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Técnicas avançadas para quantificação de pesticidas em solo – Aplicação em remediação eletrocinética
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O atual estado de degradação dos solos europeus desencadeou a proposta de criação da re-
centemente aprovada Lei de Monitorização dos Solos, que exige a criação de um quadro uni-
forme de monitorização de solos na União Europeia. A harmonização da monitorização requer
a adoção de uma metodologia de extração comum e de fácil aplicação, que combine sensibili-
dade, baixo custo e sustentabilidade. A presente dissertação foca-se na comparação de dois
métodos de extração – QuEChERS e DI-SPME Tips - e na sua aplicação na remediação eletro-
cinética de solos contaminados com pesticidas. Foram selecionados para a análise doze pesti-
cidas (buprofezina, clorpirifós, diflufenicão, epoxiconazole, metalaxil, metazacloro, metola-
cloro, penconazole, prosulfocarb, tebuconazole, tetraconazole, terbutilazina) considerados re-
levantes por serem frequentemente detetados nos solos europeus.
Os métodos de extração foram comparados com base em parâmetros metrológicos, custo e
tempo por amostra e impacto ambiental. Apesar da fraca repetibilidade, o método DI-SPME
Tips revelou-se uma alternativa económica, sensível e sustentável, com pontuações de 0,63 e
89 nas métricas AGREE e Analytical Eco-Scale, respetivamente. O método QuEChERS provou,
no entanto, ser uma alternativa mais fiável para aplicação em programas de monitorização de
larga escala.
A experiência eletrocinética foi realizada em solo franco arenoso dopado com os pesticidas em
estudo, durante sete dias, com aplicação de corrente de 10 mA em diferentes regimes (cons-
tante e periódico). Após a experiência, as amostras de solo foram analisadas através do método
DI-SPME Tips. O tratamento revelou-se eficaz na remedição do solo estudado, com destaque
para o tratamento com aplicação de corrente constante, em que a remediação atingiu valores
entre os 26% e os 80%. No entanto, as elevadas variações de pH registadas nesta experiência -
com valores de pH até 2,61 no ânodo e 12,17 no cátodo - e a acumulação de resíduos de
pesticidas junto aos elétrodos, são fatores a ter em conta ao considerar a aplicação deste mé-
todo na remediação in situ de solos franco arenosos.
The current degradation of European soils led to the proposal of the recently approved Soil Monitoring Law, which requires the establishment of a uniform soil monitoring framework across the European Union. Harmonized monitoring demands the adoption of a common and easily applicable extraction method that combines sensitivity, low cost, and sustainabil- ity. This dissertation focuses on comparing two extraction methods – QuEChERS and DI- SPME Tips – and their application in the electrokinetic remediation of pesticides. Twelve pesticides (buprofezin, chlorpyrifos, diflufenican, epoxiconazole, metalaxyl, metazachlor, metolachlor, penconazole, prosulfocarb, tebuconazole, tetraconazole, and terbuthylazine) were selected for analysis due to their frequent detection in European soils. The extraction methods were compared based on metrological parameters, cost and time per sample and environmental impact. Despite its low repeatability, the DI-SPME Tips method proved to be a low cost, sensitive, and sustainable alternative, with scores of 0.63 and 89 in the AGREE and Analytical Eco-Scale metrics, respectively. The QuEChERS method, how- ever, proved to be a more reliable alternative for large-scale monitoring programs. The electrokinetic experiment was carried out on sandy loam soil spiked with the twelve pesticides for seven days, applying a 10 mA current under different regimes (constant and periodic). After the experiment, the soil samples were analyzed using the DI-SPME Tips method. The treatment proved suitable for the remediation of these compounds in soil, par- ticularly under constant current application, where remediation ranged from 26% to 80%. However, the strong pH variations registered in this experiment – with values as low as 2.61 at the anode and as high as 12.17 at the cathode – and the accumulation of pesticide residues near the electrodes must be considered when applying this technique for the in situ remediation of sandy loam soils.
The current degradation of European soils led to the proposal of the recently approved Soil Monitoring Law, which requires the establishment of a uniform soil monitoring framework across the European Union. Harmonized monitoring demands the adoption of a common and easily applicable extraction method that combines sensitivity, low cost, and sustainabil- ity. This dissertation focuses on comparing two extraction methods – QuEChERS and DI- SPME Tips – and their application in the electrokinetic remediation of pesticides. Twelve pesticides (buprofezin, chlorpyrifos, diflufenican, epoxiconazole, metalaxyl, metazachlor, metolachlor, penconazole, prosulfocarb, tebuconazole, tetraconazole, and terbuthylazine) were selected for analysis due to their frequent detection in European soils. The extraction methods were compared based on metrological parameters, cost and time per sample and environmental impact. Despite its low repeatability, the DI-SPME Tips method proved to be a low cost, sensitive, and sustainable alternative, with scores of 0.63 and 89 in the AGREE and Analytical Eco-Scale metrics, respectively. The QuEChERS method, how- ever, proved to be a more reliable alternative for large-scale monitoring programs. The electrokinetic experiment was carried out on sandy loam soil spiked with the twelve pesticides for seven days, applying a 10 mA current under different regimes (constant and periodic). After the experiment, the soil samples were analyzed using the DI-SPME Tips method. The treatment proved suitable for the remediation of these compounds in soil, par- ticularly under constant current application, where remediation ranged from 26% to 80%. However, the strong pH variations registered in this experiment – with values as low as 2.61 at the anode and as high as 12.17 at the cathode – and the accumulation of pesticide residues near the electrodes must be considered when applying this technique for the in situ remediation of sandy loam soils.
Descrição
Palavras-chave
Monitorização de solos Pesticidas Remediação eletrocinética QuEChERS DI-SPME Tips