As an environmental chemist, Professor Barbara Kasprzyk-Hordern has always been fascinated by environmental health and the effects of pollution. Her doctoral studies focused on the development of drinking water treatment technologies such as 'catalytic ozonation', a process used to remove pollutants from water.
Taking water for granted
‘Right from the start, I felt I was trying to deal with a problem I didn’t really understand’, she says. ‘The matrix I work with is simply this: we need water to survive, and it has to be clean. Yet we draw it from underground, from reservoirs and rivers, purify it – or our water companies do – and then take for granted that it’ll be uncontaminated and available for drinking, agriculture, bathing, and industrial use. It’s extraordinary! Personally, I don’t think we value water nearly enough.’
The aim of purifying water, and making it healthier to drink, is always going to be affected by a raft of pollutants. Scientists investigate pesticides or pharmaceuticals that find their way into the environment and affect the health of humans as well as other organisms, and ozone is a powerful disinfectant and effective oxidant.
‘Wastewater joins the sewage system and then wastewater treatment works, where it’s treated and then released back into the environment it was originally collected from. And it’s not perfect, but it could be, with extra investment in new advanced treatment technologies. Energy-intensive processes like advanced oxidation, reverse osmosis or membrane filtration could be introduced. The issue is that that these processes can’t be energy-intensive because that makes them expensive; and besides, this wouldn’t be good for the environment, especially in the context of climate change issues.
There’s a third problem too, which is that consumers don’t want to pay much. Yet shouldn’t we all be happy to pay more for our water to be clean, safe and readily available on tap?
Finding out what, in water, affects us
At source, water is usually pure, but with every additional waste discharge point or sewage treatment works – whether it’s domestic or industrial effluent – the infiltration rate increases. Also, nitrogen and phosphorous from fertilisers are linked with eutrophication when rain washes them into waterways, encouraging organisms like algae to grow prolifically on the water surface.
‘Blue-green algae may look pretty,’ says Barbara, ‘but a bloom prevents light penetrating to underwater plants and when it subsequently dies and degrades, it releases toxins as well as bacteria that utilises all the water’s oxygen, so fish and organisms below can suffocate and die.
‘When we’re investigating water we’re looking for something tiny but incredibly important, such as oestrogen. And while these substances, at common environmental concentration levels, might not necessarily trigger negative strings in people, they could be harmful for organisms like fish, leading to their feminisation.’
Of course, certain prescription drugs are necessary to manage human or animal diseases and conditions. But decisions on which ones we should use – where there’s a choice – should be influenced by knowing if they’ll be harmless to aquatic organisms if they find their way into our water.
Another interesting example, says Professor Kasprzyk-Hordern, is that in India, more than 90% of the vulture population died in the 90s, with catastrophic consequences. Nobody understood why – it was mysterious. Eventually, in 2003, The Peregrine Fund worked out that cattle there were being given a nonsteroidal anti-inflammatory drug called Diclofenac.
Since Hindus don’t eat cows, vultures fed on the carcasses of dead animals, and the Diclofenac they consumed accumulated in their kidneys with fatal results. This, in turn, led to huge population growths in less efficient rats and feral dogs, who gorged themselves on the abundant supply of carcasses and spread pathogens that vultures used to killed off; just as critically, these rotting carcasses contaminated water supplies. Veterinary use of the drug has subsequently been banned in several South Asian countries, where vultures play an important part of the food chain.
Compounding the problem
‘Concentrations of pharmaceuticals vary and different organisms work and react in different ways,’ says Barbara. Around 7,000 are marketed globally, though we know very little about the consequences they may have. In fact, the EU Water Framework Directive currently has 33 priority chemicals on their list, but no pharmaceuticals.
‘However, a new proposal aiming to reduce water quality risks recommends 15 additional priority substances. Macrolide antibiotics are on their watch list, too. It’s hard to link exposure and effect, and to predict how different species will react to multiple substances in their habitat. After years of studying and researching this, I’m still trying to unravel the complexities of studied systems.
‘There are obvious understandable ethical concerns, because most people would think a few fish dying from a drug than can relieve a human’s suffering is a fair trade-off. But I think the biggest issue is that human mindsets are always target-driven, which means directives won’t be issued without concrete evidence about hazards and negative biological responses on organisms.
‘So my team and I thought: what happens if we forget about targets? What if – instead of looking at individual chemicals – we fingerprint, to gain more comprehensive information about a stretch of water? There will be thousands and thousands of chemicals in it and, to make our job harder, the patterns are ever-changing in flowing water. But then, that’s what makes it so interesting, because you never know what you’re going to find, hour by hour. We realised that we’re sitting on several large data sets, yet not using or combining our knowledge to link environmental issues and public heath!’
About ten years ago, Barbara started looking at illicit drugs that had worked their way into the environment via sewage. ‘These drugs are obviously important because they’re extremely toxic, and are being taken in large enough quantities for us to be able to see them. It was Christian Daughton who first made the link. He realised that most people consume and then excrete these drugs; and that since they’re usually metabolised when they’re excreted, they’ve gone through a human body. This, in turn, allows us to work backwards from each water sample to calculate usage in a particular community.
‘We created a network called Sewage Analysis CORe group Europe SCORE, initially to build larger data sets to source issues we thought important. Six countries took part, with the UK working in collaboration with Norway, the Netherlands, Italy, Spain and Switzerland.
