Environmental Toxicology

    Pharmaceuticals in the environment

Only recently the presence of pharmaceuticals in the environment became a growing concern.  Drugs are being excreted by humans or improperly disposed in toilets and after passing the waste water treatment plant (were they are not fully degraded) end up in the aquatic environment. Also veterinary drugs excreted by animals, used in fish farms or in manure applied on fields find their way to surface waters. Those biologically active chemicals can then have acute effects on aquatic organisms (fish, algae, bacteria…). But maybe acute toxicity is not the biggest concern we are facing. Continuously low inflow (ng/L) of pharmaceuticals in surface water could cause subtle changes in organisms which are difficult to detect, but these effects can become clear over long periods of time.

As the calculated ‘predicted environmental concentrations’ (PEC-values) of many pharmaceuticals are very low, demands on analytical equipment are extremely high. The group of drugs we focused on has PEC-values between 26 and 230 ng/L. In these PEC-values metabolisation nor degradation in waste water treatment plants, by oxidation or sunlight have been calculated, so values could be much lower then expected. The drugs of interest are flubendazole (anti-worming agent), miconazole, itraconazole, ketoconazole (anti-mycotic agents), propiconazole (pesticide), pipamperone (antipsychotic), rabeprazole (anti-ulcer agent), domperidone (anti-emetic), cinnarizine (antihistamine).

The aim of the study is to develop a qualitative and quantitative LC-MS method to analyze and monitore these pharmaceuticals in wastewater and surface waters.

(by Jet Van De Steene)

Former research:

Endocrine disrupting chemicals

Over the last few years the continuous exposure of man and wildlife to endocrine disrupting chemicals (EDCs) in the environment has drawn considerable attention. Several international studies were devoted to this topic, with a particular interest in estrogenic compounds. Research has revealed that chronic exposure to estrogenic compounds may cause hormone related cancers, developmental abnormalities and a decreased sperm quality. Of the various groups of substances with reported estrogenic activity, the female sex hormones and the synthetic steroids are considered as the most potent estrogen receptor modulators and, therefore, may cause detrimental effects on organisms even at very low concentrations. Other renowned estrogens include PCBs, phtalates, dioxins, and a variety of pesticides. Laboratory studies have shown that concentrations as low as 5 mg/L of such compounds can result in total sex reversal from male to female in Japanese medaka. The estrogens found in the environment are mainly derived from the excreta of humans and livestock, medicines, and from spills of production units. Reported studies show that municipal wastewaters already contain concentrations of estrogenic compounds that form a serious threat to the aquatic biotope.

In addition to environmental screening methods such as immunoassays, an extensive amount of research is currently performed to develop new and improved confirmatory methods. To this end liquid chromatography coupled to mass spectrometry offers great potential. Liquid chromatography has the advantage that a fairly simple sample preparation is sufficient. In addition, no derivatization is needed and water-based samples can be easily handled. Mass spectrometry, on the other hand, is known for its specificity and sensitivity.

The aim of this study was to develop an analytical method on LC-MS to analyze several groups of estrogens, known to be present in the aquatic environment.The method will be applied in a study, screening environmental waters in Flanders for endocrine disrupting chemicals.

Scientific output on this subject: Publications> articles - poster - oral presentation 

(By Tom Benijts)