Environmental impact of emerging pollutants

ROSAL (Universidad Autónoma de Madrid): What is the impact of pollutants from pharmaceuticals in waste water and drinking water?

Their paper, published in Environmental Science and Pollution Research , describes the use of three aquatic organisms in evaluating the acute toxicity of four compounds of the fibrate family found in drinking water and waste water.

Fibrates are compound derivatives of fibric acid used for controlling cholesterol; they are widely used in human medicine in developed countries. These compounds form part of the group of ‘emerging pollutants’, which includes medicines, cosmetic products and nanomaterials.

The high population density in large cities and the high consumption level of these compounds mean that these pollutants reach natural water via urban waste water treatment plants. As a result, these compounds have been detected for several years now in the effluents of water treatment plants, continental, marine and subterranean waters, and even in water used for human consumption.

These pollutants have become of great interest to the scientific community in recent years, as their applications and pharmacologic mechanisms are well known but their possible effect on the environment and ecosystems have not been well researched.

Our work analysed the toxicity of various fibrates (fenofibric acid, clofibric acid, gemfibrozil and bezafibrate) using three aquatic organisms. Two organisms were used in standard analysis methods: the marine bacterium Vibrio fischeri and the water flea Daphnia magna . A novel toxicity test was developed by the UAM research group and used with the third organism, a recombinant bioluminescent freshwater cyanobacterium called Anabaena CPB4337 . Cyanobacteria are of great relevance to ecology, as they are primary producers, with a key role in the carbon and nitrogen cycles of aquatic environments.

The study shows that all the compounds analysed were toxic to the three organisms. An interesting point was that based on the results of the standard commercial tests, only one of the drugs (fenofibric acid) would be classified as ‘dangerous for aquatic organisms’ and that the waste water would meet dumping requirements, as it would not be toxic. However, the introduction of cyanobacteria for toxicity testing means that gemfibrozil and bezafibrate can also be considered ‘dangerous for aquatic organism’ and that the waste water can be classified as ‘highly toxic’.

The results obtained support the need to develop new and more sensitive toxicity tests using ecologically relevant species to detect the possible negative effects of environmental pollutants, which may be underestimated using conventional bioassays.

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