ZHAOQING — On a pig farm near Zhaoqing, in south-western China, dozens of lifeless pigs float in the murky, stinking waters of a pond surrounded by banana trees and vegetable patches. One of the animals is still struggling, assailed by a school of catfish. Ahead, still visible in the fading daylight, is a row of seven buildings with slanted roofs at the foot of a lush hillside, where more than a thousand sows and their piglets are kept.

What happens inside is a secret as access is restricted. But there are signs to indicate dubious practices. Dead or ailing piglets are thrown into the pond, even though it's illegal to do so. It is quicker and cheaper. A few dozen meters away, a sow lies on a mud track, awaiting the arrival of the insurance firm that must make its assessment.

This is one of hundreds of pig farms set up in recent years in Zhaoqing following a shift away from the provincial capital, Guangzhou (also known as Canton), where such facilities were deemed too polluting. The arrival of the farms has altered the local landscape. Bulldozers are now at work widening a strip of red earth to clear space for a second road.

Ying Guang-Guo, a professor at the Canton Geochemistry Institute tasked with overseeing the province's big cities, has arrived with his team to study this newly polluted zone. But his biggest concern is an invisible danger, namely the large amounts of antibiotics contained in pig excrements flowing into the pond. The farm's young manager, the son of a Communist Party member, is evasive. He initially claims to use antibiotics only when sows are pregnant. But then he admits using authorized products on sick animals.

Our scientist grins behind his glasses as he listens. He is 52 but looks younger. And he doesn't believe a word he hears. In fact, he tells us, the farm probably uses about 5 kilograms of antibiotics a year, a considerable amount, and through procedures that are likely illegal.

The government recently published a list of pharmaceutical products authorized only with prescription, and presumably destined only for sick animals. This includes Colistin, used for people as a last resort. But as I was writing this report, Colistin could be readily purchased on Alibaba, China's leading online store, allowing people to buy them as they please.

Indiscriminate use

Abusing antibiotics in animal farming is common in China. To supply meat to a population of over 1.4 billion, animals are raised, as elsewhere, on an industrial scale, in restricted spaces and with sanitary conditions that weaken their health. In order to prevent illnesses and reduce mortality, farmers stuff them preventively with antibiotics mixed into their food. The antibiotics also hasten animal growth, adding a further incentive. This particularly concerns pig farms, but also numerous duck and fish ponds located alongside the highway linking Canton and Zhaoqing.

The life of these antibiotics does not end here, as waste waters channel them into streams, rivers and lakes. Our pig farm pond, which spills over when it rains abundantly, "contains a lot of it," says our researcher, who collects mud samples from lakes and waterways across the country.

There is no regulation in China, he says, on treating waste-waters from farms. As filtering systems are expensive, many small farmers pour their wastewater directly into rivers. The farm we visited had just installed a purification system in a building near the water, which was being tested. But the rather simple mechanism could not cleanse the water completely of antibiotics. Only 20% of Chinese farms use these simple systems, the Canton Geochemistry Institute found in a paper published last May.

Abusing antibiotics in animal farming is common in China, especially in pig farms — Photo: Paula Bronstein/TNS/ZUMA

This was the first in-depth study on the presence of antibiotics in China's environment. The results were shocking. It revealed "alarming" consumption levels and a "relatively high" concentration in nature, especially in the three regions with the most people and farms: Canton and the Pearl River delta, the Yangtze delta region, and Beijing and Tianjin in the north.

Deadly resistance

China, which has a fifth of the world's population, consumes half the antibiotics produced worldwide. The country ingested 162,000 tons in 2013, divided about equally between animals (52%) and people (48%). "It's a big educational problem," says Ying Guang-Guo. "The Chinese have very little information on how to use antibiotics." Doctors prescribe them merrily and people can get them without prescription in small clinics (though hospitals are stricter).

This overuse has become a health threat. Bacteria naturally develop resistance to the antibiotics they absorb, but with massive use "in the past 10 years, resistance by some bacteria has risen fast [in China] and is now above levels seen on average throughout the planet," says Ying Guang-Guo.

The evidence is that the mcr-1 gene, resistant to the most potent antibiotic Colistin and able to go from one bacterium to another, was first spotted in China in 2015 before appearing in the United States. If nothing is done, so-called "super bug" infections could kill up to 10 million people a year by 2050, Britain's Review on Antimicrobial Resistance has found.

Yin Guang-Guo adds that antibiotics can create a vicious circle of pollution affecting both food sources and drinking water. Researchers at the Canton Institute measuring the use and discharge of the main 36 antibiotics in 2013 estimated that about 54,000 tons of antibiotics made it into the country's waters.

Around 80% came from animal, especially pig and poultry farms. Even if its study has yet to find a conclusive link between this and increased germ resistance, "antibiotic pollutants have a negative impact on the ecosystem," says Yin Guang-Guo, adding this would inevitably affect our health.

Another study by the University of Fudan, cited in the Chinese press, suggests that children in Shanghai and in the Jiangsu and Zhejiang provinces were frequently exposed to small doses of antibiotics found in their food and environment. Traces have been found in the urine of almost 60% of children. Some of the antibiotics detected have been out of use for decades.

Solving the problem requires greater public awareness, stricter rules for doctors and small clinics and better water treatment. But to deal with so-called super bugs, there also needs to be research into new antibiotics. Ying Guang-Guo says the last ones came out in the 1990s.