Question

Which one of the following is responsible for blue baby syndrome?
A. Fluoride
B. Nitrate
C. Arsenic
D. Lead

Answer 1

Hint: Blue baby syndrome is a number of conditions that disturb oxygen conveyance in the blood resulting in blue coloured skin in babies. Historically the term "blue baby syndrome" has denoted to babies with one of two conditions:
$1.$ Cyanotic Heart Disease which is a type of congenital heart disease that results in low levels of oxygen in the blood. This can be caused by either insufficient blood flow to the lungs or mixing of oxygenated and deoxygenated blood.
$2.$ Methemoglobinemia which is a disease defined by raised levels of methaemoglobin in the blood. Raised levels of methemoglobin prevent oxygen from being free into the tissues and result in hypoxemia.
Both of these conditions cause cyanosis or a bluish discoloration of skin or mucous membrane. Generally oxygenated blood looks red and deoxygenated blood has more of a blue appearance. In babies with low levels of oxygen or mixing of oxygenated and deoxygenated blood the blood can have a blue or purple colour causing cyanosis.

Complete Answer:
Blue Baby Syndrome is a disease that starts when huge amounts of nitrates in water are swallowed by a baby and transformed to nitrite by the digestive system. Then the nitric reacts with oxyhemoglobin to form methemoglobin. This methemoglobin is unable to carry oxygen. If a big amount of methemoglobin is formed in the blood then body tissues may be run-down of oxygen instigating the infant to develop a blue coloration of their mucous membranes and probably digestive and respiratory problems. This illness is also known as Methemoglobinemia.
So, option B ‘Nitrate’ is the correct answer.

Additional information:
Option A – Fluoride: Disease caused by the fluoride is fluorosis. Fluorosis is a disease initiated by the deposition of fluorides in the hard and soft tissues of the body resulting in crippling. It is a public health problem initiated by surplus intake of fluoride through drinking water or through other means over a long period.
So, option A ‘Fluoride’ is not the correct answer.
Option C – Arsenic: Arsenic is associated with heart disease (hypertension related cardiovascular disease), stroke (cerebrovascular diseases), cancer, diabetes and chronic lower respiratory diseases.
So, option C ‘Arsenic’ is not the correct answer.
Option D – Lead: Lead poisoning is also known as plumbism and saturnism. It is a type of metal poisoning produced by lead in the body.
So, option D ‘Lead’ is not the correct answer.

Note:
Symptoms of blue baby syndrome are often delicate. It can be noticed in babies around their lips, tongue and sublingual area where the skin is thinnest. If cyanosis is assumed pulse oximetry can be used to monitor the oxygen saturation in the blood. While severe cyanosis can be easily noticed by the oxygen saturation as low as 80% causes only minor clinical cyanosis that is hard to see.