Zinc again: But the latent crisis of metals in the soil is not like the "even spread" of air and water pollution: Each case has its special characteristics, and there are differences in types of soil. Thus the impact of heavy metals on the soil differs, and there are differences in the degree of blight and in urgency of attention in terms of its harm to plants and human beings.
但重金屬雖在土壤中隱藏危機，卻也各有天性，加上各地土壤類型有差異，不似水與空氣那麼「均勻」，致使重金屬對土壤影響程度不同，對作物與人的危害也有輕重緩急程度之差。