Thank you for the information,
Blue color of the tongue can occur when there is lack of oxygen in the blood.
This can be due to diseases of the heart & lungs
Those are usually associated with difficulty in breathing.
In other conditions there can be blue coloration from methemoglobinemia.
This can occur from medicines or from food.
You can read this link on it.http://www.nlm.nih.gov/medlineplus/ency/article/000562.htm
However these conditions are unlikely to cause blue colored saliva or sputum.
Blue or black particles can be mixed with mucus from dust.
Acid reflux is unlikely to cause it.
Without other symptoms or previous illness it is difficult to determine a cause.
I feel you need an examination by doctor now.
The doctor then can advise for tests according to clinical findings.
I hope this information helps.
I will be happy to assist, if you need any clarification.
Please feel free for any follow up query.