The ministry and a state water research center said they have jointly examined water quality at about 3,000 underground water sources within a 300-meter radius of animal burial sites across the nation to see whether they were affected by the massive burial of animals.
According to their first assessment, 143 sources showed high rates of bacteriological contamination beyond water quality standards set by the environment authority.
"The first round of analysis showed that a considerable number of underground water sources contained pollutants beyond the standard," said an official at the National Environmental Research Institute (NERI). "We are analyzing details of whether the water sources were polluted by leachate from the burial sites or contaminated from waste water from nearby cattle sheds."
The results were released after South Korea last week eased a nationwide alert against foot-and-mouth disease, which has cost some US$2.6 billion over the past four months. Since the first case was confirmed in late November, the government has slaughtered 3.4 million livestock.
The ministry said it will notify nearby residents not to use the contaminated water. It will also conduct additional inspections to identify specific materials and announce the detailed results as soon as possible, officials noted.
Abnormal levels of nitrogenous compounds generally indicate pollution, as most of the nitrogen found in water originates from the decay of the remains of plants and animals.