Up to third of Slovenian caves polluted, but situation improving
Ljubljana, 19 December - Karst caves in Slovenia have been recognised as a natural asset of national importance but waste accumulated in them remains a problem and poses a potential threat to underground sources of drinking water. Researcher and speleologist Jure Tičar estimates that about 20-30% of Slovenian caves are polluted, and cleaning them is a challenge.
A researcher of the underground world, Jure Tičar jokingly says that at the moment he needs a hobby that has nothing to do with caves since he works with caves professionally, as a researcher of geomorphology, karstology and speleology as part of the ZRC SAZU's Anton Melik Geographic Institute, as well as in his free time as a caver and a member of multiple associations and expeditions.
He started his career at the Kostanjevica na Krki Speleologist Club and currently does research as part of the Brežice and Novo Mesto clubs. He has organised and participated in many research expeditions in Slovenia and abroad.
Currently, he is researching the Skalar cave on Mt Kanin, where they are looking for connections with adjacent cave systems. If they manage to confirm the connections, the Kanin cave system, estimated to be 1,900 metres deep, will officially become the deepest cave in Europe.
On his expeditions, Tičar has often encountered waste at the entrances to abyssal caves, which led him to think about the causes, process and extent of cave pollution in Slovenia. When as the head of service for cave protection at the Slovenian Speleological Association and started searching for data on pollution, he realised that there has been no systematic record keeping.
There was some information available about the degree of cave pollution in individual areas, but no data for the entire Slovenia, which is why he started collecting this data as part of his PhD project.
Between 20% and 30% of karst caves polluted in Slovenia
According to the Slovenian Speleological Association, 14,695 caves were registered in Slovenia in July and every year at least 300 new ones are discovered. In recent years, this number has risen to more then 500 per year.
They are all listed in the cave registry, a national database of all registered caves which cavers have visited and recorded in the cadastral registry. The registry, managed parallelly by the Slovenian Speleological Association and the ZRC SAZU's Karst Research Institute since 1947, is one of the oldest such projects and a unique project in the world.
The registry also includes information on the pollution of caves, but this is often obsolete because it is outdated. "The quantity and quality of data is also problematic, often describing merely a village's dumpsite or at other times specifically stating the structure and quantity of the waste," Tičar said.
In his PhD thesis, he systematically arranged this data, edited it and complemented it with spatial data. He wanted to answer the questions of how widespread cave pollution is in Slovenia and what is the connection between cave pollution and spatial data.
Using a new methodology, he studied data from the archives about the situation in 6,965 caves in 17 Slovenian regions. He processed the data with geographical information systems and descriptive statistics, finding that more than 2,500 of the caves from his sample, or 20% of all caves in the country, are polluted.
Tičar warns that the actual share is almost certainly much higher, as the data he collected was strongly affected by the selection of the areas studied. In the Alpine karst area, the Julian Alps, there are many caves, and many of them are clean, which affects the entire share.
But on the other hand, in low-altitude karst areas, there is much more pollution. He estimates the realistic share of polluted caves could be up to 30%.
These differences occur mostly because of spatial factors - primarily the number of inhabitants in the proximity of the cave, distance to the nearest building, altitude of the entrance to the cave, distance to the nearest road, and the level of damage done to the cave.
"The main factor affecting the level of pollution is the accessibility of the cave. The more accessible the cave, the closer it is to roads or forest paths, the easier it is to dump large quantities of waste in it." Another very important factor is the density of the population in an area and the proximity of settlements to the cave.
Most of the waste is decades old
One of the interesting things that Tičar has discovered during his research of the history of cave pollution in Slovenia is that the first records of pollution date back to 1689 Glory of the Duchy of Carniola, written by the celebrated polymath Janez Vajkard Valvasor.
Back in the 17th century, people used caves as dumping ground during special rituals or to get rid of waste. But in the past this was not a big problem, as they mostly dumped organic waste, wood or rocks.
However, as we move into the twentieth century, this problem starts to grow. The end of the Second World War was followed by intense economic development. People suddenly had a lot of goods but no functioning system of municipal waste collection was in place.
As waste began to accumulate, the population turned to the solutions that seemed most convenient. "In karst areas, unfortunately, these were caves, most often pits, where waste was easily dumped." Tičar explains.
The biggest increase in waste disposal took place in the period from the end of the Second World War until the 1990s. With modern municipal regulation, waste collection systems and the civil society addressing ecological issues, this problem is gradually and radically disappearing, Tičar believes.
Organised initiatives such as the high-profile Clean Up Slovenia campaign, have also helped raise awareness that the kind of pollution that occurred in the past is no longer acceptable, he says. But the vestiges of the past are still there and cave pollution remains a pressing issue.
Everything from household waste to unexploded ordnances found among waste in caves
The composition of the waste in caves varies a lot. Overall, household and construction waste can be found everywhere, and even a vehicle sometimes. The more dangerous waste are pesticides, electronic devices, industrial oils and other fluids.
Moreover, caves in karst areas were also used to dump unexploded ordnance after the First and Second World Wars. They are still present in caves today and pose a threat both because of the substances they contain and due to the risk of accidental ignition during a clean-up.
