Volcanic and Limnic eruption: a potential threat to one health

¹College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda, ²Global Health Focus, Africa, ³Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria, ⁴Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, United Kingdom

^&Corresponding author
Emery Manirambona, College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda

Commentary    

Democratic Republic of the Congo (DRC) has been riven by armed groups that took millions for decades. DRC´s health security has not been dwindled by armed conflicts alone. Other disasters related to climate change have caused significant casualties, with the most common being epidemics, floods, storms, volcanoes and landslides. The heavy equatorial rain in locations within the River Congo Basin results in flooding, landslides, and erosion. A recent landslide on July 20, 2020 in eastern DRC, South Kivu Province, has taken at least the lives of 8 people. Democratic Republic of the Congo has six volcanoes (Karisimbi, May-ya-moto, Nyamuragira, Nyiragongo, Tshibinda, and Visoke) [1], amongst which two (Nyamuragira and Nyiragongo) are the of the most active volcanos globally, with one being a subject of concern. The active Nyiragongo volcano is situated near Lake Kivu at around 12 Km [2] and the Congolese-Rwandese shoreline within the Western branch of the eastern African Rift Valley. Nyiragongo volcanic eruptions are notorious lava flows that stream into the city without sparing anything in their way. The havocs secondary to Nyiragongo volcanic eruption are multitudinous and could extend to Lake Kivu, which in turn could potentially cause significant adverse effects in Goma. The potential danger of Lake Kivu on the community secondary to Nyiragongo volcanic activity is nonetheless not fully documented, much less the appropriate intervention. It is essential to understand the disaster in order to advise appropriate health policies. This article aims to discuss the potential effects of the Nyiragongo volcanic eruption on Lake Kivu and how these affect the health of the community and one health, hoping to provide helpful evidence for practice to enable advocacy and change.

Nyiragongo eruption´s direct effects on the community have been described. Further, volcanic activity has been linked to the cholera outbreaks in the surrounding area [3]. Its influence on the Kivu´s physicochemical properties makes bacillus resistant in the water, resulting in cholera for the community that consumes the water and fish from Lake Kivu [3]. Under these circumstances, the Nyiragongo eruption impacted maritime health, negatively impacting residents' food and health security in Goma, eastern DRC. Lake Kivu is composed of a high concentration of carbon dioxide (CO₂) and Methane (CH4) [4]. The association of the lake´s geochemistry and factors that include landslide, earthquake, excess in gas or a very high temperature and, most importantly, an active volcano can be potentially harmful to the maritime health and surrounding communities. They can cause the dissolution of the accumulated gas in the lake and subsequently release the lethal gas. Nyiragongo volcano has a shield volcano via a fissural and phreatomagmatic eruption that can flow beneath surfaces into Lake Kivu. The rivers of lava spewed into the lake, or seism activity that often follows volcanic eruption, can trigger a limnic explosion in the lake, resulting in the same fate as Nyos lake, which caused massive destruction in Cameroon on 21 August 1986 [5]. It has been proved the Nyos incident was caused by a CO₂ explosion, which resulted in CO₂ levels rising. Currently, the normal CO₂ level in the atmosphere is 0,041%. If the air contains 5% CO₂, it will extinguish candles or car engines, while 10% will cause hyperventilation and coma. Asphyxiation and death are well-understood consequences of a 30% CO₂ concentration [6]. It is worth noting that even a slight percentage increase of CO₂ in the air for an extended period can also cause deaths [7]. Hence, if sufficient lava streams to heat the water at the bottom of Lake Kivu, they would cause CH4 explosion and CO₂ release in the surrounding atmosphere. This would result in staggering tragedy as inhabitants of the lake basin would most likely suffocate because of high CO₂ concentration [8]. Needless to say, maritime health in the waters of Lake Kivu, which hosts around 28 fish species [9], would be exterminated. Lake Kivu is surrounded by about two million people, amongst whom many owe their life to fishing. It is clear that they would be directly affected by anything that affects Lake Kivu. Rwanda has taken a step forward in extracting methane from Lake Kivu in its project called 'KivuWatt'. Gas is currently being removed, allowing the separation of methane and CO₂, minimising the potential hazard, boosting the country´s economy, and providing electricity. However, the experts reported that the extracted methane quantity is not a meaningful quantity to prevent the danger, and the extraction does not include CO₂ [10]. Interestingly, scientists insist that havoc from the potential Kivu limnic outbreak could be much more unfathomable than the Nyos disaster. Lake Kivu has remarkable characteristics that explain the possible worse outcomes compared to Nyos (Table 1).

