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  Blurred vision. 2  headache. 3  seizures. 4  slurred speech. 5  sudden and severe inability to speak. 6  temporary blindness. 7  weakness in the arm or leg on one side of the body, sudden and severe.