But heavy metals are inorganic materials, different from organic materials which can link up with carbon molecules. They are processed out of ores and originally have the special characteristic of close binding with the soil. They lack the mobility of organic matter and can stay in one place for hundreds or thousands of years. And the microbes in the soil which can dismember virtually anything are useless against them.
而重金屬是無機物質，和與碳分子結合的有機物不同，它由礦藏中提煉出來，原本與土壤就有緊密吸附的特性，移動性不似有機物質，可以千百萬年留在當地，土壤中能分解萬物的微生物，偏偏又對它莫可奈何。