Science and Innovation

Interview by Bernat Puigtobella for Barcelona Science and Universities and Núvol.

Silvia Lacorte is a researcher in the Department of Environmental Chemistry at the CSIC’s Institute of Environmental Diagnosis and Water Studies. With her team, she researches the presence of organic pollutants in water and other environmental matrices, and assesses their impact on both fauna and humans. This involves designing sampling studies to analyse contamination patterns, as well as identifying the sources of contamination and their risks. All this information is key to designing strategies to mitigate pollution.

Tell us about your current lines of research.

We study environmental contamination by chemical compounds, which can be pesticides, pharmaceuticals, plasticisers, flame retardants, detergents, perfluorinated compounds, polycyclic aromatic hydrocarbons, microplastics, etc. These are compounds that are used in agriculture, industry or domestic activities, and which inevitably reach the environment once they have been used or consumed.

Where do you look for or detect this pollution?

We mainly study birds because, due to their biology, they accumulate pollutants over the years and, therefore, they are good indicators of environmental pollution in different areas.

And where do these pollutants come from?

Pollutants are never found in a single matrix, but are distributed in different environmental compartments and can be transported over long distances, which is why today we speak of a global pollution problem.

What do we mean by “matrix”?

Water, soil, sediment, organisms, people. By profiling the pollutants in the samples we analyse, we investigate the sources of pollution and their geographical and temporal distribution, and finally determine their impact on ecosystems. Thus, depending on the toxicity of the pollutants, we can assess the risk they pose both to the environment and to people. The environment is often not given enough importance, although we are aware of the impact of pollutants on biodiversity. We must bear in mind that environmental pollution also affects people, because the environment and human health are closely linked.

In the case of water, we often end up drinking it, don’t we? Which waters do you analyse?

In recent years we have been working on the waters of rivers, lakes, the sea… especially in areas that are important for biodiversity. Natural areas have a special interest to preserve, because they are areas where many species live and are breeding grounds for birds. Despite having a certain level of protection, these areas are also affected by environmental pollution due to various human activities, such as agriculture or industrial and domestic waste.

Plastics have dyes and other additives, which are released into the waters, and we should think that they are compounds with high endocrine disrupting properties, which can affect people.

How do you analyse pollutants in a river?

It is interesting to analyse the dynamics of pollutants along a river basin. Therefore, we take water and sediment samples at the source of the river (which should normally be “clean”) and during its course up to the river mouth. We then analyse the pollutants in the samples using chromatography and mass spectrometry techniques; we assess how they are distributed, transported or degraded, and finally we determine the sources of pollution taking into account land use (urban areas, agricultural areas, sewage effluents, etc.).

And what do you find?

In most cases we analyse pollutants that are not regulated (those that are regulated are already controlled by the administrations) and we detect a good cocktail, such as drugs for people or livestock, pesticides, drugs, perfluorinated compounds, flame retardants, and even compounds such as DDT or PCBs, which have been banned for more than 30 years.

Drugs that arrive through discharges into rivers from urban centres.

Wastewater is a good indicator of drug use, which is discharged into the environment through sewage treatment plant effluents and can also infiltrate groundwater through leaks in the sewage network. We also detect perfluorinated compounds from Gorotex (the material used to make waterproof clothing) or Teflon (used in kitchen or construction utensils). And we detected many microplastics, which are polymers smaller than 5 mm in size that are widely distributed in waters and have a large effect on aquatic organisms. Plastics have dyes and other additives, which are released into waters, and we have to think of them as compounds with high endocrine disrupting properties, which can affect people. To take the heat off, some say that rivers were much more polluted thirty years ago. Visually, yes, but in terms of chemical pollution, what we detect now is much worse.

Little water flows down and it is dirty.

In Catalonia we have a problem (in fact, more than one), and that is that it rains very little, so nowadays river flows are the sum of the effluents from the wastewater treatment plants in the towns along a river basin. River water is sewage treatment plant water. In the current situation, river flows are often lower than ecological flows and, in addition, the water is polluted by a number of new chemical compounds that are not covered by legislation. This affects the quality of the environment and aquatic fauna, and also affects the quality of drinking water, as much more extensive treatment is needed to remove the load of pollutants.

What you are saying is that rivers are sewers.

Sewers of treated water, but sewers after all, because there is no water. So it is important to ensure their quality.

What other projects do you have underway?

In 2009 we started monitoring persistent organic pollutants, such as DDT, in seagull eggs. Seagull eggs are good indicators of environmental pollution; the pollutants we detect in this species give information about the level of pollution in a habitat, so other birds living in the same area must also be affected. Persistent organic compounds were banned in Spain in 1994, yet we detected them ubiquitously in gull eggs from different colonies in Catalonia, such as the Medes Islands and the Ebro Delta. We do this monitoring systematically every year, now for 15 years, and this allows us to evaluate temporal trends, i.e. whether pollution levels decrease as a result of conservation or legislative actions, or whether, on the other hand, new pollutants appear that have been recently introduced in the market.

