Lead is a naturally occurring element present in the earth's crust. It is one of the most harmful environmental pollutants. It has become difficult to control because of its wide usage. Over the years it is being used in gasoline, house paint and plumbing fixtures. Lead shows adverse effects when it builds up in the body. There are many ways in which humans are exposed to lead: through deteriorating paint, household dust, bare soil, air, drinking water, food, ceramics, home remedies, hair dyes and other cosmetics.
Much of this lead is of microscopic size, invisible to the naked eye. In 1978, the federal government banned lead-based paint from housing. Though the amount of lead that is released into the environment each year has been greatly reduced by less use of leaded gas, starting in the mid-70s. Laws forbidding use of lead in house paint (1978) and lead in plumbing solder (1986) have helped as well. Still, lead can be a problem, especially in older homes.
As a highly toxic metal contaminant in drinking water, with public health threat lead received attention over the years. However, the old lead painted houses are the primary source of lead contamination. Water has a combination of things in it, when it reaches home for household purposes. According to U.S. Environmental Protection Agency (EPA), in the United States 1 out of every 11 children has a dangerous level of lead in the bloodstream. The elevated blood-lead levels can be due to the drinking water contaminated with lead, in spite of water being the rare primary source.
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Although there is no "safe" level of lead in water, the EPA has estimated that on average up to 20% of a child's total lead exposure can potentially be attributed to lead-contaminated water. Lead poisoning is dangerous for anyone of any age, but children are particularly vulnerable because of the effects of lead poisoning on development. According to EPA, lead dosage that would have little effect on an adult can harm a small child. Lead in drinking water can be a problem for infants whose diet consists of liquids-such as baby formula and juices mixed with water. Lead can be easily and more rapidly absorbed by children compared to the adults.
Lead can cause a variety of adverse health effects when people are exposed to it at levels above the action level even for relatively short periods of time. The effects are the same whether it is breathed or swallowed. Very low levels of lead poisoning can cause reduced IQs‚ learning disabilities and behavioral problems such as hypertension and reduced attention p in children, and often these effects are life long and irreversible. Pregnant women and young children are at the greatest risk even with short-term, low level exposures. Overexposure to lead over time can have severe health effects that can last a lifetime. Lead poisoning can cause damage to brain, kidneys, nervous system, and red blood cells. Children's brains and nervous systems are more sensitive to the damaging effects of lead, so they can have behavior and learning problems (such as hyperactivity), damage to the brain and nervous system, slowed growth, hearing problems and headaches.
Because children are most vulnerable to adverse health effects from lead exposure, the adequacy of controls over lead in water supplies serving schools and child care facilities is particularly important. In adults it can cause reproductive problems, high blood pressure, digestive problems, nerve disorders, memory and concentration problems, muscle and joint pain.
The Centers for Disease Control and Prevention's (CDC), Lead Poisoning Prevention Program (LPPP) in conjunction with the Office of Refugee Resettlement developed the Lead Poisoning Prevention in Newly Arrived Refugee Children tool kit in response to the increasing number of refugee children entering in the United States and subsequently developing elevated blood lead levels. CDC’s Childhood Lead Poisoning Prevention Program is committed to the Healthy People goal of eliminating elevated blood lead levels in children by 2010. CDC continues to assist state and local childhood lead poisoning prevention programs, to provide a scientific basis for policy decisions, and to ensure that health issues are addressed in decisions about housing and the environment.
Other studies have shown that the intrusion of lead into the lens of the eye may cause protein conformational changes that decrease lens transparency. Now NIEHS grantee Howard Hu and colleagues at Harvard University have uncovered what could be another adverse health effect with global implications: cataracts. The researchers found that participants with high tibial lead were more than 2.5 times as likely to develop cataracts as men with low tibial lead (bone lead is a measure of long-term lead exposure). Blood lead levels, which are more indicative of short-term lead exposure, were not significantly associated with increased risk of cataract development.
The contamination occurs when the water is once out from the treatment plants to the individual residences. The service lines that direct the water, certain types of plumbing materials, such as lead pipes, lead solder, brass faucets and some water meter components are responsible for the leaching of lead into drinking water. Hot water can cause the lead to leach out from lead-soldered copper pipes. The longer that water stays in pipes, the greater the exposure to lead. Stray electrical currents from improperly grounded electrical outlets or equipment also may increase the level of lead in drinking water.
