Land Contamination and Remediation

What Land Contamination and Remediation covers

Land Contamination and Remediation is examined in Unit A2 1, Building and Managing a Sustainable Future, a written examination. It covers contaminated land, risk and traditional remediation, bioremediation principles and bioreactor systems, micro-organisms that degrade named pollutants, bioremediation benefits and genetically engineered microbes, phytoremediation of metals and other elements, phytoextraction with Indian mustard and alpine pennycress and biohydrometallurgy and phytomining of ores.

The 7 subtopics

Each one has its own page.

• Contaminated land, risk and traditional remediationBrownfield pollutants and PCBs, the source–pathway–receptor model, risk management and site use, the stages of dealing with a site, dig and dump, soil washing and thermal treatment, heavy metals, and in situ and ex situ treatment.Open →
• Bioremediation principles and bioreactor systemsHow microbes degrade pollutants and the conditions they need, biostimulation and bioaugmentation, bioventing, landfarming and biopiles, slurry-phase bioreactors on site, monitoring, clay soils and aerobic breakdown of oil.Open →
• Micro-organisms that degrade named pollutantsPseudomonas putida and aromatic solvents, Pseudomonas aeruginosa and biosurfactants for oil, Dehalococcoides ethenogenes and chlorinated solvents in groundwater, microbes for pesticides and PCBs, and treating mixed contamination.Open →
• Bioremediation benefits and genetically engineered microbesCost and environmental benefits of bioremediation with a worked saving, public acceptance, its disadvantages and when dig and dump is preferred, Chakrabarty's bacterium, engineered microbes and biosensors, and their risks.Open →
• Phytoremediation of metals and other elementsPhytoextraction, phytostabilisation, rhizofiltration and phytovolatilisation, hyperaccumulators, copper, cadmium, rubidium, strontium, arsenic and antimony, the Chernobyl sunflowers, disposing of plant material and depth limits.Open →
• Phytoextraction with Indian mustard and alpine pennycressAlpine pennycress for zinc and cadmium, Indian mustard for lead with EDTA, gold and uranium, the advantages and limits of each, zinc uptake and harvest calculations, a laboratory demonstration and commercial evaluation.Open →
• Biohydrometallurgy and phytomining of oresWhy smelting uses energy and pollutes, Thiobacillus ferrooxidans and the bioleaching of copper and uranium, preparing and running a heap, biorefining against smelting, a copper yield calculation, and phytomining with mustard and sunflowers.Open →

What you need to know

Answer each one before you reveal it.

Take Land Contamination and Remediation further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Bioremediation vs Phytoremediation

  Bioremediation: the use of micro-organisms to degrade or transform pollutants. Phytoremediation: the use of plants to remove or contain pollutants.

• Biostimulation vs Bioaugmentation

  Biostimulation: adding nutrients or oxygen to encourage native microbes. Bioaugmentation: adding cultured microbes known to degrade the pollutant.

• In situ remediation vs Ex situ remediation

  In situ remediation: treatment of contaminated soil where it lies, without excavation. Ex situ remediation: treatment of contaminated soil after digging it up.

Questions from this topic

Each one with the model answer underneath.

1. 1

   When is land considered contaminated?

   Model answer

   Land is contaminated when substances in or under it could cause significant harm to people, property or ecosystems. Pollution of groundwater or rivers from the land also counts.

2. 2

   What pollutants are commonly found on brownfield sites?

   Model answer

   Brownfield sites often contain waste oil, diesel oil and heavy metals such as lead and cadmium. Chlorinated pesticides and polychlorinated biphenyls (PCBs) are also common.

3. 3

   How do former industrial uses lead to land contamination?

   Model answer

   Spilt chemicals, leaky fuel tanks and buried waste can release pollutants into soil. Gasworks, shipyards, factories and scrapyards commonly leave contaminated ground.

4. 4

   What are polychlorinated biphenyls (PCBs), and why are they a concern on contaminated land?

   Model answer

   PCBs are chlorinated organic compounds once used in electrical transformers and capacitors. PCBs persist for decades and bioaccumulate in food chains. PCBs are toxic and classed as carcinogenic.

5. 5

   What is the source–pathway–receptor model?

   Model answer

   The model identifies a contaminant source, a receptor that could be harmed and a pathway linking them. A risk exists only when all three are present, forming a pollutant linkage.

6. 6

   Give examples of receptors and pathways on a contaminated site.

   Model answer

   Receptors include residents, groundwater, rivers and wildlife. Pathways include swallowing soil, breathing dust or vapour and leaching into groundwater.

What is inside Levo

Six ways to work the same material.

Land Contamination and Remediation revision questions

What does Land Contamination and Remediation cover in CCEA A-Level Environmental Technology?

7 subtopics: contaminated land, risk and traditional remediation, bioremediation principles and bioreactor systems, micro-organisms that degrade named pollutants, bioremediation benefits and genetically engineered microbes, phytoremediation of metals and other elements, phytoextraction with indian mustard and alpine pennycress and biohydrometallurgy and phytomining of ores. Each one has its own page with questions and model answers.

How is Land Contamination and Remediation organised?

By the CCEA 3930 specification, subtopic by subtopic, so it matches the order you are taught it in.