A conversation with Werner Käss (Germany) about his contributions to tracer hydrogeology and characterisation of mineral waters and spas
Nico Goldscheider & Nadine Goeppert
Transcript of interview with Werner Käss
Background Information:
· Place: Home of Werner & Hanna Käss, Umkirch, Germany
· Date: Sunday, 5 October 2008, ca. 10:10 to 11:30
· Interviewers: Nico Goldscheider, Nadine Goeppert
· The interview was held in German and recorded as an audiotape; Werner Käss’ wife Hanna was present during the entire interview.
· Transcription of the audiotape: N. Goeppert; translation: N. Goldscheider
· Proofreading: Tim Bechtel, Lancaster, USA
Nico: Werner Käss, you are internationally known as the expert in the field of tracer tests in hydrogeology. How did you come to work on tracer tests? What were your first experiences in this field?
Werner Käss (WK): This is in good part due to the geology of our home region, Baden-Württemberg [federal state in southwest Germany]. We have a lot of karst: the Swabian Alb, the Muschelkalk (see Fig. 2 of the article). Particularly after the last war, there were problems with the water supply. The farmers simply injected their wastewater into the underground, via dolines and swallow holes, without caring about contaminated water reappearing at karst springs. But with increasing sensitivity to water, the problems came to light, and our Geological Survey, with its central office in Freiburg, was charged with carrying out investigations on a scientific basis.
So it was obviously necessary to put in operation hydrogeological tracing techniques. This was already before my employment; I only came to the Geological Survey in 1957. I established the chemical laboratory and became head of the geochemistry section, and colleagues who had problems with tracer tests came to me. Up until that time, they mostly did tracer tests with salts and dyes, but more qualitatively. For the salt tracer tests, chloride was measured by titration, and breakthrough curves were established for the springs. Concerning the dyes, there was only uranine, which was monitored qualitatively, by observation. After the injection, they made round trips to different springs and noted observations such as “there is green colour, weakly visible, clearly visible or intense.” This is what results were like in those days.
But then the analytical techniques became better; this was also the beginning of electronic measurement techniques. So I was facing the task of establishing more quantitative methods in tracing techniques. And I said to myself that it should be possible to better quantify uranine by measuring its fluorescence. So I started at the beginning of the 1960s to measure fluorescence by means of new instruments, mainly from Zeiss. After the war, Zeiss came from Jena [eastern Germany] to Oberkochen [Baden-Württemberg]. Down to the present day, Zeiss instruments have always been very good, reliable, and solid. As I told you, I first dealt with uranine. I studied the properties of uranine, qualitatively and quantitatively. And so I was finally able, in the middle of the 1960s, to measure quantitatively tracer tests with uranine, resulting in detailed tracer breakthrough curves.
Nico: And which was, concretely, your first tracer test?
WK: My first tracer test was many years later for the congress of the ATH [Association of Tracer Hydrology] in 1970, which took place in Freiburg. I will tell you about this later. Until then, my colleagues at the Geological Survey, who grappled with karst groundwater, did the tracer tests and brought the samples to my laboratory. I gave advice, of course, concerning the injection quantities and the sampling programme.
Then a third possibility came into play, tracer tests with clubmoss spores. Already in the early 1960s, we were in contact with our colleagues from Graz [Austria], Prof. Zötl and Prof. Maurin, who had developed the method of clubmoss tracing in alpine karst areas, using spores of Lycopodium clavatum. The successful applications published by these two colleagues encouraged us to use clubmoss spores as a third tracer type in our karst regions. So we created international contacts, and when Prof. Maurin later changed from Graz to Karlsruhe [Baden-Württemberg], the contacts became even closer. Above all, his assistant, Heinz Hötzl, who prepared his postdoctoral thesis about the karst aquifer system of the Swabian Alb, cooperated a lot with us in the field of tracing techniques.
Nico: Now, you have already answered many questions that we had on our list… Let’s make a big leap in time: When did you do your last tracer test?