‘We all love looking at data – yes, really! But we wanted it to be useful, so the SCORE group got in touch with the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA), which looks at trends and patterns of drugs, addiction and usage across the EU, though of course it’s actually a global problem. We decided to investigate spatial-temporal connections, using funds to help with drug abuse. This has proved to be a powerful use of data because if something goes wrong with the environment it affects us all: humans, animals, birds, fish, plants. Everything that’s alive.’
One example is Mephedrone69, a stimulant and psychoactive substance that was unregulated and readily available online or in head shops from 2003. It’s a synthetic drug, known on the street as bath salts, drone or Meow Meow, and was used for ‘legal highs’ until, following several deaths, the EU illegalised it in 2010. Flushed down the toilet, it enters our water supply.
‘Sometimes people carry out surveys on drug-taking,’ says Barbara, ‘but the subjects being questioned often have no idea what drug the actually took – they just remember some pills or powder – which makes the results unreliable. You can look at hospital data and toxicology tests too, but can’t see the whole picture immediately. You have to put various components together, so there’s a delay.’
‘The beauty of our work is that when we water fingerprint, we act and get results in near real-time; and once we’ve analysed a sample in the lab the information is almost instant. We could even tell you where the chemicals we find were made, and which batch they’re from. The EMCDDA have established an early earning system, and when a new drug is found they send information on it to their HQ in Lisbon.
‘At the SCORE group we support their data with near real-time information on drug usage trends in European cities. Of course we can’t find hard evidence of the individuals the drugs have been through, so our work won’t lead to prosecutions! We don’t want to identify groups, either, but find out about towns, cities and their usage scales. There’s so much more we can do, using comparatively limited resources, especially when more and more people are living in urban areas. With massive population growth, withdrawing dirty water could have a big impact on managing the prevalence of diseases, especially in less developed countries. We’re obviously interested in exploring the pathogenic organisms there, too.
‘The levels of pharmaceuticals in water are low and there’s no risk from acute toxicity, though there are substances like endocrine disruptors, and there could be chronic effects like diabetes, over time. We want to use our tool to make links and correlations to understand exposure patterns that affect health. It’s epidemiological research, with a view to planning and evaluating strategies to prevent illnesses caused by harmful substances, in populations that are at risk. Different chemicals trigger different responses, and we carry out chemical profiling to make decisions about the reducing their impact.’
What price do we put on protecting citizens?
Project by project, this sort of work takes time and is relatively expensive. Barbara’s team collects 50ml samples from various sampling points around the world – rivers, other waterways, treatment plants – every 15 minutes. The samples are then pooled together to get daily composites, and chemicals are identified by running them though powerful mass spectrometry tools that can each cost as much as £500,000.
‘The remnants and chemical evidence of so many of our activities – personal care products, detergents, sun cream, coffee grounds, medicine, drugs, alcohol and so on – go into our water system,’ she explains. ‘There are seasonal variations that will inform decisions and spikes that can’t always be explained, such as alcohol having a small rise on Wednesdays! And while MDMA spikes at the weekend, when it’s used recreationally at clubs and so on, heroin is a constant throughout the week.’
‘We have two key aims: the first is simply making water cleaner for public and environmental health; and the next is providing information that creates something like an early warning system for communities. Let’s say we had a baseline for a city and then the data showed a spike of pathogenic organisms; we could tell people to avoid the water before they get ill, rather than waiting for a local hospital to report a slew of cases once people have ingested it. We can also see cities where there’s high prevalence of drug use, or where industrial or other chemicals have been dumped in the water.
‘Bear in mind that only about 1% of 6-acetylmorphine, heroin’s biomarker, for example, is excreted, so detecting it is dependent on the incredible sensitivity of our tool, and that technology isn’t cheap. It’s extremely hard to isolate chemicals and pathogens in an environment where lots of other things are going on, especially when some biomarkers are very unstable.’
It requires a change of mindset to see the value of detecting problems in the community from its water, rather than vice versa, but Barbara is confident that her approach could be the way forward. ‘The way I see it, technology is the easier bit,’ she says. ‘The most challenging element of what has be done is changing people’s perceptions.
‘With enough investment, I believe it would be possible to make this a global initiative. I’d like to see an early warning system that informs us of public and environmental health issues such as communicable disease spread. Additionally, this would enable us to link higher prevalence of non-communicable diseases, such as diabetics and cancer in certain communities, with global or localised causes and stressors like pollution and industrial activity.’
As part of a [Global Challenges Research Fund (GCRF) (ReNEW)(https://www.gcrf-renew.co.uk/) project), Barbara’s team is working with the University of Stellenbosch on developing a real-time, tuneable, community-wide ‘diagnostics and multi-hazard public health early warning system’, with the ultimate goal of strengthening communities' resilience. Together, they’re focusing on mitigating infectious diseases and limiting the spread of antibiotic resistant microorganisms.
Her group has also formed a strong collaborative local partnership with Wessex Water, and their most recent ENTRUST project is an assessment of wastewater fingerprinting for public health. They aim to reduce the pharmaceutical levels that reach wastewater treatment works from the aquatic environment through ‘control at source’ methods, via educational campaigns on the usage and disposal of pharmaceuticals and social prescribing.
‘The most satisfying part of my job is seeing the application working, finding ways of influencing people to make decisions that will make our lives better and environment healthier, and ultimately save lives,’ says Barbara. ‘I love working out the puzzles.’