Question

Name two pollutants for each route that are very easily absorbed through each route of exposure (lung, skin, and digestive tract) and explain why they are easily absorbed. Describe how each of their chemical/ physical characteristics aids in their absorption.  

Clarification: There should be a total of six different pollutants: 2 unique pollutants for inhalation, 2 unique pollutants for skin, and 2 unique pollutants for the digestive tract.

Answer 1

POLLUTANTS THAT AFFECT LUNGS

1. Nitrogen dioxide : it forms on burning of coal, gas, oil or diesel in high temperatures. Sources of nitrogen dioxide are vehicles like cars, trucks, buses and power plants, industrial boilers etc. It's absorption is undertaken by reaction between inhaled nitogendioxide and constituents of the pulmonary surface lining layer and it produces HNO2. Gaseous nitrogen oxide diffuses into the epithelial lining fluid of the respiratory epithelium and dissolves. Then it chemically reacts with antioxidant and lipid molecules in the epithelial lining fluid.
2. Carbon monoxide : it forms as a byproduct of combustion reactions or burning of certain fuels ( natural gas, oil , propane, wood). Lungs absorbs carbon monoxide --> combines with Hbs (85%) + myoglobin (15%). Carbon monoxide binds more readily to hemoglobin displacing oxygen and forming carboxyhemoglobin.

POLLUTANTS THAT AFFECT SKIN

1. Ozone : it is reactive enviromrntal oxidant. It causes depletion of antioxidants and in oxidation of lipid and proteins in stratum corneum. High levels of ozone through signal transduction mechanism damages the deeper layer of skin.
2. Ultra violet rays : natural source of uv rays is sun. It is invisible to human eyes. It provokes chemical changes not simply heat sites where they are absorbed. penetrate the outer skin layers that is stratum corneum and pass into deeper layers, where they can damage skincells.

POLLUTANTS THAT AFFECT DIGESTIVE TRACT

1. Heavy metals : like lead and mercury.mercury ecposure is through eating fish, amalgam based dental fillings etc. Systemic toxicity can occur
2. Particle pollutants (PM) : it can trigger onset of gastrointestinal disease. High oral dose of particulate matter decrease the diversity of gut microbiota. Increase risk of IFG.