The result of secondary-level speciation were obtained by using cation-exchange resin, Amberlite XAD-2 macroreticular resin and Chelex-100 chelating resin. Four elements almost existed on free ions with little non free ions.

• 利用阳离子交换树脂、Amberlite XAD-2型大孔吸附树脂和Chelex-100螯合树脂的研究结果表明,四种金属元素几乎都是以游离态存在,只有极少部分为非游离态。