农业用生石灰中重金属元素的测定研究

Determining Heavy Metal Elements in Agricultural Quicklime

撒施生石灰是治理土壤重金属镉污染的有效手段,为避免生石灰的施用造成农田二次污染,需要准确监测农业用生石灰中的重金属含量。建立了 150~200 ℃ 温度条件下王水消解农业用生石灰,消解液上机测定镉、铅、铬、汞、砷的含量的检测方法,其中镉、铅消解后采用火焰原子吸收分光光度计直接进行测定,铬元素稀释 5 倍后上火焰原子吸收分光光度计进行测定,汞、砷采用原子荧光光谱仪进行测定,所测5种元素测定下限为0.005~0.562 mg/kg,加标回收率为85%~110%,重复测定相对标准偏差小于10%,表明所建方法具有较好准确度和精密度,可用于农业用生石灰样品中重金属元素含量的测定。

Applying quicklime is an effective method to control soil cadmium pollution.In order to avoid the secondary farmland pollution caused by the application of quicklime,it is very necessary to accurately monitor heavy metal contents in agricultural quicklime.This paper established a method for measuring the contents of cadmium (Cd),lead (Pb),chromium (Cr),mercury (Hg) and arsenic (As) in quicklime,through digesting the quicklime samples using aqua regia at 150℃-200℃.Cd and Pb were measured directly using the digestion liquidby flame atomic absorption spectrophotometer (FAAS).Cr was determined using 5 times dilution by FAAS.Hg and As were determined by atomic fluorescence spectrometer (AFS).The minimum quantitative detection limits of the five elements in the quicklime samples were between 0.005 and 0.562 mg/kg,the spiked recovery rates ranged from 85% to 110%,and the RSD was less than 10% (n=6),indicating that the method used in this experiment has relatively good accuracy and precision,and is reliable for the determination of heavy metal element contents in agricultural quicklime samples.