Though the, Congress in1986 banned the use of solder containing more that 0.2% lead and restricted the lead content of faucets, pipes, and other plumbing materials the risk of lead contamination is not completely removed as “lead-free” plumbing may contain up to 8 percent lead. Lead in the air comes from industrial emissions. Lead deposits in soils around roadways and streets from past emissions by automobiles using leaded gas, together with paint chips and lead paint dust. Lead may be found in some imported candies, medicines, dishes, toys, jewelry, and plastics.
Under Safe Drinking Water Act law passed by Congress in 1974, EPA determined safe levels of chemicals in drinking water which do or may cause health problems. These non-enforceable levels, based solely on possible health risks and exposure, are called Maximum Contaminant Level Goals. The MCLG for lead has been set at zero because EPA believes this level of protection would not cause any of the potential health problems
Responsibility for ensuring safe drinking water is shared by EPA, the states, and, most importantly, local water systems. In general, EPA sets standards to protect drinking water quality and to ensure the proper operation and maintenance of public water systems. EPA also oversees state implementation of the Safe Drinking Water Act and applicable regulations where states have assumed primary responsibility for enforcement.
The states ensure that local water systems meet EPA and state requirements, provide technical assistance, and take enforcement action, as necessary. In addition, the states collect information on the results of drinking water monitoring, among other things, and report the information to EPA. At the local level, public water systems operate and maintain their facilities in accordance with federal and state requirements, periodically test the drinking water to ensure that it meets quality standards, install needed treatments, and report required information to the states.
Water system cannot directly detect and remove the lead contamination in drinking water as corrosion occurs in household lead pipes. To control lead and copper in drinking water, EPA implemented a regulation known as LCR (Lead and Copper Rule) or 1991 Rule in July 1991. The main aim of this program is to monitor the drinking water for the contamination and to educate the public to take precautions to protect their health when lead concentration (15 ppb) and copper concentration (0. 3 ppm) in water exceed their action level.
The LCR even replace lead service lines used to carry water from the street to the home when elevated lead levels are continued even after anti-corrosion treatment. It is compulsory that that all public water supplies should abide these regulations to meet National Primary Drinking Water Regulations. EPA regulations require that child care centers operating their own water supplies test all drinking outlets for lead. The Maximum Contaminant Level Goal for lead is 0 ppb, the EPA action level for lead in drinking water is 15 ppb. GSA requires that corrective actions be taken when lead concentrations in drinking water exceed the 15 ppb action level.
EPA played a major key role in distributing a list of banned coolers and publishing and distributing guidance on detecting and remediating lead contamination in school drinking water supplies when the Congress banned the manufacture and sale of water coolers that were not lead-free under the Lead Contamination Control Act of 1988. In addition to it EPA ordered required states to establish programs to assist local agencies in testing and correcting for lead in water supplies in schools and child care facilities.
In March 2005, EPA announced a Drinking Water Lead Reduction Plan to improve and clarify specific areas of the rule and the agency’s guidance materials. EPA proposed regulatory changes to the LCR in the following areas:
Treatment Processes: To require that utilities notify states prior to changes in treatment so that states can provide direction or require additional monitoring. EPA will also revise existing guidance to help utilities maintain corrosion control while making treatment changes.
Customer Awareness: To require that water utilities notify occupants of the results of any testing that occurs within a home or facility. EPA will also seek changes to allow states and utilities to provide customers with utility-specific advice on tap flushing to reduce lead levels.
Lead Service Line Management: To ensure that service lines that test below the action level are re-evaluated after any major changes to treatment which could affect corrosion control.
Lead in Schools: The agency will update and expand 1994 guidance on testing for lead in school drinking water. EPA will emphasize partnerships with other federal agencies, utilities and schools to protect children from lead in drinking water.
Although EPA in cooperation with NSF International, state, and water industry officials succeeded in reducing lead levels by testing the water by lead rule. According to NSF, the extent to which lead leaches from products containing lead is not directly proportional to the level of lead used in any one alloy contained in the product. NSF identified several factors that contribute to the level of leaching, including the corrosiveness of the water, lead content, the extent of the leaded surface area, and the process used to manufacture the product.
Lead contamination in water can not be detected normally because one cannot see, taste, or smell lead dissolved in water, Individuals who suspect the contamination of lead in their house, the only way to be sure of the amount of lead in their household water is to have it tested by a certified lab where water will be analyzed using the EPA's sampling and analysis procedures. While collecting water for analysis one should be sure to have a "first draw sample and a “fully flushed" sample. The first draw sample should be collected after water has sat undisturbed for at least six hours. The first draw sample should have the highest level of lead.
