Most of the heavy metals are certainly not elements that the human body must have but they are also not like pesticides and various organic substances that can bring about rapid poisoning. They often need a long time to accumulate before resulting in illness, but the style of modern living creates just the right conditions for large concentrations to build up in the human body.
大部分的重金屬並非人體必要元素，又不像農藥等其他有機物質容易產生急性中毒，因此往往需要長久累積才會致病。而現代人的生活方式，卻正好提供了重金屬在人體內大量聚積的條件。