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Zorluk: ZorEnvironmental Pollution: Types, Causes and Control Measures

Consider the following statements regarding in-situ and ex-situ biological techniques used for environmental pollution control (bioremediation):

1. Bioaugmentation involves modifying environmental conditions by adding nutrients and electron acceptors to enhance the metabolic activity of indigenous microbial populations.
2. Biosparging is an in-situ remediation process that injects air under pressure into the saturated zone below the water table to promote aerobic biodegradation of organic pollutants.
3. Phytostabilization utilizes plants to immobilize soil and groundwater contaminants through absorption and precipitation, thereby preventing their migration rather than removing them from the site.

Which of the statements given above is/are correct?

  1. A
    1 and 2 only
  2. 2 and 3 onlyCevap
  3. C
    1 and 3 only
  4. D
    1, 2 and 3

Cevap

2 and 3 only
Statements 2 and 3 are correct. Biosparging is an effective in-situ technique that forces air under pressure into the saturated zone to supply oxygen to indigenous microbes, enhancing the biodegradation of volatile hydrocarbons and organic contaminants in groundwater. Phytostabilization utilizes tolerant plants to immobilize heavy metals and organic pollutants within the soil or rhizosphere, reducing their leaching potential into groundwater without requiring plant harvesting. Statement 1 is incorrect because the process of modifying site conditions by supplying nutrients and electron acceptors to boost native microflora is defined as biostimulation; bioaugmentation specifically entails introducing exogenous, laboratory-cultured, or genetically modified microbes into the contaminated media.

Adım Adım Çözüm

1
Analyze Statement 1 regarding microbial remediation terminology.
Statement 1 describes 'biostimulation' (adding nutrients/oxygen to stimulate existing indigenous microbes) rather than 'bioaugmentation' (adding specialized, externally cultured microbial strains to the polluted site). Therefore, Statement 1 is incorrect.
Conflating biostimulation with bioaugmentation is a common technical conceptual error in bioremediation strategies.
2
Evaluate Statement 2 regarding groundwater remediation mechanisms.
Biosparging specifically involves injecting air under pressure directly into the saturated zone below the water table, facilitating volatile transport and stimulating aerobic biodegradation of organic pollutants. Therefore, Statement 2 is correct.
Biosparging targets the saturated groundwater zone, whereas bioventing targets the unsaturated vadose zone.
3
Evaluate Statement 3 regarding phytoremediation sub-types.
Phytostabilization involves using plant root systems to sorb, precipitate, or bind contaminants in the soil/rhizosphere, rendering them bio-unavailable and preventing off-site migration. Therefore, Statement 3 is correct.
Phytostabilization focuses on contaminant containment and stabilization rather than extraction (phytoextraction) or volatile emission (phytovolatilization).

Anahtar Kavram

Bioremediation and Phytoremediation Control Mechanisms
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Konular

Environmental Pollution: Types, Causes and Control Measures