MUNCIE, Ind. (AP): Indiana Department of Environmental Management officials say agricultural weed-killer breakdown products were detected in 68 of 398 groundwater samples collected from private residential water wells and small public water supply wells in Indiana.

The Star Press reports that herbicide degradation products were found in one of the eight wells sampled in Henry County and in one of the four wells sampled in Delaware County.

The degradates were acetochlor and alachlor, which are herbicides commonly used in Indiana to control broadleaf and grassy weeds in soybeans and corn. Maximum contaminant drinking water levels haven’t been established for herbicide degradates.

About 1.6 million Indiana residents, or 26 percent of the state’s population, get their water from private, domestic wells which aren’t required to be tested for quality on a regular basis.