And if it turns out to be a 30 year old contamination?

A substance that has not been used for 30 years and we still find it at levels that are not negligible.

You mean that they are not eliminated.

They are persistent organic pollutants which, because of their properties, remain intact in the environment. Gulls, or other organisms, or even people, accumulate them through diet and respiration. Females transfer accumulated pollutants to their clutches, just as people transfer pollutants to their offspring through breast milk. Last year we analysed two-month-old flamingo chicks from the Ebro Delta, and detected an incredible pollution load, especially from perfluorinated compounds, which are known as the forever chemicals.

Can the pollution suffered by these birds be extrapolated to humans?

No, because we do not have a similar diet, and our diet is varied. We have also analysed the eggs of Audouin’s gulls, which only eat fish, and curiously we have found that the load of pollutants is even higher than those that eat from the landfill.

And how does pollution affect people?

Through the air we breathe and through our diet. We are affected by as many chemical compounds as there are in our environment. Recently, apart from organic pollutants, we are looking at microplastics, which are dispersed in water, in the air and also in food, especially processed food. For those of us who breathe, we have an expulsion mechanism, such as sneezing, which helps us to eliminate larger particles, but it has been shown that smaller particles can end up entering the respiratory system: microplastics have been detected in the lungs in biopsies of patients with respiratory conditions. This is similar to what happens with asbestos. Articles have also been published that detect microplastics in blood, breast milk and placenta, which come from the diet, and mention that nanoplastics can have harmful effects. However, there is still much research to be done to assess the risk of microplastics in humans. Unlike organic pollutants, microplastics are visible to the naked eye, which has had a very high media and social impact. What is needed is to find out where this pollution comes from, what are the routes of exposure of both animals and humans, and the mechanisms of toxicity. We are also working on this.

Of the hundreds of compounds that exist in the environment and that we detect on a recurrent basis, none is legislated.

How can we reduce all this pollution?

There are two types of pollution. One is diffuse, which you don’t know where it comes from, it is distributed everywhere and is very difficult to locate and treat. And there is another type, which is point source pollution, where you can identify the sources and take action to reduce its impact. For example, spillages, effluents from wastewater treatment plants, irrigation drainage, etc. If measures are not taken now to reduce, or eliminate if possible, the load of pollutants in the environment, there may come a time when it will be impossible, then it will affect the viability of aquatic and terrestrial species, and we will have a resource that we will not be able to use.

And how can all this research be translated into actions to mitigate pollution?

It is not always possible. While from an environmental point of view we are able to identify the sources of pollution and determine what pollutants exist and the effects they produce, when it comes down to it, we face a major barrier. Many of the pollutants we analyse are not legislated, they are compounds that are not yet regulated or identified as toxic. And this prevents us from carrying out any action to control them and establish containment measures.

So your hobby horse would be to have these materials recognised as toxic and banned, right? Is there a real chance that this could happen?

That would be ideal. I am very critical of the legislation. European legislation does not foresee many of the problems that exist at the local level and therefore, from a legislative point of view, no action can be taken. In other words, nothing can be done.

And why is it precisely legislation that is an impediment?

Of the hundreds of compounds that exist in the environment and that we detect on a recurring basis, not a single one is legislated. There are currently 45 pollutants legislated by the Water Framework Directive and the Watch List, for which the countries must carry out monitoring studies and submit the corresponding results to Europe, which are used to assess the status of European water bodies. Some of these legislated compounds, which have been banned for 20 years, are still detected, but they are not the biggest problem. On the other hand, there are many everyday substances, such as pharmaceuticals, which pollute water, but because they are not regulated, there is no need to take action to improve them. In short, water quality control programmes are based on legislation that does not take into account the real problem of environmental pollution.

Has it become obsolete?

It is somewhat dangerous to say that it is obsolete, but it is true that it does not take into account a large number of compounds related to agriculture or of industrial origin from the textile, heavy industry, automobile or pharmaceutical industries, etc. Nor does it take into account urban pollution, which is generated in large cities and is having an increasing impact on health and the surrounding ecosystems. Although wastewater treatment plants eliminate a large part of the pollutants (some accumulate in the sludge), a part, perhaps 10-20%, is continuously discharged into the environment, generating the urban pollution that can be seen in river basins. Although not a pollutant as such, caffeine is a marker of urban pollution, and is very frequently found in river and groundwater.

Last week, Barcelona City Council made an emergency €14.4 million bid to improve the groundwater network. How does this groundwater become contaminated?

