In the deep mantle the highest possible concentration of radioactive materials is limited by the condition demanding temperatures below the melting point . 在地幔深部，放射物质最高的可能浓度受溶点以下的温度条件所限制。
2.
Unsealed radioactive substances . identification and certificate 非密封放射物质.标识和认证
3.
Some chemical and radiological substances such as asbestos and radon also increase the risk of the cancer 另外，吸入某些化学及放射物质如石棉和氡亦会增加患肺癌的机会。
4.
Article 31 . the discharge of radioactive substances from nuclear - powered vessels or vessels carrying such substances must be conducted in compliance with the provisions of article 19 of this law 第三十一条核动力船舶和载运放射物质的船舶，排放放射性物质，必须遵守本法第十九条的规定。
