Abstract
Since the implementation of the Law on Promoting Proper Management and Use of Livestock Excreta in 1999, the number of the farmers that do not meet the management criteria is on the decline. However, there is a possibility that many of the animal waste disposal pits that have been either abandoned or refilled according to the law have been the potential contamination source. In this study, we discussed the impacts of the abandoned disposal pits to groundwater quality. The results showed that high concentrations of nitrate (above 100mg/L) were observed in the downstream of the disposal pits. It suggests that the abandoned animal waste disposal pits have been the potential pollution source even after the period of 15 years since the termination of use. Implementation of immediate countermeasure is necessary because the animal waste disposal pits are the long-term-sources of high levels of nitrate.
