A German bunker full of blood and urine has the best record of how chemicals contaminate us

Munster, GermanyFifteen minutes southeast of this university town, residential streets give way to farm fields, and the road winds and narrows. Five old military bunkers are located next to a tall chain-link fence. Their curved roofs are covered with grass and they have low swells in their landscape.

Dominik Lermen heads toward one and takes a bunch of keys out of his pocket. The clattering is drowned out by the birds chirping and the wind howling through the trees. Finally, he locates the key and I follow him through the plain-green door, into the best archive of chemical pollutants that has ever existed.

“In here,” Lermen says, “we’ve got about 400,000 samples from more than 17,000 people. Mostly whole blood, urine, and plasma.”

We’re standing in a huge, windowless, dimly lit room, with bare concrete walls around six feet thick. The curving roof is supported by white pillars. It’s cold–a little over 50oF–but not nearly as cold as it is inside the 42 stainless steel cryo-vats that fill the room in neat rows. Each one is approximately six feet tall and two feet wide. They are connected to metal pipes that run the length the building.

This is the human-sample archive of the German Environmental Specimen Bank (ESB), an effort by the federal environment ministry “to systematically monitor and analyse human exposure to chemicals like lead, mercury, plasticizers and others,” Lermen says. It is more than 40 years old and the longest-lasting record of its kind.

Every year Lermen and his colleagues from the Fraunhofer Institute for Biomedical Engineering collect and analyze samples of blood and urine from volunteers from the four corners of Germany, then store the samples here for future research. The project has two objectives: To identify substances that have accumulated in large quantities in German bodies and to verify that bans and regulations have worked.

Regulation clearly can work: Blood levels of lead and mercury have plummeted in recent decades in Germany, as they have in other industrialized countries. The proliferation of synthetic organic chemicals such as PFAS, also known as “forever chemicals”, has created new and alarming threats that make it more urgent to get work done at this mysterious facility.

Lermen, 44, bald with a full beard and a pleasantly sonorous voice, puts on a face shield, climbs up a mobile stairway, and lifts the lid off one of the tall cryo-storage vats. The opening opens and a white fog rises. It sinks to concrete floors.

“All of these tanks are filled with about 160 liters of liquid nitrogen,” Lermen says. “Only at these extreme temperatures can we ensure the longevity of our archive.”

His hands and forearms protected by special gloves, Lermen reaches into the tank and lifts a rack full of vials from the nitrogen cloud that sits above the liquid nitrogen lake. The temperature in the cloud is below -160degC, or -256degF. After a few seconds, he lowers his rack into the container and then closes the lid.

“When we take the samples out of the tank, the vials experience a rapid change of temperature of about 170deg,” he says. “Of course we want to keep it to a minimum.” Every second counts when you’re trying preserve a record for eternity.

‘Students are our early warning’

Though scientists at the University of Munster began hatching plans for the ESB in the 1970s, it was officially launched in 1985. The first samples were collected from people near Munster, in western Germany, but after West and East Germany were reunited in 1990, the annual sampling program was expanded to Greifswald in the north, Halle in the east, and Ulm in the south. This was done to create a national picture of chemical contamination.

The ESB also collects environmental samples–bird eggs, plants, fish, mussels, deer, earthworms, and soil– from 14 different locations, including cities, nature reserves, and farms. The Munster bunker, an ex-army medical depot, is only for human samples. The archive moved here from the university in 2012. The walls are thick enough to withstand a bomb, a plane crash, and shield the samples from any cosmic radiation that could otherwise cause damage.

The samples in the bunker are taken not from Germans of all ages, but only from students between 20 and 29 years of age–in part to exclude people who might have high occupational exposure to chemicals.

” We deliberately sample students” to indicate the threat to the population, says Marike Kolossa–Gehring, lead scientist at the German Environment Agency in Berlin.

“Students are not exposed to certain substances due to their job. As we assume that persistent substances are more likely to accumulate as we age, students should be aware that they may be exposed to them.

“In a sense, students are our early warning system.”

New blood for the bunker

Anjuli Weber, a 21-year-old medical student at the University of Ulm, is one recent recruit to this system. She was intrigued to learn more about the biobank after hearing about it through an e-mail sent across campus. Participants eventually receive some of their test results.

