Question

Combustion produces oxides of nitrogen and oxides of sulfur, which can be oxidized to nitrate (NO₃^-) and sulfate (SO₄^2-) respectively in the atmosphere: the nitrate and sulfate subsequently may be deposited by both wet and dry processes. Cite and explain specific regional or global-scale problems, or potential problems, that may be exacerbated by increased levels of nitrate and sulfate deposition in precipitation.

Answer 1

Following are some environmental problems that are exacerbated by increased nitrate and sulphate deposition in precipitation(Acid rain):

A) Dry deposition of acidic material on dust smoke and aerosols.

B) Wet deposition of acid in precipitation (rain, snow, fog etc)

ACID RAIN.

1) Sources of acid rain: SO2 gas, NH3 gas and Nitroge oxides( with general formulaN_yO_x) dissolves in rain water and forms corresponding acids which ionizes and make rain water acidic. The common source of SO2 and Nitogen oxides are industrial gaseous effluents, burning of fossile fule, coal by-products etc.

2) Effect on SOIl:

a) Neutralization of soil: Normal soil pH for good productivity must be alkaline but acid rain being acidic makes decreases soil pH and make in neutral of some times slighltly acidic. ii) Leaching of nutirients: Acid leaches soil nutrients. Normally metal ions like K+, Ca2+, Mg2+, K+ and trace metals'cations are attached to soil and are easily available for plants to take. But H+ ions in soil through ion exchange replace these metal ions. These essential metals then go deep down in soil and remains no more available for plants. Hence it affects the growth of natural vegetation or even to food crops.These metalls drained to groun water of washed awayw with stream water. Nitratea and sulphates bind these metal cations and make situation more difficullt.

b) Effect on vegetation: Acid deposition deplets the metal availability also cause leaching of aluminium and nitrates and sulphates increases S and N content of soil.This lead to wweakening of trees by bark beetal infestation and various diseases.

c) Effect on marine /aquatic animals: Leached metals drained away with stream water. This deposites these metals in lake / sea water. Aluminium metal is highly toxic to some aquatic animalsespecially eggs, larvaes, young animals etc

Acidic pH (< 5) kills fishes, frog eggs, tadpoles etc.