Zhao Lijuan, Zhang Fu-Shen, Zhang Jingxin
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085, China.
J Hazard Mater. 2008 Oct 30;158(2-3):465-70. doi: 10.1016/j.jhazmat.2008.01.091. Epub 2008 Feb 6.
Medical waste (MW) ashes from different types of MW incinerators were examined to detect the characteristics and environmental impact of rare earth elements (REEs). The results showed that total REE contents in the ash samples ranged from 10.2 to 78.9 mg/kg. REEs in bottom ash were apparently higher than those in fly ash. Average REE contents in the ashes followed the sequence of Ce>La>Nd>Y>Gd>Pr>Sm>Dy>Er>Yb>Ho>Eu>Tb>Lu>Tm. Some of the elements, such as Sm, Dy, Ho, Er, Yb in the ash samples were in normal or nearly normal distribution, but Y, La, Ce, Pr, Nd, Eu, Gd, Tb, Tm, Lu were not normally distributed, indicating some of the ash samples were enriched with these elements. Crust-normalized REE patterns indicated that two types of the MW ashes were obviously enriched with Gd and La. Sequential extraction results showed that REEs in the ash mainly presented as residual fraction, while exchangeable and carbonate fractions were relatively low. DTPA- and EDTA-extraction tests indicated that REEs in the MW ashes were generally in low bioavailability.
对不同类型医疗废物（MW）焚烧炉产生的医疗废物灰进行了检测，以确定稀土元素（REEs）的特征及其环境影响。结果表明，灰样中稀土元素的总含量在10.2至78.9毫克/千克之间。底灰中的稀土元素明显高于飞灰。灰中稀土元素的平均含量顺序为：铈>镧>钕>钇>钆>镨>钐>镝>铒>镱>钬>铕>铽>镥>铥。灰样中的一些元素，如钐、镝、钬、铒、镱呈正态分布或接近正态分布，但钇、镧、铈、镨、钕、铕、钆、铽、铥、镥并非正态分布，表明部分灰样富含这些元素。经地壳归一化的稀土元素模式表明，两类医疗废物灰明显富含钆和镧。连续萃取结果表明，灰中的稀土元素主要以残渣态存在，而可交换态和碳酸盐态相对较少。二乙三胺五乙酸（DTPA）和乙二胺四乙酸（EDTA）萃取试验表明，医疗废物灰中的稀土元素生物有效性一般较低。
