TCE Contamination at Woburn

Question 1

What determines the direction of groundwater flow?

Answer 1

• Hydraulic head, which is a measurement of the height of a static water column above an arbitrary elevation, usually expressed in meters
• Groundwater flows from areas of high hydraulic head to low hydraulic head
• The hydraulic gradient between any 2 points is the slope of the hydraulic head between those points, always expressed as a decimal

Question 2

For the hydraulic gradient to have any meaning the

Answer 2

wells must be in the same aquifer. For simplicity, consider that Woburn aquifer is unconfined. Therefore, the hydraulic head is equal to the height of the water table

Question 3

What influence do pumping wells have on the direction and rate of groundwater flow?

Answer 3

Draw groundwater towards themselves by creating a pressure gradient. Rate of groundwater flow increases, esp in areas next to well

Question 4

Groundwater flow velocity depends on:

Answer 4

1) Hydraulic gradient
2) Permeability of rock or sediment

Question 5

Pumping wells create a lowering of water lvls in an unconfined aquifer called

Answer 5

a cone of depression

Question 6

Flow net

Answer 6

• Representation of groundwater flow within an area, either in plan view (map) or cross-section
• Then contour water table surface and construct water flow lines, which are perpendicular to contours. Water table contour lines are of constant hydraulic head = equipotential lines

Question 7

What is TCE and what is it used for?

Answer 7

Trichloroethylene, used as an effective solvent for organic materials (dry cleaning solvent, etc)

Question 8

What are the health effects of TCE on humans?

Answer 8

Depresses the CNS, symptoms similar to alcohol intoxication -> headache, dizziness, unconsciousness, etc. Human carcinogen.

Question 9

What industries were operating in Woburn in the vicinity of wells G and H?

Answer 9

Shoe-making, tanning, dry cleaning

Question 10

What factors raised concern in Woburn regarding the quality of drinking water?

Answer 10

Nearby children being diagnosed with leukemia, odor, taste, and rusty colour of water, all household appliances breaking and needing replacement after

Question 11

Most states now have cancer registries that provide an important means of

Answer 11

monitoring cancer rates

Question 12

Massachusetts did not have a cancer registry when the

Answer 12

Woburn health concerns emerged in the late ’70s

Question 13

In the late 1970s, it was not known if TCE ingestion was a potential cause of

Answer 13

childhood leukemia

Question 14

It was not possible to test for the presence of

Answer 14

TCE in groundwater prior to the late 1970s

Question 15

A ‘cluster’ of health-related concerns can be determined using

Answer 15

Standard Incidence Ratios (SIR)

Question 16

SIRs compare the number of observed cases of disease to

Answer 16

the number of cases that would have been expected if the community’s rate of disease were the same as the overall rate for the state

Question 17

In 1979, hazardous lvls of TCE were found in the water from wells G and H, and the wells

Answer 17

were shut down

Question 18

Trial of Anne Anderson et al (8 families) vs W.R. Grace & Co., Beatrice Foods, and UniFirst Corp

Answer 18

Anne Anderson’s son was diagnosed with leukemia in 1972, died from the disease in 1981, the law suit was filed in 1982

Question 19

Outcomes of the trial:

Answer 19

• UniFirst settled out of court for $1.05mil prior to trial
• Jury found W.R. Grace liable and Beatrice Foods not liable for contaminating wells G and H
• W.R Grace settled with plaintiffs for 8mil

Question 20

What did the jury misunderstand about groundwater flow?

Answer 20

That pumping wells can pull water towards themselves, even from the other side of rivers