Why do countries erect trade barriers that inhibit imports and exports

To protect their local markets and keep a health balance of payments.

Explanation:

They inhibit imports as those require forex and may hurt their own country's production and markets. They inhibit exports at times to prevent shortages of goods they require such as wheat when there is a drought or increases local demand.

responsibilities im assuming

explanation:

allergens: overstimulate the nerve system

neurotics: attack nerve cells

mutagens: damage or otherwise alter dna sequence

generators: cause defects during growth and development  

carcinogens: cause unchecked cell growth

i hope you get the idea according to me these are the effects that happened.