TCA in groundwater

Introduction to Environmental risk analysis - course

Groupwork

Mikko Pohjola
Juha Villman

James L. Byard: Hazard Assessment of 1,1,1-Trichloroethane in Groundwater

Identification of Hazard

In text: chapters 8 Toxicology & 9 Estimation of nontoxic dose

• TCA has been used as an industrial degreasing solvent
• TCA is absorbed from the gastrointestinal tract and 30 % from the lungs
• Chemical is rapidly distributed to all tissues via bloodstream
• Chronic toxicity
  • Reported in several studies for no toxicity, no excess cancers, no marked oncogenic effect, no effect on mortality or body weight
  • One study reported excess of leukemias in rats exposed to TCA
• Only few weakly positive results for mutagenicity of TCA
  • These results can be explained by butylene oxide present in some commercial formulations of TCA
• No teratogenic effects in rodents exposed to TCA
• TCA is relatively nontoxic chemical
• High dose of TCA can cause:
  • Narcosis
  • Mild organ pathology
  • Irritation of respiratory tract

Dose-Response assessment

In text: 8 Toxicology & 9 Estimation of nontoxic dose

• 15 minutes of vapor concentrations of TCA increasing from 0 to 2650 ppm
  • Mild eye irritation at 1000 - 1100 ppm
  • Throat irritation at 1900 - 2000 pm
  • Lightheadedness at 2600 ppm
  • Inability to stand at 2650 ppm

Exposure assessment

In text: 6 Exposure & 7 Determination of dose

Risk Characterization

In text: 10 Conclusions & 9 Estimation of nontoxic dose