The county has between 7,000 and 9,000 private wells, according to Carol Drury, the environmental health and laboratory manager at the La Crosse County Health Department.
The department warned 2,000 households last spring that their private wells could be contaminated with high levels of nitrates.
“We tested 540 wells during that time just from this particular area, the town of Holland and the town of Onalaska, and 30 percent of those tested at levels about the recommended levels of nitrates,” Drury said.
The county’s findings are high, said Mark Borchardt, a research microbiologist for the U.S. Department of Agriculture.
“The national average across the U.S. is between 4 and 5 percent.
High nitrate levels have been linked to health troubles, Borchardt said.
“It looks like the evidence is pointing toward high nitrate levels being associated with colorectal cancer, central nervous system birth defects and thyroid disease.
So, it’s not something to be taken lightly,” he said.
Drury said preventing pollution is a long-term goal and that the department is committed to better informing the public.
So in the short term, we want to do what we can.”