What controls selenium release during shale weathering?

This study demonstrates that only a combination of a chromous chloride reduction with dual sequential extraction schemes can clearly separate the proportions of Se present in the sulphide versus the organic pools in shales. The data reveals that even small amounts of pyrite outcompete the organic matter for the available Se and pyrite oxidation will control the release of selenium during shale weathering.

Research highlights► Quantification of selenium distribution in shales using various sequential extractions. ► Prime selenium host phases are organic matter and sulphides. ► Even low pyrite contents outcompete the organic matter for available Selenium. ► Pyrite oxidation controls the release of selenium during shale weathering.