kdf是最近几年十分热门的净水器滤料，这种滤料有什么危害没有？

谢谢邀请了，这个不是本专业问题，我的第一直觉这种问题应该邀

@默识先生

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我先贴一段wikipedia的小段子吧

Water passes through a bed of pure KDF or an Activated carbon/KDF mix. As the water makes contact with the KDF particles the Redox reaction takes place, removing such impurities as minerals, metals, dissolved oxygen and organic materials. The KDF itself creates a miniature electrolytic cell within the spaces between each particle, the zinc acting as the anode and the copper acting as the cathode within this cell, and the water and its impurities acting as the electrolyte through which the charge flows. When the contaminants and impurities found in water pass through this electrolytic cell, some substances, especially metals, react to the magnetic force exerted by the electrolytic cell and are attracted to the surface of the KDF particles, where they adhere. Other non-metal impurities react with the KDF and form zinc oxides, copper hydroxides, hydroxides, and sulfates in the water. These by-products remain within the drinking water, but are not dangerous[citation needed], also as part of this reaction, ozone is created and carried through into the drinking water, forming a hostile and desolate environment for algae, bacteria and any other array of micro-organism.

根据wikipedia说的，虽然虑水过后铜锌的氧化物残留在饮用水中，但是这些残留并不对人体造成危害。不过请注意，这里是没有citation的。也就是说这句话没有权威方认证。

我在网上大概搜索了一下，也许是国家的关系，kdf filter的安全性在美国并没有饱受争议，唯一找到的对kdf提出疑问的是这个从

KDF Filters - ToxicWaterSolution.com

发出的预警：

KDF water filters contain copper and zinc. Acidic water may corrode the KDF in your shower filter or water filter and release copper and zinc into your water. Copper can be absorbed through your skin. Copper in the shower or bath steam can be aborbed through your lungs. Excesscopperand zinc can become toxic.

Do the Heavy Metal Toxicity Testing or the Comprehensive Urine Element Profilebefore you use a KDF Filter. If you have toxic levels of copper or zinc in your body you should not use the KDF filter.

简单翻译一下是说，如果要使用kdf filter，最好使用者先做一个重金属毒性测试，如果你的体内有过高的铜和锌，那么就不要使用kdf filter了，因为如果是酸性的未过滤水会把kdf filter的铜锌融到水中，而过量的铜锌会产生毒性。

所以问题的关键在于是不是过量。就算有铜锌摄入人体，如果不过量，及时排除就相当于没有危害。关于这个问题，我在一小时的搜索中没有找到任何美国网站号称kdf filter会产生过量的铜锌。

一些卖kdf的厂家是这么说的：

http://www.triangularwave.com/f4.htm
KDF process media are completely safe. KDF media meet EPA and Food and Drug Administration standards for levels of zinc and copper in potable water, so the process is not toxic and does not cause any adverse side effects.

“KDF 截止符合环境局和FDA对铜锌在饮用水中的含量标准，所以无害。”

虽然这个话是kdf厂家说的，理论上有viewpoint bias，但是这个话在美国是不能乱说的。我倾向于相信其真实性，毕竟没有争议这个事本身就说明一定的问题。

最后有一个youtube视频对kdf filter发起了控诉。如果你们愿意看一下，地址在此：

http://www.youtube.com/watch?v=e1ZMJSSpnwA

对于不愿意看的，我来解释一下核心意思： 虽然这个视频是控诉kdf的，但是控诉的原因并不是因为铜锌超标，也不是因为铜锌的危害。而是kdf号称能够去除水中的氯，但是没有去除一氯胺。老头子深感自己被坑，所以发表声明。

以上包含了我在一个小时的搜索内在英文网页中能找到的所有对kdf filter的不利证据，我不想保证kdf是绝对安全，但是至少我从我的搜索