REM/Specific/TBT-REM-014

Contaminated Groundwater Handling

Remediation & Contaminated LandSpecificContaminated Groundwater Handling

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Contaminated Groundwater Handling

Toolbox Talk Record

Ref: TBT-REM-014  |  Issue: 1  |  Date: March 2026
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What?

  • Contaminated groundwater is found on former industrial sites, landfills, fuel depots, and chemical works.
  • Contaminants commonly include hydrocarbons, heavy metals, solvents, pesticides, and leachate from waste.
  • Pumping contaminated groundwater during dewatering or remediation creates exposure and disposal challenges.
  • Skin contact with contaminated water can cause dermatitis, chemical burns, and absorption of toxic substances.
  • Volatile organic compounds (VOCs) in groundwater can generate hazardous vapours when water is disturbed.
  • The Environmental Permitting Regulations require consent before discharging treated or untreated groundwater.
  • COSHH assessments must be completed for all identified contaminants before any handling begins.
  • Treatment methods include oil-water separation, carbon filtration, pH adjustment, and settlement tanks.
  • Contaminated groundwater is classified as controlled waste and must be disposed of at licensed facilities.
  • Air monitoring may be required where VOCs or other volatile contaminants are present in the water.

Why?

Protect workers' healthContaminated groundwater contains chemicals that cause skin disease, poisoning, and long-term illness on contact.
Environmental complianceDischarging contaminated water without treatment or a permit is a criminal offence with severe penalties.
Legal dutyCOSHH 2002 and Environmental Permitting Regulations require assessment, treatment, and controlled disposal.
Do Don't
  • Complete a COSHH assessment for all identified groundwater contaminants before work starts
  • Wear chemical-resistant gloves, boots, and eye protection when handling contaminated water
  • Test groundwater samples for contaminants before deciding on treatment and disposal methods
  • Obtain an environmental permit before discharging any treated groundwater off site
  • Set up oil-water separators or treatment systems as specified in the remediation design
  • Monitor air quality for VOCs where volatile contaminants are present in the groundwater
  • Contain all pumped water within bunded areas to prevent uncontrolled spills and runoff
  • Dispose of contaminated water as controlled waste at a licensed treatment facility
  • Brief all operatives on the specific contaminants present and the required precautions
  • Decontaminate equipment and PPE after contact with contaminated groundwater
  • DON'T pump contaminated groundwater directly into surface drains or watercourses
  • DON'T handle contaminated water without chemical-resistant PPE including gloves and goggles
  • DON'T assume groundwater is clean because it looks clear — contaminants are often invisible
  • DON'T discharge treated water without confirming it meets the permit discharge limits
  • DON'T store contaminated water in unbunded or unsealed containers on site
  • DON'T ignore vapour odours near pumped groundwater — they may indicate toxic VOC exposure
  • DON'T eat, drink, or smoke until hands and face are washed after handling operations
  • DON'T mix contaminated groundwater with clean water to dilute it below discharge limits
  • DON'T skip air monitoring where volatile organic compounds have been identified
  • DON'T allow contaminated water to pool on site where it could contact other workers

See also: Contaminated Land Safety Awareness | Hydrocarbon Contamination Clean-Up

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