He developed the methodology, prepared for the relevant circumstances and applied it to Gipuzkoa. He defended the thesis at the UPV / EHU, under the title Phase garapena solidoko hidrokarburo mikroerauzketan Aromatik oinarritutako poliziklikoen method determinaziorako. Eta Aplikazioa ingurumen ebaluazioa laginetan (SPMEs Development for the determination of PAHs. Implementation and evaluation in environmental samples).

Zuazagoitia has published several papers with its investigation. The latest is the magazine Soil & Sediment Contamination, entitled Evaluation of soil contamination by polycyclic aromatic hydrocarbons in Guipuzcoa (Northern Spain).

Without touching the sample extraction

The HS-SPME procedure for the analysis of samples is a screening method, these tests provide a rapid response (positive / negative) without wasting tools, time or solvents. In this particular procedure, a needle is inserted through the lid of the sample. The needle contains a fiber to be drawn once introduced, so that through the headspace absorb the analyte. This space is found between the sample and the lid, and then only can get information in the case of volatile compounds such as PAHs. The procedure for extraction from the headspace allowed to keep the fiber in good condition. Entering it directly in the sample will be damaged due to large molecules, but by HS-SPME, interference is avoided non-volatile and large molecules.

After extraction to proceed to desertion, to release the gases absorbed by the fiber and thus dividing the substance. Zuazagoitia opted for gas chromatography, with which components can be separated with a remarkable volatility at temperatures below 350-400 degrees. The following components have been quantified by flame ionization detector (FID).

Optimization of three procedures

Zuazagoitia in his thesis has developed methods based on the HS-SPME, determined simultaneously different molecular weight PAHs of small to medium, given the diverse conditions that these methods must meet depending on the matrix analysis (water, soil, sediments …). Also, due to the many variables that influence the process, it has opted for the experimental design to optimize the response of the method. Using the Statistica ® program is not necessary to test each variable to see variations in advance.

Zuazagoitia said that indeed there with fast, simple and workable tools of any analytical laboratory. Other features of these methods aim to involve a rapid response (positive / negative) and be respectful of the environment, they do not use organic solvents. The three optimized procedures in the thesis (water, soil and sediment) comply.

In San Sebastian and Pasajes Bergara

The researcher is also responsible for putting into practice methods to study water pollution, soil and sediments in Gipuzkoa. According to the samples analyzed, concentrations of PAHs in the seas and rivers of the territory are not relevant. However, it is a high level of contamination in leachate, which means that there is a large concentration of PAHs in the lands of those from these waters. The soil samples Zuazagoitia detected high levels of pollution in two areas of San Sebastian in Morlans, where stood the old gasworks in Amara, and Oriamendi in a lumberyard treated with creosote, a toxic substance . As regards sediment, PAHs are found in all locations studied, and especially in Bergara (Deba River) and Pasajes (river Oiartzun).

Source: UPV / EHU