Two pesticides and their transformation products were selected for analytical and sampling work at two agricultural areas in the Canary Islands: glyphosate and AMPA in a banana plantation in Valle Guerra (Tenerife), and metribuzin, MDADK, MDA y MDK in a tomato greenhouse in La Aide a (Gran Canaria). Three methods for sampling the unsaturated zone were compared: soil chemical extraction, the soil solution by means of suction cups and soil solution obtained by centrifugation. The comparison o f the three methods shows th a t s o il extracts give a hig her pesticide co n te n t in the soil, corresponding to the adsorbed and soluble forms of the pesticide. Results for the suction cup samples are difficult to explain due to Interactio ns betw een adsorption propertie s o f the ceramic cups, a m o u n t o f pesticide present in the s o il s o lu tio n and "m o b ile " and "im m o b ile " fractions o f the s o il w a te r captured by the devices. Evidence of pesticide pollution in groundwater has been found at the two studied areas, reaching 13.5 gg.H in groundwater in La Aldea. With the available data, it is not possible to correlate the pesticide applications at the experimental fields with the groundwater concentrations in the two research areas. Hydrogeological studies at these areas show that groundwater represents a mixing between water from the aquifer with irrigation returns, not only from the experimental fields but from all the area
Thesis Collection
Last Deposit
