A revised procedure to concentrate organic micro-pollutants in water

The test substances include hydrophobic chemicals with a (polar) narcotic mode of action, pesticides, surfactants and organotin compounds. The recovery for the narcotic cocktail, including a.o. volatile and strongly adsorbing compounds, improved remarkebly: from 18 % to 60 %. The recovery of pesticides remained at the same level as the former procedure, i.e. 70 %. For the first time, surfactants and organotin compounds were included in the test programme.

The recovery of the anionic LAS and the nonionic octaethylene glycol monotetradecyl ether, which represent the majority of the surfactants used in the industrialized world was 40 % and 80 %, respectively. The recovery of organotin compounds was zero, which confirms that the method is not suitable for metals. It is essential that the result of the chemical part of the whole procedure suits the toxicity measurements because they constitute the actual measurement of the environmental sample. It was demonstrated that the concentrated water samples are compatible to bioassays. The ease of conductance is another demand that is put on the procedure. With respect to the former the method has improved considerably (less time consuming, lower use rate of expensive materials) and is therefore more suitable for monitoring toxic risk in surface water.