Impacts of African swine fever on water quality in China

The outbreak of African swine fever (ASF) in China has significantly reduced the country's pig production capability, whilst also having far-reaching impacts on livestock products supply in the wider food system. Previous studies have quantified the potential long-terms impacts on food prices, however, little information is available regarding the direct short-term impacts on food system changes (livestock products supply and consumption patterns) and water quality protection associated with the outbreak. Here, we used multiple sources of data in relation to consumption patterns and water quality to fill this knowledge gap. Our results indicate that the ASF outbreak has changed the short-term livestock products consumption pattern in China, with increasing reliance on importation of livestock products. A rapid change in pork self-sufficiency rate has also driven a rapid increase in the consumer price index of many cities. Banned swill feeding and reversed environmental regulations in the watercourse intense regions has unintended consequences, especially on water quality. Swill, which is no longer fed, was dumped into water waste streams and lowered the sewage treatment efficiency. The re-establishment of pig production back into watercourse intense regions has led to exceedance of local manure nutrient loading capacity of agricultural land. We suggest (a) a short-term intermediate policy to prohibit discharge of swill to sewage systems, to return their previous efficiency, (b) the development of new technologies for the safe recycling of swills, and (c) the design of a long-term intelligent spatial planning of pig production, slaughter and transportation within China to ensure continued protection of water quality vulnerable zones.