By Obiabin Onukwugha
Dams and protected areas (Tailings Storage Dams (TSDs), are built for preservation and protection of Marine Species.
But a recent study by Brazilian researchers has found that streams flowing into tailings storage dams (TSDs) had fewer catfish species, including fewer armoured catfish and fewer small predaceous catfish, common to steep-slope streams.
The paper, which was published in the journal Water Biology and Security, explains that there are at least three aspects that need to be considered when analyzing the impact of tailings facilities on upstream fish assemblages.
They include; life-cycle disruption, species intolerance or tolerance to lentic or still freshwater conditions, and non-native species.
The research was said to be conducted in the Rio Doce basin in southeastern Brazil.
According to the study, to collect fish, the team used standard methods in 24 sites, half draining to TSDs (dammed) and half free from this impact (not dammed).
To identify differences between treatments, the researchers used permutational multivariate analysis of variance or PERMANOVA. This allowed them to test both environmental variables and the assemblages of fish in each water body, and evaluate the biological metrics that most influenced assemblage composition change.
“Despite natural forest cover in most of the catchment area, we observed a decrease in these species that rely on stream continuity and high-quality water. In comparison, two other widely tolerant species had increased in numbers along with one species commonly found in TSDs,” Gilberto Salvador, lead author of the study, said in a media statement.
The team attributed these results to re-colonization barriers created by tailings storage dams, as well as colonization sources for tolerant species.
“Our findings underscore the need to consider downstream alterations caused by TSDs when assessing reference conditions for biomonitoring and bioassessment studies,” Salvador said.
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Also, another study has revealed that mine waste pose great threat to marine biodiversity.
The study said nearly a third of the world’s mine tailings are stored within or near protected conservation areas, posing risks to some of the earth’s most precious species and landscapes.
The study carried out at the University of Queensland found that of the 1,721 disclosed tailings facilities, 9% were within declared protected areas and 20% were within five kilometres.
According to the study, mine waste threatens biodiversity within protected areas. It said, to assess the risks, Aska and co-authors analyzed a database of global tailings facilities and compared it with spatial data on protected areas.
Information was drawn from the disclosures of publicly listed companies as part of the Mining and Tailings Safety Initiative, set up after the dam at Vale’s Córrego do Feijão iron ore mine breached and killed 270 people near the town of Brumadinho in eastern Brazil. The disaster also destroyed 133 hectares of Atlantic forest and 70 hectares of protected areas downstream.
“Our findings suggest that mine waste threatens biodiversity within protected areas all over the world, including eight active tailings storage dams in Australian protected areas, recognized by the International Union for the Conservation of Nature.
“Given the size of tailings facilities, we’re concerned about the future risks of failures in areas important to biodiversity and conservation of species,” Bora Aska, lead author of the paper published in Nature Sustainability, said in a media statement.
On her part, senior author of the study, Laura Sonter, said managing mine waste will become an increasingly complicated sustainability challenge.
In the researchers’ view, the good news is that the data needed to manage these risks are emerging, and opportunities exist to factor this knowledge into the design of new facilities and manage those already in place.
“Total tailings production is predicted to increase significantly in the next 30 years due to the growing demand for energy transition metals and declining ore grades,” Sonter said. “Considering the current global distribution of tailings storage facilities and their failure rate, the consequences for biodiversity could be devastating.
“We must work expediently toward completely mitigating negative impacts of mining waste on people and the environment,” Sonter said.
