Sodium Cyanide can over time turn into Carbon and nitrogen from Sunlight

I was reading more about Sodium Cyanide and found that sunlight over time breaks it down in sunlight over time into Carbon and nitrogen:
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Cyanide solution can be used for both heap leaching and vat leaching applications. Heap leaching is by far the widest application and the most controversial.
Mines contain the cyanide solution by placing multiple “impermeable” liners at the base of heap leaching stockpiles and along the bottom of leachate collection ponds. During operations, the cyanide solution is collected and processed. When the mine is closed, there is a short- and long-term cleanup plan to detoxify the solution so that no residual cyanide remains to harm the environment. The detoxification and neutralization process converts cyanide into a less toxic cyanate, before combining it with the mine tailings. Some operations may also use water treatment facilities to treat and neutralize effluent discharge. Any remaining cyanide decomposes naturally as sunlight breaks the compound into carbon and nitrogen.
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The Current Status of Cyanide Regulations - EMJ

So, cyanide over time might break down into Carbon and nitrogen from the sunlight. The most damage Cyanide seems to have done in the past is in fluid releases of Sodium Cyanide into rivers and lakes like the one that wound up eventually in the Black Sea in 2000 which was called the worst ecological disaster since Chernobyl.