September 1, 2023

Sallamaari Siponen

Doctoral student Sallamaari Siponen: “Research on water microbiome can prevent health risks”

Erkki Paasikivi Foundation grant recipient Sallamaari Siponen studies how bacteria such as legionella can affect human health when found in drinking water. Research on water’s microbiome can help improve water quality.

Sallamaari Siponen has spent most of her life by the water: first growing up in Finnish Lakeland, then studying water technology in laboratories and research groups. 

Currently, she’s working on her doctoral dissertation at the University of Eastern Finland and the Finnish Institute for Health and Welfare (THL). She’s also working part-time as a project planner at the University of Helsinki in a research group that investigates waterborne pathogens.

Her thesis dives into the disinfection methods of the microbiome of drinking water – or, in layperson’s terms, how different disinfection chemicals and plumbing materials affect the microbiome of drinking water distribution systems. 

“There will always be microbes in any given body of water, there’s no way around that. Even though most of these microbes do not cause harm to human health, some of them might. That’s why we’re researching how the chosen disinfection methods affect the entire microbiome instead of just a single microbe,” Siponen says. 

With the help of Erkki Paasikivi Foundation’s grant, she’s able to analyze the lab results of her thesis research, finalize her degree, and thus reap the benefits of her meticulous work over the last few years. During her time in academia, Siponen has traveled from Eastern Finland to Sweden and Austria for student exchanges and eventually ended up at THL where she also did her master’s thesis. 

Changes in water temperature may increase health risks

Water temperature rises in Finland, too, due to climate change. According to the Finnish Environment Institute (Syke), the Baltic Sea has become increasingly warmer since the beginning of the 1990s. Experts estimate that this change will continue into the future. 

High temperature increases the bacteria in water and can lead to the release of harmful compounds into the atmosphere. Changes in water temperature are one of the main reasons why water technology and especially water microbiomes should be researched further, Siponen says. 

“Temperature rises in untreated water and building plumbing systems bring along new changes. Respiratory tract infections caused by water are not very dangerous for healthy people, but if your immune system has weakened, health risks can be significant,” she explains. 

Water microbiomes may cause, for example, respiratory infections. Siponen is specifically interested in legionella, mycobacterium, and pseudomonas, resilient bacteria that can be found in natural waters and soil. At worst, legionella can cause severe pneumonia. However, pathogens rarely live in the microbiome and are found only in small numbers. According to Siponen, the risk of a disease grows especially if hot water is not warm enough or sits still in the plumbing system for too long. 

Sallamaari Siponen

Legislation helps tackle the legionella bacteria

The persistent bacteria is a relevant research topic in the broader field of water technology as well, says Siponen – especially, since getting rid of it is one of the main objectives of the European Union’s drinking water directive and the Finnish legislation. Since the beginning of 2023, the law requires a risk assessment for water quality in so-called ”important buildings”, such as hospitals' plumbing systems. 

It is, in fact, the operators of these plumbing systems that will probably benefit from Siponen’s research findings, alongside water treatment plants and public health officials. Erkki Paasikivi Foundation’s grant has been very important to the researcher because it has given her the resources to assemble her findings for further use in both academia and practice. 

“For instance, water treatment plants can utilize the research of my field when assessing which disinfection method they should use. My research also produces information on how important it is to take the water temperature into account in order to avoid infections,” she sums up.