Examkin

Question

Difficulty: MediumPollution Types, Causes, Effects, and Control

Atmospheric pollution by industrial emissions can lead to terrestrial ecosystem degradation through acid deposition. Arrange the following sequential steps in the correct order to illustrate how acid rain forms and subsequently causes forest decline, starting from initial pollutant emission to final biological effect.

  1. 1Emission of sulfur dioxide (SO2SO_2) and nitrogen oxides (NOxNO_x) from industrial combustion into the atmosphere.
  2. 2Atmospheric reaction of emitted gases with water vapor and oxygen to form sulfuric acid (H2SO4H_2SO_4) and nitric acid (HNO3HNO_3).
  3. 3Precipitation of acidic moisture onto soil, significantly lowering the terrestrial soil pH.
  4. 4Mobilization of toxic aluminum ions (Al3+Al^{3+}) and leaching of essential plant nutrients like calcium and magnesium from the soil.
  5. 5Uptake of toxic ions and loss of nutrients causing root damage, impaired water absorption, leaf chlorosis, and eventual tree dieback.

Answer

The correct order of events begins with the emission of SO2SO_2 and NOxNO_x primary pollutants into the atmosphere, followed by their atmospheric oxidation to sulfuric and nitric acids, acid precipitation onto forest soil, mobilization of toxic aluminum ions with leaching of essential plant nutrients, and finally root damage causing leaf chlorosis and tree dieback.
Acid deposition follows a direct cause-and-effect cascade: Primary industrial gas emissions (SO2SO_2, NOxNO_x) undergo atmospheric oxidation into secondary acids (H2SO4H_2SO_4, HNO3HNO_3). When acid rain falls, it acidifies soil water, which mobilizes phytotoxic Al3+Al^{3+} ions and washes away nutrient cations (Ca2+Ca^{2+}, Mg2+Mg^{2+}). The resulting nutrient starvation and root cytotoxicity lead directly to chlorosis and forest dieback.

Step-by-Step Solution

1
Identify the primary source event of atmospheric acid pollution.
Industrial emissions release primary pollutant gases like sulfur dioxide (SO2SO_2) and oxides of nitrogen (NOxNO_x) into the air.
Chemical pollutants must first enter the environment before atmospheric reactions can occur.
2
Trace the chemical atmospheric transformation.
Gases react with atmospheric moisture and oxygen, forming dissolved sulfuric acid (H2SO4H_2SO_4) and nitric acid (HNO3HNO_3).
Primary pollutants undergo secondary chemical conversion in cloud moisture.
3
Determine the transfer mechanism from atmosphere to terrestrial habitat.
Acidic rain, snow, or fog deposits onto terrestrial habitats, lowering soil pH.
Precipitation carries dissolved acids from the atmosphere directly to soil.
4
Analyze the geochemical impact on soil composition.
Low soil pH mobilizes toxic Al3+Al^{3+} ions and leaches essential mineral ions like Ca2+Ca^{2+} and Mg2+Mg^{2+}.
Increased hydrogen ion (H+H^+) concentration displaces nutrients from soil clay minerals and releases bound toxic metals.
5
Assess the biological physiological consequence on vegetation.
Trees suffer root necrosis, leaf chlorosis due to magnesium deficiency, impaired water uptake, and dieback.
Toxic aluminum harms root tips, and lack of essential mineral ions prevents chlorophyll synthesis and cellular respiration.

Key Concept

Acid deposition sequence, cause-and-effect mechanisms of atmospheric pollution on soil chemistry and plant physiology
Rate this question

Topics

Pollution Types, Causes, Effects, and Control

More questions from this topic