The water chemistry laboratory

Topics and organization of the Water Chemistry Laboratory

Research and developments at the Water Chemistry Laboratory focus on passive sampling and analysis of artificial contaminants in various environmental matrices.
These developments support work and studies that aim to improve the characterization of the dynamics, division and bioavailability for the following contaminants in surface freshwater as well as sediments and biological matrices (macrophytes, biofilms, invertebrates):

  • macropollutants (suspended matter, organic matter and nutrients such as nitrogen and phosphorous)
  • organic micropollutants, particularly organic chemical pesticides and algal toxins (cyanotoxins).

The laboratory also performs bioorganic analyses in order to carry out ELISA tests, enzymatic activity dosing and to define chlorophyll pigment composition in conjunction with the effects and impacts of contaminants on aquatic organisms.

Specialization: Passive Sampling of pesticides in aquatic environments

Point sampling is currently the standard method used by aquatic environment monitoring networks. If this approach is carried out on a less frequent basis (monthly water samples, for example), it presents major defects in temporal representation. This is because point sampling is an instantaneous measurement that does not take into account actual variations in contaminant concentrations over time and can lead to an overestimation of risk.

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Although the most obvious solution would seem to be to increase the sampling rate, this quickly leads to a significant jump in analytical costs, which then become incompatible with large-scale monitoring of water quality.
An alternative approach has emerged over the past fifteen years that involves installing a device on site to capture contaminants continuously. This sampling technique, known as passive sampling, is currently the best compromise, as it results in integrated measurements of pollutants over time (average concentrations) yet has acceptable costs and logistics. Since 2005, work at the Water Chemistry Laboratory has focused on developing Polar Organic Chemical Integrative Samplers (POCIS).

These devices have proved to be suitable for continuous monitoring of pesticide contamination in various rivers (Charente, Leyre, Gave de Pau, Morcille-Ardières). Validation work, in the form of interlaboratory testing, is currently underway as part of the Aquaref project. In addition, we wait to know more about the future prospects of using POCIS in improving estimates of exposure in aquatic organisms and the impact of pesticides on river biofilms in particular.

Passive Sampling System

Water Chemistry Laboratory equipment

Incubators and balances

  • Incubators (Memmert) and muffle furnace (Nabertherm)
  • MS 204S (Mettler) precision balance
  • PB 1501 (Mettler) balance

Sample preparation

  • Ventilator
  • Lab table
  • Digestion apparatus (total phosphorus dosage)
  • ST16 (Thermo) Centrifuge
  • Large volume centrifuge (JOUAN)
  • MQ Neptune wastewater treatment plant (France Eau)
  • AS200 (Retsch) sieve shaker
  • B-324 (Buchik) automatic distillation unit for Kjeldahl nitrogen
  • Alpha 1/2-4 (CHRIST) freeze dryer
  • SpeedVac SPD121P (Thermo) multistation evaporator
  • ASE 200 (Dionex) high pressure solid and liquid extraction system for sediment, sludge and biological matrices

Physical and chemical analyses, organic carbon and nutrient dosage

  • EasyPlus (Mettler Toledo) TAC and pH titrator
  • TOC analyser 1010 (Bioritech) equipped with persulfate oxidation
  • UV-visible 1800 (Shimadzu) spectrophotometer
  • Compact 881 (Metrohm) ion chromatorgraphy system with 858 sample processor/automated diluter and conductometric detector

Bioorganic analyses

  • Multiskan (Thermofisher) and Synergy HT (Bioteck) microplate readers

Organic pesticide dosage

  • TSQ Quantum GC (Thermo) gas chromatograph coupled with tandem mass spectrometer
  • UltiMate 3000 (Thermo) high-performance liquid chromatograph coupled with API 2000 (AB Sciex) tandem mass spectrometer
  • ACQUITY H-Class (Waters) ultra performance liquid chromatograph coupled with Xevo G2 ToF (Waters) time-of-flight mass spectrometer

 

Health and safety and miscellaneous equipment

  • CAPTAIR storage cabinet for acids, bases and active carbon solvents
  • Showers and eye wash
  • Safety refrigerator for storing chemical products and samples
  • Safety freezers for storing chemical products and samples
  • Demineralized water (resin cartridge purification), several arrival points in the different rooms
  • Membrane nitrogen generator (F-DGSi)
  • Class 0 air compressor (Atlas Copco)
  • External area for gas bottles: Nitrogen, Argon and Helium 6.0
  • External storage area for solvents, acids and bases
  • External storage area for waste prior to recycling