environmental Strategist, between the lines: I don’t care where you own property in the United States, historical contamination is a massive environmental exposure for real estate owners.
This article gives an excellent overview on the impact storm water runoff has on third party properties from historical contamination.
This also highlights how historical mining operations are causing environmental liabilities for unsuspecting property owners. Out of sight, out of mind is the attitude of the masses but this has proven to be catastrophic for tens of thousands of real estate owners.
I recently drove from Denver to Aspen, throughout the mountains you can see old mines scattered along the hill sidess. Each one of these mines represents a contamination source to the local environment. A number of years ago Copper Mountain Ski area in Colorado was cited for exacerbating contamination while performing their snow making operations. Copper Mountain was pulling water from the river that flows along the base of Copper Mountain for snow making. Unknown to Copper Mountain was that the river is full of old mine tailings causing contamination. When Copper Mountain pulled the contaminated water from the river for snow making and spread it on their ski runs they exacerbated the extent of the contamination.
Mercury Sediment Carried Forth by California Floods
From: Robin Blackstone, ENN
Published October 29, 2013 01:59 PM
Mercury contamination in sediment has been a big concern in the Central Valley lowland areas of California. But associate researcher from the University of California, Michael Singer has unearthed new information and considerations utilizing modern topographic datasets and modeling to track mercury-laden sediment. Singer hypothesizes that the progradation process resulting from 10-year flooding events within the valleys below the Sierra Nevada Mountains are the key to understanding and tracking the presence of mercury. Singer has connected the mercury amalgamation process, which was used to extract gold from the mountains during the 19th century with the current high incidence of mercury in regional delta sediment.
Documented by Singer, the progradation process results from a combination of flood driven fan erosion and sediment redistribution over time into the valley. Of particular note are the floods of 1986 and 1997 of the Yuba River, which churned up deep river valley sediments containing toxic remnants of the gold mining amalgamation done more than 150 years prior.
The ecological impact of mercury presence throughout the sediment is significant because mercury is taken up into the food webs. This coupled with regional shifts in climate, poses a huge risk to the lowland ecosystems and the human population because many people eat fish from this system.
The initial discovery of the connection between the sediments and the gold mining was happenstance as the research team identified huge pockets of coarser sand in amongst sediment. This led them to ask why there was so much sand in the area.
“We thought that was quite strange because the floodplains around us were so much finer — composed of silt and clay materials,” recalled Singer. “So we followed the signs and ended up in a huge sand mine. They were mining sand by the truckload for the construction industry and said they would be doing so for at least the next several decades.”
Singer posits that because the upstream Yuba was the biggest gold-mining drainage of all the Sierra drainages used in the 19th century, it made sense to suspect the presence of possible mercury.
The research team compared gold rush data with modern topographic datasets, which showed that the Yuba River was progressively cutting through the sediment and in the process leaving behind massive contaminated terraces along the riverbank. Flood data and modeling indicate that these terraces move only when a flood event is big enough to saturate them so that the terraces fail and the mercury-laden sediment is carried and driven downstream.