Novel monitoring concepts to acquire new water quality knowledge

Two novel water quality monitoring concepts were developed: the HPLC-fingerprint for the monitoring of yet unidentified pollutants and the HPLC-Toxprint for the recognition of (unknown) toxic or genotoxic compounds. The paper describes applications of both concepts. The HPLC-fingerprint is used for the evaluation of the overall water quality in addition to the monitoring of individual pollutants. Based on their occurrence (frequency, concentration, location) a listing of unknown priority pollutants is set up. Participating waterworks monitor for these compounds using a dedicated HPLC-DAD library that contains the required compound data (UV-absorbance spectrum, retention time index). In five years of experience with this concept, the HPLC-fingerprint was also found very suitable for the retrieval of new priority pollutants in existing HPLC-fingerprint databases, providing historic data on these new compounds. The HPLC-fingerprint concept was also used as an Early Warning System for accidental spills or sabotage. The HPLC-Toxprint was successfully applied in identifying genotoxicity (in the umu-test) in various waste water samples. By the application of LC-MS/MS genotoxicity could be assigned to acridine-derivatives in one of these wastewaters. To enable the evaluation of drinking water resources, the sensitivity of the HPLC-Toxprint was improved, now allowing the detection of pollutants with a 10% genotoxic potential as compared to 2-aminoanthracene (the positive control compound) at concentrations as low as 0.1 microg/l.

Surface and wastewater quality monitoring: combination of liquid chromatography with (geno)toxicity detection, diode array detection and tandem mass spectrometry for identification of pollutants

Identification of unknown water pollutants with liquid chromatography and tandem mass spectrometry (LC-MS-MS) is often more complex and time consuming than identification with gas chromatography and mass spectrometry (GC-MS). In order to focus the identification effort on relevant compounds, unknown peaks need to be selected carefully. Based on its frequency of occurrence in the LC-Diode Array Detection (LC-DAD) chromatograms of surface and infiltrated waters, an unknown peak was selected for identification with LC-MS-MS. This compound was identified as hexamethoxymethylmelamine (HMMM), a chemical often used in the coating industry. This is the first time the presence of this chemical in surface waters has been reported. In addition to HMMM, two other structurally related compounds were found to be present in the investigated surface water. A standard mixture of HMMM and its by-products did not exhibit (geno)toxicity under the test conditions applied in this study. In another example, a genotoxic fraction of an industrial wastewater was isolated and examined by LC-MS-MS using a modern quadrupole-orthogonal acceleration-time-of-flight mass spectrometer (Q-TOF). Four compounds were detected. The structures of two compounds present are proposed to be 9-amino-2-hydroxy-acridine and 9-hydroxy-acridine-N-oxide or its structural isomer dihydroxy-acridine. Confirmation with standards could not be carried out, as pure compounds are not available. The other two compounds (structural isomers) could not be identified based on the data available within this study.