Atomic Spectroscopy Application In Orchard Soil Heavy Metal Monitoring Research

Soil is the material basis of human survival, the essential and non-renewable naturalresources for human. With the rapid development of socio-economic, making a large number ofharmful heavy metals released into the soil environment, resulting in the deterioration of soilquality of the environment, affecting crop growth and development, resulting in a decline in yieldand quality of agricultural products, and can cause harm to other organisms and human healththrough the food chain. Therefore, it has important theoretical and practical significance inbuilding lean detection method for the analysis of trace heavy metal and applying it in determiningthe actual samples. In this paper, sequential injection hydride generation atomic fluorescencespectrometry for the determination of soil mercury, arsenic, lead, and cadmium has beendeveloped, and the method for the determination of soil chromium, zinc, nickel, and copper bygraphite furnace atomic absorption spectrometry has also been built, combined with themicrowave digestion technique for the sample pre-treatment. We have determined the eight kindsof heavy metals in Gannan navel orange orchard soil with the developed methods. Analysis aboutthe regional distribution characteristics of heavy metal content was carried out, and thecorrelations of heavy metal content and soil properties were discussed, and made a preliminaryenvironmental quality assessment. Details are as follows:Chapter1, the application and development of methods for the analysis of trace heavy metals,hydride generation techniques, sequential injection system, and sample digestion methods weresummarized, and briefly introduced Gannan navel orange industry characteristics and pointed outthe necessity of monitoring the content of heavy metal in Gannan navel orange orchard soil.Chapter2, an analytical procedure was developed for determination of Hg, As, Pb, and Cd insoil samples using sequential injection hydride generation atomic fluorescence spectrometry withsample preparation by microwave digestion system. The effects of analytical conditions on thefluorescence intensity as carrier gas flow rate, concentration of KBH4, and the acidity of carrierliquid were investigated and optimized. Under the optimized condition, the accuracy of methodwas verified by the determination of the certified reference soi（lGBW07404）, the detection limitsfor Hg, As, Pb, and Cd were0.005,0.068,0.040, and0.003ng mL~-1respectively, and therecoveries of spiked concentrations of Hg, As, Pb, and Cd added to soil sample were in the rangeof96.0%~103.9%.Chapter3, a method was developed for determination of Cr, Zn, Ni, and Cu in soil samplesusing graphite furnace atomic absorption spectrometry with sample preparation by microwavedigestion system, and the temperature program which affected the element measurementabsorbance seriously was optimized. Under the optimized conditions, the accuracy of method was verified by the determination of the certified reference soil（GBW07404）, the detection limits forCr, Zn, Ni, and Cu were0.900,0.098,0.140, and1.200ng mL~-1respectively, and the recoveries ofspiked concentrations of Cr, Zn, Ni, and Cu added to soil sample were in the range of92.6%~112.2%.Chapter4, the contents of Hg, As, Pb, Cd, Cr, Zn, Ni, and Cu in283soil samples of Gannannavel orange orchards were determined with the developed analytical and sample pre-treatmentmethods. The distribution characteristics of soil heavy metal content in the18districts of Gannan,the correlation between heavy metal content and soil pH, soil type, and heavy metal elements werediscussed, and the heavy metal pollution environmental quality assessment was carried out withthe second grade of the National Soil Environmental Quality Standard (GB15618-1995) andbackground value of Ganzhou soil environmental quality as evaluation criteria and the singlepollution index and integrate pollution index as the evaluation method.