High Arsenic Levels in Eastern New England
The US Geological Survey New Hampshire and Vermont Water Science Center created a model for predicting locations where ground water will contain high levels of arsenic.
This information will be used by water system planners and as an exposure assessment in an epidemiologic study of bladder cancer in the region.
Interesting facts from the abstract:
In eastern New England, 20-30% of private wells exceed the arsenic drinking water standard of 10 micrograms per liter.
Previous studies suggest that arsenic in bedrock groundwater may be partly from past arsenical pesticide use. Variables representing historic agricultural inputs do not improve the model, indicating that this source does not significantly contribute to current arsenic concentrations
Indications are that the arsenic is from naturally occurring sources.
You can read the abstract here.