In Focus Czech scientists searching for ways to remove toxins from drinking water
Detergents, painkillers and contraceptives are things we use daily. What most of us don’t realize is that all of them contribute to the presence of toxins in our rivers and even drinking water. A special research team at Brno’s Masaryk University is now working to ascertain what toxins pass through water treatment plants and how they could be more effectively eliminated. I spoke to the head of the team prof. Luděk Bláha about the problems involved.
“There are many different sources of chemicals or toxic chemicals entering rivers and the majority of them –at least in our country – are passing through waste water treatment plants. They include chemicals from feces, ie. organic material, but also chemicals that we don’t even realize that we release such as pharmaceuticals, chemicals that we use in our homes and that we think were tested for toxicity, which is often not the case. So many chemicals coming from our homes enter wastewater pipelines, pass through wastewater treatment plants where they are not properly eliminated because wastewater treatment plants were not originally designed to treat these specific types of chemicals, and end up in our rivers.”
So what kind of chemicals are actually passing through?
“We have found organic chemicals, or polar chemicals such as pesticides for example, many different pesticides which we do not even realize that we use. For instance triclosan which is a common ingredient in soaps and also non-pharmaceuticals that we use at home such as paracetamol or ibuprofen, analgesics that are used worldwide on a daily basis in many households and also antibiotics and other pharmaceuticals that we take as pills. They are transformed in the body and released in urine, again entering our waterways. So there are plenty of these chemicals and we are only starting to discover their nature, what they look like and how high their levels are. “
Why are wastewater treatment plants unable to deal with them – or deal with them effectively?
“The problem is that wastewater treatment plants were originally designed to remove basically non-toxic materials, such as organic materials released from urine and feces, materials that are easily bio-degradable by the technologies used in waste water treatment plants. However with the increasing use of chemicals around us there are more and more less bio-degradable chemicals in the water that pass through because the microorganisms that work in wastewater treatment plants do not have the capacity to remove them. They are not prepared for chemicals that were designed to be non-bio-degradable, they were designed to stay in their original form for a long time because it improves their properties, they may serve for a longer time in the body. So there are many problems involved and it is only the new technologies that are being introduced now that target this problem and try to clean the water more properly.”
Are you saying that these toxic substances pass through the cleaning process completely undetected or do some of them get eliminated and others not?
“Yes, the latter is true. They do not pass 100 percent. We have to realize that it is a complex cocktail of chemicals –some of them may pass very easily such as sulphonamite antibiotics and others which are not biodegradable to a large extent. Ten to fifteen percent can be removed but a large percent of them pass through. The majority of compounds are either bio-degraded or they are absorbed in the wastewater treatment plant because there are a lot of micro-organisms and materials that absorb the chemicals and they are removed in this way. The wastewater treatment plants and their technologies work very well, but unfortunately not for all chemicals and we know that some of them end up in our rivers and that they are toxic and potentially harmful to the environment.”
“It is not only possible, but we know this to be the case. We conducted some studies on ground water specifically targeting some of these chemicals and we were able to detect pesticides and the most commonly used insecticidal repellent in Europe which we found in a large fraction of ground water samples collected all around Europe. We also found other chemicals in ground water including pharmaceuticals that got there via the way we described – wastewater treatment plant, river and then soaking underground and entering drinking water.”
What effects do these toxic substances, or traces of toxic substances, have on human health and the environment in general?
“Well, relating to human health we do not know too much. There are now debates about endocrine disruption which means disruption of the normal hormonal regulation process in our bodies and many of these chemicals that we release and that come back to us can affect our regulatory pathways adversely affecting our reproduction, immune system and so on…but scientists are at the beginning of this search, of really linking these chemicals to our health. As regards environmental problems –or eco-toxicology – it is much better researched, because fish were found, unfortunately, to be very sensitive to the human estrogens used in contraception pills. They are much more sensitive to them than humans and they stop reproducing in waters that contain these estrogens. We know the estrogens are there and there are cases Europe-wide and I dare to say world-wide documenting that fish populations are declining also in relationship to these chemicals. And there are many more examples not only of fish but also invertebrates such as crayfish and snails in our waters and so on. So the problem is really widespread.”
“We are using two approaches, two methods. One of them involves active carbon, which is a fairly old method which is not usually applied at waste water treatment plants, it is generally applied at drinking water treatment plants to really clean the water before it reaches your tap. But it is a fairly expensive method to be applied at wastewater treatment plants. The other method involves nano-technologies, various types of nano-materials iron, nano-iron, nano-titanium and others that are being tested at the outlets of wastewater treatment plants to really clean the water from these micro-pollutants that occur in very low concentrations, but even at these concentrations they are toxic. So basically these two methods are being tested and we are involved in an assessment of their safety and their efficiency in removing the toxins.”
How far has the research come and when can we expect to see the results in practice?
“Laboratory tests have been conducted for several years already and now we cooperate with our partners in Germany where they have bigger capacities and more money to implement the results in their wastewater treatment plants. Six wastewater treatment plants are currently involved in these tests. It is only a screening program at this moment, but we believe that the owners of these wastewater treatment plants and eventually regulators will change their mind and these types of treatment technologies will be required in the near future in some of the –speaking frankly –richer regions of Europe such as Germany or we also cooperate with Switzerland….there it could be a question of one to two years. But for the Czech Republic and others which do not have such resources it may take longer – my guess is ten years potentially.” `