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  Bluish-colored lips, fingernails, or palms. 2  dark urine. 3  fever. 4  headache. 5  pale skin. 6  rapid heart rate. 7  sore throat. 8  unusual bleeding or bruising.