Water at Woodstock School District 200's Greenwood Elementary School again has shown elevated arsenic levels, school officials said Thursday.
District officials have been testing the water at the elementary school on a monthly basis since the arsenic problem first arose last year, which is when multiple tests showed arsenic levels above what is considered acceptable for consumption by the U.S. Environmental Protection Agency. The acceptable standard for arsenic is set at 10 parts per billion.
District officials this week received results from a Dec. 3 water test that showed levels between 15 and 12 parts per billion, according to a notice from the district issued Thursday.
"School officials have shut off the water at Greenwood until the filtration system is repaired and repeated tests indicate that the water is below the standard for arsenic contamination," the notice stated. "The Building and Grounds Department is working with the filtration contractor to remedy the issues affecting the water system, which may be related to a problem with a chlorine pump."
The repairs shouldn't take more than two days, said district communications director Kevin Lyons. The district then will test the water to see whether the repair worked and the levels decrease. District staff members will complete an additional two tests during the next two weeks to ensure the arsenic in the system is below the safety standard before turning the water back on, he said.
Greenwood Elementary, 4618 Greenwood Road, serves students in preschool through fifth grade. The school has about 332 students, according to the Illinois State Board of Education. It is the only district school on a well.
Arsenic occurs naturally in mineral deposits in some areas of Illinois. Groundwater that flows through those deposits can dissolve the arsenic and increase the amount of the toxin in a well, according to the Illinois Department of Public Health.
Effects of arsenic exposure depend on the amount of arsenic a person has been exposed to and the duration of that exposure, according to the department.
In 2018, two November tests showed levels at 32 parts per billion and 18 parts per billion. A test in January showed arsenic levels at 17 parts per billion. All monthly tests from then until the Dec. 3 test showed levels below the safety standard, according to the district.