By VOAHello again. Welcome back to As It Is. I'm Kelly Jean Kelly.Good news for people who live in polluted cities. A common garden herb may be able to help make the water cleaner and safer.But first we talk about friendship and illness. For someone who is seriously ill, good friends can help -- or hurt.A few years ago, Letty Cottin Pogrebin learned she had breast cancer. Some of her friends could talk easily to her about her illness. But others struggled. They could not be honest or supportive.Ms. Pogrebin asked other cancer patients if their friendships had changed, too. Those conversations gave her an idea for a book. The book is called "How to Be a Friend to a Friend Who's Sick.""People aren't good at it naturally. It does not come naturally, so they really pause, they blunder, they can't find the right words."Ms. Pogrebin found that fear caused many of the communication problems. Some people feel so uncomfortable, they do not want to see the sick person at all.Rhonda Waithe says that is how her brother felt when her son was born with a serious disease."He was like, ‘I don't know how to act. I wouldn't know how to be around these people.' And I would say to him, ‘Just be yourself. Because this is what they want -- for you to just be you!'"Ms. Pogrebin found that some people who do not know what to do try too hard to be nice."Sometimes the nicest thing you can do is simply treat them normally. It's the luxury of the normal. It's the miracle of the ordinary that I sought. I didn't want to feel like ‘Cancer Girl.'"Ms. Pogrebin has some advice for people with friends or family members who are sick. She says think about what might help the person feel better, not what you think might be the "right" thing to say or do."It's very tempting to feel good about yourself when you are in a tough situation like that. ‘I called when I heard. I did the right thing.' ‘I sent a bouquet of flowers. I did the right thing.' ‘I said, you'll get past this, or I'm sure it's going to be OK.' But you do not know on the other end if that is what is really needed, and if that is what is really wanted."Often what is needed is practical help.Nicole Brown said that is what she wanted when her father was ill."We needed people to actually come and help us, be there for us. Come over, cook. Bring some food. He lp give him a bath."Ms. Pogrebin adds that the best idea is usually just to be polite. And, she says, let the person who is sick say what she or he wants."My advice to everyone, if it had to be distilled into a single sentence, is: If you're the friend, ask the sick person, ‘What do you really want us to do during this period? Do you want me to offer, or come, or just take the initiative? Are you uncomfortable asking, or would it be better to wait to hear what you really want? If I call you every day, will that drive you nuts? I will take the advice you give me right now and I will run with it for the rest of the period of time that we are in this together.'"Letty Cottin Pogrebin was treated and is now cancer-free. She is the author of the book "How to Be a Friend to a Friend Who's Sick."Miracle Herb?The herb cilantro is an important part of Latin American and Southeast Asian cooking. It is also known as Thai parsley and coriander. Cilantro is loved for its taste. It could possibly also have scientific uses. Mario Ritter reports.Scientists say the cilantro plant shows promise as what they call a biosorbent. They say it is able to drink up heavy metals that have leaked into ground water from factories.Cilantro costs very little to produce. The herb is plentiful in some of the most polluted countries in the world. These are countries in which industrial chemicals have polluted ground water supplies. The chemicals include arsenic, cadmium, copper, lead and mercury. They can come from factories and waste collection centers.In the West, new technologies are being used to remove the heavy metals, including activated carbon. But these technologies are costly.Douglas Schauer is program chair for chemical technology at Ivy Tech Community College in Lafayette, Indiana. Earlier this year, he led a few students to the Tula Valley, near Mexico City. They wanted to find low-cost and plentiful materials that could be used to filter, or separate, industrial pollutants in ground water.Douglas Schauer says several wild plants were dried out and crushed..."And then we put that into a solution that has a known amount of lead in it. That's the metal we used as our test metal. Shake it up for a little bit, and then we let the particles settle out, and then we test the water to see how much lead is left behind."Mr. Schauer says his students' tests showed cilantro was one of the most effective plants for pulling lead out of polluted water.He is suggesting that cilantro be used as a water purifier. It is especially important, he says, for people living near polluting factories, or in areas such as the Tula Valley, where Mexico City leaves all of its untreated municipal waste."Our hope is for somebody who lives in that region to simply be able go in their back yard and grab a handful of cilantro, maybe let it dry out for a couple days sitting on a rock in the sun, and then maybe a handful of that would purify a pitcher of water."He believes dried cilantro could someday be sold like tea bags, or as reusable water filters to heavy metals.The findings of field studies for cilantro in Mexico were presented at a meeting of the American Chemical Society in Indiana.I'm Mario Ritter.And I'm Kelly Jean Kelly.Thanks for joining us today on As It Is. If you would like to reach us, send an email to learningenglish@voanews.com. Or visit our website at 51voa.com.