So much more learned and understood since undertaken the review of the information gathered from many well reports in my neck of the woods.
So much politics in an area public health should prevail, but this was what I learned.
When the pesticide, chlordane was first discovered to be a potential health problem, the US EPA banned its use in agriculture, but continued to permit its use in private residences. That was an economic issue, there was a lot manufactured and much to use up and homes had to be protected from termites, more money damages.
That was finally stopped in 1988.
During the first period, 1948 to 1977, we ingested many pounds of the pesticides eating our veggies.
Most of us did not have serious effects, some of us did.
Dieldren, the other pesticide in question in my area, is still not even regulated by the US EPA, their statement is that it is not manufactured any more so does not pose a threat.
Both of these pesticides were applied on excavated areas before a home was built.
Dieldren does not seem to have a discernible half life, samples taken from the same home in 1996 had virtually the same levels in 2008.
Chlordane does degrade into alpha and gamma chlordane over time. Alpha and gamma chlordane are not regulated.
Some of this was very surprising, some of the things that were not are listed below.
Farms would have large disposal areas for their product waste and that would include large amounts of any pesticide applied.
Normal, everyday people would dispose of waste pesticides or clean out private sprayers, some where in the same place in their own back yards.
Distance of a well to a home was not regulated and so a well could be dug directly adjacent to a foundation.
Percentage of wells with contamination varies directly with how close the well is to the foundation.
Wells within 25 feet of the foundation have the greatest chance of having some trace amount of pesticides in the well. Well greater than 75 feet did not have an occurrence of pesticide in the water.
Substances found in the outfall from Scofieldtown park (a former dump site), were not found in any near by wells.
Same was true of pesticides found in the soil at Bartlett Arboretum, they were not found in any well adjacent to the property nor on the property.
That is what I have learned..