Governance and mitigation policy: 'prevention is better than cure.' Ignoring such a potential threat can result in wiping out the entire human and animal society in Goma. As such, implementing mitigation measures at the earliest opportunity is exigent. First, there is a need to educate the population on the appropriate behaviours during disasters. It is crucial to teach the fishermen and the people nearby how to recognize a possible limnic eruption. Prodromal signs such as strange odour (like 'rotten eggs') and a cloud-like white-translucent colour, as well as hot lake water, have been reported by Nyos survivors [5] as precursors for limnic eruption. People on the shorelines of the lake should know that it is required to leave towards a higher area immediately before the limnic outburst occurs while holding their breath to avoid deadly CO₂ inhalation. However, it would be challenging for most people to comply with emergency guidelines as the city´s transport system is a known issue. The 22 May 2021 Nyiragongo volcanic eruption revealed the disparities in emergencies evacuation. Further, CO₂ must be extracted from Lake Kivu. For instance, the gas can be released by using a pipe from deep in the lake as it can give a quick CO₂ gas dispersion in the air without adverse effects. This technique might be the cheapest and can serve low resource countries. Although expensive, gas can also be drained by digging down and creating a channel into the lake´s bed or neutralizing the gas by depositing a colossal quantity of lime into the lake [6]. The concerned parts should discuss the appropriate method to extract CO₂. Another possibility would be to evacuate people. Such measures are vital as they can dampen the risks. They can protect not only human beings but also maritime health will benefit from any effort targeting the reduction of the lethal gas. Similarly, it is critical to monitor the potential trigger-Nyiragongo volcanic eruption. If there is appropriate volcanic eruption monitoring, people would be warned early and prepare themselves appropriately. Notably, there is a need to set mechanisms aiming to monitor the gas in Kivu. Observation of CO₂ levels is an essential tool to document a possible abnormal increase and prevent the worst. This measure was applied in Cameron. After the tragedy of 1986, an automatic observation buoy was installed in lake Nyos to report gas rise. Interestingly, that installation is connected to satellite as an effective way to protect the population. Also, it provides accurate data to researchers, useful for scientific discussion. This approach to monitoring the potentially harmful lake turbulence is recommendable to Lake Kivu-there must be an effective way to monitor the gas in the lake. The connection of Nyiragongo volcanic eruption, Lake Kivu, Fish, CO₂ in the space and human health is a typical example of one health. We advocate for a whole dimension approach to set a healthy, resilient mechanism of prevention and preparedness. Further coordinated global research is needed to provide more evidence and recommendations.

Conclusion     

Nyiragongo volcanic eruption has caused multiple adverse effects among people. The blast, which has caused human loss, material loss, and an exodus of thousands, can cause staggering havoc to nearby water health in Lake Kivu. The lake can spew into Lake Kivu, thus causing the explosion of CH4 and CO₂, which would result in Limnic eruption. Notably, health in water will be significantly affected. In addition, people and animals on the shores of the lake would suffocate due to high levels of CO₂. There is an urgency to implement preventive mechanisms towards a sustainable solution. Gas in Lake Kivu must be regularly monitored before the worst occurs.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

EM, DELP: conception of the study. EM designed the study, collected, analysed, and interpreted data, literature review and wrote original final draft. YAA & DELP participated in formal writing, revised the manuscript critically for important intellectual content and approved the final version to be published. All authors read and approved the final manuscript.

Acknowledgement     

We thank the reviewers for their insightful comments.

Table     

Table 1: comparison between lakes Nyos and Kivu

References