WK: The last tracer test is still ongoing, at the experimental site of Merdingen, located between Umkirch, where I live, and the River Rhine, in the Upper Rhine Plain. Since 1978, we have established an experimental site there, and the current tracer test was done in this context. I once had a research mandate from the DGF [German Research Foundation] dealing with the fate and transport of trace compounds of environmental concern. And I included the elements boron and fluorine into my assessment, that is, boric acid and fluoride. We wrote a report of the results that was, however, never published. And I now want to write a paper about this. In this context, I want to further describe the transport behaviour of boric acid and fluoride in groundwater, and this is why we did this tracer test, at the beginning of September [2008] at the Merdingen test site, where we injected borax and uranine. We had already studied the fluoride during an earlier experiment. So the current experiment is the 38th at the Merdingen test site, and I do the analyses by myself in my house. As you know, I have a small tracer lab with the required instruments: spectral fluorometer, atomic absorption, and spectral photometer.
Nadine Göppert: Now let’s go back in time again. You mentioned that you worked at the Geological Survey in the field of geochemistry. But what did you actually study?
WK: I went to war without university entrance qualification. I only had a declaration that I had the right to study after having passed a so-called supplementary course. But directly after the war, in the years 1945 and 1946, schools were still closed and universities too. In October 1945, without formal permission from the occupying power USA, we started clandestinely in my former secondary school, now called gymnasium, to prepare for the regular exam. So I passed my regular secondary school final examination and university entrance qualification in March 1946. And then I started to study natural sciences to become a schoolteacher. My main subject was chemistry, and I had to select two additional topics, biology and geography. After a couple of semesters I considered carefully what I really wanted, and I said to myself that schoolteacher is not the right thing for me. I want to study chemistry and become a chemist! So I made the practical courses required to become a graduate chemist. Coincidentally, there came a professor from Breslau, Prof. Spangenberg, who presented geochemistry lectures at the technical university. And there I realised that this is the right topic for me: geochemistry!
My father was already retired at that time. The house burned down during the war, and we worked on the reconstruction. This occupied me a lot! Two days after the secondary school final exam, I went to a quarry, a gypsum quarry, to obtain a share of gypsum. At that time, natural goods were worth more than money, because you had something to exchange against all type of other goods. I did these quarry works during the semester holidays. Doing so, I learned geology quite well, at first hand. The gypsum quarry consisted of the oldest formations of the Middle Keuper. And Professor Spangenberg, he made me enthusiastic, although the university studies were progressing slowly at that time. The laboratories were barely reconstructed. It would have lasted at least 15 semesters to become a graduate chemist, and this was too long for me under these difficult circumstances.
At that time, Prof. Bräuhäuser was the head of the geology department in Stuttgart. So I studied geology. Then his successor came, Prof. Aldinger who supervised my diploma thesis about loess. I studied the phosphate geochemistry of loess deposits. As you know, loess is not a uniform substance, but within the deposition periods, there were several warmer periods with vegetation and soil formation. And the resulting variations of phosphate levels were the topic of my diploma thesis. After the diploma, I once went to Prof. Aldinger and told him “Herr Professor, I want a topic for my PhD thesis”. At that time, all geologists needed a PhD degree. And now I tell you his answer in his own words: “Herr Käss, come here and take a look. Here are two drawers. They include phosphorite concretions from the Jura. Now research them!” So I came to my dissertation topic. He went away, and I took my bicycle to the foot of the Jura Mountains, where I sampled phosphorite concretions from the Middle Jurassic. I studied these concretions, chemically and morphologically. And two years later, I wrote my dissertation.
Nico: And how did your scientific career continue?
WK: I just told you about my dissertation. I had not even completed the last letters, i.e., I did not hold my PhD certificate in my hands when I received an offer from the petroleum industry. My thesis director Aldinger told me, “Herr Käss, you should go to the Brigitta Company [in Hanover, northern Germany], but I have to tell you right now, this is a noble company!” So I came to the petroleum industry, in October 1954. I stayed three years as a petroleum geologist. I did not work much on chemistry; however, there was some research in this field. For example, I had the task to recreate a gas detector, an instrument that is typically used to detect flammable gases during the drilling process. I did this. I recreated an American FLS instrument; that means Formation Logging Service. But I added some new special features, such as an automatic writer. And the instrument proved itself for the exploration of hydrocarbons.
