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

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

In text: 6 Exposure & 7 Determination of dose

Ingestion

Toilet bowl

Shower

Highest inhalation exposure due to large volume of hot water and small air volume of a shower stall
10 minute shower
50 litres of water containing 1 ppb TCA
0,00358 ug/kg day
Additional dermal vapor absortion is 1 % of the inhalation dose
0,0072 ug/kg day

Bath

Total dose

Worst case bathroom exposure: 1 bath per day + staying bathroom for 1 hour + ingestion of 2 litres
0,0286 ug/kg day + 0,0478 ug/kg day = 0,0764 ug/kg day (Water containing 1 ppb TCA)

In text: 10 Conclusions & 9 Estimation of nontoxic dose