应用ICP-MS测定两种氮肥中重金属含量

肥料中的重金属可以通过作物直接进入人类食物链对人体产生危害，研究肥料中重金属含量对于农产品安全溯源意义重大。选用北京市场上销售的硫酸铵(NH₄)₂SO₄和尿素CO(NH₂)₂两种氮素肥料作为实验材料，分析了其中的10种有害重金属元素含量。(NH₄)₂SO₄中重金属含量分别是：Al 1 345.13 ng·g-1,Ti 35 120 μg·g-1,Cr 2 539.27, Ni 287.26, Cu 674.05, Zn 270.79, As 42.54, Cd 22.13, Hg 27.20和Pb 123.87 ng·g-1；CO(NH₂)₂中的含量分别是71.59 ng·g-1,5 360 μg·g-1,1 167.71, 188.60, 7.46, 64.45, 10.55, 0.00, 0.09和3.71 ng·g-1。上述结果表明：CO(NH₂)₂氮肥中有害金属含量非常低，尤其是Cd, Hg和Pb含量在10 ng·g-1以下，只有Cr的含量超过1.00 μg·g-1；与CO(NH₂)₂ 相比，(NH₄)₂SO₄中重金属含量虽然符合相关标准，但大部分重金属含量都是CO(NH₂)₂的几十倍，如果长期使用会对土壤环境和农产品安全造成一定影响。所以在施用氮肥时应当尽量选用CO(NH₂)₂。(NH₄)₂SO₄和CO(NH₂)₂中重金属含量差别可能与两种肥料的生产原料和工艺有关。

Application of ICP-MS to Determination of Heavy Metal Content of Heavy Metals in Two Kinds of N Fertilizer

Environmental safety has been the focus worldwide, where involved are the pollutions of heavy metals, pesticides and persistent organic pollutants. Fertilizer has become one of the polluting sources of heavy metals, which are very deleterious to human health and environmental safety. Heavy metals are difficult to metabolize in human body and very harmful, so research on the pollution of heavy metals is considered increasingly important. The pollution sources of heavy metals include waste residue, waste water and exhaust gas from industry and automobile, and garbage from human life. The heavy metals in fertilizer can endanger the human body by the crop containing heavy metals. Two kinds of nitrogen fertilizer were analyzed in terms of the content of heavy metals by ICP-MS, and the results showed that the content of 10 kinds of heavy metals (Al, Ti, Cr, Ni, Cu, Zn, As, Cd, Hg and Pb) in (NH₄)₂SO₄ was 1 345.13, 35.12,2 539.27,287.26, 674.05,270.79, 42.54,22.13,27.20 and 123.87 ng·g-1 respectively; and in CO(NH₂)₂ it is 71.59, 5.36, 1 167.71, 188.60, 7.46, 64.45, 10.55, 0.00, 0.09 and 3.71 ng·g-1 respectively. All the data showed that CO(NH₂)₂ contained much less heavy metals than (NH₄)₂SO₄,so we should select CO(NH₂)₂ as the nitrogen fertilizer in agricultural production.