New Pollution Concerns in Mwambashi River

By Womba Kasela

New alarming reports highlight the ongoing environmental threats facing Zambia’s freshwater resources. Just weeks after Sino Metals Leach Zambia’s tailings dam collapsed, causing severe contamination of the Mwambashi River, concerns have been raised once again.

Dr. Godwin Beene, a farm owner along the stream, noticed on March 12, 2025, that the river, usually crystal clear, had turned completely blue. Dr. Beene, who is also president of the Chamber of Mines, immediately alerted the Zambia Environmental Management Agency (Zema) and Nkana Water Supply and Sanitation Company.

“I’ve never seen the Mwambashi Stream turn blue like this while at the farm,” Dr. Beene said. “It wasn’t just a slight discoloration; the water was completely blue, which is why I had to report it. People rely on this water for their daily needs.”

Dr. Beene noted that this is a new instance of pollution, as the affected section of the river flows between Chambishi and Mimbula mines, as well as other mine-related operations, though he could not confirm all the sources.

After his discovery, Dr. Beene collected his own water samples and contacted Zema for analysis. However, as of his last update, the agency had not yet provided any findings from their investigation.

Following Dr. Beene’s report of unusual discolouration in the stream, Nkana Water conducted a site visit on March 13, 2025. During the visit, Managing Director Steven Mwale, confirmed that the water had indeed changed from its usual clear state.

Speaking on-site, Mwale, an engineer, revealed that initial tests conducted by Nkana Water showed a drop in the river’s pH levels, indicating slight acidity.

 “The Mwambashi River’s pH normally ranges between 6.8 and 7.2, but our on-site tests revealed a pH level of 5, suggesting that the water had become slightly acidic,” he explained.

pH is a measure of a solution’s acidity or alkalinity, standing for “potential of hydrogen.” It indicates whether a substance is acidic or basic (alkaline). The pH scale ranges from 0 to 14, where a pH of 7 is considered neutral (neither acidic nor alkaline). A pH below 7 indicates acidity, while a pH above 7 indicates alkalinity, with higher values signifying greater alkalinity.

Mwale further stated that water samples had been collected for laboratory analysis to determine the exact nature of the contamination.

“We’ve gathered samples from various points along the river for comparison. We will collaborate with colleagues from Zema and the Water Resources Management Authority (Warma) to conduct a thorough investigation,” Mwale said.

He suspects that an emission or discharge may have occurred, with the responsible parties potentially taking advantage of the heavy rains the previous day to conceal their actions.

Reassuring residents of Kalulushi, he emphasised that the town’s water supply remained unaffected.

“There’s no need for panic. The water supplied to Kalulushi comes from the Chati River, which is clear and safe for consumption. The water is gradually returning to its normal colour, and the aquatic life has not been affected,” he assured.

However, according to a Daily Mail Tuesday, March 25, 2025 story, test results from Nkana Water revealed high contamination levels, posing a significant risk to farmers who depend on the stream’s water for irrigation.

Meanwhile, when contacted for comment, Zema’s Manager for Corporate Affairs, Ruth Kamwi, stated that the agency had not received any water samples from the Mwambashi River for analysis. However, she confirmed that Zema would coordinate with other stakeholders to investigate the source of the pollution.

Kamwi further warned that any mining company found responsible for the contamination would face legal consequences under the Environmental Management Act No. 12 of 2011, as amended.

In February, Sino Metals Mine in Chambishi, Kalulushi District, caused severe environmental pollution after its tailings dam collapsed. The structural failure led to the uncontrolled discharge of acidic effluent into the Mwambashi and Kafue rivers, introducing large quantities of toxic substances into the waterways. This contamination killed aquatic life, damaged crops, and contaminated the raw water supply used for consumption in Kitwe.

Due to the pollution, Nkana Water was forced to shut down water supply services in Kitwe for four days to prevent residents from consuming the contaminated water. During this period, the mining company took emergency measures, adding lime to the rivers in an attempt to neutralize the acidity and reduce the environmental impact.

In response to the disaster, authorities ordered the closure of Sino Metals Mine and directed the company to compensate affected farmers in Kalulushi District whose crops were damaged by the acidic discharge.

PHOTO CREDIT | This AI-generated image is for illustration purposes only.

Womba is a fellow in the Wildlife Crime Prevention (WCP) journalism fellowship. The MakanDay Centre for Investigative Journalism, in partnership with WCP, provides training in investigative journalism and supports journalists in producing impactful stories that promote environmental protection and drive change.