Because the phrase "urine test" might alarm some residents, the Hernando County Health Department wants to reassure recipients of letters it will start sending out next week.
It is a chance for select members of the public to assist in scientific research, said Al Gray, the department's environmental manager.
It's also an opportunity for residents with wells contaminated by arsenic to learn how well filter systems are protecting their bodies and the bodies of their children.
The Health Department will send the letters to 520 homeowners in southeastern Hernando County as part of a study fully funded with a $60,000 grant from the federal Centers for Disease Control and Prevention.
Half of the letters will go to homes with wells that are not contaminated by arsenic, which started showing up in large numbers of wells in 2007. Though scientists aren't sure of the source, a likely culprit is the historic use of arsenic-based pesticides when the area was prime agricultural land.
The other half of the letters will go to homes with levels of contamination between 10 and 50 parts per billion.
The letters will ask residents to allow a scientist to come by to take samples of water from wells or filters as well as urine samples from an adult and, if available, one child.
The arsenic levels in the urine of people with contaminated wells will be compared to the levels in people with uncontaminated wells.
The main goal, Gray said, is to determine the effectiveness of the state's main solution to low levels of contamination: a small filter, usually installed next to the kitchen sink, that provides water for drinking and cooking.
The study will also include a survey about what residents eat and their other habits — for example, whether people use filtered water to brush their teeth and for all types of cooking.
This should allow scientists to determine whether residents are getting arsenic from foods such as apple juice and rice, which have been shown, in some cases, to contain arsenic.
Wells contaminated with more than 50 parts per billion of arsenic are not included in the study because they are considered seriously contaminated and are usually fitted with filters that purify the entire home's water supply.
The letters will go out in batches over the next several months, and the study is due to be completed by July 1.