Then there was a meeting of the Oberrheinischer Geologischer Verein [Upper Rhine Valley Geological Society], in spring 1957, near Baden-Baden [town in Baden-Württemberg]. And there was also a field trip to the Alsace [France]. In the evening, we were sitting together and chatting, with some Alsace wine. My friend and teacher Walter Carlé came to me and told me: “The Geological Survey is searching for a geochemist. Wouldn’t this be something for you?” Walter Carlé, who devoted his body and soul to tectonics, mineral and medicinal waters; this is how I got to know him. I did not take his comment very seriously in the first place. But when I came back to the Brigitta Company in Hanover, there were some circumstances, some difficulties with my superior, who was later fired by his company, by the way. I was quite young at that time, and I said to myself, well, you should think about this! And the cold and wet climate in the region of Hanover was another factor. So I made a first visit to the Geological Survey in Freiburg. President Kirchheimer welcomed me and told me: “I know your PhD thesis. It is quite interesting, and if you want, you can start to work here and manage the lab.” I agreed and my work at the Geological Survey of Baden-Württemberg started in November 1957.
Nico: Now let’s make another leap in time and talk about your book, probably your main work: Tracing Technique in Geohydrology, first published in German in 1992, translated into English in 1998, and a second German edition was published in 2004. This book is often considered as the ‘Bible of tracer hydrology’. Can you tell us the story of this book?
WK: To answer this question, I have to go back in time. I told you about the contacts with the colleagues from Graz and Karlsruhe. At that time, and still today, there were only few institutions working on tracing techniques. In 1964, I went to a meeting of the German Geological Society. During a field trip, we had lunch and I was coincidentally sitting at the same table as Prof. Maurin, who was still in Graz at that time. I said, “This is wonderful that we can finally meet each other”. And in the course of this lunch conversation, I proposed to organise a small meeting in order to exchange our experiences in tracing techniques, mainly related to groundwater, karst groundwater. Prof. Maurin implemented this suggestion, and so the 1st symposium of tracer hydrology took place in Graz in springtime 1966. This was the starting point of the Association of Tracer Hydrology, the ATH. Several experts gave interesting presentations, there were field trips, and we came closer to each other on a human level. The conference proceedings were published in the Steirische Beiträge zur Hydrogeologie [the only German-language hydrogeological journal at that time]. During the editorial meeting, we all agreed that it would be a pity to stop our cooperation. We should repeat such a meeting! I was enthusiastic about all the projects of my colleagues, and I suggested that we could meet another time in the karst region of the Swabian Alb and do some tracer tests there, maybe along with a symposium in Freiburg. And so the 2nd symposium of tracer hydrology took place in Freiburg in 1970, and so it went on. I think altogether we organised seven or eight conferences, which took place in Slovenia, Germany, Switzerland and Greece.
During one of the meetings of this working group – which was a group of tracer experts without any formal statutes, without leader, and without any budget of course – during one of these meetings at the end of the 1980s, we said that we should put together all our experiences that we have gathered over the years. All these tracer tests in groundwater, glacier waters, streams, rivers and lakes, we should collect and document these experiences. And there was a discussion, how to do this. Josef Zötl proposed a special issue of the Steirische Beiträge. But we came to the conclusion that this would be too much material for a special issue of a journal. Another proposed a loose collection of separate small papers to be published one after the other. I refused that, because such unsystematic collections are useless. Finally we came to the conclusion that we need a book! But well, how to produce a book, where to publish it? I suggested asking my friend Georg Matthess, previously working at the Geological Survey of Hessen [federal state of Germany] and then head of the department of Hydrogeology at the University of Kiel. I will ask him if he would like to include a volume about tracing techniques in his hydrogeology textbook series. He said, yes, that’s possible; please prepare an outline. I said that I would tell this to the working group. And during the next ATH meeting, I told the group “Prof. Matthess agrees to include a book about tracing techniques in his textbook series, now it’s your turn!” Well, but you know how it is! They said, “Since you launched this project, you also have to do it!”