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Difficulty: MediumSoil Pollution, Pesticides, Heavy Metals, and Waste Management

Municipal solid waste containing large amounts of polyethene packaging materials is buried in a sanitary landfill. Over time, these materials persist in the soil without decomposing. Which chemical characteristic of synthetic addition polymers accounts for their resistance to biological waste degradation in soil?

  1. They contain strong, non-polar carbon-carbon single bonds that soil microorganisms lack enzymes to cleaveAnswer
  2. B
    They readily breakdown in moist soil to release carbon(IV) oxide gas that destroys stratospheric ozone
  3. C
    They react rapidly with soil moisture through reversible esterification to form soluble alkanols
  4. D
    They behave as biodegradable natural polymers that decompose quickly into soil nutrients when exposed to water

Answer

Synthetic addition polymers resist biological breakdown in soil because they contain strong, non-polar carbon-carbon single bonds that microorganisms lack the necessary enzymes to cleave.
The correct option identifies that synthetic addition polymers like polyethene consist of unreactive, non-polar carbon-carbon single bonds. Naturally occurring soil microorganisms do not produce enzymes capable of cleaving these stable hydrocarbon backbones, causing the material to persist as non-biodegradable waste in soil.

Step-by-Step Solution

1
Analyze the chemical structure of synthetic addition polymers like polyethene
The polymer backbone consists of long, saturated hydrocarbon chains formed entirely of strong, non-polar C−CC-C and C−HC-H single bonds.
Understanding the chemical bonding of the polymer determines its chemical reactivity and biological stability.
2
Evaluate microbial decomposition mechanisms in soil waste management
Soil bacteria and fungi secrete enzymes that hydrolyze polar functional groups (such as esters or amides in natural polymers), but cannot digest long non-polar C−CC-C alkane-like backbones.
Enzymatic specificity requires compatible functional groups for microbial degradation to occur.
3
Conclude the cause of non-biodegradability in landfill soil
Due to the absence of appropriate microbial enzymes and the high stability of non-polar carbon-carbon bonds, polyethene packaging persists unchanged in soil waste sites.
This structural stability is the primary chemical reason synthetic addition polymers are classified as non-biodegradable pollutants.

Key Concept

Chemical basis of non-biodegradable waste in soil pollution and waste management
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Topics

Soil Pollution, Pesticides, Heavy Metals, and Waste Management

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