"Pollutants in soils are a global problem"

Prof Dr Jörg Rinklebe and the world's international soils

When a child loves nature, has a great biology teacher and literally soaks up all the knowledge about plants at a young age, the career path seems to be mapped out. But it wasn't quite that easy for Jörg Rinklebe, as the fact that he was set a different path during his time at school in the former GDR made things even more difficult. "I grew up in the East. And there was a lot of sifting. ... Only one, two, maximum three people from each class were allowed to do the Abitur." Achievement was not necessarily the only thing that mattered; the political criterion also showed the "rather rebellious pupil", as he puts it, a different path in life. "I was active in the church, at that time there was the new forum* and it would have been difficult for them to give me permission at all." Rinklebe completed a vocational training programme with A-levels, a combination that was initially discarded after reunification but has now been revived under the "dual" aspect. "There was either biology or agriculture." And since agriculture offered him a close relationship with nature, with soil and plants, he was accepted into the only year group that specialised in plant breeding.

The fall of communism in 1989 was a blessing for the then 20-year-old. "For my generation and for me, the reunification came at exactly the right time. Otherwise I wouldn't be sitting here and wouldn't have come to West Germany anyway, wouldn't have been allowed to study, wouldn't have been allowed to do my doctorate and certainly wouldn't have become a professor."

Professor Rinklebe went to Edinburgh in 1992, partly because he wanted to get out and partly because there were no ecology degree programmes in Germany at the time and the Scots were leading the way. In this context, the scientist talks about the beginnings of the ecological movement. "It was the time of the great forest dieback, the "Greens" were on the rise and it was all about tackling environmental problems."

There are hundreds of thousands of different types of soil worldwide

He devoted all his scientific attention to soils and over the years became an international expert in the field of alluvial soils.

"Alluvial soils are very special in soil science. They are localised near rivers, so they are flooded at times and dry out at other times." As a result, they have great water dynamics and release both nutrients and toxic substances. Soils are a medium for plant growth. Rinklebe examines these soils for toxins that the water in the rivers of all developed industrialised nations has carried and deposited over the years. Although society has now learnt a lot and water quality has improved, according to the scientist, "the harmful substances in the rivers have never disappeared. They are in the soil. The soil filters out these harmful substances and retains them. And we still have to deal with that today!" Rinklebe is pointing specifically to our doorstep, as the soils of the Wupper are also highly contaminated.

Elevated lead levels in NRW

Cleaning the soil also has its pitfalls. A distinction is made between large-scale soil contamination and that which is limited in terms of area. The former can usually be excavated and then cleaned, while the latter require new strategies. "You can't excavate half of NRW," the engineer emphasises with a laugh, "you might have to resort to alternative cleaning methods, e.g. using plant power. This means, for example, that plants are grown on large contaminated areas to extract the pollutants from the soil. These in turn then have to be harvested, incinerated and the residues disposed of. All quite expensive and, in times of tight budgets, only possible in hotspots. The attempt is therefore made to either retain the toxins in the soil by adding other chemical substances or the authorities impose utilisation restrictions for cost reasons. It is interesting to note that there is a special passage in the Federal Soil Protection Act (1998) and the associated Federal Soil Protection and Contaminated Sites Ordinance (1999) specifically for large areas with increased levels of pollutants due to settlement, as is the case in NRW. These stipulate the limit values for harmful soil contamination and are set higher for large areas with increased pollutant levels due to settlement, i.e. the soils in such areas can remain more heavily contaminated.

Ideally, the pollutants remain in place. However, the great danger is always that they are washed out and end up in the groundwater.

"We cover around 70% of our drinking water needs from groundwater"

The dilemma is obvious. Professor Rinklebe: "We want to have clean, healthy drinking water. It is therefore in our interest to keep the groundwater clean. But groundwater can only be clean if the soil is clean. So we try to keep the existing pollutants in the soil so that they are not washed out."

Every citizen can enquire about the pollution levels in their region. "In NRW, the State Office for Nature, Environment and Consumer Protection of North Rhine-Westphalia (LANUV) has a website that anyone can access," says the scientist. The specialised information system "Contaminated sites and harmful soil changes", known as FIS StoBo for short, is a database on which every citizen can check how high the pollutant content is in their region. This means that questions about the cadmium, chromium or nickel content in the region can be directed to the state office.

It is also possible to protect the soil in your own allotment garden. The expert explains: "You can add compost, humus, which works up to a certain level, and liming can also be helpful. This increases the pH value and reduces the mobility of pollutants."

The reintroduction of hemp in Germany

The busy scientist is working with hemp fibre in another area of research. Funded by the Agency for Renewable Resources (FNR), this research project is focussing on the re-cultivation of one of the oldest crops on earth: hemp. "The aim is to utilise hemp, for example as clothing. We mainly use cotton, which doesn't grow here at all. Our ancestors made everything from hemp. You can make jeans and even the finest fabrics from hemp, the car industry uses hemp for panelling. Foodstuffs such as lemonade, beer and even sweets are made from it."

Around 200 years ago, entrepreneurs realised that cotton from other countries was cheaper to buy. As a result, hemp (cannabis) was deliberately suppressed and reduced to its intoxicating effect. "We are actually living at the expense of African, Asian and South American countries today," says Rinklebe, "our entire market is dominated by cotton, even though we would theoretically and practically be able to process hemp ourselves." Of course, sustainability is also a goal close to his heart, and he wouldn't be a scientist if he didn't plan ahead, because "when the developing countries themselves become industrialised countries, even South America and Africa will manage that, then it will no longer be so easy and cost-effective to obtain tropical fruits and cotton. Then at some point we will be on our own again and will have to produce our own food. Then it will be worth growing hemp here again. We need to stockpile certain things so that we will still be able to provide for ourselves in 20 years' time."

