VOA慢速英语 家庭园艺: 怎样处理土壤中的铅

　　Still, some plants do absorb more than others. Experts say good choices for the garden include tomatoes, peppers, beans and okra. Among the plants that can absorb more contaminants, they say, are root crops, leafy vegetables and herbs. If you grow carrots, for example, you might want to peel them. Dirt may be harder to remove from some crops than from others. But all produce should be washed.

　　Gardens should be planted away from roads and structures, especially old buildings. Home gardeners should plant away from the foundation of their house. And lead amounts can be especially high near industrial areas and waste dumps.

　　Soil should also be tested for its pH level, a measure of the acid and alkaline balance. Experts say the ability to take up lead is reduced when the pH level is above six and a half. Adding organic material such as compost to soil can also make lead less available to plants.

　　Some people attempt a process called phytoremediation. They try to remove lead from soil by growing certain plants that collect it. But Professor Rosen says the process is complex and may not work.

060s.com