ABSTRACT
The patterns of agrochemical pollution in two regional coastal aquifers of different hydrological and hydrogeological setting were studied using field investigations and leaching models and upscaled using hydrogeomorphic methods. On the regional scene, nitrate was found to be above the limit in several sites mainly in the horticultural areas of the Gnangara Mound in Australia and in most of the areas of Songkhla Lake Basin in Thailand. On the other hand, the results showed that only a small number of pesticides have the potential to contaminate these aquifers. In both countries, most of the reported incidents of pesticide contamination are attributed to malpractice (i.e. spills, excessive use of pesticides and excessive irrigation).
