Experiences of Mass Pig Carcass Disposal Related to Groundwater Quality Monitoring in Taiwan

The pig industry is the most crucial animal industry in Taiwan; 10.7 million pigs were reared for consumption in 1996. A foot and mouth disease (FMD) epidemic broke out on 19 March 1997, and 3,850,536 pigs were culled before July in the same year. The major disposal method of pig carcasses from the FMD outbreak was burial, followed by burning and incineration. To investigate groundwater quality, environmental monitoring of burial sites was performed from October 1997 to June 1999; groundwater monitoring of 90–777 wells in 20 prefectures was performed wo to six times in 1998. Taiwanese governmental agencies analyzed 3723 groundwater samples using a budget of US $1.5 million. The total bacterial count, fecal coliform, Salmonella spp., nitrite-N, nitrate-N, ammonium-N, sulfate, non-purgeable organic carbon, total oil, and total dissolved solid were recognized as indicators of groundwater contamination resulting from pig carcass burial. Groundwater at the burial sites was considered to be contaminated on the basis of the aforementioned indicators, particularly groundwater at burial sites without an impermeable cloth and those located at a relatively short distance from the monitoring well. The burial sites selected during outbreaks in Taiwan should have a low surrounding population, be away from water preservation areas, and undergo regular monitoring of groundwater quality.