TVB News Magazine 新聞透視 飲水思鉛 2015.07.18
記者：趙燕婷 / 陳淑欣
Actions You Can Take To Reduce Lead In Drinking Water
Source: US Environmental Protection Agency
Q: What is the United States government doing about the problem of lead in household water?
A: There are two major governmental actions to reduce your exposure to lead:
Under the authority of the Safe Drinking Water Act, EPA set the action level for lead in drinking water at 15 ppb. This means utilities must ensure that water from the customer's tap does not exceed this level in at least 90 percent of the homes sampled. If water from the tap does exceed this limit, then the utility must take certain steps to correct the problem. Utilities must also notify citizens of all violations of the standard.
In June 1986, President Reagan signed amendments to the Safe Drinking Water Act. These amendments require the use of "lead-free" pipe, solder, and flux in the installation or repair of any public water system, or any plumbing in a residential or non-residential facility connected to a public water system.
Under the provisions of these amendments, solders and flux will be considered "lead-free" when they contain not more than 0.2 percent lead. (In the past, solder normally contained about 50 percent lead.) Pipes and fittings will be considered "lead-free" when they contain not more than 8.0 percent lead.
These requirements went into effect in June 1986. The law gave state governments until June 1988 to implement and enforce these new limitations. Although the states have banned all use of lead materials in drinking water systems, such bans do not eliminate lead contamination within existing plumbing. Also, in enforcing the ban, some states have continued to find illegally used lead solder in new plumbing installations. While responsible plumbers always observe the ban, this suggests that some plumbing installations or repairs using lead solder may be escaping detection by the limited number of enforcement personnel. (flushed sample will indicate the effectiveness of flushing the tap before using the water.)
Q: How much lead is too much?
A: Federal standards initially limited the amount of lead in water to 50 parts per billion (ppb). In light of new health and exposure data, EPA has set an action level of 15 ppb. If tests show that the level of lead in your household water is in the area of 15 ppb or higher, it is advisable - especially if there are young children in the home - to reduce the lead level in your tap water as much as possible. (EPA estimates that more than 40 million U.S. residents use water that can contain lead in excess of 15 ppb.) Note: One ppb is equal to 1.0 microgram per liter (µg/1) or 0.001 milligram per liter (mg/1).
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