In urban areas, groundwater contamination occurs either through leaching of pollutants retained in the soil or when sewage pipes break or leak. In agricultural areas, pesticides are transported through the soil and also contaminate groundwater. Sometimes there are episodes of gasoline contamination, and this occurs when fuel tanks are ruptured. When an aquifer is contaminated, it is very difficult to remove this contamination, as the conditions of the aquifers (no sun and generally cold temperatures) make the chemical compounds become stable.

Have you analysed any cases recently?

Yes, for example, the groundwater in the Besòs, which we are currently analysing.

Groundwater or surface water?

Both.

What do you find?

We detect an incredible cocktail of chemical substances, from morning coffee to the medicines consumed by the population, a range of drugs, plasticisers and perfluorinated compounds derived from the use of Teflon.

Drugs taken by the population that have been expelled through urine and have reached the river through sewage because the sewage treatment plant could not eliminate them. And they end up in the sea?

Drugs that are taken by the population, reach the river through the sewage and are finally discharged into the sea. The high dilution capacity of the sea is well known; for many years the sea has been the dumping ground of the Mediterranean. But the current situation is very complex. With the increase in population and tourism in coastal areas, the pollution of the sea is significant. In fact, pollutants are also detected at the North Pole and in Antarctica. As has been said, we are talking about global pollution. In protected coastal areas we have detected many chemical compounds related to urbanisation and tourism; therefore, the anthropogenic impact is high despite the fact that they are important ecosystems for biodiversity.

Do you mean that even though they are protected areas, they are polluted?

Important biodiversity areas exist on land and at sea, and have different degrees of protection. Some are national parks, others are nature parks, important biodiversity areas or Special Protection Areas for Birds (SPAs). When an environmental pollution control study is carried out, it should not be a one-off study, but should be done over the long term to see how it evolves. In the study of gulls, which, as I said, we have been doing for 15 years, we observed a pollution peak in these birds when sediments were extracted from the river Ebro in Flix; the data allow us to evaluate both activities that pollute and activities to improve.

You provide the administrations with indicators so that they can activate policies to reverse pollution, but from what you tell me, your main challenge is to have substances that are not yet regulated recognised as toxic.

Yes, but we must bear in mind that the European Union regulates European problems, problems that affect all member states. On the other hand, there are problems that are specific to each area and that must be controlled by each country. In other words, if it does not rain in Catalonia and the flow of the river is so low, and it is affected by the dumping of treated wastewater, the problem is ours, not that of the French or Germans or Belgians. The Catalan Water Agency does a lot of work, but one thing is to monitor, and another is to find a solution, and that is more difficult, although we have the technology to do it.

What technologies exist?

With ozone we can eliminate many pollutants and pathogens from treated water before it is discharged into the river. This is the most common technology, but it is very expensive and is not widely used in our country, except in the case of reclaimed water that is treated with ozone to make it drinkable again. This procedure is not considered for discharges into watercourses because it is too expensive. The question is whether it is not more expensive in the long run to have a polluted river, a river in which there are no more fish larvae, insects or amphibians because of such high levels of pollutants. I insist, these are our specific problems and perhaps we are the ones who must act.

A law is not enough; it is also a question of attitude and of wanting to solve the country’s own environmental pollution problems.

And does the Catalan government have the power to regulate all this?

I believe it does, but a law is not enough, it is also a question of attitude and of wanting to solve the country’s own environmental pollution problems. I think it is important to preserve the environment as much as possible, to guarantee the health of people, ecosystems and wildlife. In fact, last year Europe published the European strategy to restore biodiversity with a series of actions between now and 2030. Chemical pollution is a factor in biodiversity loss, and in Europe 69% of individuals have been lost. With these data, it is clear that no measures have been taken to preserve the environment and species, and that it is necessary to define measures and controls beyond legislation. In fact, it would be to act at the local level.

And how are we going to do this?

Many strategies related to fire prevention, combating climate change, sustainable energy transition and ecological agriculture have been planned, but pollution is not directly addressed. However, it has already been pointed out that pollutants have harmful effects on living beings and are therefore a factor to be considered in order to preserve the environment.

Why do you think it is invisible or of no interest?

Controlling environmental pollution is too expensive.

It seems like a lost battle. And while drought increases, the percentage of toxic compounds in the water rises because there is not enough water to dilute them… the situation is dramatic.

In the field of research, many studies are carried out that combine different disciplines, such as analytical and environmental chemistry, hydrology, biology and engineering, which allows for an exhaustive evaluation of the state of water and aquatic ecosystems, and to propose new treatments or measures for their correct management and control. It is true that interaction between academia, administration and business is sometimes difficult; the search is always pioneering. I am in favour of working together in these three areas, because it is much easier to find solutions and propose models of action adapted to the country’s current drought situation. There is always the excuse of resources, but it is not always the main problem, often the will to remedy the problems is necessary.