calcium contamination

例句：

1. 1. The soil was heavily contaminated with heavy metals from the factory.
   土壤被工厂的重金属严重污染。
2. 2. The water quality in this area has been severely contaminated due to industrial runoff.
   由于工业排放，该地区的水质已经严重受到污染。
3. 3. To prevent contamination, it is important to follow proper disposal procedures for hazardous waste.
   为了预防污染，对于危险废物，必须遵循适当的处置程序。