Pharmaceutical compounds in water - Occurrence, risks, and available treatments

Protecting surface water as a source of drinking water has become an important issue for society. The complete water cycle is an essential part of long-term water resource management, requiring the protection of surface water from persistent pollutants, which are difficult to remove and/or toxic.

Recently, increasing attention has been paid to the presence of micropollutants in the aquatic environment and in wastewater treatment plants. Micropollutants are pollutants that can have a toxic effect on the environment, even at very low concentrations. They are often present in the aquatic environment at very low concentrations (μg/L or even ng/L) compared to other pollutants (mg/L).

Of particular interest are pharmaceutical compounds. Their presence in effluent from wastewater treatment plants has been widely reported. The specific nature of these compounds, marketed after a rigorous selection process that selects only the most biologically active molecules, calls for particular attention. The scale of the problem is all the more significant given that, in Europe, thousands of tonnes of human medicines, as well as veterinary drugs, are excreted each year in unchanged form or as active metabolites.

Most biological wastewater treatments are unable to effectively eliminate these pharmacologically active products. What's more, the fact that these molecules are continuously discharged into aquatic environments gives them an apparent persistence. Added to this is the fact that elimination of these trace compounds, particularly during potabilization treatment, remains difficult and costly.

In the first part, the article reviews the current state of knowledge on the presence of drugs in wastewater and wastewater treatment plants. The second part reports on the state of knowledge concerning the assessment of toxicity due to the presence of these molecules in the environment, although considerable progress remains to be made, particularly in understanding and preventing synergistic effects between pollutants. The final section looks at the effectiveness of various treatment processes. All these results and data are based on laboratory research as well as on field work, with all its relevance and uncertainty.