Hemp: a winter catch crop that has it all

His long-term goal is to reintroduce hemp in Germany, and he has already done a lot to achieve this. Hemp is to be produced in Germany, but not as "competition to wheat, maize and sugar beet", which he attaches great importance to, because hemp is to be grown as a winter catch crop, i.e. as an additional crop. This means that it can be wonderfully "intercropped". Rinklebe explains: "In the gap when I harvest the winter barley in August, I can still see the hemp growing until the end of October. It remains standing over the winter, which also offers other ecological benefits (e.g. ground cover, protection for animals) and it doesn't compete economically with the main crops."

So far, he has been able to convince 15 farmers to grow hemp in a further project phase in cooperation with the NRW Chamber of Agriculture. But there is still a long way to go, the renowned researcher knows, because suitable agricultural machinery, processing technology, expertise and a well-functioning sales organisation are needed for nationwide cultivation.

Would you drink a glass of Wupper water?

Groundwater is another area of his specialism that he focuses on alongside alluvial soils. As he knows what pollutants lie dormant in our cool water, he would also be reluctant to taste the local Wupper water. "The Wupper has good water quality, but I personally wouldn't drink surface water except in particularly natural regions such as the Alps. It also contains coliform bacteria and other microorganisms and we humans are no longer used to processing it."

When asked about the toxins that could be found in our groundwater, Rinklebe mentions PFT compounds (industrially produced, carcinogenic surfactants) in the Ruhr and Lake Möhne as well as the fire at Düsseldorf Airport. The best-known inorganic pollutants in NRW include the major toxic substances such as cadmium, lead, mercury, arsenic and cyanides, as well as nickel, chromium, cobalt, manganese and zinc. Organic pollutants such as dioxins and furans, HCH compounds (hexachlorocyclohexane), PCB compounds (carcinogenic organic chlorine compounds) and others should also be mentioned.

"The first, simplest and most important thing is not to dump waste into the ground."

Every single citizen can do something about environmental pollution. It seems so simple when Professor Rinklebe says: "The first, simplest and most important thing is not to tip waste into the soil so that it doesn't all end up in the rivers and groundwater". And his advice to hobby gardeners and farmers to be more careful with pesticides and fertilisers also appeals to the expertise of each individual, because: "The EU has already taken Germany to court because of the excessive nitrate levels in the groundwater." One cause of this is diffuse agricultural sources, especially from excessive nitrogen fertilisers. Experts therefore speak of so-called "adapted fertilisation", which calls for the careful use of chemicals.

Every pesticide is poison... for all organisms

"You usually not only kill the maggot that shouldn't be in the apple", but also promote resistance. "A normal apple," says Rinklebe, "if you buy it from a conventional grower, has been sprayed around 30 times. And this poison is on the apple. That's why you should at least wash it."

He himself buys organic apples and grapes in particular, although he admits that buying from organic farmers is still a matter of trust.

Statistically interesting is the fact that the market share of organic farming in Germany, which was still around 1% in the 1990s, has now risen to around 10%, which is proof of the great interest in healthy eating.

Ambassador of honour in South Korea

The expert's international network shows that the problems of soil and water do not stop at Germany's borders. He has been working closely with South Korea for years. The floodplain soil expert is a valued guest there, as the problems relating to pollutants in the soil of flooded areas could pose a serious threat to rice cultivation. "In Asia, rice cultivation is the dominant crop, the staple food of all. Care must be taken to ensure that the rice is free from harmful substances. And the biggest problems in rice cultivation in terms of harmful substances are arsenic, cadmium and mercury. We have flooded fields and a very special geochemistry. And these geochemical processes are incredibly similar to floodplain soils."

Rinklebe describes the existential threat using China as an example. "The government knows that something has to be done because otherwise people will die off in their 30s or 40s. In industry, environmental standards are far behind European standards. They produce a lot, but pay no attention to the environment. In the last year or two, we've noticed that things are changing. An awareness process has begun." But he is not only active in Asia. Observations on the Nile and the Mississippi round off his experiences.

Motivation is the be-all and end-all

Rinklebe knows that new students often don't know what to expect, so he says welcomingly: "I train people here from the ground up, i.e. when they arrive here with their A-levels and study civil engineering and transport engineering, they hear the basics of soil science from me. We start with the absolute basics." The development into a soil scientist can only come after two to three years, because that's how long it takes to learn the basics. Many students go on to work for environmental authorities, geological services or private engineering firms.

In the summer, Rinklebe is travelling to another conference in the USA. As the keynote speaker, he will be talking about "Pollutants in wet soils", which includes not only alluvial soils but also rice soils, bogs and coastal areas that are struggling with the same problems as North Rhine-Westphalian alluvial soils.

Uwe Blass (interview from 22/02/2018)

*One of the citizens' movements that emerged during the peaceful revolution in the GDR.

Prof Dr Jörg Rinklebe has been a professor of soil and groundwater management at the University of Wuppertal since 2006. From 1997 to 2006, he worked as a scientist, research assistant and project manager in the Soil Research Section of the UFZ Environmental Research Centre Leipzig-Halle GmbH in Halle. He studied ecology for a year at the University of Edinburgh in Scotland (UK). He studied agriculture at Martin Luther University in Halle-Wittenberg, specialising in soil science and plant nutrition.