG&E's hydro-electric system. He highlighted the impacts of these actions and the toxins that were released into the environment and spread his awareness, which is what we will need in order to take action and get these toxins cleaned up.