The fully flushed sample should be collected after the water has been running from the tap for several minutes, at least until the water becomes noticeably cooler. This two-sample procedure indicates whether flushing the tap can reduce the lead to safe levels. Water testing is especially important for apartment dwellers, because flushing may not be effective in high-rise buildings with lead-soldered central piping.
According to the Toxics Release Inventory, from 1987 to 1993 a total of nearly 144 million lbs of lead compounds were released to land and water by lead and copper smelting industries. When released to land, lead binds to soils and does not migrate to ground water. In water, it binds to sediments. It does not accumulate in fish, but does in some shellfish, such as mussels
One can temporarily reduce lead hazards by taking actions like repairing damaged painted surfaces and planting grass to cover soil with high lead levels. Appropriate precautions should be taken to prevent the contamination using specialized cleaning techniques that are effective in removing lead-contaminated dust. Cleaning should be done time to time in addition to a final cleanup at the end of the job. These actions (called "interim controls") are not permanent solutions and will not eliminate all risks of exposure.
Peeling, chipping, chalking, or cracking lead-based paint is a hazard and needs immediate attention Lead from paint chips, and lead dust, both cause serious hazards. Lead dust can form when lead-based paint is dry scraped, dry sanded, or heated. Dust also forms when painted surfaces bump or rub together. Lead chips and dust can get on surfaces and objects that people touch. Settled lead dust can reenter the air when people vacuum, sweep, or walk through it.
There are many ways to reduce lead exposure at home specially for children. Precautions should be taken to keep children away from chipping, peeling and flaking paint. Children should wash their hands before meals, snacks, nap time and bedtime and the areas where children play as dust-free as possible. Care should be taken to give clean pacifiers for infants to suck. Pacifiers often and pin them on a short ribbon to the child's shirt and children’s clothes clean by changing frequently. Stuffed animals and toys should be washed regularly.
Lead contaminated water can be avoided to some extent by following simple measures. Hard water can actually offer some protection against lead contamination because mineral build-up on the inside of pipes reduces contact between water and the lead or solder. Use only lead-free materials in all plumbing repairs or new faucets and pipes. Homes with plastic drinking water lines, which are glued rather than soldered, should not have problems with lead contamination from pipes. Before using water for drinking or cooking, run the cold water for a minute until it is as cold as it can get. This will flush out the water that has been sitting around for awhile so lead concentration won't be as high. Also, use only cold water for drinking and cooking since hot water dissolves lead more quickly than cold water.
Some precaution can be taken to prevent ourselves from continuous exposure. When renovating homes, Do not use a belt-sander, propane torch, heat gun, dry scraper, or dry sandpaper to remove lead-based paint. These actions create large amounts of lead dust and fumes. Federal law requires that contractors provide lead information to residents before renovating pre-1978 housing. Many houses and apartments built before 1978 have paint that contains lead (called lead-based paint). Landlords have to disclose known information on lead-based paint and lead-based paint hazards before leases take effect.
Some of the activities that should be done to prevent lead contamination are:
Create aerator (screen) cleaning maintenance schedule and clean debris from all accessible aerators frequently. Use only cold water for food and beverage preparation as hot will dissolve lead more quickly. Instruct the users to run the water before drinking. Regularly flush the piping system in the building. The degree to which flushing helps reduce lead levels can also vary depending upon the age and condition of the plumbing and the corrosiveness of the water.
Bottled water can be an expensive alternative but might be warranted if you expect or are aware of widespread contamination and flushing is not an option. If you use bottled water, be aware that it is not regulated by EPA but rather by the Food and Drug Administration (FDA).
Reverse osmosis units are commercially available and can be effective in removing lead. Since these devices also tend to make the water corrosive, they should only be used when placed at water outlets. Electrical current may accelerate the corrosion of lead in piping materials. Existing wires already grounded to the water pipes can possibly be removed by a qualified electrician, and replaced by an alternative grounding system.
Apart from the efforts of EPA and associated bodies, as general public we too have some responsibility in educating people towards the adverse effects of the lead contaminated water. We should discourage people from using materials that induce lead into the environment. Care should be taken that industrial effluents are not released into the water streams and any such incidence should be reported to the concerning authority.
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