Arsenic News, Pelican Lake

David Majkrzak, May 8, 2004

During the spring and summer of 2003 many lakes area residents became aware of high levels of Arsenic in their deep-water wells. Because of this drinking water concern, I have been collecting data and information from Pelican Lake property owners about their individual well tests. This information is also being reported back to the Directors of PGOLID and PLPOA.

Arsenic is measured in micrograms per liter (ug/L, or as ppb, parts per billion). I have received written reports on about 25 well tests, as well as verbal input on several dozen other water tests. Around Pelican lakes, we have seen arsenic numbers from a low of less than 2.5 ug/L (the lowest number reported in most tests), to a high of 75 ug/L. The acceptable standard for arsenic in drinking water is 10 ug/L, and is set by the US Environmental Protection Agency (EPA). This standard was lowered from 50 ug/L to 10 ug/L in March of 2001 because of concerns the EPA had with recent research on the effects of arsenic in drinking water.

Several lake residences have done repeated tests on the same well. The results can change from an existing well based on the time of year, well usage, and other factors. One lake resident tested his well in October and had a 37.2 ug/l reading, but the same well had a 14.0 ug/L in April. The accuracy and repeatability of the arsenic test procedure itself is good, meaning the same water sample, if taken to different labs on different days, should come back with results within less than 1% error.

Several people have asked about water softeners and reverse osmosis (RO) units and there effect on arsenic. A water softener will make no difference on the arsenic level in your water. RO filter systems do help with one report showing a 14.0 to 6.3 ug/L change, a second lake resident seen his lever drop from 14 to 3 ug/L after RO. This same lake resident went on to purchase a special RO filter system that was rated to remove arsenic, a follow up test on this system showed his arsenic lever dropped to 0 (zero).

The arsenic is occurring in deep wells (deep wells are usually considered over 90 feet deep) and the arsenic problem does not usually, and has never been reported here, to occur in sand point wells. Arsenic is naturally occurring mineral in soil and bedrock, and the elevated readings in our area are not believed to be associated with any man made problem. Many arsenic tests in deep wells within a 20-mile radius of our lakes are coming back with readings in the 90-110 ug/L range.

Arsenic water tests can be processed through several water testing labs in the area, and the tests usually cost between $15-$25. There is additional information available on the PGOLID and PLPOA web site.