TCE contamination at Woburn Flashcards
what determines direction of groundwater flow
-hydraulic head
- height of static water column above arbitrary elevation
- high hydraulic head to low hydraulic head flow
What is the hydraulic gradient?
2 points is the slope of hydraulic head in between
- y distances diff/ x distances diff
simple definition of hydraulic head
It is equal to the height of the water table
is the woburn aquifer confined
Yes , we assume so
how does groundwater flow
High elevation to low elevation
high to river
what effect do pumping wells have on groundwater flow
they draw water towards themselves to make pressure gradient
rate of flow will increase
draw down water table
what does groundwater flow velocity depend on
- Hydraulic gradient
- Permeability to rock or sediment
Porosity meaning
measure of its ability to hold a fluid
permeability meaning
measure of the ease of flow of a fluid through a porous solid.
What do pumping wells create in unconfined aquifer
cone of depression
woburn cone of depression zones
wells G and H
What is flow net
representation of groundwater flow in a area
what do blue lines present in groundwater flow
Equipotential lines
what do red lines present in groundwater flow
Groundwater flow lines
what is TCE
Trichloroethylene is a toxic chlorinated hydrocarbon
what is TCE used for
- effective solvent for organic materials
- before was used to extract vegetable oils, coffee decaffeination, dry cleaning
- used to dissolve grease and oil
Health effects of TCE
Carcinogenic in animals
what industries were operating in woburn in the vicinity of wells G and H?
- close to boston: tanning and shoemaking
- leather production
what raised concerns in woburn on their drinking water quality
- tasted and smelled weird whenever G and H got pumped
Do most states now have cancer registries that provide an important
means of monitoring cancer rates
True
Massachusetts did have a cancer registry when the
Woburn health concerns emerged in the late 1970’
False
In the late 1970’s, it was not known if TCE ingestion was a
potential cause of childhood leukemia.
True
It was possible to test for the presence of TCE in
groundwater prior to the late 1970’s
False
A “cluster” of health-related concerns can be determined using
Standard Incidence Ratios (SIR)
True
how does SIR do its job
compares number of observed cases of disease that is expected in that community to overall rate
for age <5, what was expected case #
1.43
for age 5-9, what was expected case #
0.82
for age 10-14, what was expected case #
0.64
what was the outcomes of Anne from woburn case about her kid’s cancer death?
Uni First 1.05M before trial
WR grace liable and Beatrice foods not liable
wr grace paid 8 million
what did jury misunderstand about groundwater flow?
didn’t know groundwater could travel under river
where is Woburn
Massachusetts US
