Fresh Water Oxygen Isotopic Of Phosphate Analysis Method And Application

With the development of urban economy and the increase of population, a large number of industrial wastewater, domestic sewage and agricultural non-point source pollution enter the water with the excessive phosphorus. Phosphorus as a limiting factor that eutrophication the water body if it excessive accumulation in water that can cause eutrophication degree aggravating and affect the water quality and destruction of aquatic ecosystems. The traditional analytical way of phosphorus pollution source which through the on-the-spot investigation, not only to spend a lot of manpower and financial resources, and also have no timeliness that there is no way to deal with emergency events. Stable isotope technology development and the development of isotope testing technology that has brought a new direction for analyze the sources of phosphorus pollution.The P-O key is very stable in the Phosphate that can resistance to inorganic hydrolysis very well and it only exchange with water for oxygen atoms under the biological function. Oxygen atom has three stable isotopes, the value of the isotopes of the oxygen in phosphate can be used for a condition that determining phosphate source.There is low phosphate content in the fresh water, in order to satisfy the dosage of isotope testing samples that the taken for sampling water which amount is larger. Mg(0H)2co-precipitation as a kind of method widely used for pretreatment deal with phosphate oxygen isotope, although it has greatly simplified the dosage of the water samples and the experiment operation, compared others, it still need to gather a lot of water and has a long time to experiment.This study aimed at the problem for the present stage of phosphate oxygen isotope pretreatment method, that use ion to exchange resin adsorption phosphate to replace Mg(0H)2coprecipitation method in order to improve the process of phosphate oxygen isotope pre-treatment. Through a series of experiment, it can get the optimal experimental conditions for the icon exchange resin method to treatment of phosphate oxygen isotopes. The result show that use the D-201strong basic anion resin, pH=11, the dosage of resin1000:5and under the condition of adsorption time for1h that works best for adsorption of phosphate in the fresh water. Choosing the35ml NaCl solution as the eluent to elution of the5ml of D-201resin and the desolation could reach 96%efficiency. Through three kinds of phosphate oxygen isotope standard material to test the method, the results proved that the method has good accuracy and repeatability.Using the improved phosphate oxygen isotope test method that determined the values of phosphate oxygen isotopic in the water which from the seven sampling point in orchid valley waters of the Taihu lake and throng the water oxygen-phosphorus oxygen balance equation to judgment the biological cycle effect is not obvious in the water so it can shows that phosphate xxygen isotopes can be used the Taihu valley water to discriminate the phosphorus source from Taihu valley water.