The severe foot and mouth epidemic that started in South Korea at the end of November could have even more serious repercussions for public health. Some 3m head of livestock have already been slaughtered but now the environment ministry is concerned about burial of the carcasses.

Under the pressure of events some cattle were buried alive and the authorities sometimes failed to take the necessary precautions: digging pits four or five metres deep and lining them with two layers of plastic sheeting. Farm animals were buried at more than 4,000 sites, often in easily accessible spots, for instance beside rivers.

As spring temperatures rise the corpses will start to rot. Rainfall leaching through the pits, above all during the June monsoon, could contaminate rivers and aquifers. This could be a hazard for drinking water with the risk of another outbreak of foot and mouth disease. To prevent "an unprecedented environmental disaster" the environment minister Lee Maanee last week called for "a full, detailed study of all the [burial] sites before spring".

According to a survey carried out in the eastern province of North Gyeongsang, where the epidemic started, more than one in 10 burial sites needs to be reinforced. New pits may be dug and lined with concrete.

The new problem comes on top of those posed by the epidemic itself, which has already cost South Korea 2,000bn won ($1.75bn) and pushed up food prices. The price of pork rose by nearly 12% in January alone. With about 5% of beef and dairy cattle having been destroyed the authorities are afraid there may be milk shortages, production having dropped by as much as one-fifth in some places. All these worries compound the suffering endured by farmers.

More generally criticism has focused on the governments slow response. Some critics claim it delayed the campaign to vaccinate livestock for fear the country would lose its vaccination-free status, certified by the World Organisation for Animal Health, putting an end to meat exports.

The meat industry has also been blamed for spreading the disease. To keep prices low and meet demand, most livestock is raised in factory-farms under terrible conditions.

Meanwhile the epidemic continues. The 146th centre of infection was detected on 7 February in Busan, in the south-east. The virus has been identified in air samples, prompting fears of further contamination and the need for stricter quarantine measures.