Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about the process of bioremediation, specifically the use of plants, or phytoremediation, to clean up contaminated soil. Now, this isn't a new idea, but it's gaining more attention as we seek cost-effective alternatives to traditional methods like excavation or chemical treatment. One of the most promising plants for this purpose is a species called alpine pennycress, which has a remarkable ability to absorb heavy metals like zinc and cadmium from the ground. When the plant is harvested, the metals are removed with it, and the soil is left cleaner. However, there's a catch. The process is slow, often taking years to achieve significant results. Also, the plant biomass is contaminated and must be disposed of as hazardous waste, which can offset some of the cost savings. But researchers are working on genetic modifications to make these plants grow faster and accumulate more metals, and they're also exploring ways to recover the metals from the plants for commercial use. So, while it's not a quick fix, phytoremediation offers a sustainable long-term solution for certain types of pollution.
❓ 题目 What is the main challenge of using phytoremediation mentioned by the professor?
A. A. The plants are difficult to grow in contaminated soil.
B. B. The process is slow and requires hazardous waste disposal.
C. C. The method is too expensive for large-scale use.
D. D. The plants cannot absorb enough heavy metals.
✅ 正确答案
B. The process is slow and requires hazardous waste disposal.