Balancing chemical equations is a key chemistry skill. Use these step by step instructions to write and balance chemical equations. Balancing chemical equations is a key chemistry skill. Use these step by step instructions to write and balance chemical equations.
So, there are many signs and symptoms of Selenium Overdose- some occur very early and some occur much later. 1  Early Signs: Some of the early signs of Selenium Toxicity are endocrine hormone disturbances- particularly thyroid issues. Poor hair and nail growth are early signs that are probably the easiest to notice.
Symptoms of overdose: 1  Irregular heartbeat. 2  nervousness. 3  numbness or tingling in the hands, feet, or lips. 4  rash with flat lesions or small raised lesions on the skin. 5  reddened skin. 6  weakness or heaviness of the legs.