Guest Commentary: Greater Pine Island Water Association report on arsenic
A few residents of Pine Island have recently asked about the safety of the drinking water supply on the island following reports on the radio in December and in May. Our source water is withdrawn from the Lower Hawthorn artesian aquifer via five wells ranging in depth from 525 to 750 feet below land surface.
That said, as general manager, I understood it was important to inquire with our Geologic Consultant to concisely answer in scientific terms how safe our aquifer is from arsenic contamination from other sources. Below is an excerpt from RMA Geologic Consultants:
“The recent radio broadcasts were related to arsenic levels in the surficial aquifer at a particular site on Pine Island. The surficial aquifer is the shallowest water-bearing zone or aquifer on the island. It is directly recharged by rainfall and the water table elevation is typically (depending on the season) between two and four feet below land surface. The aquifer is about forty feet thick and consists of fine grained sand. Because Pine Island is, in fact, an island surrounded by seawater, the surficial aquifer typically contains brackish (i.e. dissolved chloride concentrations between 500 and 5,000 mg/l) to saline groundwater. Because of its salinity, as well as its low yield, it is nearly everywhere on the island unusable for human consumption. The only fresh groundwater in the aquifer is in the highest topographic areas of the island, which in southern Pine Island is a narrow strip paralleling Stringfellow Road.
“Between the base of the surficial aquifer and the top of the Lower Hawthorn aquifer are several hundred feet of impermeable clay. Therefore, because of the confinement and artesian pressure, there is no possibility of contaminants from surface land use activities entering the GPIWA PWS source aquifer. In addition, Lee County has a Wellfield Protection Ordinance, which applies to all PWS wellfields which have a South Florida Water Management District (SFWMD) withdrawal allocation of more than one million gallons per day. This includes the GPIWA wellfield. The ordinance prohibits certain land use activities within specified distances around PWS wells. The State of Florida also has a wellhead protection rule that restricts certain land use activities within 500 feet of PWS wells, regardless of their depth.”
Adding secondary filtration devices in your home are, of course, your choice but not necessary. Some customers do not like the chlorine smell or taste. The easiest solution for chlorine sensitivity is to keep an open pitcher in your refrigerator. The chlorine residual will dissipate in a short period of time. However, should you decide to put in some additional treatment in your home it is very important to follow manufacturer’s maintenance protocol.
We encourage our customers to visit our website www.pineislandwater.com to learn about our water produced by reverse osmosis. At our publications tab you will be able to see all contaminants detected, in relation to the maximum contaminant level (MCL) regulated by EPA. In 2016 there were no MCL violations.
Laurie Adams is General Manager for the Greater Pine Island Water Association,