2. Objectives
Four objectives were identified in this study.
2.1   Is Current Guidance Working?
The primary objective of this study was to determine if the current well construction guidance- case 80
feet into the StP - is consistently having the intended result of permanently eliminating, or at least
dramatically reducing, naturally-occurring arsenic in drinking water. If the findings showed that the
guidance is valid, this study could help the WDNR decide if the special well casing advisory should be
elevated to a well casing requirement. If it appears to be invalid, this research can help the WDNR
make modifications to the guidelines. As previously mentioned, the special well casing was in fact
made a requirement during the course of this study, and as of April 2002, this became a requirement for
portions of Algoma and Omro Townships in Winnebago County. In addition, just prior to this report
going to press, in October of 2004, a special casing requirement was imposed upon all of Outagamie
and Winnebago Counties.
2.2   Are There Seasonal Variations?
A second objective was to determine if there were seasonal variations in arsenic levels. A Study of Well
Construction Guidance for Arsenic Contamination in Northeast Wisconsin (Weissbach et al., 1998) did
not find that seasonal variations occur, but there were two wells that each experienced one unexplained
significant increase in arsenic levels. This finding led the authors to caution that "seasonal variations of
arsenic levels in drinking water are possible." It has also been noted from other data that some seasonal
trends may exist, with higher results in the fall than other months of the years. Therefore, this study
also attempted to assess seasonal variations. To accomplish this, sampling was conducted during each
of the four seasons.
2.3   Are Arsenic Levels Increasing Over Time?
A third objective of this study was to determine if arsenic levels in individual wells increase over time.
The results of the 1998 Weissbach et al study "did not show any appreciable rise in arsenic
concentrations over time." However, many of the wells that were sampled during that study had been
drilled or reconstructed between January 1, 1994 and December 31, 1995 with sampling events
occurring between April of 1997 and January of 1998. Consequently, it is possible that these wells
were not in existence long enough for the chemical reaction to occur. This, combined with the fact that