Global warming is filling rivers with toxic metals: here’s how this phenomenon occurs in different areas
Research has revealed how i Colorado mountain rivers they are contaminated due to global warming. The American state, which attracts millions of tourists every year thanks to its magnificent panoramas, presents an increase in toxic heavy metals in their rivers. A phenomenon also verified in Arctic waterways. There are fears that it may be more widespread than believed.
Heavy metals in rivers
Over the past few decades researchers have observed a considerable increase in heavy metals in mountain streams. The underlying cause of this phenomenon was not understood for a long time but, after analyzing 40 years of data on the water chemistry of 22 mountain streams in Colorado, here is the answer.
It was discovered as the concentration of copper, sulphate and zinc have doubled over the last 30 years. A study has been published on this matter Water Resources Researchwhich revealed that the drier climate and, in general, the reduction of stream flow, are responsible for about half of the increase.
The rest is most likely due to thawing of underground ice, therefore in contact with a greater number of rocks. All this results in a greater release of the metals contained in them.
There water dilution full of metals ensures that for now you don’t represent a problem significant, once they reach the cities downstream. The situation is different for mountain communities. In fact, in this air the water may require further treatment in order to make it safe. A problem that is certainly destined to increase, considering the continuous warming of the climate.
Why Alaska’s rivers turn orange
It also raises alarm condition of Alaskan rivers. In fact, they are turning orange. A phenomenon similar to what occurs near the mines. We talk about acid mine drainage, in that case.
This happens when compounds such as iron sulfide are exposed to water or air. The Water pH drops and the release of toxic metals into the environment occurs. This can cause, as a visual impact, a rust and orange tint of the rivers. In Alaska, in the Brooks Range mountain range where the phenomenon was observed, however, there are no mines.
A study conducted by scientists from the National Park Service and the University of California Davis, in collaboration with colleagues from the US Geological Survey and the Environment and Natural Resources Institute at the University of Alaska Anchorage, has provided an answer.
In this specific territory of Alaska There are as many as 75 waterways affected by this problem. The average pH is extremely acidic (2.3). High concentrations of polluting metals such as copper, iron, lead and nickel, but not only, were also detected. It’s the fault of the global warming, catalyzed by emissions of carbon dioxide and other gases. This is inducing an acceleration of thawing of permafrostor perennial ice.
The fusion of the latter releases metallic minerals trapped in the past, allowing interaction with water and oxygen in the air. The process releases toxic metals into river water, which turns orange. A huge problem, which goes far beyond coloring.
