某地区环境重金属污染物超标通常与哪项（ ）无关 Which item is usually unrelated to the excess of heavy metal pollutants in an area（ ）

A、金属冶炼与再生 Metal smelting and regeneration
B、金属加工与制造 Metal processing and manufacture
C、金属产品使用 Use of metal products
D、金属物质自然地表迁移 Natural migration of metal substance on the earth surface