Does heavy use of cell phones lead to a risk of cancer? This question has caused serious arguments for many years. A new study in rats now adds to those concerns. Its data linked long-term, intense exposure (强烈的暴露) to radiation (辐射) from cell phones with an increased risk of cancer in the heart or brain.
The results have yet to be confirmed(确认), the authors note. Moreover, they add, it’s not yet clear what the findings may mean in terms of human health.
Indeed, although the rat study found a link between cell-phone radiation and cancer, it offers no clues to why such a link might exist, says Jonathan Samet. He teaches preventative medicine and directs the Institute for Global Health at the University of Southern California in Los Angeles. Still, he calls the new study’s findings “important”. They could lead to studies looking into how cell-phone radiation might result in cancer, he says.
Phone signals are relayed between cell towers and cell phones through radio waves. This radio frequency – or RF – radiation is a type known as non-ionizing(非离子化). Unlike X-rays and alpha particles, non-ionizing radiation does not put enough energy into cells to release electrons from atoms(原子) or molecules(分子), producing ions(离子). So it tends to be far less harmful than ionizing radiation, such as X-rays. But that does not mean radio waves might not cause harm.
This radiation will heat the body and cause tissue damage. But it’s not yet known what much lower RF levels might do, such as those from cell-phone use. Five years ago, the World Health Organization’s International Agency for Research on Cancer, or IARC, concluded that cell-phone use “is possibly carcinogenic.” That means it might cause cancer.
Its conclusion was based on what little research data were available at that time. But notice that IARC was not certain. It said only that phone use might “possibly” cause cancer. So scientists at the National Toxicology Program, or NTP, decided to investigate further.
36. What concern does a new study cause?
A.Long- term, intense radiation exists in cell phones. |
B.Heavy use of cell phones leads to a risk of cancer. |
C.The new study has caused serious arguments for many years. |
D.People have intense exposure to radiation. |
37. What has been confirmed according to the new study?
A.If people use cell phones all the time, they will certainly have cancer. |
B.The reason why the link between cell-phone and cancer exists is known. |
C.What much RF levels might do, such as those from cell- phone use is already clear. |
D.There is a link between cell-phone radiation and cancer. |
38. What does the underlined word “
relay” mean in Paragraph 4?
A.To pass a message from one place to another |
B.To exist |
C.To release electricity from atoms or molecules |
D.To cause cancer |
39. Who will look into the research further?
A.Doctor Jonathan Samet. |
B.The Institute for Global Health at the University of Southern California. |
C.The author of this article. |
D.Scientists at the National Toxicology Program, or NTP. |
40. Where is the article possibly from?
A.An educational magazine . | B.A science website. |
C.A science fiction . | D.A fashion report. |