| ||N° 40 - February 2004|
| MEDICINES AND THE ENVIRONMENT - Taking the pollution out of health care
'The attention paid to date by governments and scientists to the impact of pharmaceutical products on the environment can be described as weak or negligible.' That is the verdict of Professor Roberto Andreozzi (University of Naples 'Federico II'), chemist, expert on oxidation, and coordinator of one of the three European research projects in the Pharma Cluster. The aim of this research is to make a detailed study of the toxicity of the principal persistent molecules found in waste of medicinal – or para-medicinal – origin, and to propose effective treatment solutions.
Antibiotics: cautious optimism
Launched in 2000(1), the three research projects included in the Pharma Cluster are looking at the three main facets of the problem of waste of medicinal origin(2). The Eravmis project is concentrating on the impact of veterinary antibiotics. 'With production running at over 5 000 tonnes a year in Europe, these are by far the most widely used molecules,' explains project coordinator Alistair Boxall of the Cranfield Centre for Eco Chemistry (UK). The research has focused on three major antibiotics, members of the tetracycline, macrolide and sulphonamide families. ‘Along with our Dutch, Danish and Spanish partners, we had already acquired expertise in studying and detecting these substances, but this European co-operation has made it possible to draw on a pool of skills not possible at national level,' stresses the project coordinator.
Eravmis tested the migration of these three classes of antibiotics into soils and groundwater, as well as their life expectancy in these environments. Researchers studied what happens to their metabolites and their impact on various families of living organisms – bacteria, of course, but also algae, aquatic plants, worms, freshwater invertebrates and fish cell lines. So, what did they find? Apart from aquatic plants, which proved sensitive to sulphonamides (whose structure is similar to certain pesticides), it is only bacteria that react to the concentrations generally found in the environment. As these products are, in fact, designed mainly to combat bacteria, this is hardly surprising.
For other living organisms, the first effects are only found at concentrations above 1 mg/kg. Even the most contaminated sites studied scarcely reached half this concentration.
Although a reassuring result, a word of caution must be sounded. 'Much remains to be done,' reports Boxall. 'Our studies were over short periods – three weeks at the most – and we know that some of these molecules remain in the environment for months. And as farm animals are treated regularly with antibiotics, some environments are subject to continuous exposure, the effects of which require further investigation.'
'In the effluent analysed we recorded the presence of 26 pharmaceutical agents belonging to six therapeutic classes: antibiotics, beta blockers, antiseptics, anti-inflammatories and lipid regulators,' explains project coordinator Roberto Andreozzi of the University of Naples ‘Federico II’. The researchers then scrutinised the behaviour of six of the most common such products: carbamazepine, clofibric acid, diclofenac, sulfamethoxazole, ofloxacin, and propanolol(3).
Having established their half-life (the time required for half their molecules to break down naturally) in the laboratory they found themselves facing some very worrying results: for the first two compounds, this half-life was 1 712 and 600 days respectively – or almost five years in the case of carbamazepine. 'Although tests carried out on algae, fish and invertebrates showed that these products generally only produce an effect at concentrations higher than those found in the environment, it must be stressed that such tests, especially those using algae, are not able to reproduce the real conditions of their potential activity. Additional research and evaluations are therefore needed to define the risks posed by these molecules, as well as by other similar products.'
There is one note of optimism, however. The researchers also made an evaluation of how this pharmaceutical residue behaved when exposed to the latest treatment, in particular exposure to powerful oxidants such as ozone or hydrogen peroxide. To do so, they concocted a concentrated cocktail of their six molecules, subjected it to oxidation, then administered it to the alga S. Leopolensis, known to be particularly sensitive to pollutants. The alga showed no adverse affects, indicating that such treatment effectively combats toxicity.
Kind to body and environment
Poseidon(4), the third project in the cluster, concentrated on studying the different water treatment technologies currently available. This involved scrutinising the results achieved in the case of pollution by both medicines and by pharmaceutical and personal care products – PPCPs for short. The latter – with over 8 000 preparations currently available over the counter at shops across Europe – represent a huge volume, with 140 000 tonnes of shampoo products alone entering the water cycle every year in Germany.
Thomas Ternes of the Bundesanstalt für Gewaesserkunde (BFG – Koblenz, DE), the project coordinator, explains that 'we have identified many possible avenues for improvement. In some cases, we can collect and treat urine separately, considerably reducing contamination at the treatment plant outlet. Also, simply increasing the retention time, by using modern waste-water treatments, makes it possible to effectively eliminate all the hormones. Finally, if ozonation is added to these methods, all pharmaceutical products are rendered biologically inactive, at least as far as we can detect at present.'
As regards drinking water, Poseidon has served to establish that we have the technology (active carbon filtration, nanofiltration, oxidation) to eliminate all the products studied – although at a price, of course. Researchers recommend creating an ecological label as an incentive to industrialists to make available products which are kindest to the ecosystem.
(1) The key action Sustainable management and quality of water under the Fifth Framework Programme.
(2) The results of these studies will form the basis for regulations under the Reach legislative initiative. Proposed by the Commission, this aims to regulate the impact of chemical products on the environment (see In brief [ news_en.html ]).
(3) The principal prescriptions for these products are as follows: carbamazepine: epilepsy; clofibric acid: anticholesterol; diclofenac: anti-inflammatory; sulfamethoxazole: antibiotic; ofloxacin: urogenital infections; and propanolol: Parkinson's disease.
(4) Poseidon brought together eight partners, in Germany (2), Switzerland, Austria, Finland, France, Spain and Poland.