Investigators believe they have figured out why a tributary of China’s Yangtze River turned bright red. Video footage captured on June 28 shows the blood-colored Xiangbi River flowing through the jungles near Yibin City, sparking concern from locals who feared the contaminant might make its way to Asia’s longest waterways.
Residents reported the incident to local officials, who worked to identify where the red color was coming from. They found the source of the pollutant and treated the water before it made its way to other water systems. The water was reported to be clean by July 1.
According to a Chinese news source, the crimson color occurred when workers at the nearby Heshun Packing Company spilled large amounts of enamel paint into the river.
Locals don’t use the river as a water source and a spokesperson confirmed that the water-based glaze is non-toxic and will not cause harm to people or livestock. The Environmental Protection Bureau says it continues to monitor toxin levels in the river and is conducting an investigation at the company’s site. If responsible, the packing company could face fines.
China’s rivers are no stranger to sangria-hued flows. A similar incident occurred on China’s Wenzhou River in 2014. The river is home to businesses that at the time included a food-coloring company, a paper manufacturer, and a clothing maker. Officials said the color was due to illegal dumping.
Two years earlier, a stretch of the Yangtze River took on a similar shade. Scientists in an opinion piece for Nature suggested more natural causes, such as high levels of sediments being turned up following heavy rains or a large algal bloom. Environmental officials investigating the cause hinted at the possibility of industrial pollution.
In 2011, the Jian River in China also flowed sanguine following an illegal dump by a nearby chemical plant. Investigators pointed to red dye used in plastic bags and firework wrappers, according to CNN.
More recently, a blockage at a slaughterhouse sewage pipe last year turned a river in Jiangxi a deep red, reported People’s Daily Online.
Although seemingly apocalyptic, red rivers often have a basic explanation. Spain’s Rio Tinto, for example, is tinted red from 5,000 years of mining. In 2016, Russia’s Daldykan River changed from its usual blue-green to a bright red (see below) over a matter of days, either due to a chemical leak or a large quantity of naturally occurring iron.