Mestrado em Engenharia Agronómica - Instituto Superior de Agronomia | This study aims to assess groundwater exposure to pesticides in agricultural ecosystems of potato and carrot of a hidrogeologycal vulnerable area of the aquifer system of the Tagus left margin, belong to the Palmela, Alcochete e Montijo councils. Besides a region characterisation under several aspects, a priori environmental exposure assessment of the registered pesticides to potato and carrot was assessed, on the basis of a selection of the physical-chemical properties and partition coefficients, and through multicompartimental models and leaching indexes. It was shown that several of these molecules have affinity to the water compartment and leaching potential. Pesticide residue analysis was performed by solid phase microextraction (SPME) followed of gas chromatography coupled to mass spectrometer (GC-MS) in 15 samples collected from five irrigation wells and in three dates. It was detected at least one pesticide in 53% of the analysed samples, namely pesticides metribuzin, α-endosulfan and β-endosulfan, with maximum concentration levels of 0,17; 3,92 and 1,53 µg/L, respectively. In this study it was shown the need for a careful selection of the pesticides to apply, taking into account their intrinsic characteristics and environmental conditions, towards a pesticide sustainable use.

RESUMO O experimento foi conduzido no campo experimental do Centro de Ciências Rurais da Universidade Federal de Santa Maria, RS. Determinou-se o consumo de água no ciclo e nos diversos subperíodos de desenvolvimento, através do método do balanço hídrico. 0s resultados indicam que: a) os subperíodos de maior exigência hídrica são a estolonização, tuberização e desenvolvimento de tubérculos; b) o consumo hídrico no ciclo foi de 524,9mm, 493,8mm e 348,5mm para os tratamentos com limite inferior de disponibilidade hídrica à uma tensão de 45 kPa, 85 kPa e testemunha sem irrigação, respectivamente.

RESUMO O experimento foi conduzido no campo experimental do Centro de Ciências Rurais da Universidade Federal de Santa Maria, RS. Determinou-se o consumo de água no ciclo e nos diversos subperíodos de desenvolvimento, através do método do balanço hídrico. 0s resultados indicam que: a) os subperíodos de maior exigência hídrica são a estolonização, tuberização e desenvolvimento de tubérculos; b) o consumo hídrico no ciclo foi de 524,9mm, 493,8mm e 348,5mm para os tratamentos com limite inferior de disponibilidade hídrica à uma tensão de 45 kPa, 85 kPa e testemunha sem irrigação, respectivamente. | SUMMARY An experiment was performed at the Campus of the Federal University of Santa Maria, Brazil. Water consumption during the crop cycle and different subperiods was determined applyng water balance methods. The results indicate that: a) the subperiods with greater water demand are stolonization, tuberization and tuber development; b) water consumption during the crop's cycle was 524.9mm, 493.8mm and 348.5mm for treatments at lower limit of water availability, with a tension of 45 kPa, 85 kPa and unirrigated control, respectively.

Mestrado em Engenharia Agronómica - Instituto Superior de Agronomia | An ecotoxicological characterisation of the potential hazard of the registered pesticides for potato and carrot was made throught modelling. It was evaluated surface water exposure to pesticides and toxic effects to aquatic biota in an agricultural area of the sub-basin South Estuary, where those crops have particular importance. Pesticide analysis in water was performed by solid phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS). Acute toxic effects were determined by microbiotests on the basis of Daphnia magna crustacean and Pseudokirchneriella subcapitata algal. In 15 surface water samples, detection frequency was higher for the herbicides metribuzine, terbuthylazine and the insecticide chlorpyrifos. The maximum value of growth inhibition for algal was 62,42% in a sample from a lake, where the higher pesticide concentration level (metribuzine, 17,02 µg/L) was also registered. Immobility values to the crustacean were below 30%. The results showed that environmental conditions and agricultural management, namely pesticide use, associated to their potential contamination, and irrigation, influence surface water contamination by those products, pointed out the need for their adequate selection.