New Way to Clean Mercury Pollution Using Microbes and Magnets

Mercury enters the environment through both natural processes and human activities. Historical silver mining, for example, released substantial amounts of mercury into the atmosphere, significantly increasing global levels compared to pre-industrial times^[2]. This increase has led to wider distribution of mercury in soils and water systems, with a roughly 450% increase in atmospheric concentrations above natural levels^[2]. The challenge isn’t just the presence of mercury, but its conversion into more toxic forms, particularly methylmercury, which readily accumulates in organisms^[3][4].

The recent study explores a novel way to enhance bioremediation. They focused on using a specific bacterium, *Pseudomonas stutzeri* LBR, known for its ability to interact with mercury. However, the researchers didn’t stop there; they also applied a static magnetic field (SMF) to the contaminated soil at the beginning of the remediation process. A static magnetic field is a constant magnetic force, unlike a changing magnetic field.

The experiment involved two types of soil: one with its natural microbial community (non-sterile) and one sterilized to remove existing microorganisms. Both types of soil were contaminated with mercury and then treated with *Pseudomonas stutzeri* LBR, with and without the application of the SMF. The researchers then monitored the amount of mercury removed over a 30-day period.

The results showed a clear benefit from combining the SMF with bioremediation. In non-sterile soils, the combination of the SMF, the existing soil microbes, and *Pseudomonas stutzeri* LBR increased mercury removal by 49.36% compared to using only bioaugmentation (adding the bacteria) without the magnetic field. Even more striking was the effect in sterile soils, where the combined approach increased mercury removal by 72.49% compared to 38.1% without the SMF.

These findings suggest that the SMF isn’t simply acting as a standalone solution, but rather enhancing the activity of the bacteria and potentially the overall microbial community. While the exact mechanism isn’t fully understood, it’s hypothesized that the magnetic field could alter the permeability of bacterial cell walls, making it easier for them to take up and process mercury. It could also influence enzymatic reactions involved in mercury transformation.

This research builds on the broader understanding of mercury cycling in the environment. Studies have shown that specific genes, like *hgcAB*, play a crucial role in mercury methylation by anaerobic bacteria^[4]. Understanding these microbial processes is key to developing effective bioremediation strategies. The work by researchers^[3] also highlights the potential of using “Omics” techniques – large-scale analysis of genes and proteins – to identify new bacterial strains and their biotechnological applications for bioremediation. The current study takes this a step further by adding a physical factor – the SMF – to the equation, potentially unlocking even greater remediation efficiency.

The increased mercury deposition observed in surface marine waters^[2] underscores the need for effective remediation techniques. While the increase in deeper marine waters is smaller, the overall environmental burden of mercury remains significant. The approach developed by the University of Carthage and Universidad Tecnica de Manabi offers a promising avenue for addressing this challenge, particularly in soil environments.