IMPACTS OF INTENSIVE AGRICULTURAL ACTIVITIES ON ENVIRONMENTAL POLLUTION RISK OF PHOSPHORUS COMPOUNDS IN SURFACE AND GROUND WATERS.

Over the last twenty years, many intensive agricultural practices have been expanded in the sandy soils of northern coastal area of Nile Delta, Egypt, but with great environmental risks. In particular, substantial surface and groundwater phosphorus pollution has resulted from the coupling of different agricultural production systems demanding large inputs and leaving large organic wastes to be disposed of in physical setting areas that consists of coarse sandy soils and shallow groundwater.  Water table piezometers were installed at selected locations include all traditional crop growing sites differently fertilized with mineral fertilizers, poultry manures, fish farming wastes and farmyard manure.  Water samples for phosphorus examining were collected from water table piezometers and main surface drains over one year period (4 times) in areas with different and intensive agricultural activities.
From the results of this study, it could be concluded that, based on phosphorus concentrations reported in surface and ground water, organic wastes of fish farming activity represents the highest P pollution potential to sandy soils. In contrast, the lowest risk under the conditions of the studied area was the application of organic and inorganic fertilizers in different combinations under drip irrigation systems. Surface and furrow irrigation systems are likely to show similar P leaching risk when applied to sandy soils.   The results of this study indicated that there is a significant relationship between the intensive agricultural activities and water courses contamination.
  In general, none of the water samples collected from all piezometers installed closer to or even inside each agricultural activity as well as from main drains had an average phosphorus concentration over 2 mg/l.  Concentrations of phosphorus in most groundwater samples were below the recommended level of drinking water for human (1 mg/l). From the results of this study, it appears that P leaching from such sandy soil if managed properly is not sensitive to land management practices and reflecting the low risk of environmental contamination in the studied area.