In the course of his research, Tičar has also come across a number of cases of extreme pollution. One such example is a cave in Trnovo Forest, where more than 180 cubic metres of used tyres were dumped. Another example is a cave near Socerb, where several containers of spoiled salami from the port of Koper were dumped.
According to Tičar, the perpetrator is not known but the result is: the pit is still very polluted and full of organic residues. The absolute record-holder for pollution is the Ravnica Cave in Pivka, where four thousand cubic metres of waste has been dumped. According to Tičar, this cave will be cleaned in the near future, which will be an important milestone in tackling cave pollution in Slovenia.
Although caves are no longer being polluted to such an extent as in the past, individual cases of pollution still occur. One example of frequent pollution is the release of waste water from waste water treatment plants. For example, a waste water treatment plant in Bloke occasionally releases access water into a local underground water source.
"That is when we have problems in Križna Cave, an underground gem, which we very much protect and which is a very well preserved cave. In this case, foam shows in the water in the cave, which indicates pollution." Tičar says there are many more such stories, which is why this issue should be tackled systematically.
Apart from pollution, cavers also warn of other damage done to caves mostly caused by vandals or profit-seekers. In the past, for example, the removal of stalactites with the intention of selling them was one such phenomenon. Today, in some of the more easily accessible caves, large graffiti can be found, which completely defaces the natural space and destroys its value.
Clean-up demands professional and systemic approaches
The process of cleaning caves is very demanding and must be conducted only by well trained cavers who are skilled at using ropes and are used to working in caves. But they too are faced with security risks that need to be properly addressed during preparations for clean-up.
The use of construction machinery, which allows loads to be lifted smoothly from vertical pits, greatly facilitates and speeds up the cleaning process. However, this is only possible in caves where the entrance allows it. The work in the cave itself is still mainly manual and all waste must first be placed in transport bags or special containers, properly lifted and later recycled.
The lion's share of underground cleaning is done by cavers on a voluntary basis, as part of caving clubs that organise annual clean-up campaigns. Around 20 caves are cleaned this way in Slovenia every year. Tičar thinks one good solution would be is to involve polluted caves in project activities, as has been done in the past in the framework of the EU-sponsored LIFE Kočevsko project.
Caves with larger quantities of waste that have been polluted for decades often do not get cleaned as part of these campaigns as more people, infrastructure and financial support would be needed for such projects.
"This is why cavers are striving to find systemic solutions at the state level, which would allow for part of the funds to be allocated to returning these habitats into their original state and tackling even the most critical cases of cave pollution."
The legal foundation for this already exists. A law on protection of underground caves that entered into force in 2004 defines the operation and management of underground caves in a specific way. The law is unique in the world.
It defines caves as natural assets of national importance, which is a very high level of protection, Tičar points out, and at the same time, the caves become natural assets owned by the state. A specific part of the law defines the monitoring of the condition of caves, the sanctioning of pollution, and the need for an operational clean-up programme.
Given that 47% of Slovenia's surface is karst, legal protection of these natural environments is important, Tičar stresses. Historically, karst and karst phenomena began to be explored on Slovenian soil, with the origins of research dating back to the Habsburg monarchy and the construction of the railway from Vienna to Trieste.
Even more than history, however, the legal protection of cave environments was prompted by the realisation that the karst world provides us with access to a high quality and sustainable supply of drinking water, and a very specific and endemic underground habitat for various cave species.
"These two factors are very strongly accepted in society and it is through them that we address the very issue of cave pollution and its impact on the quality of this groundwater," says Tičar.
Clean-up requires quality data and a plan
Although a direct connection between cave pollution and underground water pollution has not been experimentally confirmed yet, experts agree this connection is very probable. At a time when the supply of clean, drinking water is becoming an increasingly pressing global issue, the systematic clean-up of polluted caves is becoming a must.
As part of his PhD theses, Tičar has created a model for a priority clean-up of caves. The model singles out the most problematic caves in Slovenia, which are located in water protection areas or protected areas, and contain large amounts of waste or highly hazardous waste. As a result, hey can be cleaned up as a priority.
Apart from obtaining pollution data from the cave registry, future field monitoring will be conducted to address the problem of obsolete data. Tičar also wants to change the way data is collected. The project is financially supported by the Public Research Agency and the Ministry of the Environment and Spatial Planning.
One of the project's objectives is to develop approaches and guidelines for cleaning operations that would tell organisations, caving associations or private operators how to meet all legal and safety rules to make sure the work is done safely and efficiently. Tičar adds that this area is currently unregulated.
He thinks such a systemic solution would be possible through more cooperation between caving associations and the Ministry of the Environment and Spatial Planning. Caving associations can offer a treasure trove of knowledge and experience from the field, while ministries can provide legal opinions on whether certain requirements are appropriate for a particular approach and whether the clean-up can be carried out in accordance with the law.
"I envision this first and foremost as an exchange of experience between managers and those taking action. The answers to the challenges of the future, as in other areas, lie in cooperation," Tičar says.