A friend uses hot water from the tap for cooking and even for making tea. She says it is perfectly safe. I think she’s wrong. Can you settle this argument?
You win this one. You should never use hot water from the tap for drinking or cooking, and especially not for preparing baby formula. The main reason is that hot water is more likely to be contaminated by lead from pipes than cold water. Hot water can dissolve lead from corrosion in the pipes or from lead solder used in copper pipes more quickly than cold water. According to the Environmental Protection Agency (EPA) most of the lead in household water comes from residential plumbing, not from the local water supply.
If your friend has children, she should know that lead poisoning is a serious child health issue. Lead in the body can cause mental retardation, and even low levels can slow a young child's development and cause learning and behavior problems. In order to reduce the amount of lead in your household water supply, be sure to flush your cold water pipes whenever a faucet hasn't been used for six hours or longer. The more time water has been sitting in the pipes, the more lead it may contain.
Even if your copper pipes were joined with lead-free solder, lead can leach from new brass faucets and fittings, according to the EPA. And lead is not the only concern here. Water sitting in hot water tanks is likely to contain other contaminants as well. And hot water dissolves more substances than cold. The EPA advises running the water until it becomes as cold as it will get before drinking it or using it in food. I recommend letting it run for three to five minutes.
I also advise having your water tested. Use an independent lab, not the free testing offered by companies selling water purifiers - it's not thorough enough. In addition to detecting the presence of lead, tests can reveal such contaminants as fecal coliform bacteria, fluoride, chlorine, arsenic, and nitrates, as well as parasites, other microorganisms, sulfates, herbicides, and pesticides. As far as lead is concerned, the EPA says that testing is especially important for residents of high-rise apartment buildings with lead-soldered central piping.
Andrew Weil, M.D.
Read More
译文:
使用热水也会有安全隐患？
问：我的一位朋友喜欢用水管里的热水来烹煮食物，甚至还用它来泡茶。她说这些热水是绝对安全的，但我认为她错了。你能帮助我们解决这一争论吗？
答：关于这个问题的争论，你是正确的。你决不应该将水管里的热水作为饮用水，或拿它来做饭，更加不该用它为宝宝烹制食物。主要的原因就是，热水比冷水更易受到水管中铅的污染。热水可以比冷水用更快的速度溶解水管中的铅，这些铅可能是由水管腐蚀造成，也有可能来自于铜管中的含铅焊接剂。美国环境保护暑称，大多数家庭用水中铅的来源不是地方的供水系统，而是来自于家居住宅中的各种铅管。
如果你的朋友有孩子，她就应该知道，铅中毒是有关儿童健康的一个重要问题。身体中含铅会导致儿童脑力发育迟缓，即使是微量，也会减缓儿童的发展过程，引发学习和行为方面的问题。为了减少家庭用水中的含铅量，务必注意清洗家中的自来水管道。任一水龙头只要有6个小时以上没有被使用，就必须得到清洗。水在管子中滞留的时间越长，水中的含铅量就越高。
美国环保暑说，即使你的铜管是由无铅焊接剂焊接的，你仍旧可以在新使用的铜制水龙头和配件中发现铅的踪迹。而且，在这里，铅还不是唯一的安全隐患。因为热水可以比冷水溶解更多的物质，所以储存在热水箱中的水有可能含有其他污染物。美国环保暑建议，在喝水或用水做饭时，最好先放掉热水箱中的水，直到它成为冷水为止。我的推荐时间是3~5分钟。
我还建议你去做一个水质测试。不是那种净水器公司所提供的免费测试，那样不够彻底，而是要去一所独立的实验室做测试。除了探测是否有铅的存在，水质测试还可以显示出其它污染物的含量，如粪大肠菌群，氟化物，氯化物，砷化物，硝酸盐以及寄生虫，微生物，硫酸盐，除草剂和杀虫剂成分。美国环保署说，就是否含铅这个问题而言，水质测试对于居住在高层大楼并由中央含铅管道供水的居民来说尤为重要。
Andrew Weil, M.D.