Weber reports to Fraunhofer Institute’s large mobile laboratory in May. The lab has pulled into a parking area on the outskirts Ulm for three days worth of testing. Before Weber enters, a staff member reviews Weber’s medical history, living situation, and includes details about her eating habits, medication, and cosmetics. Weber has her teeth checked by a dentist for mercury and other metals.

Inside the truck, Weber encounters a state-of-the-art medical facility, with a shielded biosafety 2 lab for six workers, a mobile cryo-tank for storing samples, and a back office. She hands over a large, brown plastic bottle containing her urine from the past 24 hours. It is immediately analyzed by a technician.

Then another technician draws about 180 milliliters, or six ounces, of Weber’s blood–around six times more than you might surrender in an ordinary medical test, but much less than the pint you give up when you donate. Within 45 minutes, the blood has been analyzed for routine parameters and divided into 16 whole blood and 24 plasma aliquots. They are registered and bar-coded before being placed in the liquid nitrogen container to be transported to one of the larger cryo-tanks at the bunker near Munster. They will then travel to other labs to be tested for toxic chemicals. This is done through an uninterrupted cold chain which keeps the samples deep frozen and reduces the chance of them being altered.

There are about two dozen environmental specimen banks worldwide; the oldest, in Stockholm, dates to the 1960s. What makes the German ESB unique are the quality and consistency of its data. Whereas some ESBs work opportunistically–when a dead otter or whale washes up on shore, its tissues go into the bank too–the German archive follows a strict protocol and standard procedures. Every year, the same mobile lab travels to all four sampling locations in Germany.

” We have used the same storage and sampling methods for more than three decades. Kolossa-Gehring says that this makes our data comparable and allows us confident analyses and predictions.

Good news and bad

Back in the bunker, another environment agency scientist named Till Weber (no relation to Anjuli Weber) tells me that researchers from many countries have studied the German data. These results were both encouraging and alarming.

One study shows that mercury levels in blood and urine fell by 57 percent and 86 percent respectively between 1995 and 2018. Weber states that one reason for this steady decline is the declining use of amalgam in dentistry, and possibly the increased awareness of mercury exposure from seafood and fish.

Lead follows a similar trend. Data derived from 3,851 young adults in Munster shows that the average blood lead level decreased by about 87 percent between 1981 and 2019. The main reason: Germany’s ban on leaded gasoline took effect in 1988, and so car exhaust no longer pollutes the air with lead.

” No manufacturer intentionally puts harmful substances on the market,” Weber believes. “But sometimes, only with time can we discover the true toxicity and dangers of certain chemicals. That’s what makes bio-monitoring like ours so important for the entire society.”

Even though certain testing is mandatory before using new substances in commercial products, data about long-term health effects is scarce for most of them. It’s nearly impossible to keep track how many synthetic chemicals are being produced.

The strongest chemical regulations are likely to be found in. In April, the European Commission published a “restriction roadmap“: Up to 12,000 substances linked to hormonal disruption, cancer, obesity, or diabetes could be banned, officials said. According to the European Environmental Bureau, a network made up of citizens groups, it would be the “largest ever ban on toxic chemicals”. This could be a severe blow to the petrochemical sector.

The main target is PFAS, also known as “forever chemicals” due to the fact that they take hundreds of thousands of years to naturally decay. Food-packaging, flame retardants, waterproof clothing, outdoor gear, umbrellas, and non-stick pans all contain toxic PFAS-substances.

Traces of these and other substances such as phthalates, which are used as solvents and as plasticizers, have been found in literally every sample since the ESB began looking for them, Lermen and Weber say. It is difficult to trace the source of these chemicals as they are everywhere. It is therefore crucial to regulate their use.

Europe has banned or regulated individual phthalates, identified as endocrine disruptors that might interfere with reproduction, since 1999. Manufacturers have responded by altering the formula of banned substances to create new, unregulated chemicals that have similar features. The overall exposure to phthalates has increased according to studies by the German ESB.

“This clearly indicates that the number of substitute chemicals keeps rising–and we don’t know a lot about their effects yet,” Kolossa-Gehring says.

It’s important that people know as much about the chemicals they are exposed to as possible, Till Weber states before closing the green door to the bunker.

” We don’t want anyone to be scared or to tell them to stop using plastic in their lives. But all of us need to build an awareness of what’s around us, and, eventually, also inside our bodies.”

Esther Horvath is a Germany-based photographer who documents polar regions. Follow her on Instagram. Freelance journalist Florian Sturm is also based in Germany.